The cost of replacing 3,000 ‘mega-bolts’ on Rogers Stirk Harbour + Partners’ Leadenhall Building could reach £6million, according to new estimates
Steel contractor Severfield has already carried out £1million worth of ‘precautionary’ remedial work replacing the skyscraper’s bolts, three of which have fractured since November 2014.
However, it has said further work in conjuction with developer British Land, as well as Laing O’Rourke and Arup could now cost an extra £5million and take until the end of the year to complete.
Chief executive Ian Lawson said discussions between the building’s project teams have so far failed to reach agreement on where the liability for the costs should lie.
Lawson told the AJ’s sister title Construction News: ‘The importance is about making a solution and getting on with the remedial work required . All parties have got on with that work and we are bearing our costs.
‘In terms of where the liabilities lie, those discussions are ongoing.’
In January this year, British Land reported a third bolt had fallen from the 238m-high building, dubbed the Cheesegrater. However the steel bolt, described as the size of a human arm, had been caught by precautionary tethering put in place when two similar components broke in late 2014.
According to laboratory tests, the bolts fractured ‘due to a material failure mechanism called hydrogen embrittlement’, which caused a ‘crack growth mechanism’ to develop within the bolts.
Lawson said: ‘The Leadenhall building is particular and unusual and the bolts used are specific for this building and unfortunately, they have become susceptible to hydrogen brittlement.
‘Although this was evidence in a small number of the bolts, all parties agree that it is sensible to change the bolts, so that is what we are doing.’
It is not the first problem Severfield has encountered over its Cheesegrater contract; in 2013, the steel contractor announced it had lost £10m on the project after a contract overrun.
Despite these issues, Severfield revealed a turnaround in its finacial fortune, announcing a pre-tax profit of £144,000 for the year ending 31 March 2015.
Last year, the company suffered losses of £2.6m before tax over the same period.
This recovery was helped by new contracts, including Manchester’s Ordsall Chord link bridge and Liverpool FC’s Anfield stadium. Its total order book was valued at £194m.
Mr Lawson said: “We are very pleased with the continued good progress made across the business, both in the UK and India, operationally and financially.
“Margin improvement is being sustained, we have a very solid order book and pipeline and we are particularly pleased that we have recommended the reintroduction of a final dividend.”
He told Construction News that the key to this turnaround had been “discipline in processes, management of risk, empowerment of our people and good honest hard work.”
Cheesegrater bolt replacement could cost £6m