18 March 2008

CSS GOES BACK TO BASICS WITH LESSONS IN STRUCTURAL FAILURE

CSS has urged the 200 delegates at the Bridges 2008; Back to Basics conference that they must learn from the mistakes of the Mississippi bridge collapse of August 2007 in the US state of Minnesota.

Richard Fish, Chairman of the CSS Bridges Group and chair of the UK Bridges Board (which incorporates all UK bridge owners), told the local authority bridge engineers and consultants working on their behalf that they need to take on board all aspects of structural failure when designing a bridge and mapping out its maintenance schedule.

He quoted the words of American philosopher George Santayana, who said: “Those who do not learn from history are doomed to repeat it.”

The conference, organised by Surveyor magazine in collaboration with the CSS, tackled the fundamental issues facing bridge engineers and managers in maintaining a ‘safe for use’ and ‘fit for purpose’ bridge network.

Mr Fish told delegates that there had been 10 major bridge failures in the world from July 2006 to December 2007, with eight of them in the last five months of 2007.

And he quoted from the American Association of State Highway and Transportation Officials statement earlier this year which said that although the investigation into the Mississippi bridge disaster was not yet complete “….the original design process of the I-35W bridge led to a serious error in sizing some of the gusset plates in the main truss.” That apparently resulted in gussets that “were roughly half of the thickness required and too thin to provide the margin of safety expected in a properly designed bridge.”

Mr Fish, who has more than 25 years’ experience in bridge design, maintenance and construction, said: “A collapse of this type was a huge shock. It was a wake-up call to owners across the world that bridges are a vital but vulnerable part of our transportation networks and must be regularly inspected and maintained if they are expected to last their design life under modern traffic loading.

“While a similar type of failure is highly unlikely in the UK, no bridge owner can afford to be complacent and must ensure that appropriate management regimes are in place and properly financed. This emphasised the need to ensure that good practices are in place for bridge inspection and maintenance as well as for wider asset management.”

He told delegates that bridge engineers need to take design, construction, usage, maintenance and management lessons into account, otherwise we risk major failures occurring in the UK.

David Thomas, Marketing and Sales Manager at Surveyor magazine, said: “It is vital that the lessons learned from the Mississippi bridge collapse are tackled by the UK’s bridge engineers and managers, and Surveyor and CSS were committed to the education and addressing of these issues at Surveyor’s annual Bridges event.”

The truss girder construction of the American bridge is not common in the UK and the great majority of our 55,000 bridges are small span and built in stone or concrete. But after the Mississippi bridge disaster, the CSS (which represents local authority strategic directors responsible for three quarters of the nation’s road network and bridge stock) warned that no authority can afford to ignore the need for a rigorous maintenance and inspection regime.

An alert was issued to all CSS members across the UK, asking for any who had similar bridges to get in touch with the Bridges Group so developments from Minneapolis could be monitored in order to learn from any issues that came to light.

The CSS supported and endorsed a code of practice, published in 2005, which provides a best practice guide for managing bridges. It has also been pressing for a specialist qualification for bridge inspectors.

ends

Media contact  

Susan Tolman, Daybreak Communications office 0845 644 3845; mobile 07786 543430; susan.tolman@daybreakcomm.co.uk  

Notes to editors

• CSS represents local authority chief officers who manage some of the most pressing issues facing the UK today. Membership is drawn from all four corners of the United Kingdom with members responsible for three-quarters of the road network, two thirds of the land area and just under half of the population of England and Wales. Operating at the strategic tier of local government, they are closely involved in crucial transport, waste management, environment, planning, energy and economic development issues.

• Richard Fish is Director of Planning and Transportation for Cornwall County Council. He chairs the CSS Bridges Group which is part of the Engineering Committee. He also chairs the UK Bridges Board, which incorporates all UK bridge owners. UKBB is a sub-board of the UK Roads Liaison Group. He is a Fellow of the Institution of Civil Engineers and a Fellow of the Institution of Structural Engineers.