Direct Displacement Design of Vertically and Horizontally Irregular Woodframe Buildings

摘要

The seismic performance of multi-story buildings can be ascertained from structural deformations and accelerations. Direct displacement design (DDD), is a procedure that allows one to distribute the vertical stiffness to the levels of a multistory building such that all stories of the building meet the desired performance criteria. DDD, in its original form, provides a simple and effective procedure to ensure a multi-story building meets the desired story drift requirements when subjected to the specified seismic intensity by considering the stiffness and strength degradation at target story drift level believed or demonstrated to provide the desired building performance. However, this design methodology has not been able to be applied to buildings with severe in-plane torsional irregularities. This paper presents the details of a methodology to perform DDD on multi-story buildings with any level of translational and torsional response and with or without a soft story, thereby generalizing DDD for all buildings. The proposed method can be applied to any nonlinear system, and is illustrated here for woodframe buildings. The design method, which does not require time history analysis, was found to provide a design with the target performance and for building with torsion, was shown to provide significantly better accuracy than DDD in its original form.