| Short limb shear wall structure is a kind of structure form whose performance is between special-shaped column and shear wall.It is widely applied because of its good use function.So studying its seismic performance is of great significance.And seismic response of structure is multi-dimensional which makes structure torsion effect become an important cause of structure damage.In the study of short limb shear wall structure,there are a lot for single wall limb components or single node component.And there are few researches on the torsion of joint using three-dimensional space structure model under horizontal seismic load.The obtained conclusion can not totally explain the failure mechanism of short limb shear wall joint.This paper,through the pseudo static test on a short limb shear wall structure model by applying eccentric reciprocating horizontal load to simulate seismic torsion effect,studies the seismic performance of short limb shear wall structure and its joints and further analyzes mechanical properties and deformation characteristics of short limb shear wall structure and wall limb joint by combining the finite element theory and finite element calculation software.This paper mainly do the work as follows:1、design and make a 1/4 scale ratio of short limb shear wall structure model,and conduct a pseudo static test on the model of the structure under eccentric horizontal loads.The test results show that the short limb shear wall space structure belongs to the typical structure which has strong wall limbs and weak beam.The end of tie beam is a weak area of structure on which a beam plastic hinge appears first.This energy dissipation mechanism can provide good seismic energy transfer and consumption.The part of outer edge wall limb which is near joint,whose tensile effect is strengthened,suffering the double effect of torque and large bending moment of floor,is a weak part of the wall limb.During the process of force transfer,the joint which suffers the effect of bending,shear and torsion transfers shear through baroclinic rod mechanism which is composed of concrete and longitudinal reinforcement while the stirrup stress is not obvious.2、establish a finite element model which has the same parameters with experimental model by useing ANSYS finite element analysis software,and compare the calculated results with the structural model test results,do further research based on the experiment,study torsion resistance of modelunder the single working condition through the analysis of structural deformation,cracks and concrete stress,change the control parameters and loading conditions,and further study the influence of axial compression ratio,and joint area stirrup reinforcement ratio on the short-limb shear walls’ torsion carrying capacity,put forward a shear formula suitable for L-shape joint of short shear wall structure through consulting the calculation results and special-shaped columns code’s shear formula,by comparing the shear simulation value with the safe value.3、select the T-shape joint as the research object and establish its finite element model,change axial compression ratio,longitudinal reinforcement ratio of wall limb,longitudinal reinforcement ratio of the beam,stirrup reinforcement ratio of wall limbs and concrete strength grade,study the effect of various parameters on its torsion performance through the analysis of the hysteretic performance,ductility of joint. |
