British Ports engaged Hydro Soil Services to carry out strengthening works to quay wall 205 at Southampton. The contract was a lump sum contract based on the ICE conditions as amended. Hydro in turn engaged Haecon NV to carry out the design of the strengthening works to the quay wall. The design required ground anchors to be attached to the steel wall, and also the insertion of high pressure vertical grout columns along the berth.
While the work was being carried out the sheet piles cracked and bulged. In some places the bulging was almost a metre from the original installed position. Remedial work was clearly needed.
British Ports claimed damages for the breach of contract, and the contractor brought a counter claim under clause 12 for unforeseen physical conditions. In addition, a claim was made against Haecon for their design. British Ports argued that the works were not fit for their purpose and that Hydro should pay for all rectification of work.
Was the contractor responsible for the defects, and were the defects a result of the workmanship or design?
Based upon expert evidence it was held that the existing condition of the sheet piling wall did not account for the widespread bulging and cracking that had taken place during the grouting. The potential over stressing of the sheet pile wall is something that an experienced contractor should have seen, and therefore the clause 12 claim failed.
The spacing of the columns was greater than the design spacing and there was insufficient sheer strength of the grout wall. As a result the works were unfit for their purpose.
In respect of liability for workmanship or design, it was held that the design of the columns was unfit for their purpose. The original design spacing could not be adhered to, and the revised greater spacing had been designed by Haecon, and once again that matter was therefore an issue of design. Much of the workmanship falls within acceptable tolerances, and so design should have taken that into account such that the final design should have catered for potential variance of acceptable workmanship tolerances. The only issue arising from workmanship was the decreased diameter of the columns, which was simply bad workmanship.
*Fuil case details
Associated British Ports vs Hydro Soil Services NV and Dredging International (UK) Limited and Haecon NV Others,  EWHC 1187 (TCC) HHJ Havery QC
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In Mirant v Ove Arup we saw that the court found that an engineer had a duty to warn irrespective of assumptions that were made during the design of the foundation. In this case, much of the liability once again is that of the engineer and many of these professional negligence liability cases turn upon their particular facts. However, note that in this case the design had not taken into account the potential tolerances that might occur once the work was carried out, and a failure to take those tolerances into account when putting together a final design was negligent.
An engineering designer therefore needs not only to warn their clients about all assumptions made, but also must take into account construction tolerances in respect of every aspect of their final complete design.