An area at the base of the 225-metre London skyscraper dubbed the Cheesegrater had to be cordoned off to pedestrians in November, after it was revealed that two of metal bolts had shattered and that some parts had fallen to the ground.
British Land has now revealed that a third bolt on the Rogers Stirk Harbour + Partners building "fractured recently" and was discovered using a warning system known as "precautionary tethering". A number of bolts will now be replaced as a precautionary measure.
Contractor Laing O'Rourke and structural engineers Arup carried out an investigation of the building after the first two broken components were discovered and found that the problem is limited to certain bolts.
"The tests concluded that the bolts had fractured due to a material failure mechanism called Hydrogen Embrittlement. This is a crack growth mechanism within the bolt material," said British Land in a statement.
According to the developer, the bolts will have no adverse effect on the structural integrity of the building.
The news comes the same day that Richard Rogers' firm – whose best-known projects include the Lloyds Building and the Centre Pompidou – has confirmed it will move out of its current home in west London to open a new office on level 14 of the 47-storey tower.
"After 30 years at Thames Wharf Studios, it is important for us to be moving into a building that reflects the ethos and evolution of our design practice, clearly stated in its urban relationship with the Lloyd's building opposite," said the practice directors.
"We will begin this new phase of our history in a building that already feels like home but allows us the advantages of a contemporary, flexible office space in a prime location in the increasingly vibrant and exciting City of London."
The Leandenhall Building officially opened in September and is the tallest structure in the City of London. It earned the nickname the Cheesegrater in reference to its distinctive tapered shape, which was designed to preserve views of St Paul's Cathedral.