Residual Displacement Response Spectrum

Structures subjected to strong earthquake ground shaking may be left in a displaced condition. The amount of this residual or permanent displacement is determined by structural characteristics, including mass and hysteretic behavior, as well as ground motion. Residual displacement is undesirable because it presents problems during repair and reconstruction after an earthquake. This paper describes analyses of many single-degree-of-freedom bilinear oscillators, with different natural periods, damping ratios, ductility factors, bilinear factors, and input ground motions. These analyses were carried out in order to obtain a method of estimating the likely residual displacements of real single-degree-of-freedom structures. The residual displacement was normalized by the maximum possible residual displacement. Although there was scatter in the normalized residual displacement for different earthquake records, trends in behavior were dominated by the slope of post-yielding branch of bilinear loop. A residual displacement response spectrum is presented for design of a single-degree-of-freedom structures and a design application is also provided.