Research On The Rigidity Reduction Coefficient Of Superimposed Slab Shear Wall Structure

In recent years,under the wave of housing industrialization that the country vigorously promotes,superimposed slab shear wall structure stands out with its superior performance.It can not only realize semi-automatic production through factories,greatly shorten the construction period while also reducing the labor demand;It can also reduce the waste of a lot of materials during on-site construction and reduce the frequency of water.Many advantages make the superimposed slab shear wall structure become the main force for green and sustainable development of buildings.Many experts and scholars have never stopped the research on the mechanical performance of superimposed slab shear wall structure,and a series of encouraging developments has been made.However,the current design of superimposed slab shear wall structure is still more cumbersome than cast-in-place shear wall structures.In fact,during the construction and installation,it is inevitable to produce joint,and the existence of joint will have a certain influence on the stiffness of superimposed slab shear wall structures.Based on the seismic performance test of the connection,the finite element software ABAQUS is used to carry out a large number of modeling and analysis of the superimposed shear wall with a single horizontal joint and a horizontal joint and a vertical joint at the same time.The main research work includes the following aspects.Firstly,it analyzes the concrete material failure criterion,the constitutive relationship of steel bar and concrete in detail,and selects the concrete model suitable for simulation analysis in the ABAQUS software.Secondly,according to the specific conditions of the test,select appropriate material parameters,element types,boundary conditions,contact surface relationships,etc.,to ensure that in ABAQUS,shear wall modeling and test are as consistent as possible.The test results are compared with the finite element simulation values,and it is found that the two shear walls The development trend of the force wall crack distribution,the final failure form,the trend of the hysteresis curve and the skeleton curve,the size of the ductility,etc.are not much different,which verifies the rationality and feasibility of the finite element modeling and parameter selection.Then,the focus will be on the initial stiffness values of the three failure modes of shear walls under the premise of reasonable selection of experimental and finite element parameters,the existence of a single horizontal joint and the simultaneous existence of horizontal and vertical joints.,namely,the failure mode is shear type and the aspect ratio is 1.the failure mode of the shear wall is a bending shear wall with an aspect ratio of 1.7 and the failure mode is a bending shear wall with an aspect ratio of 2.3.Using the controlled variable method,the parameters that affect the stiffness are changed,select the slope of the straight line that just enters the elastic phase in the stress-strain curve as the required initial stiffness value,analyze the influence of the axial compression ratio,the strength of the precast concrete cube,the strength of the cast-in-place concrete cube and the aspect ratio on the initial stiffness of the shear wall.Comparative analysis found:For cast-in-place concrete shear walls,when other conditions remain the same,the initial stiffness of the shear wall decreases as the axial compression ratio increases,but the change trend is small;as the strength of the concrete cube increases And increase;decrease with the increase of the aspect ratio.For laminated slab concrete shear walls,when there are only horizontal joints and other conditions remain the same,the initial stiffness of the shear wall increases as the axial compression ratio increases,and when the axial compression ratio When it is 0.05,the initial stiffness is obviously smaller than that of the cast-in-place structure;it increases with the increase of the strength of the precast concrete cube and the strength of the cast-in-place concrete cube;decrease as the aspect ratio increases.When horizontal seams and vertical seams exist at the same time,when other conditions are consistent,the initial stiffness of the shear wall increases with the increase of the strength of the precast concrete and the cast-in-place concrete cube;it decreases with the increase of the aspect ratio;when the axial compression ratio is less than 0.1,the initial stiffness is smaller,from 0.05 to0.1stiffness can be significantly improved,and then increase the axial compression ratio stiffness on the contrary.Finally,three groups of 540 models were designed for ABAQUS finite element numerical simulation.The structural rigidity of the superimposed slab shear wall structure with only horizontal joints was set to K1,and the superimposed slab shear wall structure with horizontal and vertical joints was also present.The rigidity of the structure is set to K2,and the rigidity of the cast-in-place shear wall is set to K3.The stiffness reduction coefficient when only horizontal joints exist is K₁=K1/K3,and the reduction coefficients exist at the same time for horizontal joints and vertical joints.As K₂=K2/K3,a large number of composite slab concrete shear wall stiffness reduction coefficients under different conditions are obtained.When there are only horizontal joints,the stiffness reduction ratio increases with the increase of axial compression ratio,precast concrete strength,and aspect ratio,and decreases with the increase of grouting strength.When horizontal joints and vertical joints exist at the same time,the stiffness reduction ratio of the superimposed slab concrete shear wall and the cast-in-place concrete shear wall is comprehensively affected by multiple factors,and the stiffness reduction ratio under different failure modes and different axial compression ratios The trend is not the same,but overall it seems that the stiffness reduction ratio fluctuates between 0.85-0.96.The impact of the superimposed slab shear wall with horizontal and vertical joints on the stiffness reduction is greater than that of the laminated shear wall with only horizontal joints.Figure[21]table[17]reference[66]...