A third bolt has fractured at the Leadenhall Building, popularly known as the Cheesegrater, British Land has reported.
In an update, British Land said a third bolt fractured recently and was “captured by precautionary tethering put in place last year”.
In November, the real estate group reported that two steel bolts had broken, with part of one of them falling to the ground.
The update said investigations by the building’s contractor Laing O’Rourke and structural engineer Arup had been completed and confirmed “that the problem is limited to certain bolts”.
Work to replace “a number of bolts” will now take place “as a precautionary measure”, British Land said.
It said laboratory tests revealed the bolts had fractured “due to a material failure mechanism called hydrogen embrittlement”, which it described as a “crack growth mechanism within the bolt material”.
The update came as British Land announced the Cheesegrater’s architects Rogers Stirk Harbour + Partners had signed a 15-year lease for level 14 of the building.
British Land said Arup had confirmed there was “no adverse effect on the structural integrity of the building”.