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	England and Wales High Court (Technology and Construction Court) Decisions
You are here: BAILII >> Databases >> England and Wales High Court (Technology and Construction Court) Decisions >> MJS Projects (March) Ltd v RPS Consulting Services Ltd [2025] EWHC 831 (TCC) (09 April 2025) URL: https://www.bailii.org/ew/cases/EWHC/TCC/2025/831.html Cite as: [2025] EWHC 831 (TCC)

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IN THE HIGH COURT OF JUSTICE
BUSINESS AND PROPERTY COURTS IN LEEDS
TECHNOLOGY AND CONSTRUCTION COURT (KBD)

		The Court House Oxford Row Leeds LS1 3BG
		09 April 2025

 
This judgment was handed down by the Judge remotely by circulation to the
parties' representatives by email and release to The National Archives. The date
and time for hand-down is deemed to be 10:30am on 09 April 2025.

Her Honour Judge Kelly

1. This judgment follows the trial of a claim arising out of the design and construction of a container park near Felixstowe Port. MJS Projects (March) Limited ("the Claimant") was the contractor for the construction of the container park under a JCT design and build contract. The Claimant subcontracted the design of the container park to RPS Consulting Services Limited ("the Defendant"). The Claimant subcontracted the construction of the container park to MJS Construction (March) Ltd ("MJS Construction").
2. The container park had two main areas – the service yard and the container yard (sometimes referred to as the reach stacker yard). The dispute concerns the container yard at the container park. In various areas of the container yard, drains were required. Three Gatic slot drains were part of the design in the container yard. The build was completed in August 2017.
3. By December 2017, areas of concrete surrounding the slot drains in particular in the container yard were suffering from deterioration and damage. The dispute between the parties is whether the deterioration and damage was caused by the Defendant's design, by the manner in which the drains were constructed or both. The Claimant alleges both negligence and breach of contract by the Defendant designer. No claim has been brought by the Claimant against MJS Construction.
4. I had the benefit of oral and written opening and written closing submissions from both Mr Richard Sage for the Claimant and Ms Anna Laney (now King's Counsel) for the Defendant.

Background

5. Perhaps unusually, there are few factual disagreements between the parties. Those factual disputes that there are mainly relate to what the Defendant's design actually showed and what was constructed. Both of those issues are intertwined with the expert evidence, on which this case mainly turns. The parties now agree that some of the construction work done by MJS Construction was negligent or in breach of contract with the Claimant. They do not agree on the extent of that negligence and breach of contract by MJS Construction. The central issue between the parties is causation of the damage.
6. I had the benefit of reading the following witness statements dealing with issues of fact:

a. Mr Nick Mann dated 3 November 2023 for the Claimant;

b. Mr Mark Richard Harris dated 3 November 2023 for the Defendant; and

c. Mr Michael John Roys dated 3 November 2023 for the Defendant.

I had the benefit of hearing oral evidence from all three witnesses.

7. I also had the benefit of reading the following structural engineering expert reports:

a. the Joint Statement of Mr Barham and Mr Rushton dated 15 December 2023;

b. the Report of Mr Barham for the Claimant dated 12 January 2024;

c. the Report of Mr Rushton for the Defendant dated 26 January 2024;

d. the Reply Report of Mr Barham dated 9 February 2024;

e. the Reply Report of Mr Rushton dated 9 February 2024;

f. the Supplementary Note of Mr Rushton dated 19 February 2024; and

g. the Supplementary Report of Mr Barham dated 22 February 2024.

I also had the benefit of hearing oral evidence from both Mr Barham and Mr Rushton.

8. I had the benefit of reading the Joint Statement of Mr Schmidt and Mr Tapper dated 2 February 2024, quantity surveyor experts, in respect of quantum. The quantity surveyor experts were not called to give oral evidence.
9. As well as reading the witness statements and expert reports, I have had the benefit of reading the various documents to which I was taken during the course of the trial and directed to in skeleton arguments. I do not propose to rehearse all of the arguments raised, nor all of the evidence referred to during the course of the hearing. However, I record that I read and considered the evidence as a whole before coming to my decision.
10. The following chronology is of assistance:

Date	Event / document
October 2016	The Defendant provided its Groundworks, Drainage and External Works Specification, its Specification for Container Yard and tender drawing (dated 31/10/16) SK051 (T01)
10 February 2017	Defendant's calculations entitled "Reach Stacker Yard Design – 25 year lifespan" ("the February 2017 calculations"). Dynamic loads considered in the context of required lifespan for the yard.
15 February 2017	Defendant's construction drawing SK051 (C01) "Typical Gatic Slot Drain Details" This plan showed the use of mesh at the top of the Gatic drain concrete surround and 25mm diameter dowels, 600mm long with sawn ends and 2/3 of the dowel to be coated with debonding compound. The dowels were to be placed at 300mm intervals. The drawing was headed "Service Yard Slab".
22 February 2017	The Defendant's preliminary drawing SK058 (P01) "Hardstanding Joint Layout" This plan showed the use of a Mass Concrete Taper ("MCT") and 25mm dowels between the Service Yard slab and the Container Yard slab.
March 2017	Defendant's manual calculations entitled "Checks on dowels to Gatic Slot Drain Surrounds" ("the March 2017 calculations")
24 March 2017	Defendant's construction drawing SK040 Revision C04 "Site Layout"
24 March 2017	Defendant's construction drawing SK042 Revision C04 "Drainage Layout" This plan identified the locations for the Gatic Slot Drains and details for other drainage.
27 March 2017	Defendant's construction drawing SK051 Revision C02 "Typical Gatic Slot Drain Details" This plan showed the use of mesh both at the top of the Gatic drain concrete surround and along the sides of the drain. The dowels are 25mm diameter, 600mm long with sawn ends and 2/3 of the dowel to be coated with debonding compound. The dowels were to be placed at 300mm intervals. Again, the drawing was headed "Service Yard Slab". However, there was an additional note under the dowel description next to the drawing which stated "In Container Storage area where slab >200mm thick use R32 dowels". The R32 dowels were 32mm in diameter. In addition, the notes stated that the drawing should be read in conjunction with all other relevant drawings and specifications. The notes also referred to a different load class for the two yards – D400 for the storage yard and E600 for the container yard. The drawing tracker noted the change of dowel size to 32mm diameter for the container yard.
27 March 2017	Defendant's construction drawing SK058 Revision C01 "Hardstanding Joint Layout" A note is added "Slot Drain surround to receive sawn joints at a maximum 3m centers (sic) or to match slot drain unit lengths/joint positions"
5 April 2017	JCT Contract between Ocean Gateway (2) LLP and the Claimant
6 April 2017	Defendant's construction drawing SK044 Revision C03 "Construction Thicknesses" This drawing set out the different materials and thicknesses for the different areas on site including for the service and reach stacker yards.
6 April 2017	Defendant's construction drawing SK059 Revision C01 "Hardstanding Joint Details" This drawing gave information dealing with how to construct different joint types.
April 2017	Construction of container yard begins
27 June 2017	Defendant's construction drawing SK058 Revision C03 "Hardstanding Joint Layout" further updated
August 2017	Construction works practically complete
December 2017	Damage to container yard around the slot drains was apparent by this date
6 February 2018	Initial notification of damage from the Claimant was given to the Defendant by email including photographs of damage to the Gatic slot drain surrounds.
07 February 2018	The Defendant suggests further investigations after reviewing the information sent by the Claimant.
12 April 2018	The Claimant sends the Defendant an email with the results of further investigations including a summary of a CCTV survey report of the Gatic slot drains which shows "integrity of the Gatic units are sound with no visual signs of damage or deformation".
17 July/1 August 2018	AF Howland perform some soil and core sampling. The holes created by the tests show "Type 1 and 6F1/6F material differ slightly from that shown on construction drawings"
22 August 2018	The Defendant provides a Geotechnical Note relating to the factual information provided by the soil sampling. The note concludes "From a geotechnical perspective it is considered that the ground conditions appear to be adequate to support this structure".
28 August 2018	Concrete Cores taken, and third level survey.
5 September 2018	The Defendant provides its "Gatic Damage Investigation Report".
5 September 2018	Defendant's remedial works drawing SK074 (P01) "Hardstanding Joint Repair Locations & Details"
7 September 2018	Meeting attended by the Parties, the Employer, & Jon Frith to discuss the damage and cause(s) with remedial works to be considered.
13 September 2018	Defendant's remedial works drawing SK074 (P02) "Hardstanding Joint Repair Locations & Details" This plan identified areas of damage and some of the results from the sample cores which had been taken. The damage identified included that the slot drain surround had dropped relative to adjacent concrete slabs, the wrong 25mm size dowels had been used in the container yard and were now deformed. A remedial solution was set out.
13 September 2018	Updated version of 5 September 2018 Gatic Damage Investigation Report
21 September 2018	The March 2017 Dowel Calculation Check was circulated by email.
13 November 2018	The Defendant provided a supplemental calculation sheet to supplement the March 2017 "Checks on Dowels to Gatic Slot Drain"
14 November 2018	Defendant's remedial works drawing SK074 (P03) "Hardstanding Joint Repair Locations & Details"
26 November 2018	Defendant's remedial works drawing SK074 (P04) "Hardstanding Joint Repair Locations & Details"
29 November 2018	Meeting to outline and agree the programme for remedial works.
13 December 2018	Date of the Appointment between Defendant and Ocean Gateway (2) LLP for the Defendant to provide civil and structural consultancy "Services" for the development to "the Required Standard" to Ocean Gateway (2) LLP as "Employer" and "Client". The agreement was entered into earlier as the Defendant's designs were all produced in 2016 and 2017.
28 February 2019	Defendant's remedial works drawing SK074 (P05) "Hardstanding Joint Repair Locations & Details"
25 March 2019	Novation agreement, novating the appointment of the Defendant to the Claimant, instead of Ocean Gateway (2) LLP as "Employer" and "Client".
28 March 2019	Defendant's remedial works drawing SK074 (F01) "Hardstanding Joint Repair Locations & Details" This drawing showed various remedial options for the concrete surrounding the Gatic slot drains.
19 March 2020	Invoice from MJS Construction re remedial works

11. The Defendant used various guidance materials as the design was developed. The materials included:

a. guidance in Technical Report 66 "External in-situ concrete paving" written by the Concrete Society ("TR66").

b. guidance in Technical Report 34 "Concrete industrial ground floors – a guide to design and construction" written by the Concrete Society ("TR34"). concerning the number of effective dowels for load transfer in a design.

c. Knapton & Meletiou "The structural design of heavy duty pavements for ports and other industries" 2007 4^th Edition ("Knapton").

d. guidance set out in "Interpave – Heavy Duty Pavements – The Structural Design of Heavy Duty Pavements for Ports and other Industries" ("Interpave") for design of the container yard.

e. guidance produced by Gatic including in September 2016 about installation of its slot drain.

f. British Standard EN 1433 ("BS EN 1433") relating to drainage channels for vehicular and pedestrian areas.

The guidance provided assistance with the appropriate design issues in respect of different load classes and the need for reinforcement in the slot drains.

12. The parties agree the relevant terms of the contract between them. The contracts in respect of this project appear to have been agreed between various parties months or years before they were formally executed. Nothing turns on this. The sub-contract for design of the project was originally between the Defendant and Ocean Gateway (2) LLP (referred to in that contract as the "Employer" and "Client"). By a novation agreement dated 25 March 2019, the Claimant was substituted as the Employer and Client in the contract originally between Ocean Gateway (2) LLP and the Defendant. Although all of the work done by the Defendant was carried out before the relevant contracts were executed or novated, the parties agree that the terms of the agreements apply to the work carried out by the Defendant on this project.
13. The relevant terms of the contract between the Employer and Client (now the Claimant) and Defendant (therein described as the Consultant) were set out in paragraphs 4 to 9 of the Particulars of Claim as follows:

"4. Paragraph 2.1 of the Appointment provides that: "The Client appoints the

Consultant to carry out the Services, subject to the terms of this Agreement."

14. Paragraph 3.2.1 of the Appointment provides that "The Consultant warrants and undertakes that it shall exercise the Required Standard when performing the Services".
15. Clause 1.1 of the Appointment defines the "Required Standard" as: "all the

reasonable skill, care and diligence to be expected of a qualified and experienced member of the Consultant's profession undertaking the Services on works similar in scope and character to the Project."

16. Clause 1.1 of the Appointment defines the "Services" as "the Basic Services and the Additional Services (if any)". It provides that the "Basic Services" are set out in Part 1 of Schedule 1. Part 1 of Schedule 1 of the Appointment provides that the Basic Services include:

"Construction Design

- Detailed drainage design to include all pipe sizes and a manhole schedule with invert and cover levels fully coordinated with all services on-site.

- Drainage design strategy with full WinDes simulation modelling to discharge planning condition.

- Lorry & Reach Stacker yard detailed joint layout

- […]

- Coordinated underground service duct drawing.

- Detailed setting out drawing of yards and fence lines"

17. Clause 3.2.6 of the Appointment provides that:

"The Consultant warrants and undertakes that it shall exercise

the Required Standard not to cause or contribute to any breach

by the Client of any Third Party Agreement provided that, where

the Client notifies the Consultant of a Third Party Agreement

after the date of this agreement, the Consultant is not required

to act in any way that may increase its liability in excess of that

which was reasonably foreseeable at the date of this

agreement."

18. Clause 16 of the Appointment provides that:

"Notwithstanding any provision of this agreement restricting the

Client's right to assign or transfer the benefit or burden of this

agreement, within five Business Days of receiving a written

request from the Client, the Consultant shall:

16.1 enter into a deed of novation with the Client and the

Contractor in the form attached at Schedule 7; and

16.2 enter into a Collateral Warranty in favour of the person who

is the Client immediately before novation takes place.""

19. The relevant terms of the novation agreement were set out in paragraphs 17 to 21 of the Particulars of Claim as follows:

"17. Clause 2 of the Novation provides that:

"The Employer is substituted and replaced as client under the

Appointment by the Contractor and the Appointment will take effect

as if the same has been entered into originally between the

Contractor and the Consultant."

20. Clause 4 of the Novation provides that:

"For the avoidance of doubt the Employer confirms that it hereby

assigns to the Contractor all rights of action arising from the

Appointment including any which have already arisen."

21. Clause 7 of the Novation provides:

"7.1 The Consultant acknowledges and warrants to the Contractor

that he has observed and performed and will continue to observe

and perform all the terms and obligations on the part of the

Consultant under the Appointment.

7.2 The Consultant acknowledges that the Contractor has relied

upon, and will rely upon, the Consultant's performance of such

terms and obligations prior to, on, and following the date of this

Agreement. It is agreed that the Consultant shall be liable for all

loss or damage suffered or incurred by the Contractor as a result

of any breaches of such terms or obligations, irrespective of

whether such losses were also suffered or incurred by the

Employer (whether solely, or jointly with the Contractor, or

otherwise) and irrespective of such loss or damage was suffered

or incurred prior to the date of this Agreement."

22. By clause 9 of the Novation, the Claimant and the Defendant further agreed to

amend the terms of the Appointment as set out in Schedule 2 of the Novation.

23. Schedule 2 of the Novation identifies the following services, among others, that the Defendant is to provide as part of the Basic Services under the Appointment:

"001. Review entire Employer's Requirements documentation.

002. Comment on Employer's Requirements and advise

accordingly.""

The Issues

24. The parties broadly agree on the issues to be determined although they disagreed as to how the issues should be framed. In my judgment, a fair statement of the issues is:

(1) What was the damage to the container yard by December 2017?

(2) Were there construction errors and, if so, did the construction errors cause or contribute to any of the damage identified to the container yard by December 2017? In particular:

a. Did the use of 25mm dowels instead of 32mm dowels as designed cause any of the damage identified to the container yard?

b. Did the incorrect placement of the dowels and/or missing dowels cause or contribute to any damage?

c. Were there other construction errors (such as the absence of mesh, incorrect excavation depth, incorrect concrete depth) which caused or contributed to the damage?

(3) Was the Defendant's design for the slot drains in the container yard negligent or in breach of contract? In particular:

a. Was the design for distribution of loads across the concrete slab, concrete surround and drain adequate?

b. Did the Defendant's design take into account dynamic factors adequately?

c. Would 32mm dowels have failed in any event?

d. Were the hand calculations performed by the Defendant in February and March 2017 sufficient to demonstrate that 32 mm dowels could be used ?

e. Was the methodology used by the Defendant inadequate because of the use of E600 or should the F900 higher loading class have been used?

f. Was there other misapplication of guidance concerning load transfer?

g. Was the Defendant's design process inadequate and in breach of duty?

h. Was an MCT necessary for the Defendant's design not to fail?

i. Were changes to other aspects of the design necessary for the design not to fail (such as different requirements or details for mesh, depth of excavation, compaction of materials under the Gatic slot drain)

(4) If the Defendant's design was negligent or in breach of contract, did that negligence or breach of contract cause any of the damage identified to the container yard by December 2017?

(5) Quantum, if breach of duty and causation of damage are established against the Defendant.

25. There was disagreement as to what issues were pleaded. The Claimant's case was opened on the basis that the alleged negligence or contractual breach of duty (hereafter "breach of duty") of the Defendant was the dominant cause or as a minimum an effective cause of the damage which had materialised by December 2017. I accept the submissions made by Ms Laney that in fact, the Claimant had "squarely and solely" pleaded in the Particulars of Claim that the damage which had materialised by December 2017 was caused by the Defendant's breach of duty. The Claimant pleaded at paragraph 40 of the Particulars of Claim that:

"Save for the diameter of the dowels used to tie the concrete surround to the Pavements, the works were carried out in accordance with the Defendant's design".

26. I accept that the Claimant did plead in its Reply that if there were construction errors which caused damage, that would be a concurrent cause with the damage caused by the Defendant's defective design.
27. However, in relation to damage, in my judgment the damage identified was clearly and consistently identified in the pleadings as having occurred by December 2017. It was pleaded at paragraph 41of the Particulars of Claim that:

"In December 2017, shortly after the completion of the Development, all three of the Slotdrains were suffering from deterioration and damage, with settlement of and cracking to the concrete surround of the Slotdrains, and cracking in the Pavements. Differential settlement between the Pavements and the concrete surrounds of the slot drains was found to be taking place".

28. In respect of causation, the sole case on causation in the Particulars of Claim was that it was the Defendant's breach of duty which had caused the damage to the slot drains and surrounding concrete and "As a result of that damage the Claimant has incurred loss and damage".
29. In its Defence, the Defendant pleaded that the work had not been carried out in accordance with the Defendant's design in multiple respects. The case in respect of negligent construction was pleaded by the Defendant against the Claimant. It later became clear that the construction was dealt with by a separate legal entity to the Claimant, albeit a limited company closely associated with the Claimant. Nothing turns on this for the purpose of this judgment.
30. As well as the incorrect size of dowel being used, the following were identified in the Defence as not being in accordance with the Defendant's design:

a. The dowels were not positioned correctly, both in respect of the depth installed, at right angles and centred on the joint,

b. some dowels were omitted,

c. mesh was missing,

d. the concrete pavement was constructed in such a way that differences in levels were between 10 mm and 35mm thus creating a step which had the effect of increasing impact damage from wheels,

e. the concrete pavement was not cast in all areas to the designed thickness,

f. the sub-base and capping layers provided were substantially inadequate, with samples showing a sub-base of less than 90 mm in each of the four samples taken when a sub-base of at least 150 mm was designed and two of four samples showing the capping layer of 250 mm and 350 mm when 400 mm was required.

Those construction defects were each said to compromise the Defendant's design causing or contributing to the damage which occurred.

31. In the Claimant's Reply to that Defence, the pleading admitted that 32 mm dowels were not used but it was denied that had any causative effect. It was specifically denied that the Defendant's design required the Claimant to cast the dowels at the mid-depth of the pavement. The Defendant was put to proof or no admissions were made about the causative effect of the other alleged construction defects. In respect of causation, whilst it was admitted that the incorrect diameter of dowels had been used, the other alleged construction defects were not admitted or denied. If the Defendant proved any of the damage was caused or contributed to by MJS Construction, it was pleaded that this was a concurrent cause of the damage pleaded.
32. In my judgment, it is clear that the Claimant's case in respect of breach of duty and causation against the Defendant was developing somewhat over the months before trial as the parties' experts discussed the case, finalised their Reports and then produced Reply and Supplemental Reports. However, I accept the submission made by Ms Laney that there is no plea that the damage identified as having occurred by December 2017 was due to workmanship in part. It has never been the Claimant's case that repairs would have been necessary as a result of the Defendant's negligence in any event and despite workmanship issues. I further accept her submission that the case could have been framed in that way but it was not.
33. I accept that in the Reply, the Claimant states that if the damage was caused or contributed to by workmanship difficulties, that was a "concurrent cause" of the damage. However, in order to succeed, the Claimant must establish that there was some damage as a result of the Defendant's negligence which had manifested itself by the date of damage complained of, that is December 2017. If the 2017 damage was not caused by any breach of duty on the part of the Defendant, the claim fails.
34. Development of the case was not solely attempted by the Claimant. The Defendant wanted to introduce an argument that the Claimant had failed to supervise the builders, MJS Construction. I accept the Claimant's submission that what is pleaded in the Defence is not sufficient to raise this allegation. If there was to be a specific allegation of failure to supervise, it should have been explicitly pleaded. However, whilst there was some argument and evidence surrounding this allegation, it was not in fact pursued by the Defendant in closing submissions and I take no further account of any alleged failure to supervise as being causative of the damage claimed even if it were proven.

The Law

35. Happily, counsel largely agree on the legal principles, even if they disagree as to whether some of the principles apply to the facts of this case. I adopt passages from the skeleton arguments for some of the law set out below. Perhaps understandably, the Defendant focused significantly on what is required to establish breach of duty (whether in contract, tort or collateral warranty) and the Claimant has focused on causation when there are competing causes.
36. The basic question is: did the Defendant act with reasonable care and skill? As is set out in Jackson & Powell On Professional Liability (9^th edition ) at paragraph 2-177:

"a Defendant professional will not be found to have acted in breach of the obligation and/or duty to exercise reasonable skill and care so long as he acted in accordance with a body of competent professional practice. There are two elements to the Bolam test. The first element is that the standard of skill and care is determined by reference to members of the profession concerned, rather than the person on the Clapham omnibus. The second element is that the Defendant is acquitted of any culpability so long as his conduct finds support from at least one body of competent professional practice even if practitioners falling within a distinct body of competent practice would have behaved or advised differently."

37. Where a claim such as this is based on an allegedly defective design, the court is concerned with the final design and not the design process. The observations of Morritt LJ in Adams v Rhymney Valley District Council [2001] PNLR 4 at paragraph 61 assist:

"The experienced surgeon may act in a particular way out of habit or from intuition. If his choice gives rise to damage to his patient he is sued for causing the damage by that action, not for failing to sit down and think about it in advance. If his action satisfies the Bolam test he is not liable; if it does not then he is liable however long and carefully he thought in advance about what to do. So in this case, the council is to be judged according to the standards of the reasonably skilful window designer and installer. Such a person would be entitled to the benefit of the Bolam test whether or not he had sat down and considered exactly which sort of lock to provide. The council is not to be made liable for selecting the same lock just because it did not make a reasoned choice."

38. That said, as observed in Hudson's Building and Engineering Contracts (14th edition) at 2-067:

"Designers may be liable if the design that they produce is not one that is "buildable" having regard to ordinary competent standards of workmanship and/or if it could only be built with a high degree of supervision to ensure compliance by the Contractor."

39. The authors of Hudson cite George Fischer Holding Limited (formerly George Fischer (Great Britain) Limited) v Multi Design Consultants Limited (unrep. 10 February 1998) where the court held that a designer was negligent for producing a design for joints on a roof which were very difficult to build, and which resulted in water ingress. At para 131 of the judgment, the judge (HHJ Hicks QC) says:

"It is argued for MDC [the designer] that the defects in the lap joints were purely matters of bad workmanship; reliance is placed on the experts' agreement that the cause of water ingress is that lap seals have not been properly installed and on evidence that a perfectly made seal will not admit water, even at slopes of as little as 1°. But to make every lap joint perfectly is difficult and expensive and unlikely to be achieved by the ordinary standards of workmanship and ordinary levels of supervision which suffice in less extreme conditions…".

40. On causation, paragraph 9–212 of Jackson and Powell sets out two principles for claims in contract:

"1. If a breach of contract is one of two causes of a loss, both causes co-operating and of approximately equal efficacy, the Claimant can recover his loss in full on the basis that the breach materially contributed to the loss;

41. If one cause of a loss is the Defendant's breach of contract and another cause is the contractual responsibility of the Claimant, the Claimant will recover if he can establish that the cause for which the Defendant is responsible is an effective cause of the loss."
42. The Claimant relied upon the summary of the law as set out in Smith, Hogg and Co Ltd v Black Sea and Baltic General Insurance Co Ltd [1940] A.C. 997 pages 1006 and 1007, where Lord Wright observed:

"The sole question, apart from an express exception, must then be: "Was that breach of contract 'a' cause of the damage." It may be preferred to describe it as an effective or real or actual cause though the adjectives in my opinion in fact add nothing. If the question is answered in the affirmative the ship owner is liable though there were other operating causes, whether they are such causes as perils of the seas, fire and similar matters, or causes due to human action, such as the acts or omissions of the master, whether negligent or not or a combination of both kinds of cause."

43. The Claimant also drew my attention to the words of Devlin J (as he then was) in Heskell v Continental Express Ltd [1950] 1 All ER 1033 considering concurrent causes in contract:

"I am satisfied that if a breach of contract is one of two causes, both co-operating and both of equal efficacy, as I find in this case, it is sufficient to carry judgment for damages".

44. Causation is considered from the point of view of the "Engineer on The Clapham Omnibus"(see Jackson & Powell at footnote 463 considering the case of Department of National Heritage v Steensen Varming Mulcahy (1998) 60 Con. L.R. 33 QB at 102) in the following terms:

"Judge Bowsher QC provided a helpful review of the authorities bearing upon questions of causation and stated: "The test is what an informed person in the building industry (not the man in the street) would take to be the cause without too much microscopic analysis but on a broad view. Where a loss has been occasioned by more than one cause, a Claimant must show on the balance of probabilities that the breach complained of caused or materially contributed to the loss complained of."

45. The burden of proof in respect of breach of duty and causation remains upon the Claimant. In respect of causation, the Defendant drew my attention to the judgment of Lord Brandon in Rhesa Shipping SA v Edmunds ("The Popi M") [1985] 1 WLR 948 to support its submission that it is not for a Defendant to establish an alternative cause of damage:

"…. it is important that two matters should be borne constantly in mind. The first matter is that the burden of proving, on the balance of probabilities, that the ship was lost by perils of the sea, is and remains throughout on the shipowners. Although it is open to underwriters to suggest and seek to prove some other cause of loss, against which the ship was not insured, there is no obligation on them to do so. Moreover, if they chose to do so, there is no obligation on them to prove, even on the balance of probabilities, the truth of their alternative case.

The second matter is that it is always open to a court, even after the kind of prolonged inquiry with a mass of expert evidence which took place in this case, to conclude, at the end of the day, that the proximate cause of the ship's loss, even on a balance of probabilities, remains in doubt, with the consequence that the shipowners have failed to discharge the burden of proof which lay upon them."

46. The Claimant drew my attention to the Court of Appeal decision in Azhar v All Money Matters [2023] EWCA Civ 1341 in relation to the importance of looking at the pleadings to see what issues are raised. In his judgment, Lewison LJ said (at paragraph 25) that "elementary fairness requires that each side knows what points the other side will take". He cited Prudential Assurance Co Ltd v HMRC [2016] EWCA Civ 376, [2017] 1 WLR 4031, where the Court of Appeal said, at paragraph 20:

"Our procedural system is and remains an adversarial one. It is for the parties (subject to the control of the court) to define the issues on which the court is invited to adjudicate. This function is the purpose of statements of case. The setting out of a party's case in a statement of case enables the other party to know what points are in issue, what documents to disclose, what evidence to call and how to prepare for trial. It is inimical to a fair hearing that a party should be exposed to issues and arguments of which he has had no fair warning. If a party wishes to raise a new point, he should do so by amending a statement of case."

The Evidence

Mr Nick Mann

47. Mr Mann is the commercial director of the Claimant. He was the commercial manager of the Claimant at the time works began on site. His role included periodically visiting the site to oversee procurement of and compliance with the Claimant's contracts. There was also a contract manager and site manager involved in day-to-day activities. Mr Mann signed the Statement of Truth on the Particulars of Claim on 10 February 2023, on the Reply on 19 May 2023 and on the Part 18 Response to the Request for Further Information on 14 June 2023.
48. The majority of design work required for the container yard related to drainage and the formation of the concrete slabs across the yard. MJS Construction (which Mr Mann was keen throughout his evidence to point out was a separate legal entity to the Claimant) was appointed to install the drainage systems including the Gatic slot drains. He worked with the Defendant's designer, Mr Roys.
49. After initial drawings have been prepared at the tender stage, Mr Mann referred to a meeting with Mr Roys. At that meeting, Mr Mann questioned why the design did not include the use of dowel bars. In Mr Mann's experience, dowel bars were usually used to tie the concrete surround of the Gatic drainage to the adjacent concrete slabs. Instead, the design called for the MCT which Mr Mann described as a 'thickening' into the Gatic slot drain.
50. After that meeting, a revised drawing was produced which called for the use of 25 mm dowels and removed the MCT. Work on site began in February 2017 and initial work was done by other sub-contractors. MJS Construction started work on the Gatic drainage while other subcontractors dealt with topping layers and the installation of reinforced concrete slabs into which the drains would be inserted.
51. In about April 2017, the contracts manager of the Claimant resigned. Mr Mann took over his responsibilities and then oversaw the project until completion. Although keen to emphasise that the Claimant and MJS Construction were separate legal entities, it was obvious when he gave evidence that Mr Mann did not always separate out what each of the two companies did on the project. For example, he said the Claimant (and not MJS Construction) was approximately one quarter of the way through the concrete pours including some work having started on the slot drain concrete surrounds in the container yard.
52. Throughout the construction, site inspections took place which included the designers and he said that Mr Roys attended site inspections. He described Mr Roys as "diligent" and as having identified issues during site inspections.
53. Mr Mann acknowledged that in late March 2017, and before construction of the container yard had started, the Defendant had issued a further and final drawing for the Gatic drainage. That drawing introduced 32mm dowels (not 25mm) where the slab was greater than 200mm thick. That fact was missed both by the Claimant and by MJS Construction and, as a result, the wrong size 25mm dowels were installed in the container yard. Mr Mann criticised the Defendant's drawings stating that the change should have been set out more clearly.
54. Cracks began appearing in the concrete slabs. These were noticed in the container yard. Mr Mann described cracking around the slot drain locations and a fall in the concrete surround to the Gatic drains being noticed. The Claimant "started recording this shortly after practical completion in or around August 2017". He stated that a 10mm drop around the Gatic slot drains was part of the design but in the most frequently trafficked zones by the reach stacker vehicles, the drops were approximately 45mm.
55. To try to minimise the damage, the Claimant covered the areas with 35mm thick metal load plates but they buckled under the weight of the reach stackers until the metal plates were grouted down and secured.
56. In September 2017, Mr Mann emailed Mr Roys about the damage being seen and provided surveys and a schedule of cracks. The Defendant accepted some of the surveys but contested others and said that the drop in level between the Gatic slot drain concrete surround and the adjacent slab occurred because of how they had been constructed. Mr Mann thought that Mr Roys should have identified and raised this as an issue during construction.
57. In or around October 2017, other subcontractors were brought into deal with some repair works. At this point, Mr Mann said that he raised a question as to whether the cracks arose as a result of a problem with the design. Some repairs were carried out in October 2017 but some of the cracks reopened not long after the repairs were done. Mr Mann suggested the Defendant was reluctant to engage with the issue and attend site visits. A preliminary remedial strategy was not produced until mid May 2018.
58. Core drilling of the affected concrete surround was done to determine the depth of the cracking and whether the cracking occurred under the dowels used. That revealed that some dowels had bent. The cores were provided to the Defendant to investigate the damage. The suggestion for repairs was that the concrete Gatic surround was broken and recast with rapid hardening concrete to the same level as the adjacent slabs with any straight dowels to be retained. It was around this time in September 2018 that Mr Mann realised that the wrong size dowels had been used by MJS Construction.
59. Various proposals were made for repairs and an option was chosen in November 2018. Remedial works were completed in late March 2019. Mr Mann set out the cost of remedial works.
60. Mr Mann also commented on the mesh design and installation. He noted the change in requirements for mesh with earlier drawings calling for a 55mm mesh with the final drawing SK 051 C02 introducing provision for mesh at the side and bottom of the Gatic slot drain if the channel width was greater than 400mm. There are two sections of the Gatic slot drain with this width.
61. In respect of the fixing of the dowels, Mr Mann stated that the design did not include a reference to the depth at which dowels should have been installed. He did not see instances where dowels were missing nor where dowels were not at perfect right angles, although he accepted that a small proportion of them may not have been.
62. In cross-examination, Mr Mann accepted that he was mainly involved in the contractual side of things. He oversaw the on-site team. Mr Mann accepted that the Claimant and MJS Construction worked closely together. When looking at designs, for example, the MJS Construction site manager was copied into emails considering plans and raising any matters about which MJS Construction had concerns.
63. Mr Mann was taken to the Defendant's design document concerning ground work, drainage and external work specification which dealt with the installation of the Gatic slot drains. He then accepted that in fact detailed information had been given concerning the installation of the dowels. He accepted that the plans had to be read with the specification and that the specification identified that the dowels must be at mid-depth and mid slab and other details were specifically given as to their installation in relation to the joints. He also accepted that the version tracker on each plan identified both the most recent plan and what had been added or changed. He acknowledged that this would be known by anybody looking at the drawing.
64. Mr Mann also accepted that instructions were given about the required manner that concrete at the joints must be constructed, in one continuous operation to avoid cold joints which cause a weakness. Mr Mann acknowledged that he would not necessarily have looked at the specification at the time. When asked if he had looked at it when doing his witness statement, he initially said he had not looked at it in great detail. When pressed, he conceded that he did not look at it at all.
65. Mr Mann accepted that overseeing the day-to-day carrying out of the work was done by Colin Chapman, who was on site, and that his job was to achieve construction in line with the drawings and design. If something was not done correctly, Mr Mann would have expected Mr Chapman, the Claimant's site manager, to identify and flag up the issue. Mr Mann said that neither he nor Mr Chapman or other visitors to site picked up any deviation from the plans although he himself had not read the design specification.
66. Mr Mann had criticised the response of the Defendant as being slow until he was taken to an email chain in June 2017. The Claimant had been on site for four months when a problem was identified that a section had not been built in accordance with the plans. A response was received from the Defendant within nine minutes. Mr Mann then accepted that the Defendant was responsive throughout the project.
67. Mr Mann was taken to a number of photographs taken during construction. He accepted that you could see that some dowels were missing. He accepted that if the correct position for a dowel clashed with the temporary formwork supporting a concrete pour that the formwork should have been altered, although he said dowels could be added retrospectively by drilling.
68. Mr Mann was then taken through further photographs which showed other dowels in different locations to be missing or significantly bent. He was shown another example of a photograph with different coloured concrete which suggested that there had not been a single pour of concrete. He accepted that bent dowels would not work. When it was suggested the photographs showed very poor workmanship, he would not accept that, saying he could not say what had happened and as a result of other marks in the ground, other work may have gone on near the dowels which caused damage to them.
69. Mr Mann had taken some of the photographs himself but he did not know which ones he had taken. He accepted that the point of taking the photographs was to demonstrate the damage. Mr John Frith was engaged to look at the damage. In an email dated 18 May 2018 to MJS Construction, Mr Frith indicated that it appeared that the movement between the slot drain and adjacent slabs suggested failure or movement of the dowels at the joints and he suggested cores be taken. At that stage, Mr Mann explained that it was wrongly thought that MJS Construction had built in accordance with the Defendant's design. In an email dated 25 July 2018, Mr Mann told Mr Roys that the drains had been built in accordance with the design and therefore movement must be as a consequence of another issue. It was suggested to him that it was at that point the Claimant stopped considering any workmanship issues at all. Mr Mann did not answer the question directly but said that the Claimant acknowledged that the wrong dowels had been used. At the date of the email on 25 July 2018, he did not know that the wrong dowels had been used and he thought that the design was faulty.
70. Mr Mann did not realise that the wrong dowels had been used until September or October or November 2018 when the Defendant had examined the cores taken. One core showed that the wrong size dowel was used. In addition, it was bent and had not been installed correctly. It was installed at an angle which led to a void adjacent to the dowel. Mr Mann said he was "disappointed" about the use of the wrong size dowel. He said that he had told both MJS Construction and the Defendant to notify their insurers, but confirmed no claim had been brought against MJS Construction. The Claimant and MJS Construction share an insurance policy as part of an umbrella agreement.
71. Mr Mann said no claim had been brought against MJS Construction because John Frith had been involved. Mr Frith was employed by MJS Construction. Mr Mann understood that Mr Frith felt workmanship was not an issue but the problem was with the design. However, Mr Mann did not know whether Mr Frith had in fact been asked to look at any problems with workmanship or if he had just been asked to look at the design.
72. Mr Mann was taken to a number of emails in September and October 2017 which dealt with problems with cracks in the concrete slabs in other areas (i.e. not around the drains). He was taken to a photograph of part of a slab repair which showed a void in the concrete such that you could see what appeared to be clean dowel bars and the underlying membrane which was undamaged. It was suggested that if the void had been caused by breaking out concrete, the dowels and membrane would not appear as they do on the photograph. Mr Mann said you would have to ask the experts.
73. As to the use of metal plates over the damaged areas, he accepted they could be secured in some areas. He could not really remember when or why fixing had been done nor whether voids under the plates caused buckling. After being taken to his witness statement, he then agreed that any damage caused by movement of the metal plates, for example to tyres, was foreseeable if the plates were not secured.

Mr Roys

74. Mr Roys was employed by the Defendant as principal engineer at the time of the project. He headed up the design team for the Defendant and was responsible for producing the "for construction" civil and structural engineering designs. He followed the guidance in TR66 in respect of the external in situ concrete paving. For the container yard, the guidance set out in Interpave – Heavy Duty Pavements – The Structural Design of Heavy Duty Pavements for Ports and other Industries ("Interpave") was also used.
75. Mr Roys described the design of the container yard and slot drain. In order to achieve finished surface levels, the design required a cut and fill exercise across site. Imported stone needed to be used to create a formation profile 950mm below the finished level profile. The base layer needed to be compacted. The concrete bed for the slot drain is then formed within the capping layer.
76. The design for the Gatic slot drain used guidance produced by Gatic in September 2016 and BS EN 1433 relating to drainage channels for vehicular and pedestrian areas, which documents provided guidance in respect of different load classes to determine the requirements for the inclusion of reinforcement in the slot drains. This construction was in E600 class being an area "subjected to high wheel loads, e.g. ports and dock sides". The "for construction" design included 32mm dowel bars in the container yard area.
77. Mr Roys had attended various progress meetings on site. The primary purpose of those progress meetings was for MJS Construction to report to the Claimant. On occasions, he was asked to provide limited design input in relation to a query. When on site, he would carry out visual inspections to check progress and identify any issues. He recalled identifying a few instances where dowels had not been installed straight and he raised this with the MJS Construction site manager who advised those issues would be rectified.
78. When cross-examined, Mr Roys accepted that the Gatic slot drains were part of the design before he became involved in the project and that, as the designer, he had to consider how joints around the drains were formed. He accepted that the Gatic literature did not specifically explain how to form a joint. The Gatic literature did not say dowels or an MCT or both were required so it was down to the engineer to design the joint. He accepted that it was possible, and indeed the intent of the design, to form the joint in such a way that there is no differential settlement. He would not accept that if a joint leads to differential settlement, that is necessarily a defective design. Other factors may affect settlement. He did accept that if a design inevitably would lead to a differential settlement regardless of other factors then that would be a defective design.
79. Mr Roys was taken to the various design drawings. He accepted that no calculations had been produced to show how the loads were distributed at the joints before his involvement. He explained that was because the designs were based on the recommendations in TR66. He was aware of the types of load which would be used in the reach stacker yard including a very high front axle load. He accepted that the forces to which the drains would be subject would be much greater in the container yard.
80. Mr Roys accepted that on the initial drawings, including on the initial "for construction" drawing, showing the drains in both the container and the other yard, the drawings would not alert the builder to the fact that there was a different load class in the reach stacker yard. Mr Roys stated that was an oversight. It was also realised that 32mm dowels needed to be specified for the container yard and those changes were incorporated on the CO2 updated version of the plan. It was suggested that the earlier designs were inadequate because they only showed 25mm dowels. Mr Roys did not accept that it was inadequate per se and in any event the errors were corrected before construction began.
81. Although Mr Roys accepted there were errors on the earlier drawings, he did not accept that demonstrated that the Defendant had not considered loading. He did accept that he had made a mistake at the time about the 25mm dowel size in the first version of the drawing. Mr Roys also accepted that in the second version of the drawing, mesh was shown both at the sides and the bottom of the drain. In the first version of the drawing, mesh was only shown on top. Mr Roys accepted this but did not accept that the earlier drawing was therefore prepared without adequate skill or care. He accepted that on the final drawings, no MCT was specified at the joint. He said this was not needed on the drawing.
82. Mr Roys was taken to calculations which he had done in February 2017. The calculations considered the Interpave guidance and checked the proposed pavement design when considering the likely dynamic loads placed on the container yard by the loaded reach stackers. The calculations determined a Static Effective Wheel Load ("SEWL") of 52,063kg. Mr Roys accepted that the calculations and design did not mention dowels nor the joints between the slab and the drain. He explained that was because that was not the purpose of those calculations. The purpose was whether the slab would support the weight of the reach stacker vehicles. He maintained that the Defendant had considered dynamic loads before February 2017. He accepted that the single equivalent wheel load was 970kN and that the calculation did not calculate how weight was transferred across the slot drain. He explained again these calculations were not for that purpose.
83. He was then taken to calculations he had done in March 2017 which did look at load transfer. By this stage, as far as he could recall, Mr Roys agreed that 32mm dowels had already been included in the design and this was a check. The purpose was to identify whether the strength of the proposed dowel of 52kN was adequate. If a dowel was loaded over 52kN, Mr Roys agreed it would be overloaded. Reach stackers have a drive axle load of 98.4 tons so over four wheels that would lead to 214kN per wheel. The effective distribution level at foundation area was calculated at 7.23m² which led to the calculation of bearing pressure of 66.7kN per metre squared. Calculating the size of the drain with the loads, the required load per dowel was 34.5kN per dowel. Mr Roys said there was therefore a safety factor of 1.5 because the 32mm dowels could resist up to 52 kN.
84. Mr Roys was then questioned about dynamic loading. He accepted that if a reach stacker braked suddenly, a greater load would be created on the front axle and if it turns suddenly, a greater load would be created on one corner. Those were the dynamic load factors. He described the March 2017 calculations as being a first principles check. Dynamic factors were not considered at the time although they were checked later. Mr Roys would not accept it was negligent not to do a dynamic load check in this calculation. He also explained that it was relevant that the dynamic figure or load would be transient. He maintained that bearing pressure on dowels could not be equated with transient loads.
85. It was suggested to him that if a dynamic load factor had been used in the calculations, it would have been immediately obvious that the loads were well in excess of the dowels' design. Mr Roys accepted that on a straight mathematical calculation using different figures from across the February and March 2017 calculations, the final numbers showed an excess load on the dowels. However, he maintained that the design calculations were not the same for static and dynamic loads so the numbers could not just be moved between the calculations.
86. He explained how the two calculations had been done and what factors were used. He was taken to the joint statement of the experts where they agreed that a dynamic factor of 1.7 should have been applied. He accepted that, but stated that the dowel calculation was not done in the March 2017 calculation, although he thought it may have been done later. He also observed that he was not sure if the methodology being referred to in the joint statement was the same one used.
87. Mr Roys was taken to the joint experts' statement consideration of TR34 where the experts agreed that in the absence of more appropriate design guidance, TR34 was the most appropriate guidance to assess the load capacity of the dowels. Mr Roys did not accept the determined loads would necessarily be dynamic but he did accept that redesign would be needed if the appropriate load exceeded capacity.
88. Mr Roys accepted that the joints were not slab-to-slab (as defined by Claimant's Counsel in that there were not identical side-to-side structures) but he maintained they were still concrete to concrete joints. He would not agree that the joint would act differently in this circumstance, because the loads would be distributed through the various elements whether through the slab or the surround of the drain. Mr Roys said it was wrong to suggest that because the concrete surround was a long thin structure, if there was no longitudinal mesh reinforcement along the side, that there would be a limited capacity for the concrete surround to remain un-cracked and to distribute loads along its length.
89. Mr Roys maintained that the design was not flawed. The design was based on TR34 and TR66, but first principles were also used. He did not accept that the design did not specify an MCT. But he also said that using an MCT was one way only of doing it and the design did not specifically require the use of use an MCT. Mr Roys accepted that if it was necessary to use an MCT in order to make the concrete to concrete joints work, it would be negligent not add it into the design.
90. When asked about whether the yard should have been designed using E600 or F900 load classes, he agreed that if there was doubt in the design, the higher F900 should be used. However, he maintained that there was no doubt. He did not accept that the design had been done without any proper assessment of loads at the joints.

Mr Harris

91. Mr Harris is employed by the Defendant as a chartered structural engineer. He is presently a technical director. At the time of the project, he was an associate and was promoted to associate director during the project. He was involved in the initial early stages of the project with concept designs. His involvement continued in the planning and tender stages. After the tender stage, as associate director he was responsible for overseeing the project for the director but was not involved in the day-to-day design development. The "for construction" designs were completed around February and March 2017.
92. Mr Harris did not attend the site during construction. In February 2018 after practical completion of the project, Mr Harris was notified by the Claimant of ongoing damage around the Gatic slot drain surrounds. The Defendant was told that the drains appeared to be settling in comparison to the adjacent storage yard and there was damage and cracking to the concrete finish. Shortly after that notification, Mr Harris attended site to carry out a visual inspection and further investigations were agreed to establish the root cause of the damage. Mr Harris reviewed construction photographs and survey information and site investigation reports and arranged a CCTV drainage survey which showed no evidence of damage to the metal Gatic slot drains themselves. The Claimant then did monitoring of the settlement levels to establish if settlement was progressive. The results of the monitoring identified no evidence of ongoing movement.
93. Investigations took place between February and September 2018. Mr Harris then produced the results of the investigations in a report called the Gatic Damage Investigation Report dated 13 September 2018. The core samples had revealed that the incorrect diameter of dowel had been used, that dowels had failed and were bending which caused an oval-shaped void in the concrete at one side. There was also variance in the level of the slot drain surround and adjoining slab and variance in the alignment of the dowels. The conclusion of the report was that the smaller incorrect dowels did not enable load transfer as intended. The dowels failed, and the bending led to increased loads on smaller contact areas. That overloading crushed the concrete beneath the dowel and caused an uneven distribution of the load through the ground. Following remedial works and correct installation of 32 mm dowels, Mr Harris was not aware of any further instances of cracking in the container yard.
94. In cross-examination, Mr Harris explained he had been involved in discussions about the design and drawings but Mr Roys was more involved. There was a significant overlap between his role and that of Mr Roys. Mr Harris was senior to Mr Roys. Once damage was reported, Mr Harris accepted that he went back and looked at the design. However, that was only one element and he looked at all aspects including the materials. He also looked at the design calculations including the February 2017 loads on slab calculation and the March 2017 dowel check calculation. He was aware that the dowel check calculation did not apply a dynamic load factor. He was aware of the figure of 1.5 for the safety factor. He was not aware if anybody did a specific calculation on the impact of dynamic load on the joints.
95. Mr Harris was taken to a drawing produced after the event which he understood to be what was found in the investigations and the potential proposals which were being considered. It had been checked by Mr Harris himself. He was taken to the drawing at the bottom left of the plan which showed mesh in concrete at the top of the drain. Mr Harris agreed that was what the plan showed and that the plan had been produced based on information taken from the concrete core. However, he stated that he could not actually recall seeing any top mesh in the core which was sampled.
96. Mr Harris was then taken to the final drawing of the various remedial options. He accepted that none of the remedial options included a slab directly abutting the concrete surround in the same way as a concrete slab. He accepted that the repairs were done in such a way that the joints became slab to slab, same depth of slab to same depth of slab. However, in re-examination, he went on to explain that it simply was not practical to reinstate the original design detail because of the damage to the adjacent slabs which had been shown in the photographs. Any joint is a potential point of weakness so you would try to minimise that weakness wherever possible. The remedial design cut back the damaged concrete so as to have only two joints with the area of concrete extended so that the replacement dowels are much further over into the concrete slab.

Assessment of the lay witnesses

97. The lay witnesses all struck me as men who were doing their best to recall what had happened and explain the reasoning behind their answers when challenged. Although I was invited to do so, I did not find any of them to be partisan.
98. Criticism was made of Mr Roys by the Claimant on the basis that inadequate, if any, consideration was given to how a load or loads would cross the joint between the concrete slab onto the concrete surrounding the Gatic slot drain. I do not accept the submission that his evidence, if accepted, demonstrates that the Defendant failed to carry out the design with reasonable skill, care and diligence.
99. What was clear from Mr Roys's evidence was that the design had developed and evolved over a period of time when the Defendant was considering the design of the joint. It was clear that there were mistakes made in not distinguishing between the slot drain in the container yard and the service yard despite different loadings. The initial specification did not call for any dowels to be used, then 25 mm dowels were specified before that was changed to 32 mm dowels. In addition, in some of the drawings, no mesh was specified and that was later changed.
100. I accept Mr Sage's submission that the two experts agreed that the joints would not react in a uniform way as if a typical concrete slab to concrete slab joints, which did not appear to be the view of Mr Roys. However, in my judgment, the establishment of breach of duty and causation turns on the expert evidence and not on the lay evidence.

Expert Evidence

101. I will summarise the position of each of the experts and deal with their detailed findings, as set out in their reports, below. I will then consider the oral evidence of the experts and consider the different issues which may affect either breach of duty or causation or both.

The Joint Statement dated 15 December 2023

102. In the joint report dated 15 December 2023, the two experts set out their various positions as to what was agreed and what was not agreed in respect of various matters in dispute. Agreed and not agreed items will be discussed in respect of the various items in dispute. Not all of the various matters agreed and disagreed need to be set out.

Dowels

103. In respect of the dowels, the experts agreed that the Defendant had specified 32mm diameter dowel bars which must be placed at 300mm centres at mid-depth of the 400mm slab. Further, the experts agreed that the dowels used were 25mm diameter dowels and not the 32mm diameter dowels as specified. They also agreed that was a detrimental change. Further, they agreed that the dowels were placed incorrectly at around 75mm from the surface of the slab and concrete surround rather than approximately 200mm from the surface where they should have been placed. This too was a detrimental change.
104. As a result of the wrong size and incorrect placing of the dowels, the experts agreed that MJS Construction had not built the container yard either in accordance with the Defendant's design nor in a proper and workmanlike manner.
105. The main dispute between the experts in relation to the dowels was that Mr Barham stated that the Defendant's design would have failed in any event even if 32mm dowels had been installed at the correct level. He came to this conclusion as a result of his Finite Element ("FE") analysis modelling. However, his opinion was that the damage would have been less than it was if 32mm dowels had been used instead of using 25mm dowels. Mr Barham thought that Mr Rushton's calculations themselves showed that the 32mm dowels would fail if the correct loading factors were used in the calculations.
106. In contrast, Mr Rushton asserted that he had not seen any evidence of calculations by Mr Barham that a practical structure model or a load case existed which showed that 32mm dowels placed at 300mm centres were inadequate. He maintained his views about the inadequacy of the FE analysis modelling.

MCT

107. One of the key issues in this case is the requirement (or not) for an MCT. As was clear from his reports, Mr Rushton based his opinions, at least in part, on his (latterly accepted as incorrect) assumption that the Defendant's design included a requirement for an MCT to be built at the joints adjacent to the Gatic slot drain. The specific drawing of the concrete surround and the drain joint did not show an MCT at the joint. However, Mr Rushton was of the opinion that MJS Construction should have assumed this was required below the dowelled joints in order to deal with the challenge of compacting the ground underneath the dowels.
108. The design required a level of compaction underneath the Gatic slot drain. Mr Rushton did not think that compaction using hand tools was realistic given the linear metreage of compaction required along the length of the drains compared with what he considered as a more reliable method of using an MCT.
109. Mr Barham noted that an MCT was not part of the design at the transition joint between a concrete slab and the concrete surrounding the Gatic slot drain. The experts agreed that an MCT was shown on one drawing but Mr Barham was of the opinion that the design was specific to the joint between two concrete slabs and not specified by the Defendant at the joint adjacent to the concrete surrounding the drain. However, he also was of the opinion that it was not only feasible but relatively straightforward to compact the ground around and below the dowels at that joint using hand tools if necessary. In other words, Mr Rushton's reason for requiring application of the MCT at this joint would not arise. Mr Barham did not identify evidence to suggest that an MCT was built anywhere by MJS Construction. Although there was an indication of an over pour of concrete immediately adjacent to a concrete surround on analysis of one of the cores taken.

Mesh

110. The Defendant's design showed reinforcement in the base and sides of the concrete surround with a note which stated "mesh reinforcement where required" and referenced the Gatic drawing. The Gatic drawing showed reinforcement in the sides and base of the concrete surround in the largest slot drain (400 mm wide channel). For the smaller slot drains, no reinforcement was shown in the sides or base of the concrete surround.
111. The Defendant had also specified mesh reinforcement in the top of the concrete surrounds. The experts agreed that MJS Construction did not appear to have put in reinforcement at the base of any of the concrete surrounds nor at the top of any of the concrete surrounds. They did appear to have installed reinforcement at the sides of the concrete surrounds irrespective of the size of the channel.
112. The experts also agreed that as wheel loads would have been transferred to the base of the concrete surround in a non-uniform manner, without longitudinal mesh reinforcement, there was a limited capacity for the concrete surround to remain uncracked and to distribute loads longitudinally.
113. The experts agreed that the omission of the reinforcement by MJS Construction at the base of the 400 mm drains was a detrimental change. However, Mr Barham did not think that this appeared to have had a significant effect as the damage was not generally occurring in the 400 mm slot drains. There was a beneficial change by installing side reinforcement to the smaller slot drains of less than 400 mm when it was not required.
114. As to the top mesh reinforcement, they agreed that if MJS Construction had omitted the top mesh reinforcement which was specified, that would have had a detrimental effect on the performance of the slot drains and resulted in an increased risk of cracking to the top surface. However, the experts then disagreed. Mr Barham's view was that he had not seen evidence from construction photographs which demonstrated whether or not the top mesh reinforcement was included or not. In his view, the mere fact of damage to the top of the concrete surround did not by itself imply omission of the mesh reinforcement at the top. Mr Rushton's view was that as there were photographs of extensive surface cracking of the concrete surround it was likely that the top reinforcement mesh was omitted despite its presence being recorded in the as built plan.

Individual Expert Reports

Mr Nick Barham

115. In his report dated 12 January 2024, Mr Barham set out his instructions. The matters set out all related to specific questions relating to the Defendant's design. Although he said that the Claimant was pursuing a claim against MJS Construction in respect of construction defects, it did not appear that he had been instructed by the Claimant to give an opinion, initially at least, in respect of any construction defects. Under a heading "Pleadings", Mr Barham set out various extracts from pre-action correspondence. He did not set out anything from the pleadings themselves.
116. Mr Barham engaged in discussions with Mr Rushton, the Defendant's expert, and a joint expert statement dated 15 December 2023 was prepared. He stated at paragraph 1.16 of his report that "During the course of my discussions with Mr Rushton, I have also investigated certain alleged construction issues with the yard slab and slot drain, in addition to the design issues described in my instructions above" (emphasis added).
117. In the 12 January 2024 report, Mr Barham set out the brief background to the dispute and noted that by December 2017, shortly after the completion of the work, damage including settlement of and cracking in the concrete surround and cracking in the adjacent slabs had occurred to all three slot drains in the container yard. In order to consider the adequacy of the Defendant's design, Mr Barham stated that he had given his analysis "based on engineering first principles". However, thereafter, he and his assistant had prepared an FE analysis model of the Gatic slot drain and adjacent slabs to examine the behaviour and performance of the design. He asserted that analysis of the FE analysis modelling demonstrated that greater than anticipated bearing pressures would be transmitted to the formation soil and a large proportion of the 32 mm diameter dowels close to the loaded areas failed in bearing capacity. He therefore asserted that the FE analysis model supported the views he formed using first engineering principles.
118. His conclusions summarised in his Executive Summary were as follows:

(1) In relation to design loading, the Defendant's design only considered a static SEWL. A dynamic SEWL should have been considered. Had a dynamic wheel load been considered, the loads used in the design were too low. The Defendant's conclusion that E600 (rather than F900) should be used when doing dowel calculations was "not appropriate". The Defendant's design was "inadequate with respect to design loading".

(2) The Defendant's assumptions about the transfer of wheel load through the concrete surround to the slot drains and to an adjacent slab were not applicable and the calculations done by the Defendant were therefore wrong. As a result of the wrong assumptions about load distribution, bearing pressures are likely to be experienced in the formation soil below the Gatic slot drains.

(3) The Defendant's calculations on dowel connections assumed identically stiff formation beds below the concrete elements and so wrongly overestimated loads which could be transferred through the concrete surround and underestimated loads transferred through the dowels.

(4) The Defendant wrongly assumed that the dowel connections would act in the same way at the joint between a concrete slab and the U-shaped concrete which surrounded the drain as they would in a slab to slab joint. In his view, the design was inadequate because the Defendant's approach did not account for the difference in stiffness in the concrete surrounding a slot drain, as the U-shaped concrete surround is founded on or very close to the formation soil. As a result, loads would be distributed differently to underlying soils and loads could not be transferred across the full width of the concrete surround in the way assumed. The design was thus inadequate.

(5) For the concrete surrounding the slot drain to act in the way assumed by the Defendant, the concrete surrounds would have to contain a significant amount of reinforcement which was not present in the design.

119. Mr Barham then saw Mr Rushton's Report dated 26 January 2024 and produced a Reply Report in response. In his Reply Report dated 9 February 2024, Mr Barham set out that he and Mr Rushton had met a number of times between June and December 2023 before preparation of their joint statement. Mr Barham did not consider that any of the points made by Mr Rushton undermined the validity of the FE analysis modelling or his associated analysis. He maintained the load distribution assumptions made by the Defendant underestimated the loads which would be placed on the dowels. As an unfactored load had been used by the Defendant in its calculations, the results and assumed loadings were too low. If factored loads had been used, the calculations would have shown that 32 mm dowels were not adequate. In addition, he stated "the workmanship failures exacerbated the design failures, and resulted in greater extent of damage, and/or resulted in the damage occurring sooner, than would otherwise have occurred".
120. Mr Rushton provided his Reply Report dated 9 February 2024 and Supplementary Note dated 19 February 2024. Mr Barham replied again with his Supplementary Report dated 22 February 2024. In that report, Mr Barham criticised the basis and assumptions used by Mr Rushton in his new calculations.

Mr John Rushton

121. In Mr Rushton's Report dated 26 January 2024 for the Defendant, Mr Rushton set out his instructions to review the structural design for the concrete pavement slab at the site including the Gatic slot drains, as well as any items of disagreement as set out in the joint statement between the experts. He was required to consider if there were any shortcomings in the design which may have caused or contributed to the concrete cracking adjacent to the slot drains and as to the cause of settlement relative to the concrete pavement slab.
122. In his executive summary, he set out that the cause of the damage was because the construction was not in accordance with the Defendant's design. He set out five causes of the damage:

(1) the dowels used were too small;

(2) the dowels were placed shallower than was specified;

(3) the trench depth for the concrete surround had been over excavated;

(4) an MCT had not been cast under the dowelled joint; and

(5) mesh reinforcement was not provided in the top of the concrete surrounds.

123. As part of his report, Mr Rushton produced a number of design checks manually when justifying his conclusions. He also commented on Mr Barham's use of his FE analysis model. Mr Rushton was unconvinced that the FE analysis model should be used when considering the adequacy or otherwise of the Defendants design. He set out the various problems which he had with use of the FE modelling.
124. In his Reply Report dated 9 February 2024, Mr Rushton dealt with various matters which had arisen in the joint statement and Mr Barham's report dated 12 January 2024. In particular, Mr Rushton considered Mr Barham's conclusions on the calculations done by the Defendant in February and March 2017 and the interpretation of those calculations by Mr Barham. Mr Rushton's conclusion was that he did not agree with Mr Barham and thought that Mr Barham "may not have fully reviewed and appreciated the impact of the construction defects". Mr Rushton set out why he did not accept that the FE modelling analysis would demonstrate real world behaviour because it did not accurately model the required redistribution of load between dowels and the resulting greater areas of ground support mobilised.
125. In his supplementary note dated 19 February 2024, Mr Rushton responded to Mr Barham's hand calculations which had been provided for the first time in Mr Barham's Reply Report. The calculations had been provided to support Mr Barham's assertion that the 32 mm dowels were not adequate. Having replied to the various calculations, Mr Rushton remained firmly of the view that had the design of the Defendants actually been built, it was a reasonable one and the damage only occurred as a result of workmanship errors.

Oral evidence of the experts generally and on the individual issues

Generally

126. Mr Barham was cross examined initially about his qualifications. He explained that between 2005 and 2012, he was involved in various civil engineering projects with houses. He did not have experience with design of container yards. He did have experience of above ground structures but they were mostly residential. From October 2012, he moved to WJ Marshall where the vast majority of his work was providing expert witness reports. There was a degree of new design and remedial work. When it was suggested that Mr Barham did not have experience of working in a smaller firm such as the Defendant, he said he had worked with Alan Baxter and Associates which had a hundred people and their work was very broad. He got experience of designing every aspect of a building. He agreed that he had not dealt with projects such as this container yard. However, he said he had designed paving using TR36 but he had not used TR34. Mr Barham said that part of being an expert was to put himself in the shoes of a reasonably competent designer. He saw it "almost as a benefit" that he was "not the best designer or technician" so he could opine on what a reasonably competent engineer could do.
127. Mr Barham explained that he moved to his current position with CCi in 2021 and again does lots of expert report work. He was now based in Singapore. He agreed that since 2012, his focus had been forensic engineering and looking at why things went wrong.
128. He was asked about the discussions with Mr Rushton since June 2023 and he agreed that since the joint statement in December 2023, he had done lots of work. He said that both he and Mr Rushton had done some more modelling work. It was put to him that despite that, he and Mr Rushton were still divided on the central issue – that is whether the design produced by the Defendant was one which a reasonable body of competent engineers would have produced. His answer was interesting against the background of some of his later evidence when he answered: "Yes – I don't think John and I spoke in those terms but yes".
129. Mr Barham agreed that he should have given a view on all matters that were within the bounds of the construction and design in dispute and that he would say if he was limited by his instructions. He initially said that no limit was imposed on his report and agreed that initially, there was no dedicated section dealing with workmanship. This was despite his understanding that the Claimant was pursuing a claim against MJS Construction in respect of construction defects. He was unsure if that was still the position.
130. He explained that he had initially drafted his report in 2022 and then revisited it in early 2023 after the joint statement had been prepared. When asked how much care he took, he stated he dealt with all the important points through the joint discussion process so he did not seek to recap all of the matters in this report. He agreed that a report should contain a fair and balanced reference to pleadings. He agreed that he had not referred to any of the pleadings despite having seen them. He could not recall if he had seen the pleadings when he started discussing the project with Mr Rushton in June 2023 but he thought he would have at least seen the Particulars of Claim as that would have started the ball rolling.
131. He agreed that he had not set out what should have been set out by an expert in a report. He justified this by saying he was trying to keep things proportionate by updating an earlier draft. He then agreed that he had not been asked initially to look at workmanship issues. It became apparent that workmanship issues had to be dealt with during the joint statement process and so they were. He eventually agreed that in his initial report, his consideration of workmanship issues was contained within a single paragraph. The workmanship considered in paragraph 6.15 of his report was in response to a question asked by his Instructing Solicitors. He said his Reply Report had more detail about workmanship and it would have been better if he drafted his initial report from scratch rather than updating an earlier report to keep costs proportionate.
132. When challenged about whether he was limited in his fees, he agreed that he was not. There was a budget but he could say if he was likely to exceed it. He said that he wanted to draft the report so that he could deal with workmanship issues. He eventually agreed that the issue was not "about a fee cap but you doing your job properly". Again he sought to justify his approach by saying that he had discussed workmanship and conceded significant workmanship issues. When it was suggested he had a duty to give his opinion on all issues in his report, he said he also had to consider his instructions. On being pushed, he agreed that if issues were within his remit, he should have addressed them in the report. He would not accept that he had failed in his duty to the court by not dealing with specific issues because he had "given some consideration to workmanship issues".
133. He was also challenged about his approach to the report. Whilst he stated that he had looked at the design from first principles, he accepted that he had not set out any calculations. He said that what he meant was not going through a calculation as such but "using basic physics and engineering principles as distinct from a more analytical approach". He agreed that in considering whether a design was adequate or not, one could have an illogical process to get to a final design but the final design may in fact work. He then agreed that in order to analyse a final design from first principles, the only way would be to use manual checks and calculations. Importantly, he also agreed that an engineer in a practice such as the Defendant would not use FE analysis when designing.
134. Mr Barham accepted that he had not explained in his first report what FE analysis was. He accepted that calculations until November 2023 had all been hand calculations done by Mr Rushton. No other calculations were done until that point when there was a difference of opinion between the experts because Mr Rushton thought the design worked and Mr Barham did not. Mr Barham accepted that the background for his opinion had not been set out. He accepted that he could have provided more information, particularly if he had written his report from scratch after the joint statement had been provided. However, he stated that he only had eight days after the Christmas break to write the report. He could have asked for more time. However, he did not think that providing a background explanation of FE analysis was "a suitable basis for applying for an extension". He went on to suggest that if the Judge did not know what FE analysis was, they "could Google it". He did not accept that if it was as simple as Googling it, the report could have been amended quickly. He said that the specific details would need to be looked at in the context of this case.
135. When Mr Rushton gave oral evidence, he was taken to his list of five contributing factors for the cause of the damage. He would not accept that he had changed his mind about damage caused by the failure to cast an MCT under the dowels joint. He maintained that whilst all five of those elements would interact to create damage, in the joint statement he had set out that his view was and remains that an MCT would be needed if compaction under the dowels joint was not adequate. Mr Rushton's view was that it would not be feasible to compact adequately by hand.
136. He did however accept that, contrary to his opinion, he accepted Mr Roys' evidence that the Defendant had not specified that an MCT was required at the joint between the Gatic slot drains around on the concrete slab. In addition, he accepted that he viewed the failure to cast an MCT as a contributory cause because he thought it would be challenging to adequately compact the ground by hand and adequate compaction probably would not be achieved by hand. He thought it would be cheaper and easier to use an MCT. It was suggested that there was no specific evidence showing poor compaction of the ground underneath the concrete slab. From the photographs, Mr Rushton thought that was a complicated question because settlement seen in areas of concrete not restricted to the areas around the slot drains also showed cracks and depressions in the concrete slab. He thought that was evidence of poor compaction generally and not just in the concrete surround area around the Gatic slot drain.
137. Mr Rushton accepted that part of the duty of a designer was to produce a buildable design. If hand compaction was not achievable, it was suggested the designer should have specified use of an MCT at the joint. It is fair to say that Mr Rushton was somewhat evasive and did not initially answer the question. He maintained that the Defendant had showed an MCT on another drawing. He did in the end accept that the MCT was not shown on the drawing for this joint.

Dowels/Loading

138. Mr Barham was taken through the process for constructing the slot drain as demonstrated on the Gatic detail within plan SK 051 version C02. He agreed that the feet of the drain itself would initially be concreted in. He agreed that on the Defendant's plan, the dowels were positioned mid-depth and that additional mesh was to be inserted in the top of the drain to restrain cracking. He also agreed that the instruction was for side mesh where required and that he would worry if a design did not use the manufacturers standard detail (here the side mesh) unless there was a good reason why. That was because the manufacturers would have tested that design.
139. It was put to him that the Gatic plan did not include the use of dowels. Mr Barham said he did not know why but he agreed. He then observed that the Gatic design was not for a slab, it just showed what the surround of the drain should look like. He agreed that the Defendant's design showed the dowels to be used as being size R32 600mm long to be placed at 300mm centres, the dowels two thirds de-bonded to make them stronger for the container yard. All of those specifications (R32, 600mm long put at 300mm centres and two thirds de-bonded) were all taken from Table 12 of TR66. When asked if the specification it was reasonable, Mr Barham said he could not recall anything which stood out as being wrong or missing.
140. When challenged about his view that TR34 and TR66 should not have been used during this design, he said not in isolation because those documents produced by the Concrete Society were for slab to slab connections where the depth of concrete was the same both sides. Also, the loads factored in to those documents were lower than you would expect on a container yard. He asserted it was therefore necessary to look at different wheel classes and the load position. However, he asserted you would have to be careful using hand calculations because that would only show a simplified version of what was happening in reality. He agreed that the sorts of calculations which could be done were those which Mr Rushton had performed for his reports.
141. Mr Barham stated that he had done the FE analysis because Mr Rushton would not accept that the design of the Defendant did not work. He asserted that his own conclusion that the design did not work had been borne out because Mr Rushton had now changed his calculations in order to make them work. He said he had wanted to avoid a costly FE analysis but there was no option. Despite that assertion, he accepted he had not produced his own first principles calculations. He said this was because if he kept Mr Rushton's calculations and then used the FE analysis, if he considered Mr Rushton's calculations were wrong, that would limit the areas for disagreement because you would be comparing the same things. He went on to accept that at the time he first made allegations of inadequacy of the Defendant's design, he had not undertaken any hand calculations of the type done by Mr Rushton to check if the design physically worked in practice and it was a "theoretical criticism".
142. He was also asked about load class. In the joint statement, he agreed that the Defendant's use of the load class E600 was appropriate. He then changed his mind and said in his January 2024 report that the E600 loading class was not appropriate because the SEWL used in the dowel calculations was too low because of the omission by the Defendant of a dynamic factor. He justified his change of mind by saying that the SEWL of 916kN used by the Defendant in calculations done in December 2020 was more appropriate such that F900 should have been used.
143. When that change of opinion was questioned by Ms Laney, Mr Barham accepted that he had agreed in the joint statement that E600 was the appropriate classification knowing what the Defendant's figures used were in the December 2020 calculations. He then said he then thought very little turned on the load class and he did not really think it was relevant. He went on to say that he continued to think that E600 was not adequate despite the guidance given in BS EN 1433. The Gatic product guide available at the time which suggested that was the load class to be used. When asked if his initial report was sloppy, he replied "I changed my view. It was a finely balanced decision. I changed my view to very slightly on one side of the fence to the other side. I would have had an easier life if I had not changed my view". He continued "on balance, if the Defendant had considered a dynamic factor and understood the magnitude of the load" F900 should have been used "but I accept it's a finely balanced question".
144. Mr Barham was then taken through some of the detail of the 2002 version of BS EN 1433. Mr Barham accepted that the examples given for use of appropriate installation for a minimum class of E600 was described as areas subjected to high wheel loads, e.g. ports and dockside. The description for class F900 was areas subjected to especially high wheel loads e.g. aircraft pavements. He accepted that docksides and ports would have to have the means of moving many containers including crane lifting although he said he did not know if the work would be done by reach stackers. He accepted however that heavy equipment would be used on dockside.
145. Mr Barham accepted that the slab thickness designed by the Defendant in the February 2017 calculations was in accordance with the Knapton process and was acceptable. He also agreed that the total dynamic load factor used in that calculation was higher than he and Mr Rushton had agreed was appropriate. The strength test calculations in BS EN 1433 were considered. Mr Barham's understanding was that when a CCTV survey of the Gatic drains on site was done, the drains themselves were deformed and some had to be replaced. He had not seen the survey himself. When the report of the CCTV was put to him which reported there was no evidence of damage to the slot drain, Mr Barham accepted that was what the report said. However, he said his interpretation of slot drain included the concrete surround and the CCTV would not show damage to the concrete surround. He was taken to photographs of the CCTV footage and accepted that he could not see any significant deformation.
146. He accepted that the focus of BS EN 1433 was looking at the metal grating and the drain itself when considering load classes. Despite that, he did not accept that if the load was too heavy the metal parts of the slot drain would be deformed. He said that he had had discussions with Gatic directly about this. This was surprising as he had not mentioned any discussions with Gatic in any part of any of his reports.
147. Mr Barham was asked about Mr Rushton's calculations in relation to the SEWL in the context of the dowel calculations. Mr Barham accepted that the load area in his calculations of 0.047m² was much smaller than that used by Mr Rushton looking at one wheel of a pair under the design dynamic load of 0.616m². Mr Barham stated that he had assessed the design load of the Defendant on the total load on a smaller area. He accepted that the BS EN 1433 tests suggested a load close to the E600 categorisation and that the nature of the test was specifically looking at a point load rather than distribution over a larger area.
148. Mr Barham maintained that he did not think that load class was critical and that the design would have failed even if F900 was used and not E600. He would not accept that the slot drain did not fail but the surround failed. He considered the concrete and the drain surround as a whole arrangement and would not accept that he had "seen enough evidence to say that the drain was not damaged". He said he had asked for all damage information although he did not request the CCTV footage. He said it was not provided after the issue came up in discussions with Mr Rushton. He did not think he had asked his instructing solicitor specifically. He was primarily concerned with looking at the concrete damage.
149. Mr Barham was next taken through what Ms Laney termed the "elephant" in the calculations. The February 2017 calculations were a Knapton calculation and a dynamic SEWL was considered at paragraph 11.4 of that calculation. Mr Barham accepted that the calculation included a dynamic factor. At paragraph 11.2 of that calculation, the highest load for the static load front wheel ("SLFW") calculation was 98,400 kg.
150. By email dated 21 September 2018, Mr Roys had sent the March 2017 dowel check calculations to Mr Mann in standard form. At no point in that document was the SEWL mentioned. Mr Barham stated that this was because the calculation had been done on the basis of a static load of 482kN. Mr Barham accepted that if the purpose of this document was to check to see whether the dowels could take a static load it was the correct calculation. However, he thought that this was the wrong thing to check. Mr Barham agreed that the calculation was correct and that the strength of the dowel was identified as being 52.5 kN. When the March 2017 calculation looked at the worst case load, Mr Barham agreed with the weight used of 98.4 tons (that is the weight of a loaded reach stacker with its arms out) which would be divided over four wheels to give 241 kN. The contact area of the wheel is then considered looking at the construction thickness to give a bearing pressure of 66.7 kN/m².
151. Mr Barham accepted that the foundation for this construction development was stiff to firm London clay which he accepted as being a not very reactive material. He accepted Ms Laney's description that the clay was "a bit stupid" and would take a while to react. It was put to Mr Barham that the calculation from the March 2017 calculations was not looking at how the dowels react with a transient dynamic load, but rather what the position would be if a fully loaded reach stacker was parked up and sat on the dowels for a while. It considered whether the dowels could take the load over a period of time. Mr Barham did not directly answer the question but accepted that that was logically reasonable if the calculation was just to look at a static load case. However, he still believed that left the dynamic scenario unchecked.
152. The March 2017 calculation went on, at page 3 of 4, to consider the position when wheels were positioned over the Gatic slot drain and considered the wheel centre and load per dowel. The transfer load and the required load per dowel was calculated at 34.5kN. As the maximum capacity of each dowel was 52 kN, that gave a partial safety factor on the loads of 1.5. Again, Mr Barham accepted the accuracy of the calculation and accepted that for a static load case, the calculation showed the design worked. However, he maintained that it was the wrong calculation when considering dynamic factors.
153. Mr Barham was asked about his FE analysis. He said it replicated the design as closely as he could although all models were simplification. He accepted that he could have modelled the poor workmanship issues for example if the dowels used were too small or placed at a level too shallow. He agreed he could have but asserted that would not have made much difference. He said the behaviour of the model he had designed in his FE analysis was not dependent on the size of dowel. This was even though he accepted that the purpose of a test was to show how dowels would operate in reality as they have to deform slightly in order to pass a load to other dowels. The point at which the load would pass would be different in a 25mm dowel to a 32mm dowel.
154. Mr Barham explained that he had used a linear model. There were more complex models which could be used in FE analysis. A more complex model would give more accurate results that would be closer to reality. Hand calculations were the most simplified calculations. Linear models assume linear elastic behaviour – if a load is placed on something, it bends. If the load is taken off, that material goes back to its original position. However, there comes a point where the stress is too much so the material does not go back to exactly how it was at the beginning. Non-linear models can calculate the behaviour of the material after it starts to deform. Mr Barham agreed that the description of how a dowelled joint works given by Mr Rushton in paragraph 1.24 of his 9 February 2024 report was a very good description. Mr Barham then explained that a non-linear model would be needed to recreate the behaviour described by Mr Rushton.
155. Mr Barham accepted that if he had done a non-linear model, that model would have looked at the relationship between the dowels and, in addition, such a model could show how load would go through the capping material to the foundation and radiate outwards. He said that it would be incredibly complex to create an FE analysis model for this. It was put to him that the 4^th edition of TR34 stated that it advised against using a linear FE analysis. He stated he did not recall seeing that line but accepted it may be in TR34. It was also put to him that TR34 stated that one should get input from a geotechnical engineer if one had to analyse soil behaviour. Mr Barham stated this was his K value in the model. He would not accept that geotechnical engineering input was necessary.
156. Mr Barham was taken to the FE analysis model results in his report. He maintained that his use of Winkler springs in the analysis was sufficient to represent a reasonable approximation of soil behaviour. Mr Barham stated that he was satisfied that using a comparison between K values and CBR values was a reasonable way of calculating the load formation relying on the 3^rd edition of TR34. Mr Barham was asked why he had not referred in his report to the 4^th edition of TR34 which was the relevant edition at the time. He did not accept that he was being misleading by not referring to the most up-to-date edition at all. He said he was simply "trying to justify his methodology" even though the up-to-date guide and said that you should seek the assistance of a geotechnical engineer for modelling of this kind. Mr Barham did not think that the additional expense of getting geotechnical engineering input would be justified because he did not think that there would be a significant change to the values. He maintained that he was justified using an old British Standard stating it would still work.
157. In the calculation, Mr Barham explained how he had estimated the sub foundation by extrapolating from the range of typical foundations for concrete pavements as set out in TRRL report number 87. He accepted that when looking at spring stiffness, one was looking at how the load was transferred down. That would be a calculation of force per metre, not force per metre squared. When applied over an area (for example springs on a mattress) it would be kN/m/m². The description used in TRRL number 87 used mega pascals. As 1 megapascal equals 1000kN/m², it was put to Mr Barham that one could not just extrapolate. He stated he thought that the TRRL report must have missed out a unit when setting out its numbers.
158. Mr Barham accepted that Mr Rushton had made criticisms over some of the inputs used by Mr Barham into the FE analysis. For example reductions were made in reducing cornering and braking factors. Mr Barham was taken through the various criticisms of the FE analysis model by Mr Rushton. For example, the Knapton guidance looking at dynamic braking factor explains how the dynamic factor is "additive for the front wheels and subtracted for the rear wheels". The relevant increase for the load would be 13.6% rather than the 30% used in Mr Barham's FE analysis. Mr Barham accepted that in practice, the loads used for cornering and braking would not happen regularly, but he said he did not know enough about how the figures were calculated.
159. Mr Barham stated he could see the physics argument which made sense but questioned whether it would be appropriate to reduce the guidance figure unilaterally from Knapton. Mr Barham accepted that he could have run Mr Rushton's figures as part of the analysis, which process would have taken a day or so to do. Mr Barham stated that he had sent the file to Mr Rushton but did not know if Mr Rushton had access to the FE analysis software. When told that Mr Rushton did not, Mr Barham stated that he had offered the chance to go through some calculations together on screen and work through it. He did not think it would have made a substantial difference. He accepted that if had he done the calculations, he would not now be speculating. He said there was only so far that it was reasonable for him to go to change his modelling.
160. Mr Barham agreed that Mr Rushton had suggested some alternative numbers to use in the FE analysis. Mr Barham said that Mr Rushton made some good points in his report and so he had amended the FE model to take account of Mr Rushton's points. Despite making those changes, Mr Barham had not provided Mr Rushton (or indeed the Defendant or the court) with the further information produced as a result of the additional changes made to the FE analysis. Mr Barham stated that he had only done the amendments over the weekend before the trial started.
161. Mr Barham said he was not intentionally being unfair. He accepted that the FE analysis he had previously reported on had changed. As a result of the observations made by Mr Rushton, Mr Barham accepted that the model on which he had just been giving evidence had changed such that the initial modelling outputs as set out in his reports had been superseded and the outputs were no longer reliable. In other words, his opinion had changed. Mr Barham accepted that in the modelling he had done, he had used a high tensile dowel which was different in strength to those used. The dowels used were made of mild steel. He stated he did not know that that was the position at the time the FE analysis was prepared. He stated that he had not seen all of the drawings showing all of the joints when he did the initial calculations. When taken through some of his own calculations in relation to the 32mm dowels, he accepted that there must be errors in the modelling because the numbers just did not add up.
162. He said he chose to utilise a more tensile steel in the calculation because that was more commonly used. When it was pointed out to him that the relevant loading was set out in the pleadings, he was very hesitant in his reply and stated that he was satisfied with the way he proceeded. He would not use what was written in the proceedings because he had not identified that the Defendant had set out in its design the dowel capacity. Belatedly he saw it so he changed his assessment of how the dowels would fail. He asserted that in fact the changes would make the design worse.
163. Mr Barham was next taken through the FE analysis result images when looking at load combinations and showing the effect of the loads on soil bearing pressures and the dowels. He explained and demonstrated how the load shape changes as it starts to approach and then cross the concrete surround. He explained that the image colouring showed how the pressures would affect the foundation soil and so would not be directly related to the dowels. When asked if the model was showing the pressure on top of the Winkler Springs, Mr Barham changed his mind as to whether the pressure was shown on top of the Winkler Springs or pressure at foundation level. Mr Barham accepted that although he had produced a drawing dated 9 February 2024 which he asserted showed that the loading design produced by the Defendant did not work, he had never produced a drawing which showed what should have been done.
164. Mr Barham accepted that he had shown the tyre load completely on the concrete surround and across the slot drain itself. He accepted that the diagram on calculations done by Mr Rushton showed the wheel partly on the concrete slab and not entirely on the concrete surround. Mr Barham accepted that if some of the wheels are on the slab, the dowels would react differently. Despite this, he would not accept that he should have done a like-for-like drawing and calculation. He said that was justified by considering the worst case scenario. Doing that without explanation he thought was justified because an explanation would not help but probably cause more confusion.
165. Mr Barham went back to his FE analysis in considering the loading. He accepted that when considering the adequacy of and the likelihood of failure of the dowels, one would not get to a loading of 52.5kN and then they would simply fail. Mr Barham agreed that there was an element of confidence in the design of the engineer and some judgement calls to be made in deciding whether the design was adequate. He had not done a hand calculation to check, because his opinion was that the FE analysis more accurately showed load distribution through the soil. When asked what process the reasonably competent engineer would do to check the figures, Mr Barham agreed that would be a hand calculation and the overall methodology used by the Defendant was "ok".
166. The most recent calculations done by Mr Rushton showing an expanded distribution of load were put to Mr Barham. It was suggested that when the wheels were wholly across the slot drain and its concrete surround, the load would be distributed further along the concrete surround such that 12 dowels would be engaged rather than 10. This also made the design work. Mr Barham accepted Mr Rushton's maths but maintained that 10 dowels only should be used in the calculation because that was the number of dowels taken from TR34 for a slab to slab connection. He maintained that was the position even though he accepted that the connections here would not operate as a slab to slab design.
167. In relation to workmanship issues, Mr Barham accepted that some details of a design would be put into the drawing and some aspects would be in the specifications. The design required the builder to build as per the design. Deviations from the specification undermine the design. On being taken to photographs taken during construction, he accepted that there was evidence that some dowels were missing, some had been bent, some had not been installed at the correct depth but too shallowly. Mr Barham's view was that if installation of dowels was difficult because of the temporary support structures, additional dowels could be inserted afterwards. That said, retrofitting would not be the preferred way to fit a dowel. Mr Barham also accepted that if dowels were not installed properly, for example at an angle, the dowels would not be able to do their job properly and would not be able to resist the forces which they should.
168. Mr Barham was shown other examples of repair works which needed to be performed. One example showed that there was a void where concrete should have been. Mr Barham accepted when looking at another photograph of a core which had been taken that it was likely that mesh which should have been installed had not been installed. Mr Barham stated that significant cracking and spalling on some of the concrete areas was most likely directly related to the installation of dowels at a shallow depth. Perhaps most importantly in relation to the damage claimed and said to have occurred by December 2017, Mr Barham's opinion was that the damage claimed for and subsequently repaired happened "a lot sooner than it would have" because of the use of 25 mm dowels installed at a shallow depth or an absence of mesh. The damage and differential settlement complained of by December 2017 would not be as a result of any defect in the design because of the "stupid" clay.
169. When asked questions about the adequacy of the design in respect of load transfer, Mr Rushton was adamant that the use of FE analysis was fundamentally wrong. He accepted that the apparent design assumption was that of a slab to slab load transfer (meaning slab to slab same thickness to same thickness). Mr Rushton thought that was an approximation. Mr Rushton's calculations of how loads were distributed was not shown on a drawing but he maintained that the design was still adequate as justified by his calculations in his supplemental report.
170. Mr Rushton stated that where there were two thicknesses of concrete, that would lead to added complexity. That was why he thought an MCT was useful because it would turn the joint into a slab to slab connection, as the depth would be equivalent each side of the joint. Since his initial report, his later calculations had established that the MCT was not necessary. He also agreed that his position on the need for an MCT had shifted since his initial report.
171. When considering the dowels, Mr Rushton's view was that the Defendant had approximated their calculations based on a uniform load, that is a load spread equally. In Mr Rushton's view, the approximation used was adequate when specifying the number and location of the dowels. Mr Rushton's view was that the March 2017 calculation was an approximate check on the load cases and he could not see anything wrong with that. Mr Rushton accepted that the guidance in TR66 referred to vehicles with a maximum load up to 105 kN. In fact, a reach stacker load could reach 965kN and so it was put to him that the guidance was for lighter vehicles with less load. Mr Rushton thought that this did not matter. There was not much guidance available and the issue in this case was about pressure, that is load over area (kN/m²). The guidance examined the tyres of HGVs which are 0.6m wide whereas a tyre on a reach stacker is 1.67m wide. Those tyre size differences create different pressures. Although TR34 was the best available guide, it still had to be used with care because of the way loads behave differently.
172. Mr Rushton accepted that the checks done by the Defendant were for static loads and not for a dynamic load. For a dynamic load, a factor of 1.7 should have been applied. Mr Rushton agreed he had not seen any evidence that testing was done by the Defendant of a dynamic load. He said the only way it was partially taken into account was within the factor of safety 1.5. Although Mr Rushton agreed that the factor of safety of 1.5 was less than the 1.7 detailed design number, he thought the 1.7 figure was obtained with the benefit of hindsight. At the time, the Defendant engineers thought 1.5 safety factor was okay. Mr Rushton maintained that suitable testing was done by the Defendant's engineers at the time.
173. Mr Rushton did not accept that a reasonable competent engineer would not make these mistakes. Mr Rushton's assessment was that the engineers were not incompetent in the design because the figure of 1.7 was "incredibly conservative". That 1.7 figure was obtained by looking at the Interspan/Knapton calculations and when considering how the reach stacker is actually used on the container yard, Mr Rushton thought 0.3 itself was a very conservative figure.
174. Mr Rushton accepted that he had originally used 10 dowels when calculating a safety factor and had changed his opinion to use 12 dowels in the calculation. Mr Rushton explained that using 10 dowels was a conservative approach. He had picked that figure using first principles and not TR34. Ten dowels was the number used by the Defendant in their March 2017 calculations. Mr Rushton explained that what he was doing in his later calculations was experimenting with different ways of working out how many dowels would be engaged by loads. At the time he was doing that, he was working on the premise, that he now accepted was wrong, that an MCT was specified. The absence of an MCT would not necessarily mean the load would increase. What mattered was whether the ground was weak. If the concrete was too close to the foundation soil because the ground had been over excavated, that would increase the loads to be resisted by the dowels. The Defendant had not specified a maximum depth for the drainage channel excavation.
175. Despite all of that, Mr Rushton maintained that the design worked in practice. Although he had initially been concerned about the lack of mesh reinforcement affecting the longitudinal coherence of the structure, he had since then been able to justify it with his calculations. When doing the joint statement, Mr Rushton stated that he and Mr Barham were not considering the design holistically but rather looking at individual components. Mr Rushton had said in the joint statement at item 6.b(c) that without longitudinal reinforcement, there was limited capacity of the concrete surround to remain uncracked and to distribute loads along it. However, as only 15% of the drains required longitudinal reinforcement, the design holds together.
176. Mr Rushton was next taken to his hand calculations. He was taken to his calculation where a pair of wheels were at the joint of the concrete surround. He calculated the load to be transferred as 495kN. He explained that the calculation had been produced in October 2023 and then referred to in the joint statement in December. Thereafter, he produced his January 2024 report. The Reply Report from Mr Barham was put to Mr Rushton whereby Mr Barham's calculations showed 61.2kN per dowel. The maths of that calculation was accepted by Mr Rushton. However, he explained that the calculation contained in his January report was looking at an issue (which he said Mr Barham thought was critical at the time) considering the situation when the wheels were about to cross the joint. He explained that Mr Barham's main concern at that time was that the surround could not move the load to the other side of the joint and that was the second load case (considering the pair of wheels on half of the Gatic concrete) considered in Mr Rushton's January report.
177. If there was no transfer of the load across the concrete surround and into the concrete slab on the other side, the length of Gatic concrete required to be mobilised to resist sub-grade pressure would be 116kN/m². Recalculating the position, Mr Rushton came to the conclusion that the load bearing on the foundation soil below the concrete surround and capping was reasonable, considering the length of concrete which was mobilised for the previous load position considered, that is with the pair of wheels immediately adjacent to the concrete surround.
178. Mr Rushton explained that he accepted that Mr Barham had not changed the parameters from Mr Rushton's original October 2023 calculation which led to the 61.2kN per dowel. Mr Rushton went on to explain that he had dealt with that calculation done by Mr Barham in his 19 February 2024 Supplemental Note Report. As explained in this report, the reason for a supplemental report was that the first time that Mr Barham had produced any hand calculation was in his 9 February Reply Report. The hand calculations were asserted to demonstrate why the dowels designed of 32mm were not adequate. Mr Rushton felt this was an important issue and as Mr Barham's calculation relied upon numbers taken from calculations done by Mr Rushton but taken out of context, Mr Rushton felt it important to explain why Mr Barham's calculations were wrong and how they should be corrected.
179. The reason Mr Barham's calculations were wrong was because he took numbers calculated for a load case where a wheel was partially supported on the slab and partially on the surround. He then directly imported that number to a situation where a wheel was wholly supported by the surround. That difference in wheel position affected the calculation. The calculation done in October 2023 was to deal with Mr Barham's concern that loads could not be transferred across the U-shaped concrete surround into the slab on the opposite side. The calculation from October 2023 demonstrated that loads could be transferred across. Mr Barham had also taken two other numbers from Mr Rushton's previous calculations which also needed to be amended due to the change of wheel position.
180. Recalculating, Mr Rushton explained that Mr Barham had incorrectly interpreted Mr Rushton's assessed value of the 116kN/m² as being the limit when Mr Rushton was considering whether the allowable bearing pressure of the formation was reasonable. However, Mr Rushton explained that was not the position – it was not the limit. Mr Rushton had now reassessed the bearing pressure value for a case where the whole wheel was on the concrete surround. This was necessary because of an overlap effect of the pair of wheels at the opposite end of the axle on pressures on the formation level is minor. However, if the whole axle is parallel and supported by the surround, the surround is required to distribute the load along its length and so it becomes important to consider the overlap between the pair of wheels. Mr Barham did not appear to have considered this.
181. In addition, Mr Rushton was concerned that Mr Barham had assumed that only 10 dowels can be deemed to act. Again, Mr Rushton assumed that Mr Barham had taken that from Mr Rushton's first report. However, Mr Rushton said this calculation was simply a check to see what the methodology from TR34 indicated for a slab to slab joint. This was not a slab to slab joint. Further, Mr Rushton said that he had conservatively estimated the kN load because the load would be affected by cornering factors, part of which had not been agreed by Mr Barham. He therefore reduced the area which he previously assumed could be deemed to act under a pair of wheels. Adding those corrections into the calculation, the load would be spread along an effective length long enough to include 12 dowels (if they were installed correctly as per the design). Mr Barham had simply taken the 10 dowels from Mr Rushton's initial report. If 12 dowels were engaged (as they would be if Mr Rushton's calculations were correct) the loads for the engaged dowels were below 52.5 kN on both the left and right side of the joint as the wheels crossed from one slab across the concrete surround onto the other slab. In other words, the dowels designed were adequate to transfer the loads.
182. Mr Rushton's calculations and methodology were challenged by Mr Sage. This was because the new calculations included an additional area which had not previously been taken into account when considering tolerable loads. Mr Rushton accepted that in the initial calculations, bearing pressure was increased by chopping off an area to take account of some overlap. It was suggested that Mr Rushton had not therefore done an identical calculation. Mr Rushton explained that he had corrected a number which Mr Barham had used incorrectly, as he explained in the Supplemental Note. It was suggested to Mr Rushton that until the Supplemental Note, the issue of overlap of wheels necessitating a deduction has never been raised. Mr Rushton explained that the position had been set out in his Reply Report of 9 February 2024. In addition, the position was not, as he put it, "a bolt from the blue". Mr Rushton explained it was a development of the calculations because the recent calculations were looking at the situation where a pair of wheels were in a different position.
183. Mr Rushton accepted that when the Defendant had done its design check, they used 10 dowels and not 12. He also agreed that if 10 dowels are used, the dowels showed themselves as being overloaded. In order to get the load under 52.5kN, 12 dowels needed to be engaged. Mr Rushton would not agree that 10 dowels should be used as that was the best available method as taken from TR34. Ten dowels was previously used because that was the calculation which had been done before the latest calculations were developed. He accepted that in the joint statement, he had accepted that in the absence of more appropriate design guidance, TR34 was the most appropriate guidance to assess the capacity of the dowels. However, Mr Rushton remained solid in his view that the additional calculations showed that in fact 12 dowels would be engaged.
184. Mr Rushton was challenged that his "new methodology" was not supported by literature. Mr Rushton agreed that the result for effective dowels was different to TR34, but that was because there were different thicknesses of concrete. Mr Rushton's view was that the thicker side, that is the concrete surround, would attract more load than the shallower side because the concrete surround was able to distribute load in a longitudinal direction. The result was therefore more engagement of dowels than was suggested by TR 34.
185. Mr Rushton disputed that the FE analysis model could be relied upon. Mr Rushton accepted that on the approach to the surround, the FE analysis looked right. However, once the analysis showed the wheels nearing the concrete surround, you needed to be able to model through the soil to see what the distribution of load actually was. Mr Rushton was criticised because he had not taken up Mr Barham's offer to meet so that Mr Rushton could input his own data into the FEA analysis model. Mr Rushton explained that he was not just being fickle – he and his assistant had worked quite a lot with FE models of this sort and if they did not model real-world behaviour, the analysis was not worth much.
186. Mr Rushton said he could see from looking at the FE analysis that it was not really useful because it did not demonstrate how the dowels would work. In addition, the deadline was rushing up for the Joint Statement at the time. The Defendant did not have the programme. Mr Rushton's view was that the FE analysis could not model the dowels using springs. He accepted that Mr Barham was probably right that such analysis could be used for designing foundations. But here, Mr Rushton stated that the design was for a structural system which would need to analyse how complicated soil masses would react. For example, in the linear model, if one pushed a single spring, the other springs would not react. In reality, in geotechnical terms, the surrounding material from the area of pressure would also go down around it. Once the load starts to get too much for a single dowel, the adjacent dowels start to take up more of the load. The position was that in reality, the 25mm dowels may have worked but once they had been put into shallowly, the concrete would fail, as it in fact did.
187. Mr Rushton accepted that the criticisms that were made of the FE analysis model could also be made of the hand calculations when it came to modelling soil behaviour. Mr Rushton accepted that the methodology and results in TR34 were a basis for stiffness considering soil reaction. However, he stated that he had noted that the K values used by Mr Barham from the 3^rd edition of TR34 had been used instead of the updated 4^th edition of TR34 where geotechnical engineers were advised. In addition, Mr Rushton explained that he had found a PhD thesis, which he had referenced in his Supplementary Note, demonstrating just how complex soil modelling was. This emphasised that the out of date literature from the 3^rd edition of TR34 used by Mr Barham in his FE analysis (when he used Winkler spring stiffness) did not adequately show how soil would react.
188. It was suggested to Mr Rushton that the FE analysis would produce a better result than hand calculations. Mr Rushton accepted that in a structural problem, that was probably right. However, this was a combined elastic and plastic problem with the dowels which were not accurately represented by the Winkler springs because the dowels' behaviour was non-linear.
189. When making calculations, Mr Rushton explained that approximations meant that a conservative load assessment would be done. If a more complex FE analysis was done, you would still do approximation hand checks as they are a sense check. The factors of safety taken by the Defendant were an approximation. When looking at the March 2017 checks, the safety factor for the dowel calculations was 1.5 on load. The safety factor increased to 2.02 if the reach stacker was not on the Gatic slot drain itself. Considering again the design of the Defendant, those checks done by the Defendant showed that the design looked okay.

MCT

190. When considering the MCT, Mr Barham said that an MCT was not shown on the drawing for the container yard. When asked about the construction process for the area surrounding the Gatic slot drain, Mr Barham described excavation to the clay formation level. There was then a capping layer of 450 mm which would be compacted and rolled across the whole site. The area around the slot drain would then be excavated to a wider area than the necessary concrete surround for the slot drain. The area around the slot drain would need to be re-compacted to the designed level.
191. Mr Barham was of the view that this re-compacting process could be done by hand, although he thought that would not give an optimal result. He said you would need the right supervision of the workers and the right workers with "verve". Mr Barham also accepted that a company like MJS Construction which does lots of ground drainage works might choose to put some extra concrete in that area rather than compacting by hand. Indeed, Mr Barham accepted that some of the photographs taken during the construction showed examples of extra concrete being used in the area surrounding the slot drain.
192. When looking at the February calculation, Mr Barham had not assumed an MCT would be used but that the compacted areas would have been compacted properly. When cores were taken around the slot drains, he did not see evidence of poor compaction. As far as Mr Barham was concerned, the MCT was irrelevant when looking at the calculations. He did not think it was significant whether it was the specified or not.
193. In his oral evidence, Mr Rushton changed his written evidence, having now understood that an MCT was not in fact part of the design as he had previously thought. Mr Rushton was cross examined in some detail about an MCT and that his evidence was that an MCT was needed to make the design work. He did not accept that he had changed his evidence as such in respect of an MCT being necessary. Although he accepted that the failure to install an MCT was one of five factors set out in his initial report, he referred back to the Joint Statement. In the Joint Statement, Mr Rushton referred to the fact that MJS Construction should have assumed that an MCT was required, even though it was not shown on a cross-section drawing. The reason was to deal with the challenge faced by MJS Construction for compacting the ground underneath the dowels. In the joint statement he set out that an MCT would be required if compaction underneath the dowel joints was inadequate.
194. He also set out that he had concerns that compaction using hand tools would not reliably achieve the compaction needed, when compared with the easier solution of installing an MCT. As it appeared that an MCT had not been installed throughout, and Mr Rushton was of the view that the dowels and other aspects of the design was adequate, the compaction of the ground under the edge of the slab underneath the dowels must be suspect and not built in accordance with the design. He further set out that where the MCT had been omitted or only partially built at a dowels joint, there would be an increase in the estimated dowel load as a result of the change in thickness between an adjacent concrete slab and the concrete strain surround. An inadequately compacted subbase would cause the dowel joints to fail.
195. Mr Rushton was heavily criticised in cross-examination and it was asserted that he had changed his view that an MCT was in any event necessary. Mr Rushton gave consistent answers responding to that accusation. He clarified, as he said he had attempted to do in the joint statement, that an MCT was necessary if compaction under the joint was inadequate. He said he thought it would be challenging to achieve the necessary compaction. He did not think that it was likely the necessary compaction will be achieved using hand compactors and therefore an MCT was a simple solution. However, when it was put to him that an MCT had to be shown on the design to make it work, Mr Rushton did not accept that this was the case. In his opinion specifying the MCT was "crossing the boundary between design and workmanship responsibilities". What the designer had to do was to alert the contractor to the outcome that was required – here adequate compaction. It was then a matter for the constructor to decide how to achieve the compaction required.
196. That said, Mr Rushton accepted that there was no point in a design requiring something which could not be built. He thought that the compaction would be challenging and not likely achieved. In addition, he accepted that the drawing of the relevant joint did not specify or draw an MCT. Mr Rushton also agreed that a lack of adequate compaction was one of the contributing causes to the damage.
197. As he was cross examined, Mr Rushton developed his position in relation to the MCT. However, he maintained that the design was still adequate and the failure to install an MCT was a workmanship error. The two relevant drawings dealing with joints required a specific level of compaction. Mr Rushton also agreed that the Defendant designed the dowels joint on the basis of it being a slab to slab connection, which was not correct for the drain surround concrete. He was taken through various load transfer calculations. Mr Rushton agreed that loads would behave differently across a slab-to-slab joint when compared with the slab to concrete surround of the drain joint. In those circumstances, the soil structure complexity needed to be examined. However, Mr Rushton went on to explain that the additional calculations he had done (testing the hand calculations belatedly produced by Mr Barham) had caused Mr Rushton to shift his position. His previous position had been superseded by his calculations in his Supplemental Report. He accepted that he had initially thought the MCT was important but as the case had developed and more calculations had been done, he had decided that actually it was not.

Assessment of the expert evidence

198. As noted above, this case turns largely on the expert evidence. The Claimant heavily criticised the impartiality of Mr Rushton's evidence for the Defendant, accusing him of giving "dishonest evidence" to the court at the start of his cross-examination in relation to his evidence about the MCT, such evidence said to be given dishonestly in order to protect the Defendant.
199. The Claimant relies heavily on the fact that Mr Rushton, until trial, had the failure to install an MCT as necessary and an integral part of the design to enable the design to work and the lack of its installation by MJS construction as a cause of the damage.
200. However, in my judgment, the expert upon whose opinion I do not have confidence is Mr Barham. I agree with the submission made by Miss Laney that the court should treat Mr Barham's evidence with significant caution. Having heard his evidence, Mr Barham did not impress me as an expert witness. He did not appear to have considered adequately the applicable legal test in professional negligence cases. His evidence did not make me confident that he understood properly his duty to the court as an expert pursuant to CPR 35. Although Mr Barham's report was dated 12 January 2024, it was (as he accepted) based on a draft which had been prepared significantly earlier. It did not appear to have been updated with sufficient thought to his duty to "state the substance of all material instructions, whether written or oral, on the basis of which the report was written" as is required by CPR 35.10(3) and Practice Direction 35.
201. For example, under his heading "pleadings", there was in fact no reference whatsoever to the actual pleadings in this case. The only references here were to pre-action correspondence. He was very slow to accept that he had a duty to provide the court with a proper opinion on workmanship issues as a result of matters raised in the defence. He had not set out the nature of the oral instructions which he eventually said he had been given. He did not appear to view his consideration of poor workmanship issues as perfunctory. This was despite the fact that just one paragraph in his report dealt with poor workmanship and then only dealt with one of the numerous allegations made by the Defendant about poor workmanship.
202. I acknowledge that he addressed the issue of the incorrect size dowels being used and stated that in his opinion the installation of the smaller dowels was not the "principal cause" of the damage. However, he made no mention of the other criticisms of poor workmanship and construction not in accordance with the design as set out in the defence. There was no consideration of the following matters:

a. the dowels being installed at the wrong depth;

b. the dowels not being fixed at right angles;

c. the dowels not being centred on the joint;

d. missing dowels;

e. missing mesh;

f. an inadequate sub-base and capping layer in some locations; and

g. inadequate casting of concrete to the correct thickness and in such a way that the step between joins in some locations was not within tolerance.

203. I accept that there was some limited consideration of these issues in the experts' Joint Statement. However, there was no consideration at all of the effect on causation of the damage said to be in existence by December 2017 if some or all of those workmanship criticisms were established. His explanation for not including the allegations of poor workmanship pleaded by the Defendant was "in order to keep things simple".
204. Mr Barham appeared to suggest that he was subject to both time and cost constraints when he was challenged about the adequacy of his first report. However, he then acknowledged that he was not limited by budget and went on to accept that his report would have been better if he had not "updated a previously drafted report". He sought to excuse criticisms made of his report and the lack of detail to being under time pressure over Christmas. When it was suggested he could have asked for more time if needed, he said he was acting proportionately despite the fact he was not on a fixed fee or budget.
205. Having acknowledged that one of Mr Rushton's criticisms of Mr Barham's FE analysis was valid, Mr Barham told the court that he had rerun his FE analysis over the weekend before the trial. The fact that he had rerun the FE test and various parameters for the test had been amended to take into account the criticism was not mentioned until cross-examination. As Miss Laney observed, it was unclear whether the Claimant's legal team were aware of what Mr Barham had done over the weekend. When challenged about the new undisclosed FE analysis, Mr Barham appeared genuinely surprised by the astonished reaction in court about his undisclosed actions and that there was any objection to him having done this – he plainly did not think he had done anything untoward.
206. In my judgment, these issues alone undermine the reliability of Mr Barham's expert evidence. However, in addition, other factors also go to undermine his opinion. Mr Barham relies heavily on his FE analysis as the basis for his opinion that the Defendants design is defective. However, he did not provide any explanation as to what an FE analysis is, how it works, whether there were any limitations to its use or the outcomes it produced. When he was asked how the court was supposed to understand FE analysis without an explanation, he said the court could "Google" FE analysis and that would probably give a better answer than he could.
207. In addition, I was troubled by Mr Barham's reliance on his FE analysis, rather than undertaking basic calculations as Mr Rushton had done, in circumstances where Mr Barham accepted and agreed that a reasonably competent engineer would not use FE analysis when designing a project like this. In addition, he used the out of date 3^rd edition of TR34 from 2003, without mentioning the existence of the 4^th edition of TR34 published in 2014. He seemed unaware that the 4^th edition of TR 34 warned against the use of FE analysis modelling and was seemingly untroubled by the advice given in the up-to-date 4^th edition of TR34 that the input of a geotechnical specialist should be obtained in FE analysis modelling where the behaviour of soil/foundation materials was being modelled in order to obtain accurate results.
208. In respect of his relevant experience, it was clear that he had little experience dealing with the type of work about which his opinion was sought. When asked about relevant experience, he said:

"Part of being an expert witness is putting yourself in the shoes of an expert designer. I'm not sure if I should say this but I am almost of the view that it is a benefit that I am not the best designer as it gives me a better view of what the reasonably competent designer should do."

In some cases, this may enhance the value of an expert's opinion. However, I do not find this to be the case for Mr Barham. In my judgment, there is a material difference between an expert professional and a professional expert.

209. Further, he accepted that he had not discussed the central issue of whether the Defendant's design was one that a reasonably competent body of engineers would not produce "in those terms". Throughout his evidence both written and oral, he made references to the "reasonableness" of the Defendant's approach rather than expressing his view when criticising the Defendant that there was not a reasonably competent body of engineers who would have done what the Defendant did.
210. In the light of all of his answers, I am not satisfied that Mr Barham applied properly or adequately the legal test for the issues on which he was providing an opinion. For example, in the Joint Statement, he agreed that the Defendant's use of the E600 load class was appropriate. He then changed his mind and said that the Defendant should have used the F900 load class when designing. When questioned about whether no reasonably competent engineer would have selected the E600 class in order to make calculations and design decisions about the installation of the Gatic slot drain, he described the issue as "finely balanced". His approach, in my judgment, demonstrated that he was not asking himself the right question, that is whether no reasonably competent engineer would have selected the E600 class. In my judgment, that lack of asking the correct question pervaded the entirety of his evidence.
211. In contrast, I did find the evidence given by Mr Rushton to be reliable. I accept immediately that Mr Rushton did change his evidence in relation to the MCT. Once the witnesses of fact agreed that it was never part of the design that an MCT would be formed at the joint between concrete pavements and the Gatic slot drain concrete surround, Mr Rushton had to reconsider his evidence. It is fair to say that Mr Rushton was somewhat evasive and did not initially answer the question directly when it was put to him that from his summary of conclusions and considering his reports as a whole, his view was that an MCT was required in order to make the Defendant's design work.
212. Initially, Mr Rushton maintained that the Defendant had showed an MCT on another drawing and therefore it was a reasonable assumption that the constructor would choose the simplest and easiest solution of an MCT rather than choosing to compact the ground when achieving the appropriate level of compaction by hand would be difficult. However, he did in the end accept that the MCT was not shown on the drawing for this joint and that the parties did not consider that an MCT was part of the design for this joint.
213. I do not accept the Claimant's submission that Mr Rushton was dishonest nor do I find that he was trying to mislead the court. I do not accept the submissions made by Mr Sage in this regard. The submissions are beautifully crafted to seek to persuade me that Mr Rushton's evidence was always that an MCT was necessary. I do not accept that to have been the evidence of Mr Rushton when his oral and written evidence as a whole is considered.
214. Whilst perhaps the joint statement could have been more clearly worded in respect of this issue, I accept the evidence given orally by Mr Rushton that an MCT was needed if adequate compaction of materials underneath the joints could not be achieved. In his initial report at paragraph 8.4, Mr Rushton made it clear that the failure to use an MCT under the joint "introduced the workmanship risk of poor compaction under the slab edge at the joint and settlement that would increase the load in the dowels their design being based on a sharing of load assuming the ground is stiff" (emphasis added).
215. Both Mr Barham and Mr Rushton changed various areas of their evidence through the process of discussion and responding to each other. Although I accept that a design has to be buildable and that Mr Rushton did state that his opinion was that compaction would not easily be achieved, eventually being pushed to say he thought it was unlikely it would be achieved by hand, that was not the view of Mr Barham. Mr Barham thought hand compaction to be achievable.
216. Aside from the fact that the absence of an MCT was not pleaded as a specific allegation of breach of duty, Mr Barham did not assert that the absence of an MCT was part of any deficiency in the Defendant's final design.
217. Aside from the attacks on Mr Rushton as a result of the MCT issue, in my judgment, Mr Rushton was the expert who had plainly considered his duty under CPR 35 and had gone out of his way to help the Court on matters within his expertise. His reports provided detailed analysis and explanation of the processes which the Defendant appeared to have undertaken and the final design for the business Park from the outset. He explained elements of the design and performed hand calculations of the various factors which would influence the design in the same way that an ordinary engineer faced with a design of this sort would in practice. When issues were raised by Mr Barham from his high level first principles analysis, Mr Rushton crunched the numbers and responded with detailed explanation. He built an extremely helpful scale model of the joint and a scaled wheel to interact with it to enable the court to see more easily the various elements comprised in the joint.
218. I recognise that a comparison of Curriculum Vitae is not always helpful. However, in this instance in my judgment it is. The vast majority of Mr Barham's work has focused on forensic engineering and dispute resolution for all sorts of different projects, Mr Rushton's experience includes forensic work but also engineering publications and most importantly extensive experience in the practical design of structures. These include involvement in the rebuilding of roads and services infrastructure at Southampton airport, which project won numerous industry awards. He was also involved in the provision of a new air cargo handling facility at Heathrow airport. The design issues and the dispute in this case in my judgment involve the sorts of design conundrums which would inevitably have been faced on those projects. Having real-world experience of issues such as these in my judgment lends credibility to Mr Rushton's analysis of the design issues and his conclusion that the design works.
219. For all of the above reasons, I do not accept the opinion of Mr Barham unless it was in accordance with the opinion of Mr Rushton or was such that his opinion undermined the Claimant's case.

Findings

What was the damage to the container yard in December 2017?

220. As demonstrated by the numerous photographs, as well as the oral evidence of the lay witnesses, damage to the concrete surround and the joints adjacent to the concrete surround of the Gatic slot drain became apparent almost immediately after practical completion in August 2017 and continued developing until at least December 2017. In December 2017, all three of the Gatic slot drains in the container yard were suffering from deterioration and damage, with cracking of the Gatic slot in concrete surrounds and cracking in the some other concrete slabs. The photographs demonstrated different problems in different locations.
221. In various photographs taken during the initial construction of the Gatic slot drains, dowels could be seen to have been installed at the wrong level and at the wrong angle. It was clear that some dowels were missing. Some dowels were obviously very bent having been installed in the concrete surround before the adjacent concrete slabs not yet constructed.
222. In some photographs, the concrete surround showed some relatively minimal damage and cracking whilst the adjacent concrete slab showed significant cracking and concrete breakdown immediately adjacent to that area of the concrete surround. In other photographs, there appeared to be significantly more damage to the Gatic slot drain concrete surround itself with cracks and general concrete deterioration, but the adjacent concrete slabs were largely unaffected. In some photographs, there was significant cracking and deterioration across the concrete slabs themselves which did not appear to be related to the Gatic slot drain concrete surrounds. In addition, there was cracking and disrepair apparent in some areas surrounding other metalwork, such as an inspection cover close to a joint between two concrete slabs.
223. Differential settlement was shown on the photographs to be taking place between the concrete slabs and the concrete surround of the Gatic slot drain to differing levels in excess of what was designed. The drain and concrete surround were settling into the ground compared with the adjacent concrete slab.
224. When cores were taken to investigate the unexpected damage, there was evidence of missing mesh in various locations. Whilst the experts disagreed as to the evidence about whether top mesh reinforcement was omitted, I prefer the evidence of Mr Rushton that the damage indicated it probably was missing, at least in some locations. In addition, there was evidence of poor compaction in the areas surrounding the Gatic slot drains, of bent and incorrectly placed dowels and voids under dowels where concrete should have been. In various areas, the concrete installed was not of the correct depth.

Were there construction errors and, if so, did the construction errors cause or contribute to any of the damage identified to the container yard by December 2017?

225. In my judgment, all of the damage identified by December 2017 was caused by construction errors. Dowels of the wrong size were installed. The dowels were installed at the wrong depth in the concrete and at the wrong angle. Some dowels were bent. Some dowels were missing. The experts agreed that those were all detrimental changes.
226. There was damage to concrete slabs at joints between two concrete slabs where no criticism was made of that aspect of the design by the experts. Reinforcement mesh was not installed in accordance with the design. Where it was missing from the base of the Gatic slot drains concrete surround, that was a detrimental change. Where it was missing from the top of the Gatic slot drain concrete surround, that was a detrimental change. In some areas, side reinforcement mesh was added to the Gatic slot drains concrete surround, that was a beneficial change. Despite that, damage still occurred in those areas where side mesh had been installed.
227. In respect of the differential settlement identified, Mr Barham accepted that as a result of the "stupid clay", that settlement would not have been caused by the design by December 2017. It must therefore have been caused by workmanship issues.

Was the Defendant's design for the slot drains in the container yard negligent or in breach of contract?

228. In short, I do not find that the Defendant's design was negligent or in breach of contract. That is not to say that errors were not made in the design process and in some of the assumptions made by the Defendant as the design developed. Some of the earlier drawings had errors, as Mr Roys acknowledged. However, as those errors were corrected before work commenced on site, those errors cannot have caused the damage of which complaint is made.
229. I do not accept Mr Barham's evidence that the load assessment undertaken by the Defendant was inadequate. I reject his criticisms of the February and March 2017 calculations because I find that he did not consider adequately the purpose and function of those calculations. I prefer the evidence of Mr Rushton in respect of the adequacy of the dowels. I accept the evidence of Mr Roys that other calculations as to load transfer had been undertaken, even if those calculations were not available to the court. Whilst I accept (as Mr Rushton confirmed) that the March 2017 calculation done by Mr Roys to check the dowels was an approximation, I accept Mr Rushton's evidence that the 32mm diameter dowels and the design and instructions for the installation of those dowels was adequate to transfer loads across the Gatic slot drain surrounds.
230. Criticism was also made by the Claimant as the experts agreed that the Defendant failed to give proper thought as to how load would transfer across the joint. Dowels were not initially part of the design. When dowels were put into the design, the dowels in the design were too small. In the early design, reinforcement mesh was not specified in the sides or bottom of any of the slot drains. Assumptions made by the Defendant about load transfer were wrong. The difficulty, however, is that although incorrect assumptions and other errors were made, I accept the evidence of Mr Rushton and find that the final design provided before construction began in fact worked.
231. In relation to whether E600 or F900 should have been used, again I prefer the evidence of Mr Rushton. In particular, I accept the submission made by Miss Laney that as Mr Barham had initially agreed that the use of E600 was appropriate, and that the issue was finely balanced, it is unrealistic to hope to establish that E600 could not have been used by a body of reasonably competent engineers. The same point can be made in respect of the Claimant's reliance on Mr Rushton's view that compaction by hand underneath the Gatic slot drain was not realistically buildable. Mr Barham's evidence was that compaction was achievable. I do not therefore accept that the MCT must have been part of the design when a body of reasonable engineers would have considered hand compaction underneath the Gatic slot drain to be achievable.
232. I do not accept that the Claimant has established that the Defendant's design is one which a body of reasonably competent engineers could not have produced. No alternative design was proffered to show what should have been designed. The Claimant's case relied upon criticism of the design produced by the Defendant by Mr Barham. For the reasons already given, I do not accept Mr Barham's evidence establishes negligence or breach of contract by the Defendant.

If the Defendant's design was negligent or in breach of contract, did that negligence or breach of contract cause any of the damage identified to the container yard?

233. Even if I am mistaken and the Defendant's design was negligent, in breach of contract or both, I do not accept that any breach caused the damage to the container yard. The initial evidence of Mr Barham on causation was minimal, addressing solely use of the wrong size dowels. I prefer the calculations performed by Mr Rushton and his evidence about the realistic loads and adjustment to loads taking into account reductions of loading for wheel position.
234. Whilst criticism was made of Mr Rushton for changing the number of dowels engaged in his calculation from 10 to 12, I do not accept that criticism is justified. I accept the evidence of Mr Rushton that what he was considering was how many of the 32mm dowels were in fact engaged when performing his calculations. Whilst 10 dowels was originally used because that was the figure drawn from the guidance in TR34, I accept Mr Rushton's explanation that having considered some of the criticisms and conclusions of Mr Barham, further calculation was necessary in order to check the worst case scenario in circumstances where a pair of wheels of a reach stacker were wholly on the Gatic slot drain concrete surround. Having done that calculation, 12 and not 10 dowels would be actively engaged and therefore 32mm dowels were adequate to transfer the load.
235. Further, I do not accept that Mr Barham's use of FE analysis provided adequate support to his assertion that the Defendant's design did not allow for adequate load transfer across the Gatic slot drain concrete surround. He used out of date guidance. He accepted that various criticisms of his FE analysis, as made by Mr Rushton, were not only justified but sufficient to make him change the inputs for the FE analysis over the weekend before trial. However, he did not then provide the outputs generated. I accept the submission made by Ms Laney that the use of Winkler springs in the linear model provided an entirely artificial output. Various other criticisms of the FE analysis were validly made, including that both experts agreed that it required calibration to assess the validity of its outputs and Mr Barham accepted that some of the outputs were obviously wrong. In those circumstances, I do not consider the FE analysis outputs provided to the court to be reliable or of evidential value.
236. In any event, and in my view determinatively, Mr Barham's view when giving oral evidence was that the December 2017 damage could not be due to design because there would have been insufficient time for any settlement of the "stupid clay". I accept the submission made by Ms Laney that when he expressed opinions in his written reports, Mr Barham had not considered the question of when the damage had manifested. Even if the design was defective, it did not cause the damage and thus was not cause of the necessity for remedial works.
237. Further and in any event, I accept the evidence of Mr Harris that following the remedial works, there was no complaint that there was further cracking around the slot drains or to the container yard when the originally detailed 32mm diameter dowels had been used. Whilst I accept that the remedial works did not just consist of replacement 32mm dowels, the fact that there is no evidence of any further or additional deterioration after remedial works tends to support the Defendant's assertion that the 32mm dowels specified worked.

Quantum.

238. It is not necessary to consider quantum as the claim has failed.
239. For all of the above reasons, the Claimant's claim is dismissed.
240. I am grateful to counsel for their very able assistance in this matter.