Prof Michel Bruneau, an earthquake engineering expert at New York State’s University, Buffalo, said that there is a need to protect bridges from both events since as well as being terrorist targets they are also often located in areas of moderate or high seismic activity.
Intended primarily for small and medium sized bridges, Bruneau’s concept focuses primarily on the design of the bridge piers.
Bruneau said that most existing bridges are supported by conventional reinforced concrete columns which, in the event of a major blast, would breach, causing the bridge to collapse.
In his design, the piers are made from corrosion-resistant steel tubes filled with concrete, but without reinforcing bars. The steel and concrete bind together, forming a composite structure, which is claimed to give the piers superior strength and ductility.
Bruneau said that this means they will bend without breaking when subjected to significant blast and seismic forces. For the pier’s footing, additional structural shapes are embedded in concrete to resist the large bending forces developing at the base of the piers.
During trials carried out by the
He added that while the design is primarily intended for new bridges, future research will focus on the development of systems that could be retrofitted to existing ones.