Study On Seismic Behavior Of L-section Double Steel Plate Composite Shear Wall With Variable Flange Width

As a new type of composite shear wall,double steel plate composite shear wall is more and more widely used in high-rise structures.In engineering applications,in order to meet the requirements of structural layout,it is usually necessary to arrange special-shaped shear walls to meet the building requirements.However,there is interaction between flange and web of L-shaped shear wall,which is obviously different from that of I-shaped shear wall in seismic performance.At the same time,there is shear lag effect on flange.Scholars at home and abroad have done the relevant numerical simulation analysis on the special-shaped section double steel plate composite shear wall,but there are still some deficiencies in the research content,In order to study the seismic behavior of L-shaped double steel plate composite shear wall with flange width under low cyclic loading and the shear lag effect under horizontal loading,this paper presents a method to analyze the shear lag effect of L-shaped double steel plate composite shear wall with flange width,The relevant L-section double steel plate composite shear wall specimens are designed,and the low cycle repeated loading test is carried out on the specimens.According to the test data,the numerical simulation software is used to carry out the numerical simulation analysis on the relevant specimens:(1)In order to study the influence of flange width on the seismic performance of L-shaped double steel plate composite shear wall under seismic load,Based on the experimental data,the failure characteristics,hysteretic behavior,bearing capacity,strength and stiffness changes,deformation capacity,equivalent viscous damping coefficient and shear lag phenomenon of L-shaped double steel plate composite shear wall are analyzed,The data of L-section double steel plate composite shear wall with different wall parameters are compared.The results show that the main failure characteristics of shear wall are weld tearing at the end of wing wall,bulging at the middle and upper end of wing wall,crushing at the end of web wall and bulging at the bottom of wall.The bulging phenomenon of web wall of narrow flange specimen is more serious than that of wide flange specimen in the failure stage.The peak load of the wide flange specimen is 10% ～ 20% higher than that of the narrow flange specimen under the same condition.However,in terms of bearing capacity degradation,the narrow flange specimen performs better,and the energy dissipation capacity is about20% higher than that of the wide flange specimen.The results show that the shear lag phenomenon of L-shaped double steel plate composite shear wall is obvious during the loading process.With the continuous test,the maximum strain on the flange section appears at the corner of flange and web.(2)On the basis of the above experiments,a refined model of L-shaped double steel plate composite shear wall is established by selecting the more suitable concrete and steel constitutive laws and the correct boundary constraints.The experimental skeleton curve and failure characteristics are compared with those of the finite element simulation results.It is found that the failure characteristics of the test specimen are basically consistent with those of the simulation,and the skeleton curve is basically consistent.The established finite element model can better simulate the test results.(3)According to the established finite element model,parametric analysis is carried out.The analysis parameters include concrete strength,loading stages,axial compression ratio,flange height width ratio,steel strength and thickness.Stress concentration factor is used to discuss the influence of shear lag effect,and the value of effective flange width under different working conditions is obtained,with the increase of loading series,the shear lag effect becomes more and more obvious.The change of axial compression ratio will have a greater impact on the shear lag phenomenon.The shear lag phenomenon will weaken with the increase of axial compression ratio,and will also weaken with the increase of flange height width ratio;When the test is in the elastic stage,the shear lag is not significantly affected by the change of shear wall steel.However,when the plastic deformation occurs,the shear lag phenomenon is more obvious;The change of concrete strength has little effect on shear lag.The simplified calculation formula of effective flange width in elastic stage is established,and the finite element models with different height width ratio are established to verify the reliability of the formula,which provides some reference for the performance research of double steel plate composite shear wall in the future.