Applicability Study Of Pushover Analysis Method On RC Frame Cliff-structures

Pushover analysis method is an important method to evaluate the elastic-plasticdrift of structures. Studies have pointed out that higher modes have serious influence ondown-floors, it is different from the assumptions of pushover analysis method.So far,wedon’t know how serious the higher modes of down-floors affect the pushover analysismethod.We also don’t know how to choose the positive or negative direction of thedownslope direction. It isn’t clear that how serious lateral force pattern affect thecliff-structures.In this article,the time-history analysis results is regarded as correct,study the applicability of pushover analysis method on the downslope direction of RCframe cliff-structures.This article describes the process that the models’ design and analysis based onPERFORM-3D software, chooses contrast method based on time-history analysismethod results, defines the permissible range of drift error, proposes the stratifiedloading pattern based on cliff-structure, establishes9models that have differentheight,different down-floors and different off-layer spans, and analyzes the influence ofpushover method,influence of lateral loading pattern and influence of pushoverdirection.Through the analysis of the above9models, there are several findings as follows:①It is unreasonable if pushover analysis method simply used in RC framecliff-structures. It is resulted that down-floors have serious drift errors.②If the stratified loading pattern is used in pushover analysis method, the drift ofdown-floors can be estimated efficiently.③Several limitations must be considered if improved pushover analysis methodbe used in RC frame cliff-structures: the first of all, the total height of the RC framecliff-structure should not exceed30meters and the the floors of down-floors should notmore than3floors. The second, the earthquake action should not stronger than rareearthquake in Chinese seismic code.The third, Modification of coefficient method ismore suitable than capacity spectrum method for performance evaluation of RC framecliff-structures.The fourth, the pushover analysis must be the direction of upslope andthe lateral loading must be loaded at every floors from lower foundations to the top. Thelast, stratified loading pattern, triange loading pattern and exponent loading pattern should be used to evaluate RC frame cliff-structures, uniform loading pattern should notbe used in RC frame cliff-structures.