DEMOLITION OF a wind damaged 1960s concrete chimney was expected to be advanced enough for 300 London families to return home this weekend, council officials said on Monday.
Wind loading from tough protective sheeting fixed to full height scaffolding around the 24m high chimney in Camden, north London is blamed for the structure's near catastrophic failure. This occurred during violent wind storms on Sunday 3 November.
The scaffolding had been erected before the storm, ahead of programmed repair work.
'It was designed to protect the public from falling concrete spalling off the chimney, which is suffering from carbonation and reinforcement corrosion, ' said Camden Borough Council head of building control Pascal O'Neil.
'The chimney ultimately failed in bending about 7m from the top, but was prevented by the scaffolding from collapsing completely.'
Camden evacuated local residents before calling in its emergency contractor Costain.
As an immediate safety precaution, the chimney was tied back to another existing scaffolding around a nearby five story block of flats.
Kentledge was lifted onto the roof and props installed to stabilise the chimney.
'Then the priority was to remove the sheeting in case of high winds reoccurring, ' O'Neil explained.
An operative in a safety cage suspended from a crane dismantled the buckled scaffolding from the top down.
With the eccentric loading reduced, a separate scaffold was erected around the original structure.
By Monday this week around 4m of the chimney's precast outer skin and reinforced insitu annulus had been cut down, leaving the steel liner exposed.
'Once the residents are home, the next problem is getting heating back on, ' O'Neil said. 'This was the chimney to a district heating scheme, and until it's replaced we'll have to find a temporary alternative.'