Seismic Bridge Design and Retrofit -- Structural Solutions

Book excerpt: Bridge structures can give the impression that they are rather simple structural systems, whose seismic responses can be easily predicted. On the contrary, however, many bridges did not perform well in recent earthquakes, showing a need for increased research to understand various potential problems and collapse mechanisms. Indeed, progress has been made lately in design and assessment procedures around the world, and consequently many practices have changed. In this context, the objective of fib Bulletin 39 is to present, discuss and critically compare structural solutions for bridge seismic design and retrofit that have been developed and are now used all over the world, ten years after the publication of the last comprehensive manual on the subject. It is the result of the work of an international team of experts that collaborated intensively for over three years. The first four chapters of the Bulletin present a regional review of design choices, compare and discuss international design practices, and indicate their relative merits and potential problems. Current developments are treated in the next three chapters, with particular emphasis on design for enhanced damage control, for spatial variation of ground motion and for fault crossing. The last part presents a summary of current issues related to existing bridges. Extensive technical developments have been taking place in the last two decades with the goal of making bridges an important transportation infrastructure with limited damage during earthquakes. Realising this goal depends on regional seismicity, transportation systems, seismic performance goals, local cultures, and a wide range of design and construction practices, which are presented and discussed in this Bulletin.