Simplified Nonlinear Modeling for Seismic Assessment of Complex Bridges

Abstract

A common procedure used for the seismic assessment of complex bridges is a three-dimensional linear-response spectrum analysis. The linear nature of such an analysis can lead to erroneous results and misdiagnosis of vulnerable components. Analysis that accounts for the nonlinear behavior of components is desirable, but the human resource effort required to properly model an entire bridge is usually more than what most owners would like to invest. The use of simplified nonlinear modeling as a complement to larger linear models is discussed, providing the engineer with a true sense of structure response during the seismic event. The result is a proper diagnosis of vulnerabilities without a large analytical design effort. Three bridge case studies illustrate examples of nonlinear assessment of retaining walls, reinforced concrete connections, steel members, and viscous damping devices.