CONNECTION FAILURE is suspected to have made one of the 175 steel spikes fall from Manchester's landmark 'B of the Bang' sculpture last year, it emerged this week.
The news came as the project's designers confirmed that they had pulled it from the NCE-backed British Construction Industry Awards.
Engineers were this week examining the £1.4M, 55m high weathered steel structure, to determine why it lost one of its steel spikes last December.
B of the Bang comprises an array of steel spikes up to 7m long. They protrude from a tightly packed nucleus, and the prickly 165t mass is canted over at 30 degrees from the vertical, supported on five legs (NCE 26 February 2004).
A second spike came loose in April but did not fall off. This was found to have a weak point at the bolted connection between the outer end of the spike and the structural core.
This connection is made up of 12 bolts wrapped in a welded plate.
The sculpture's designer, Thomas Heatherwick Studio, confirmed that wind loading did not exceed the design capacity and the investigation is concentrating on why the structure did not behave as expected.
These complications led to the project's withdrawal from the BCI Awards. It had been shortlisted for the 'small civil engineering project' award.
'We have pulled out of the awards because work is ongoing at the site. There are bound to be teething problems with any new structure that pushes the limits of what has been done previously, ' said Thomas Heatherwick studio project manager Sally Cohen.
Engineers have been on site fi ting dampers inside each of the spikes to minimise wind induced movement.
'We are now investigating whether this will be enough to ensure the long term integrity of the structure, ' said Cohen.
The project will not be formally handed over to client Manchester City Council until the investigation and remedial works are completed.