| Side corridor RC frame building is one of the architectural forms commonly used in school buildings in primary and high schools in China because of its advantages,such as flexibility in architectural planning,Good lighting and ventilation,the lower cost.In recent earthquakes in China,the news that such structures collapsed during the earthquake disaster was common,causing heavy casualties.However,the research on the seismic performance of this kind of structure is not sufficient and there is still a gap between the expectations and actual conditions of seismic design.In this paper,the seismic analysis and assessment of this typical side corridor school building are carried out by using the bidirectional endurance time method.This paper mainly researches on the following several aspects:(1)The basic principle of the incremental dynamic analysis method and the analysis steps are introduced briefly,including the selection of ground motion,the strength index of ground motion and the selection of the engineering demand parameters.The research status and background of the endurance time method are introduced,and the method is described vividly by the shaking table.The basic concept of the endurance time method is introduced,and the generation method of the endurance time accelerogram is introduced.and the acceleration response spectrum of the three endurance time accelerograms is compared with the code spectrum,the validity of the endurance time accelerations are verified.(2)Introduce the basic situation of OpenSEES software briefly,understand the uniaxialmaterial model and element model that this paper needs to use.Taking the Xuankou middle school buildings which collapsed in the 2008 Wenchuan Earthquake as a representative model,taking into account the presence or absence of the influence of infill walls,the finite element model was built using OpenSEES software,and the bidirectional endurance time method and bidirectional incremental dynamic analysis were applied.The model is analyzed and compared by using the bidirectional endurance time method and the bidirectional incremental dynamic analysis,the results show that BETM and BID A analysis results are similar and can simulate the seismic damage of structures well(3)The response results of the model with or without infilled walls based on the bidirectional endurance time method are compared and analyzed.At the same time,the plastic hinges development of the lower beams and columns and the maximum angle of rotation at the end of each story column are analyzed.It is found that the plastic development of the same layer column member is earlier than that of the beam member,which is not consistent with the concept of "strong column weak beam".(4)A multi-angle endurance time method is put forward.and the premise of this method is determined by comparing the time consuming of bidirectional endurance time method with that of bidirectional incremental dynamic analysis.The most disadvantageous angle of the model is obtained by using the multi-angle endurance time method.The structural response of endurance time method at the most unfavorable angle is compared with the results of the previous bidirectional endurance time method.Although the result has certain error,but can be combined with high efficiency and reliability of ETM,multi-angle loading using ETM structure model,find out its most unfavourable angle,it can be predicted for the seismic design of the structure of the direction of the collapsed,prevent structure collapsed on rest not collapsed buildings or outdoor secondary damage... |
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