Evaluation of ground motion intensity-response relations for performance-based design of frame buildings.

摘要

The main objective of this research is to achieve a reliable basis for efficient performance-based design of ductile moment resisting frames in terms of description of the damage potential of design ground motions and description of structural performance criteria.; The overall strategy followed in this study consisted in (1) selecting a site in Downtown Los Angeles and identifying the earthquake magnitude and distance that govern the seismic hazard at the site. (2) Nineteen buildings designed for the designated site are subjected to more than 300 records of original and scaled ground motions compatible with the building. (3) Code design criteria are assessed, factors affecting inelastic response modeling were identified, simple design ground motion parameters and structural performance/damage indices are suggested. (4) Guidelines for efficient use of pushover analysis are presented.; Structural overstrength is evaluated for the prototype buildings in addition to more than 50 other steel and reinforced concrete frames reported in the literature. A period-dependent regression curve for overstrength factors is proposed and used to evaluate R-factors in seismic codes.; A survey of measured structural damping in buildings during seismic events was conducted and a practical range of damping values was adopted. Subsequently, the variation of linear and nonlinear response of buildings within the adopted range was investigated.; A thorough review of earthquake intensities and measures is presented. More than 120 ground motion parameters were identified and checked against more than 40 structural response parameters. Duration and orientation of ground motion were also studied. More than 15,000 nonlinear analyses were performed and ground motion and structural response parameters were reduced to a few parameters that showed high correlation.; Dynamic response envelopes were compared to nonlinear static pushover analysis curves. A variety of force distributions were tested and were finally reduced to a couple distributions that envelope dynamic response.