Study On The Effect Of Floor Opening Layer On Seismic Performance Of Frame Structure

Floor opening is a common phenomenon in engineering.However,domestic and foreign researches still focus on the opening rate and opening position of a certain floor,and the analysis of continuous floor opening layer and single floor opening layer is still relatively lack.In response to the above problems,a large number of finite element models were established,both linear elastic analysis and nonlinear elastoplastic analysis were carried out with finite element software and the calculation conclusion were combined with theoretical results.The influence of different opening floors on the overall seismic performance of frame structure was expounded in this thesis.As the working principle and failure mechanism of multi-story and high-rise frame structures are similar under the action of frequent earthquakes,only multi-story frame structures were studied in this thesis.The main research contents of this thesis are as follows:(1)The research background of this thesis is a 6-story frame structure office building.The controlling factors are the opening rates and opening positions.The research objects are the continuous-layer floor opening layer and single-layer floor opening layer.The theoretical basis is the influence parameters of floor openings on the structural performance.By comparing the calculation results of finite element software in static elastic analysis and static elastoplastic analysis,the influence of continuous-layer floor opening layer and single-layer floor opening layer on the overall working performance of the structure was analyzed.Among them,the continuous(single-layer)opening floor layer refers to the opening floor layer from the 1-story opening floor to the 2-story continuous(single-story)opening floor...until the 6-story continuous(single-story)opening floor.(2)Taking the continuous opening layer of the floor as the research object,modal analysis,mode decomposition response spectrum analysis and static elastoplastic analysis were carried out with different floor opening rates and different floor opening positions.The research results show that when the floor opening rate is constant,both the natural vibration period and the maximum inter-story displacement angle of the structure increase first and then decrease with the increase in the number of continuous opening layer no matter the opening is in the middle or in the edge of the floor.This conclusion shows that with the increase in the number of continuous opening layer in the building,the opening of the floor helps to enhance the overall working performance of the structure.By analyzing the influencing parameters of the structure’s working performance calculated under different conditions,we can find that the maximum value of the structure’s natural vibration period and the maximum interlayer displacement angle is mainly concentrated on the bottom layer.Through the analysis of the development of plastic hinge by static elastoplastic method,it is found that the number of plastic hinges in failure state increases first and then decreases with the increase in the number of continuous opening layer,and the failure points of plastic hinges are mainly concentrated in the bottom floors.The results show that the lateral stiffness of the structure is greatly weakened when the openings are in the bottom floors.(3)The static elastic analysis method was used to analyze the influence of the continuous opening layer of the floor and the single-layer opening layer of the floor on the overall working performance of the structure under the action of frequent earthquakes;and then the static elastic-plastic analysis method was used to verify the correctness of the calculation results of static elastic analysis under small earthquakes.Through the analysis of calculation results and the development process of the plastic hinge,it is found that the conclusion of the small earthquake elastic analysis is still valid.(4)Taking the single-layer opening of the floor as the research object,modal analysis,mode decomposition response spectrum analysis and static elastoplastic analysis were carried out under different floor opening ratios and different floor opening positions.The results show that the analysis and calculation results of single floor openings are consistent with those of continuous openings.