Multi-span Simply Supported Bridges Research Articles

Effects Of Impact On The Seismic Response Of MSSS Bridges

This paper presents results of a study on the effect of impact on seismic response of Multi-Span Simply-Supported (MSSS) bridges. The investigation includes detailed dynamic analysis of three actual bridges as representatives of 2,3, and 4 span bridges, which are common in the Eastern United States. Furthermore, using a Stiffening Single-Degree-Of-Freedom (S-SDOF) model a series of parametric study are performed. The objectives are to better quanti~ the effect of impact on the seismic performance of MSSS bridges and to provide the knowledge base for development of design guidelines within a performancebased framework. Several damage criteria, namely displacemen~ dissipated hysteretic energy, and low-cycle fatigue darnage index are considered. It is shown that on the average displacement dem&ds are lower for S-SDOF systems, consistent with pushover analysis based on current seismic codes. However, considering other damage criteria, it is quite possible for an S-SDOF system to sustain more damage than an elastic-plastic system. Design implications and the needs for future research are also discussed.

Seismic modeling of multi-span simply-supported bridges using ADINA

A major component of the Seismic Retrofit Program in the State of New Jersey includes analysis and evaluation of high-risk bridges. Most bridges in New Jersey (and more generally in the eastern U. S. A.) are multi-span simply-supported, thus creating the high possibility of impact of adjacent spans in the longitudinal direction. The results of an ongoing study on modeling and the effect of impact on the seismic response of bridges is presented. ADINA is used for development of nonlinear bridge models. A number of practical examples indicating how ADINA can be used for analysis of different bridge components are also illustrated.