Minneapolis Bridge Collapse: Investigations focus on Construction
The investigation continues into what exactly caused the collapse of the Minneapolis Bridge on August 1st 2007. The most recent factor to enter the ongoing analysis was raised on Wednesday 8th, when the National Transportation Safety Board announced it had discovered a possible weakness in the bridge's construction. This, the board specified, could be in respect of the gusset plates (responsible for holding together steel beams), which it thinks could have been incorrectly designed.
Following this revelation, the Federal Highway Administration's J. Richard Capka confirmed that an urgent and nationwide announcement would result, should a general issue in respect of gusset plates subsequently be identified. He added to this that no such warning was anticipated at this date. "Gusset plates have been around a long time, and they've been a reliable feature, and we have no indication that they've ever been part of a suspect bridge problem or a bridge failure before", said Capka, on the 9th August. He added: "They have not concluded that they've discovered anything specific that might have contributed to the collapse."
Meanwhile Mary Peters, the US Transportation Secretary, has highlighted the extra stress bridges are placed under when construction programmes, such as that at Minneapolis, are in progress. At the time of the August 1st tragedy, in which six fatalities and approximately 100 injuries ensued, 18 workmen were in situ. Speaking on Wednesday, Ms Peters stated: "Given the questions being raised by the NTSB, it is vital that states remain mindful of the extra weight construction projects place on bridges".
Also on Wednesday, the National Transportation Safety Board drew attention to aerial assessments of the bridge, post-collapse, which showed multiple "tensile fractures" at its Northern end. However, neither these, nor any other information gathered, the board added, seemed to indicate the origin of the collapse.
Another possibility being scrutinised at the present time has emanated in respect of Progressive Contractors Inc. - the company working on the bridge. One worker, it is alleged, reported the bridge swaying in an unusual motion prior to August 1st. However, the situation has been rejected by the firm, which, in a statement, said: "We have now met with every single worker who was on the bridge when it collapsed... None of them observed or reported any unusual swaying."
Source - Construction International's US Reporter
