There is increased awareness towards vulnerabilities due to blast and other accidental damages to highway bridges since September 2001 attack on WTC in New York. Recent collapse of I-35 Bridge in Minnesota on August 1, 2007 has demonstrated psychological, societal and economic impacts of collapse of bridges in urban areas. Recently, the PI has carried out an extensive investigation on blast load effects on highway bridges to develop multi-hazard blast-seismic correlations by investigating blast effects on the same type of bridge designed for different levels of seismic resistance. It has been observed that a bridge designed for better seismic resistance is capable of withstanding large magnitude of blast pressures. One of very significant outcome of this research has been the identification of various failure modes during blast loads and their correlations with seismic failure modes. This information can be utilized to developed guidelines that can prevent occurrence of catastrophic failure modes by optimizing detailing for both seismic and blast loads. The objectives of the proposed research are to achieve this objective through numerical simulation of blast loads on a typical three span highway bridge model. It should be noted that a recent NHCRP report 645 (Williamson et al. 2010) has presented guidelines on blast resistant design of bridges that is likely to be adopted by NCHRP. However, there is very limited information on effectiveness of these guidelines. In this research, we will also investigate effectiveness of guidelines presented in NCHRP 645 through high fidelity numerical simulations.

The proposed work is important, and is urgently needed for design of multi-hazard aspects of highway bridges. The proposed research will be carried out by the PI, Professor Anil K. Agrawal. Dr. Mohammed Ettouney, Principal of Applied Research at Weidlinder Associates, New York, and Dr. Sreenivas Alampalli, Director of Bridge Program and Evaluation Services Bureau at the New York State Department of Transportation will be members of advisory committee to evaluate research work, progress and reports. The outcome of this project will be necessary tools on design of blast resistant design of highway bridges that engineers and DOT decision makers across the country can use.