Validation of Numerical Modeling and Analysis of Steel Bridge Towers Subjected to Blast Loadings

Most major long span bridges in the United States are vulnerable to terrorism. They are high visibility structures, with a potential for extensive media exposure and public reaction if an incident were to occur. As a result of the long spans, complicated designs, site locations, etc., these bridges have very high replacement costs, and multi-year replacement construction periods. The potential for impacting regional and national economy is also greater because of the increased time for reconstruction. Many of these bridges serve as transportation arteries critical for emergency evacuation and for carrying lifelines besides vehicular traffic. Depending on the location, there is potential for mass casualties because of the volume of traffic it can carry at any given time. Most if not all of these long span bridges cross rivers, bays or other navigational channels. Damage resulting from an attack can be major. The objectives of this study are to develop better analytical modeling and numerical analysis capabilities of steel bridge towers subjected to airblast, and to develop retrofit schemes for the towers. The numerical analysis, both with and without retrofits are to be verified through large scale experimental testing.