Factors Influencing Maximum and Residual Deformations of SDOF Systems Subjected to Large Ground Motions

The maximum and residual deformations of structures subjected to strong ground motions are the most importance indexes, particularly under the performance-based design framework, thus understanding the influencing factors is of great importance to seismic design. In this study, single degree of freedom (SDOF) systems with varying structural properties are analyzed using a series of strong ground motions from FEM/SAC project. The influences of three structural parameters, i.e., yield force, second stiffness after yielding, and stiffness degradation, on the maximum and residual deformations are investigated based on the statistics of the analysis results. The analysis results suggest the follows: (1) larger yield forces lead to smaller residual and maximum deformations for short period structures, and they lead to smaller residual deformations but no necessarily smaller maximum deformation for intermediate and long period structures; (2) larger second stiffness lead to smaller residual and maximum deformations for short period structures, and they lead to smaller residual deformations but no necessarily smaller maximum deformation for intermediate and long period structures; (3) smaller stiffness degradation index leads to smaller maximum deformations but larger residual deformations.