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Assessing responsibility for the Gerrards Cross collapse

I am in total agreement with Mike Franklin’s letter in the August edition of NCE pertaining to the collapse of the arch during construction at the Gerrards Cross rail tunnel.

The preparation and presentation of a method statement for back filling the arch would have been provided by the contractor.

However, this does not in any way minimise culpability for the collapse provided the works were being constructed in accordance with the method statement.

The consultant is not without blame. The client has, in good faith, commissioned a competent consultant to design the structure.

When the tenders were returned, presumably the design consultant produced a report making recommendations based not just on the tender price, but also on the suitability of the contractors based on their track record for constructing similar works.

In general it is the norm for clients to favour the lowest bidder. However, herein lies the root of a host of problems. The lowest bid will almost certainly bring forth a host of claims throughout the contract in order to generate the desired profit margin that the group requires to stay in business.

The highest bidder usually, but not always, has “taken a punt” and if it pays off, secures a handsome profit at the end of the contract.

It is my experience that the contractor whose tender price is nearest the engineer’s estimate is more than likely to be on the right track.

Europe has a more pragmatic way of selecting the contractor. Usually, but not always, they disregard the lowest and highest bidders, average the price of the remaining bids and award the contract to the one nearest the engineer’s estimate.

Clients also have a responsibility when appointing construction supervision. The best bet is to employ the consultants responsible for the design to supervise the construction. They have detailed knowledge of how the structure will behave during construction.

I have no knowledge of the tender returns or how the contractor was chosen and I am sure that all normal procedure and protocols were followed. However, the structure collapsed and fortunately there were no fatalities.

Mario Donnetti (F), mariodonnetti@gmail.com

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