This report presents the seismic evaluation of the US41 Northbound bridge over the Ohio River connecting Evansville, Indiana and Henderson, Kentucky. The main bridge is a four-span cantilever through-truss type. The approach bridge has 8 spans on the Evansville, IN side and 35 spans on the Henderson, KY side. Although this bridge has not yet been subjected to a moderate or major earthquake, it is situated within the influence of the New Madrid and Wabash Valley Seismic Zones.

The seismic evaluation program consisted of field testing and seismic response analysis. The modal properties of the main bridge were determined through field testing, and were used to calibrate a three dimensional finite element model. The finite element model was then subjected to time histories of the 50-year earthquake event. Stresses and displacements obtained were found to be within the acceptable limits. Analytical results indicate that the superstructure of the main bridge will survive the projected 50-year earthquake without any damage and no loss-of-span. However, all supports on the piers of the main bridge require additional anchor bolts or seismic isolation bearings.

The approach spans were analyzed using response spectrum method with simplified single-degree-of-freedom models. Thirteen out of forty-two supports having fixed bearings on both the Kentucky and Indiana approach spans require additional anchor bolts at the fixed bearings or seismic isolation bearings.

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The contents of this report reflect the views of the authors who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky, the Kentucky Transportation Cabinet, nor the Federal Highway Administration. This report does not constitute a standard, specification or regulation. The inclusion of manufacturer names or trade names are for identification purposes and are not to be considered as endorsement.