“It was expert advice that this figure [the 35 kilograms per cubic metre fibre figure that Stuarts was said to be using] was not reliable and needed to be verified. Fibre content had now become a critical factor that affected the area of concrete that needed to be removed relating to the edge condition as well as the actual capacity of the floor. This verification could be done by examining the actual fibre content and samples of concrete from the floor. If the fibre content was lower than 35 kilograms per cubic metre then this would change the analysis above and more floor may need to be removed.”
“The results were presented to BSP [the remedial works consulting engineer] on 14th March. BSP then re-analysed the floor using the new data to see whether the lower fibre content would satisfy the floor loading of 70 kilonewton racking leg load for the intended thickness of the 150 millimetres. The results were reported on 15th and 16th March that the lower fibre content would not meet 70 kilonewton racking leg load and that the leg load would have to be downgraded to 55 kilonewtons.”
“Fibre content and thickness are critical parameters in an SFRC floor. To meet design loads, the designer will select a concrete strength, floor thickness and fibre dosage that would produce the least cost design. In this case, the floor was assumed to be designed to have 35 kilogram per cubic metre fibre and 150 millimetre thickness.”
“Reduction in the thickness of the floor or the fibre content or both due to poor workmanship or control onsite will reduce the structural capacity on the floor. At Swift Valley, Stuarts has contrived to produce a floor that has a variable thickness, with some areas reduced to 70 millimetres as a result of deleterious materials left beneath the polythene separation membrane. The floor has never seen, as far as we are aware, the intended racking leg load of 70 kilonewtons, which would require five levels of racking stacked with 1.4 tonne Euro-pallets either side of the central frame back to back. This type of loading was not used by Woolworths but could happen with a future tenant for any recording [...]”
“There remains a high probability that the floor could fail in service due to undetected thin areas beneath or adjacent to racking legs irrespective of the fibre content. Confirmation that the fibre content is also low and below what would be needed in a design of compliant 150 millimetre thickness is also reason to condemn the floor. In Swift Valley, we have both situations.”
“I regret to have to be the bearer of such bad news and appreciate the Co-op’s frustrations with the development. As I set out above, this is an unusual situation with an expert (inaudible) and reconstruction occurring in parallel. We have been doing all we could to reduce the cost of slab replacement. If there is a failing in our approach, it has been to fail to grasp sufficiently early that Stuarts produced a rogue floor that is well below the high standing that they have in the SFRC flooring community. The Co-op should have followed the advice I gave in January 2012 that the variability and thickness was in itself sufficient to condemn the floor anyway.”
“Had the fibre content been correct then, the original spec was for a leg load of 70 kilonewtons. The repaired floor would have supported a leg load of 70 kilonewtons [...] Now we know the fibre content is not correct then, before the floor was repaired it would be susceptible to ongoing deterioration and in places not have been suitable for, say, 30 kilonewtons per leg. In reality, it would have just become unusable in the short period of time just from trafficking. If the repairs are completed, the evidence we have of the existing floor suggests that it will support 55 kilonewton leg load. This may well be acceptable for a company such as DHL. However, I cannot comment on any one company’s individual requirements without more knowledge of their operation.”
“The engineering advice is that the slabs have failed and they can justify replacement. There remains some risk of floor puncturing even with the works done so far, but it depends on future use and future tenants will need to be clear on the bearing capacity which, as advised, is still not unreasonable. Existing racking appears to be limited to 50 kNs.”
“The expenditure of further sums to replace the internal slabs of both warehouses was approved by the capital committee as set out in the email of 31st May and then referred to the board chairs committee in order to expedite approval to minimise delay to the works onsite. This final approval was obtained on 20th June.”
“Moira, you will recall I presented and gained approval for the additional flooring works for the rugby RDC at the last capcom. This now needs the board’s approval and is scheduled to go to the 20th June meeting. Would you be in agreement to this paper going to chairs committee for earlier signoff, the key reason being that this will allow work to continue on site and minimise the delay in re-letting the premises? We are suing the original contractor for both cost of repairs and our loss of rental earnings, and this would also help as part of our attempt to be seen to mitigate our losses.”
“Len is happy to deal with by chairs committee if you [let] me have paper. I’ll issue or, if next week, send to Pat Wade.”
“Can you convert the Rugby capcom paper to board for chairs committee and send tomorrow?”
“The central and consistent concern which operated on the mind of the Co-op and its advisors, principally Professor Peter Rowberry, was whether the thickness of the warehouse floors were such as to be capable of reasonably satisfying the specification and/or reasonably satisfying a range of needs of possible tenants based upon the specification. It was only because of increasing concerns over the thickness of the warehouse floors that separate considerations arose as to the true level of fibre within the concrete. Co-op and/or its experts would never have gone down the route of looking at the question of actual fibre content used in the floors if the thickness of the floors had been judged to be reasonably adequate. Moreover, if the thickness of the warehouse floors had been in the order of 135 millimetres and if the general level of workmanship had been adequate then there would have been no question in the view of Professor Rowberry and/or in the mind of the Co-op of replacing the floors. The problems with the thickness of the warehouse floors taken together with the mounting evidence of exceptionally poor workmanship in the construction of the warehouse floors were the cause of the decision to replace the whole of the warehouse floors.”
“It is inevitably a matter of conjecture as to whether, absent the discovery of steel fibre issues, the decision would have been taken to replace the slabs. The final decision was not taken until the steel fibre issue was known.”
“Although the issue of steel fibre cannot be artificially separated from the history of events leading up to the decision to replace the slabs, the Co-op will seek to prove at trial that: (a) but for the thickness issues, the steel fibre issue would not have been discovered; (b) but for the thickness issues, the steel fibre issue would not have required the replacement of the slabs; (c) but for the steel fibre issue, the replacement of the slabs may have been required.”
“In the circumstances, it will be for the court to determine, on considering all of the evidence, what the relative importance of steel fibre and slab thickness was in the decision making process and whether the Co-op will be entitled to recover all, some or none of the costs of the replacement works.”
“Although the inadequate levels were not causative of any structural failure the defendant’s failure to achieve a slab which was sufficiently level was a further instance of very poor workmanship which, together with other instances of poor workmanship, diminished confidence in the quality of construction of the existing slab overall.”
“The slab, as constructed by the defendant, is not of sufficient thickness to reliably and over the life of the floor deal with the load duty called for by clause 2.08 contained within the employers’ requirements.”