Minnesota Bridge Collapse Highlights Research Needs
Following the collapse of the I-35W Bridge in Minneapolis, Minnesota, MCEER’s Senior Program Officer for Transportation Research, Jerry O’Connor, shared his knowledge on bridge safety with a variety of local and national members of the media. The collapse of the 8-lane steel arch bridge, which occurred August 1, 2007, brought attention to a potentially growing problem facing our nation’s bridge network – that is, the effects of aging and repair/maintenance over the lifespan of a bridge.
Drawing on his bridge inspection experience, O’Connor shared information on bridge safety in general, explaining the most common causes of bridge failure. These include scour, steel fatigue, and overload. He explained that often a bridge’s condition can be weakened by corrosion of its structural members and connections, so it is no longer able to carry its design load. He also discussed the use of sufficiency rating by DOTs to identify and prioritize bridge repairs, rehabilitations and replacements (see related article on International Bridge Study).
Several of these factors are being studied as part of MCEER’s highway and bridge research, funded by the Federal Highway Administration. For instance, MCEER produced the Seismic Retrofitting Manual for Highway Structures and Seismic Retrofitting Guidelines for Complex Steel Truss Highway Bridges that were released in 2006. These contain an abundance of information about analysis of bridges similar to the I-35W bridge. Recently, engineers have realized that past research done to advance the state-of-the-art of bridge design for earthquake protection is also applicable to other extreme loads. In the future, MCEER’s research program is expected to lead to new, improved methods of bridge design.
Individuals interested in the use of seismic technologies for extreme loads should consider attending the Sixth National Conference on Bridges and Highways.