A third bolt has broken on the Cheesegrater skyscraper in the City of London.
British Land, which owns the 47-storey Cheesegrater with Oxford Properties, said it made the discovery during investigations into the fracturing of two bolts on the tower in November.
One of the broken bolts on the 225m tall Leadenhall Building – its official name – fell to the ground, and the surrounding area was cordoned off from pedestrians.
The third fractured bolt was captured by precautionary tethering put in place during November, British Land said.
The investigations were carried out by by contractor Laing O’Rourke and structural engineer Arup and have now been completed.
“These confirm that the problem is limited to certain bolts,” said British Land. “Arup has also confirmed that there is no adverse effect on the structural integrity of the building. A programme to replace a number of bolts will take place as a precautionary measure.”
The investigations included site and laboratory testing of both the broken bolts and additional bolts on the building.
“The tests concluded that the bolts had fractured due to a material failure mechanism called Hydrogen Embrittlement,” said British Land. “This is a crack growth mechanism within the bolt material.
“As the problem has been identified and is being rectified no further update is scheduled.”
The Leadenhall Building is the fifth tallest building in London.
Construction of the skyscraper was completed earlier this year.