Study On Seismic Behavior Of Joints Of Fabricated Concrete Shear Wall With Built-in Section Steel

In this paper,the commonly used fabricated concrete shear wall structure is discussed about the faults.Such as the connection nodes are complex,The construction efficiency is low,the construction quality of connection joints is not easy to check and control.Based on above,a new type of built-in steel fabricated concrete shear wall structure is proposed.The safety and reliability of the joints of fabricated building determine the success or failure of the fabricated structure.China is an earthquake-prone country.So that the requirement for joint performance of assembled building structure is higher.In this paper,the seismic behavior of the joints of a new type of built-in steel fabricated concrete shear wall structure is studied.This article is a full investigation of development and application of fabricated structures at home and abroad.It is also a full investigation of research progress at home and abroad.On this basis,reinforced concrete structure with the section steel is combined with the fabricated structure.A joint of prefabricated concrete shear wall with built-in section steel is designed and obtained patent authorization.The scheme of joint connection gives full play to the combined action of section steel skeleton and concrete.It is helpful to improve the seismic performance.And it simplifies the construction steps and control construction quality easily.It also reduces the difficulty of construction.In this paper,the quasi-static test,theoretical analysis and finite element simulation are used to study the seismic performance of such joints.Specific research contents are as follows:(a)I-beam is proposed as the core.It is wrapped in stirrups and concrete.All of above is an edge restraint zone in fabricated shear Wall.Uniform arrangement of vertical and vertical horizontal reinforcing bars in fabricated wallboard.Bending and anchoring of longitudinal reinforcement bars in upper and lower wall limbs at post-pouring Layer.This is a new type of fabricated joint connection.(b)Through quasi-static test,the relevant test parameters of the joint specimens of the built-in steel-fabricated concrete shear wall are obtained.Including:hysteresis curve,skeleton curve,stiffness degradation trend,ductility coefficient,energy dissipation capacity,failure mode and so on.(c)Since the post-pouring layer is located at the bottom of the fabricated wall,it is bearing maximum bending moment.Cracks first appear in the contact gap between prefabricated wall and post-pouring layer.Therefore,the performance of specimens with upgraded post-pouring layer under cyclic loading is further studied.The similarities and differences of seismic performance of wall joints with two different post-pouring layers are compared and evaluated.(d)Based on the data of hysteric curve and skeleton curve obtained from quasi-static test.A restoring force model of built-in steel-fabricated concrete shear wall is proposed.The validity of the method is verified by comparison with the experimental results.(e)Applying ABAQUS software,according to the material performance parameters obtained from the test,the finite element model corresponding to the test is established.The finite element analysis model is established.Referring to the norms and existing research result.The definition of constitutive relation attributes of concrete,section steel and reinforcing steel bars is emphasized.The damage model is introduced to simulate the failure characteristics of concrete under cyclic loading.The strain,stress,deformation and structural damage nephograms of the finite element test results are obtained.Hysteretic curve also is obtained.The similarities and differences between finite element simulation analysis and experimental research are compared.It also analyzed the reasons.The main conclusions are as follows:(a)because of the pin action of bending steel bar and section steel,there was no obvious slip deformation between the post-poured layer and the prefabricated wall board and the foundation base.For short steel bar welded on side of I-beam,the anti-slip ability of wall and I-beam is improved.The cracks in the wall are gradually developed upward and the damage is delayed.The joints have goodductility and deformation ability.Axial compression ratio has a significant effect on ductility of specimens.(b)There was no obvious slip deformation between the post-poured layer and the prefabricated wall panels of Joints of prefabricated concrete shear wall with built-in section steel specimens with upgraded post-pouring layer.Compared with the specimens with the post-poured layer at the top of the foundation beam,the ultimate bearing capacity is slightly higher,the ductility is slightly increased,and the overall seismic performance is better.The failure characteristics of the two groups of specimens are similar.The specimens with low axial compression ratio of built-in steel fabricated shear wall joints show bending-shear failure.Under yield load,the displacement ratio satisfies the requirement that the interlayer displacement angle should not exceed 1/120.(c)Based on the hysteretic curve and skeleton curve obtained from quasi-static test,used the experimental fitting method,the quadruple-line skeleton curves of the specimens with built-in steel-fabricated concrete joints under low cyclic repeated loads are obtained.The calculation method of crack stiffness is given by mechanical calculation and experimental correction.Then the stiffness of each key point is deduced.A method for calculating the peak load considering the increase of ultimate compressive strain of concrete in confined zone is presented.Based on the above,the restoring force model of the built-in steel fabricated concrete shear wall is established.(d)Through ABAQUS finite element software,the finite element simulation analysis of the test specimens of the joints of the built-in steel-fabricated concrete shear wall is carried out.The structural damage is obvious and the k Neading effect of hysteretic curve reflects the characteristics of bending and shearing failure.Compared with the experimental results,the finite element analysis model can better simulate the test conditions.The process of stress,strain,displacement,damage and failure characteristics of the specimens are basically embodied.The above-mentioned research is the foundation of building the structural system of steel-reinforced prefabricated concrete shear wall.It provides theoreticalsupport for the study of its seismic performance.It will be beneficial to the popularization and application of this structural system.Furthermore,it contributes to the industrialization of assembled buildings in China.