| The prefabricated foam concrete composite wallboard is a new type of wallboard made of foam concrete as the core board,composed of a fine stone concrete with steel wire mesh as surface,reinforced concrete as concealed columns and beams.Its overall prefabrication and large slab width make up for the shortcomings of prefabricated slat joint cracking and cumbersome construction,catering to the development trend of building industrialization and construction mechanization.However,as a new type of wallboard,the mechanical properties of the wallboard itself and the influence of the wallboard on the seismic performance of the RC frame are still unclear,which hinders the popularization and application of the composite wallboard.In this paper,the mechanical properties of the composite wallboard and the seismic performance of the composite wallboard filled wall RC frame are studied.The main research contents and conclusions are as follows:The most unfavorable working conditions in the production is analyzed,witch conclude the bending performance is determined as the key mechanical property of the wallboard.According to the design of wall panel turning and lifting,the out-of-plane bending performance test of the composite wall panel was carried out to verify the safety of the wall panel under the most unfavorable conditions.The test showed that:(1)The composite wall panel exhibited great bending resistance The bearing capacity and the cracking load are 10.00 times of the weight of the wallboard,which can meet the safety requirements under the most unfavorable working conditions.(2)The composite wall board is designed to be reinforced according to the bending member,and the positive effect of the surface steel wire mesh on the bending performance of the wall board is used as a safety reserve.This type of reinforcement is too conservative.(3)The composite wall panel exhibits good ductility,and the specimen still has a certain load-bearing capacity(85%peak load)after failure.In order to study the influence of composite wall panels on the seismic performance of RC frames,a pure frame CK,a masonry filled wall frame QK,a wall-frame rigid connection composite wall panel filled wall frame GK and a wall-frame The quasi-static test of the flexible connected composite wall panel filled wall frame RK.The test shows:(1)The filling of composite wallboard improves the bearing capacity and rigidity of the frame.The ratio of the ultimate bearing capacity of each test piece CK:QK:GK:RK=1.00:1.42:4.05:1.99;the initial stiffness ratio CK:QK:GK:RK=1:2.03:4.22:2.75.(2)The composite wallboard has a great influence on the ductility of the RC frame.The ductility coefficient ratio of each specimen is CK:QK:GK:RK=1:1.14:0.55:1.13,and the GK displacement ductility coefficient is about half of CK.(3)The filling of composite wallboard changes the stress characteristics of the frame structure,which is specifically manifested by the increase of the overall axial force of the frame and the sudden increase of corner shear.(4)The composite wallboard has a great influence on the RC frame and is not suitable for use as a filled wall.Adding a flexible material XPS between the wall and the frame can effectively improve the seismic performance of the composite wallboard filled wall RC frame structure.Compared with GK,RK peak load is reduced by 51%;initial stiffness is reduced by 35%;displacement ductility coefficient is increased by 105%.In order to gain a deeper understanding of the effect of composite wall panels on the internal forces of the RC frame,the finite element modeling of GK and CK was completed based on ABAQUS.In the modeling process,two basic assumptions were proposed in consideration of the convergence,accuracy and calculation speed of the model calculation:(1)the impact of foam concrete on the seismic performance of the RC frame was not considered when modeling the composite wall panel;(2)the wall-Frame contact only defines normal contact as "hard" contact,without considering tangential force.After trial calculation,this assumption can better simulate the failure mode and peak load of the wall panel and frame,but the simulation effect of the initial stiffness of the specimen is not good.In order to more fully understand the advantages and disadvantages of using composite wallboard as a filler wall,the impact of the composite wallboard and light concrete slab on the seismic performance of the RC frame was compared and analyzed.(1)Failure mode:The RC frame(No.TK)of the slat-filled wall has obvious brittle failure characteristics.The slat basically collapses after suddenly breaking down;GK and RK are relatively ductile,and the wall panel can still share part of the level after loading Load.(2)Internal force:The filling of two types of wallboard filling walls will cause the local shear force of the frame to increase,and the bending moment and axial force increase overall.The increase in the internal force of the frame in GK relative to the pure frame is about 2 to 3 times the corresponding increase in the TK frame.(3)Strength and stiffness:the effect of the slat on the pure frame strength and stiffness is roughly between the rigid and flexible jointed wall panels.Peak relative strength of each test piece(intensity of filled wall frame strength/maximum pure frame strength)ratio QK:GK:RK:TK=1.00:1.30:2.58:1.44;relative initial stiffness(initial stiffness of filled wall frame/initial stiffness of pure frame))Than QK:GK:RK:TK=1.00:1.53:0.74:0.97.However,the brittle failure of the TK strip caused a sudden drop in strength,and its bearing capacity was not much different from that of the pure frame in the late loading stage.For the seismic design,the design recommendations given in this paper are as follows:(1)The rigid-connected composite wallboard has too much influence on the RC frame,and the wall-frame connection structure should adopt flexible connection.(2)Two methods for correcting the seismic action value of RC frames of composite wall panels with flexible connection are proposed:1)Considering the effect of the infill wall on the stiffness of the frame,the period reduction factor is compared by the RK to QK period in the seismic design stage Correction,it is recommended to take the period reduction factor of flexible frame=0.52?0.60,the period correction value;2)Considering the seismic force sharing effect of the filling wall on the RC frame,the seismic impact coefficient is corrected by the RK and QK resistance ratio in the seismic design stage It is recommended that the reduction coefficient of the seismic influence of the flexible frame be taken as=0.80,and the revised value of the seismic influence coefficient. |
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