Seismic Performance Of Isolated Modular Steel Frames System Using Friction Pendulum Bearing

Industrial buildings that are in conformity with modern ecological concepts and sustainable development in China are helping the urbanization construction.As one of the more advanced architectural models in current industrial buildings,modular building technology possesses many advantages such as high-efficiency manufacturing,low carbon-energy saving,safe operation,and high prefabrication ratio,etc.Prefabricated modular buildings have expanded to multi-buildings and high-rise buildings now.In order to improve the safety and performance of the modular structure and study the seismic isolation performance of industrial buildings,the modular structure is explored by applying the mature friction pendulum system.To better promote this new structural system,the main content of the study are as follows:(1)Through conducting simulation and parametric study of the modular structure connection node,the effect of the node domain and the rigid domain coefficient of the beam-column joints on the mechanical behavior of the modular steel frame structure is investigated.The modular steel frame structure of seven-layers finite element model is built by EYABS.The calculation problem of the rigid length of the steel frame module is taked as the research object.The study found that the rigid domain coefficient has great influence on the overall stiffness of the structure.The error caused by the displacement of the modular steel frame rigid domain design can be up to 25%.(2)The design method and process of isolated modular steel frames system using friction pendulum bearing are proposed to study the overall performance of modular structure under the influence of the friction pendulum bearing.Based on the ETABS,the finite element analysis model of the modular steel frame structure is established.Nonlinear analysis of non-isolated and isolated modular steel frame structure is carried out and compared under the selection of ground motion with seismic fortification intensity of 7 with three differentseismic records.Firstly,the ETABS and SATWE models of modularized non-isolated structures are established for comparing the results.The results show that the period and quality are similar,which verifies the accuracy of the model and prepares for the subsequent nonlinear time-history analysis.On this foundation,the simulation of FPS is realized in ETABS,and base-isolated modular building is designed and investigated by using friction pendulum system herein.the nonlinear properties of FPS is considered under the moderate and rare earthquakes.(3)For modular steel frame structures,the dynamic response results of layer displacement,layer shear force,layer peak acceleration of non-isolated structures and isolated structures are compared.It is concluded that the modular structure isolation effect after adding FPS is obvious.the isolated structure can exert certain isolation effect under the moderate earthquakes and the isolation effect is remarkable under rare earthquakes.the isolation structure is basically elastic under rare earthquakes.A small amount of beam hinges appear,and the displacement angle between the layers of the structure is far less than the specification limit.The maximum displacement angle under rare earthquake action is 1/115,which is less than the specification limit of 1/50.(4)Based on the traditional friction pendulum bearing,a variable friction pendulum bearing is proposed.The traditional friction single pendulum isolation bearing has self-adaptiveness through improving its performance,and the variable friction bearing divides the sliding surface into two slip areas with different friction coefficients.And the friction coefficient of the center friction slip area is smaller than the friction coefficient of the edge friction slip region.On the basis,the numerical simulation method of the variable friction pendulum bearing was developed based on ETABS.Without detriment to the isolating affection,the displacement of the variable friction isolation bearing has a certain reduction,and the energy dissipation capacity is stronger by comparing with the analysis result of the friction pendulum bearing under the rare earthquakes.