EVALUATION OF CYCLIC DEMAND IN DUCTILE RC STRUCTURES

摘要

The emergence of performance-based seismic engineering principles, which are largely based ondeformation-controlled design, has brought renewed focus on nonlinear structural analysis and the effectsof cyclic demand and deterioration on seismic performance of structures. This paper explores therelevance of cumulative damage, arising from considerations of low-cycle fatigue, in establishingperformance criteria for seismic design and evaluation of structures. A comprehensive evaluation ofsingle-degree-of-freedom (SDOF) systems, representing ductile reinforced concrete structures, subjectedto a large database of earthquake ground motions is carried out to establish the role of critical system andground motion parameters on cyclic demand. Cyclic demand relationships are developed for numeroussystem variables to aid in the understanding of low-cycle fatigue effects on seismic response of genericRC structures. It is demonstrated that the characteristics of the system such as fundamental period andenergy dissipation capacity and ground motion characteristics such as input energy play a significant rolein the cyclic demand imposed on a structure during severe earthquakes.