9309757 Marsh An option included in current seismic retrofit programs of poorly confined reinforced concrete columns in older bridges is to leave the plastic hinging region just above the foundation of multiple column bents unretrofitted. It is based on the assumption that the flexural strength of such columns will degrade quickly in response to inelastic demands and thus will not transmit much moment to the foundation. It is also assumed that the shear capacity at the plastic hinge region will not be lost. However, the state of knowledge regarding the mechanism of shear strength loss is poor. The purpose of the proposed research is to assess the shear transfer capacity of such columns. The proposed work involves the testing of 10 reduced scale reinforced concrete columns. A range of potential configurations would be tested so that the specific conditions under both the flexural and shear capacities are lost could be identified. The proposed work would provide essential information regarding the performance of unretrofitted, seismically deficient bridge elements, and would help in the rational prioritization of resource allotment for seismic retrofitting of poorly designed bridges. ***
