The UK’s largest structural steel provider, Severfield, is facing a bill of around £1 million for replacing the two massive bolts that broke and fell from London’s iconic ‘Cheesegrater’ skyscraper last November.
The news came in a trading update, which the company used to reveal the costs it has so far incurred for a programme to examine and replace the bolts on the building, which was designed by Richard Rogers and stands at 737ft high.
At the time of the incident, co-developer, British Land reported that an investigation with Laing O’Rourke and structural engineers Arup had begun. According to Severfield, this is now expected to last until the end of this year, and the company – which provided 18,000 tonnes of steel for the Cheesegrater – is in talks to work out where liability for the bolt replacement programme lies.
It is understood that one of the bolts fell from the 15th floor to the ground, while another fell from a lower level but stayed within the distinctive sloped building’s framework.
In January, British Land said that a third bolt had broken, but was caught by ‘precautionary tethering’ which was installed on the building after the earlier incidents.
The loss of the bolts – which connect the building’s nodes to its megaframe and are described as being the size of a human arm – did not affect the building’s structural integrity.
They were found to have fractured because of a process known as ‘hydrogen embrittlement’. This is where hydrogen atoms diffuse into a substance and combine to create internal pressure.
Severfield went on to reassure investors that the costs incurred “are seen as exceptional and should not affect underlying profitability for the current year”.