Study On The Drift Angle Limit Of Frame Bent Structure In Gymnasiums

The frame bent structure of the large space part of the gymnasiums building is not a frame structure in strict sense.In the engineering design,the pure frame structure is adopted to control the deformation and aseismic design and check calculation directly by using the limit value of the drift angle between floors of the pure frame structure Research and demonstration of step.Therefore,in this paper,the rationality of the limit value of elastic drift angle and elastic-plastic drift angle of the frame bent structure of the mixed structure of the gymnasiums building is studied.Based on the damage and damage of the structure,the rationality of the limit value of the drift angle of the structure is studied.At the same time,whether the infilled wall should be considered in the structural analysis is also discussed.The research in this paper is similar to that the upper part is empty The lower part of the inter grid structure roof provides a reference for the deformation control of the mixed structure of the concrete frame bent structure.Under the earthquake action,the main structural component and the non structural component infill wall share the seismic action.Whether or not to consider the influence of infill wall in structural analysis will lead to the difference of calculation results.In this paper,considering the influence of infilled wall,the calculation model of infilled wall proposed by scholars at home and abroad is simplified and improved from the aspects of mechanical behavior,seismic damage and simple modeling of infilled wall.The double inclined strut model is adopted to simulate the infilled wall.In this paper,a single-layer open gymnasiums building is selected as the research object.With the help of the finite element analysis software ABAQUS,the integral model of the mixed structure of the gymnasiums without considering the infilled wall and considering the infilled wall is established respectively,and the dynamic elastic-plastic time history analysis of the structure is carried out.The influence of infilled wall on the analysis results and the limit value of drift angle is studied and judged under the action of frequent earthquake,rare earthquake and extremely rare earthquake.Based on the statistics of the damage of load-bearing members and infilled walls,combined with the deformation of structural members,the seismic capacity of the structure is analyzed and judged by comparing the performance objectives.The results show that the lateral stiffness of the whole structure increases and the deformation of the grid and the whole structure decreases obviously when the infill wall is considered,which is more in line with the actual situation of the structure and the results are more reasonable.According to the elastic drift angle limit of frame structure 1/550,the mixed structure of gymnasiums can meet the requirements of small earthquake protection,while the drift angle limit value is relaxed to 1/500,the re designed gymnasiums hybrid structure can still meet the requirements of small earthquake.Under rare earthquake,whether the structure is designed with 1/550 or 1/500 and with or without infill wall,the calculated maximum displacement angle of single column does not exceed the requirement of 1/50elastic-plastic interlayer displacement angle limit.When the infill wall is considered and the stiffness of the lower part of the structure is small,i.e.1/500 design,the calculated value of the maximum drift angle of single column under rare earthquake action is obviously larger than that without considering the influence of infill wall,and the damage is relatively serious.However,from the damage of the lower structure and the upper grid structure,the structure can still meet the requirements of earthquake resistance.The results show that the 1/550 elastic drift angle limit value of the frame structure is used to control the building stiffness of the gymnasiums,and the seismic capacity of the structure has certain redundancy.Under extremely rare earthquake,when the stiffness of the lower part of the frame bent structure in the gymnasiums is small,i.e.1/500 design,the calculation result considering the influence of infill wall is also more serious than that without considering the influence of infill wall.The infilled wall can not only restrain the overall deformation of the structure,but also increase the deformation and damage of the structure.Considering the effect of infill wall in the rare and extremely rare earthquake time history analysis is more in line with the actual situation of the structure and is more helpful to identify the weak parts of the structure.When the maximum drift angle of a single column reaches about 1/50,the structure will be seriously damaged or even collapsed from the damage of substructure components.No matter whether the infilled wall is considered or not,it is reasonable to control the elastic-plastic deformation of the frame bent structure under the mixed structure of the single-layer open gymnasiums building by adopting the limit value of 1/50 elastic-plastic drift angle in the code,but the analysis result considering the infilled wall is more reasonable and reliable,which is more helpful to identify the weak parts of the structure.