Displacement-based seismic design of SDOF concentrically braced frames.

The concept of designing structures to achieve a specified performance limit state defined by strain or drift limits is now well established. In particular, the direct displacement-based design approach has been developed for many structural systems, including frames, cantilevers and coupled walls, dual systems, bridges, wharves, timber structures and seismically isolated structures. This paper investigates the performance of a simplified displacement-based design approach for concentrically braced frame (CBF) systems during earthquakes. The performance of the trial DBD methodology is gauged through comparison of design values with experimental results obtained from a series of shake table tests on steel braced frames. The performance of non-linear time-history analyses to assess the response of the braced frames is also presented. The results highlight the need for specific equivalent viscous damping expressions for the DBD of CBF systems and also demonstrate that non-linear time-history analysis techniques should be developed further, to better predict the displacement response of CBF systems.