This report presents the seismic evaluation of the US41 Southbound 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 9 spans on the Evansville, IN side and 20 spans on the Henderson, 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 the acceleration time histories of the 50-year earthquake event. Stresses and displacements due to projected earthquakes are found to be very low. Analytical results indicate that the main bridge superstructure will survive the projected 50-year earthquake without any damage and no loss-of-span. However, all the supports on the piers of the main bridge require additional anchor bolts or seismic isolation bearings.

The Kentucky and Indiana approach spans are analyzed using the response spectrum method with simplified single-degree-of-freedom models. Ten out of twelve supports having fixed bearings on both the approach spans require additional anchor bolts or seismic isolation bearings. At three out of twenty-five supports having expansion bearings, the existing rocker bearings need to be replaced with elastomeric bearings or cable restrainers need to be provided to avoid loss-of-span.

Report Date


Report Number


Digital Object Identifier



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.