Manchester City Council issued proceedings against Thomas Heatherwick Studio and its subcontractors Packman Lucas, Flint & Neill, and Westbury Structures for negligence and failure to meet their contract, following a series of failures on the sculpture.
The 56m high structure stands next to the City of Manchester Stadium and consists of 180 spikes, the longest 35m and the shortest 2.5m. Each spike is bolted and then welded to the central core mounted on five converging legs.
Twelve of the spikes have had to be removed over the last two years for testing or as precautionary measure on public safety grounds after defects were discovered.
The first spike fell off the £1.4M sculpture in January 2005, two weeks before it was unveiled.
Preliminary laboratory investigations suggested that the spike had failed in a circumferential weld region and site investigations showed that the potential problem affected 53 of the 180 spikes. The design team also monitored the movement of the spikes to confirm that their behaviour was as predicted by calculations.
Based on investigations by Arup, Manchester City Council estimates remedial works will cost up to £2M.
Consultant Flint & Neill undertook structural design checks and acted as specialist wind consultant during construction.
The firm has released a statement claiming that it had offered every assistance to Manchester City Council to resolve difficulties which were not of its making.
However, the council claims the design team has been too slow to provide a solution.
"I want to emphasise the Council's commitment to securing a structurally sound and viable B of the Bang on this site," said Manchester City Council chief executive Howard Bernstein. "The project has taken too long to bring forward. Our forbearance has now been tested to the full."
Papers were lodged in court last week and a hearing is expected to be set for a date in 2008.
Thomas Heatherwick Studio, Packman Lucas and Westbury Structures were unable to comment as NCE went to press
March 2002 Heatherwick Studio chosen to design, construct and install a major piece of public art by Manchester City Stadium to commemorate the Commonwealth games.
January 2005 One part of the structure becomes detached and had to be repaired.
May 2005 A second spike exhibits defects and has to be removed.
September 2007 A further spike exhibits defects and is removed. Nine other spikes are removed for testing as a precautionary measure.