| In recent years,the state has vigorously advocated green building and accelerated the process of building industrialization.In this context,prefabricated light concrete slabs are gradually replacing bricks and blocks as the main filling wall materials.However,there is a lack of research on the effect of slab-filled walls on the seismic performance of structures,which makes the seismic design of structures with slab-filled walls lack of basis and hinders the popularization and application of this kind of walls to a certain extent.With the help of ABAQUS finite element analysis platform,combined with experimental and theoretical analysis,the seismic performance of RC frame structure with light slab infilled wall is studied in this paper.The main research work and conclusions are as follows:(1)The mechanical properties of lightweight slab-filled wall specimens were measured.The compressive strength,modulus of elasticity and Poisson's ratio of the standard lightweight slab are 11.43 MPa,9300 MPa and 0.21 respectively.On the basis of the test,the relationship between the strength of the strip material and the strength of the standard strip is obtained,and the constitutive equation of the strip material under uniaxial compression is established.(2)Three RC frame specimens with different aspect ratios of slab-filled walls were simulated under low-cycle repeated loading.The initial stiffness ratios of three specimens A-TK2,TK1 and A-TK3 are 1:0.87:0.76.The results show that the ratio of height to width of infilled wall has a great influence on the failure mode of structure.When the ratio of height to width of infilled wall is small,the failure of infilled wall concentrates around the corner.When the ratio of height to width of infilled wall is large,the failure of infilled wall occurs in the whole range of wall panels.When the failure mode of the specimen is corner failure,the height-width ratio of the infilled wall has little effect on the bearing capacity of the structure because the local strength of the infilled wall plays a controlling role.(3)Three RC frame specimens with different wall-frame stiffness ratios were simulated under low-cycle repeated loading.The initial stiffness ratios of B-TK2,TK1 and B-TK3 are 1:1.33:1.75.The results show that the three specimens are damaged at the corner of the filling wall and the beam-column joints of the frame.After the corner of the wall is damaged,the stiffness of the whole wall decreases sharply,and the smaller the stiffness ratio of the wall to the frame,the more obvious the degradation of the stiffness of the whole specimen is.(4)Three RC frame specimens with slab-filled walls with different axial compression ratios of frame columns were simulated under low-cycle repeated loading.The results show that the axial compression ratio of the columns is different,but the bad modes of the specimens are basically the same,all of them are corner failure;the ratio of TK1,C-TK2 and C-TK3 peak bearing capacity of the three specimens is 1:1.05:1.11.With the increase of column axial compression ratio,the peak bearing capacity of the slab-filled wall frame increases,but the increase is not significant.(5)The interaction force between slab-filled wall and RC frame under earthquake action is defined as the third kind of load.By extracting the bending moment,shear force and axial force of frame in RC frame structure with slab-filled wall and comparing with pure frame,it is found that the third kind of load changes the internal force distribution of frame.The third kind of load makes the frame produce additional bending moment,additional shear force and additional axial force,among which the additional bending moment and additional axial force have little effect on the force of the frame,so they can not be considered in seismic design.Additional shear force increases the shear force at the top and end of columns on one side of the frame and at the bottom of columns on the other side.When checking the shear strength of beams and columns of the frame,it is necessary to consider the effect of the third kind of load on the increase of shear force of the frame.When the shear capacity of the frame is insufficient,structural measures can be taken to improve the shear capacity,such as full-length stirrups of columns,inclined reinforcement at beam-column joints and so on.(6)The comprehensive impact ratio(SIR)is used to evaluate the favorable and adverse effects of infilled walls on the seismic performance of RC frame structures.The comprehensive influence ratio is the ratio of the increase of horizontal resistance of RC frame caused by infilled walls to the increase of earthquake resistance of RC frame.It is found that the comprehensive influence ratio of the three groups of specimens is greater than 1 at each stage of loading,which indicates that the beneficial effect of light slab infilled wall on seismic resistance of RC frame is greater than the adverse effect.In addition,the comprehensive influence ratio is related to the stiffness ratio of the wall-frame.The larger the stiffness ratio of the wall-frame,the more significant the beneficial effect of the infilled wall on the frame structure is.(7)Using the equivalent stiffness method,the periodic reduction coefficient of RC frame structures with slab-filled walls is suggested.The periodic reduction coefficient of RC frame structure filled with masonry filling wall is taken as the reference value,and the recommended value of the periodic reduction coefficient of light slab filling wall filled with RC frame is estimated to be 0.52-0.62 by stiffness equivalence method,which can be used as a reference for engineers. |
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