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Abstract

Feasibility of a proposed seismic retrofitting technique for typical bridges in the Central US has been studied. The retrofitting technique is based on modifying the fixity conditions of the bearings for response modification purposes to eliminate the need for costly retrofitting of substructures. For this purpose, a seismically vulnerable bridge, typical of those in the Central US was selected. Detailed seismic analyses of the bridge were then conducted. It was found that its bearings, wing-walls and pier foundations needed to be retrofitted. A conventional retrofitting strategy was developed and the cost of retrofit was estimated. Next, the abutment bearings were fixed longitudinally to modify the response of the bridge so as to alleviate the effect of seismic forces transferred to vulnerable pier foundations. It was observed that the proposed retrofitting technique effectively mitigated the seismic forces transferred to the pier foundations and eliminated the need for their costly retrofitting. Thus, the proposed retrofitting method may be used for economical seismic retrofitting of such bridges in the Central US or in similar regions of low to moderate risk of seismic activity.