Research On Seismic Behavior Of Buckling-restrained Steel Plate Shear Wall With Out-of-plane Deformation Spaces

Buckling-restrained steel plate shear wall,which owns excellent seismic behavior,is an important side member in structure.For traditional buckling-restrained steel plate shear walls,the internal stress of the embedded steel plate will be concentrated in four corners under low-cycle repeated loads,resulting in cracking and failure of four corners of the embedded steel plate.In order to improve the stress concentration at four corners of the embedded steel plate,this paper proposes a novel structural anti-lateral force energy dissipation member — buckling-restrained steel plate shear wall with outof-plane deformation spaces.The novel steel plate shear wall includes embedded steel plate,covering concrete slabs which are installed on both sides of the embedded steel plate to constrain the out-of-plane deformation of embedded steel plate,and angle steel stiffeners which are installed on both edges of the embedded steel plate.The seismic behavior of the novel steel plate shear wall was revealed by methods of theoretical analysis,numerical simulation and experimental research.The main research contents of this paper are as follows:(1)The elastic buckling analysis was carried out on two-side connected steel plate shear walls with the other two sides free,constrained,and stiffened,respectively.The influence of dimensions of the side stiffeners on the elastic buckling performance of the buckling-restrained steel plate shear wall with out-of-plane deformation spaces was revealed.And the parameters of side stiffeners’ dimensions were optimized.The shear performance of the buckling-restrained steel plate shear wall with out-of-plane deformation spaces was also analyzed.The influence of gap size between the embedded steel plate and the covering concrete slabs and thickness of the covering concrete slabs on initial stiffness and shear bearing capacity was studied.And the parameters of gap size between the embedded steel plate and the covering concrete slabs and thickness of the covering concrete slabs were optimized.The research shows that the completely limited out-of-plane buckling deformation of free sides can be achieved by reasonable design of the side stiffeners’ dimensions.This paper proposes that the ratio of the width of stiffener to the thickness of embedded steel plate should be greater than 30,and the ratio of the thickness of stiffener to the thickness of embedded steel plate should be greater than 1.5.When the thickness of the covering concrete slabs is the same,both the initial stiffness and the yield load decrease with the increase of gap size between the embedded steel plate and the covering concrete slabs.This paper proposes that the gap size between the embedded steel plate and the covering concrete slabs should be less than 11 mm.When the gap size between the embedded steel plate and the covering concrete slabs is the same,both the initial stiffness and yield load increase with the increase of the thickness of the covering concrete slabs.Howerer,the initial stiffness and yield load will no more increase by continuing increasing the thickness of the covering concrete slabs after the thickness the covering concrete slabs after reaches 45 mm.(2)The influence of the embedded steel plate’s height-to-thickness ratio and spanto-height ratio on shear performance was studied.The initial stiffness values and yield load values with different height-to-thickness ratios and span-to-height ratios were calculated.Combined with mechanics theory and the design codes’ content,the calculation formulas of initial stiffness and shear bearing capacity of flat steel plate shear walls were deduced.Then the calculation formulas of initial stiffness and shear bearing capacity of the buckling-restrained steel plate shear wall with out-of-plane deformation spaces were obtained by proposed improvement coefficients of stiffness and bearing capacity.The research shows that the initial stiffness of the bucklingrestrained steel plate shear wall with out-of-plane deformation spaces can be accurately predicted by the calculation formula of the initial stiffness when the span-to-height ratio is 0.75,1.0 and 1.5,no matter what the height-to-thickness ratio is.The shear bearing capacity of the buckling-restrained steel plate shear wall with out-of-plane deformation spaces can be accurately predicted by the calculation formula of shear bearing capacity when the embedded steel plate is thin and the span-to-height ratio is not greater than 1.5.(3)A single-story single-span buckling-restrained steel plate shear wall with outof-plane deformation spaces specimen has been tested under cyclic loading at the scale ratio of 1/3.A flat steel plate shear wall has also been tested in order to reveal the seismic behavior of the buckling-restrained steel plate shear wall with out-of-plane deformation spaces.The research shows that the seismic behavior of the bucklingrestrained steel plate shear wall with out-of-plane deformation spaces has been improved due to the covering concrete slabs which are installed on both sides of the embedded steel plate.The embedded steel plate can remain basically intact at the end of the test.The covering concrete slabs were seriously damaged and should be strengthened in the design.The initial stiffness and the shear bearing capacity of the buckling-restrained steel plate shear wall with out-of-plane deformation spaces can be accurately predicted by the calculation formulas of the initial stiffness and the shear bearing capacity,whicn can be applied in engineering practice.The finite element models of flat steel plate shear wall and buckling-restrained steel plate shear wall with out-of-plane deformation spaces were established by ABAQUS 2018.The finite element models,whose availability were validated by test data,have been used for numerical analysis of seismic behavior.The research shows that the seismic behavior of flat steel plate shear wall is significantly influenced by height-to-thickness ratio,span-to-height ratio and thickness of stiffeners of embedded steel plates,yet hardly influenced by initial geometric defects.The seismic behavior of buckling-restrained steel plate shear wall with out-of-plane deformation spaces is significantly influenced by height-to-thickness ratio,span-to-height ratio,thickness of the covering concrete slabs,and gap size between the embedded steel plate and the covering concrete slabs.(4)According to the conclusions of numerical analysis of buckling-restrained steel plate shear wall with out-of-plane deformation spaces,the buckling-restrained steel plate shear walls with partitions have been composed by installing the transverse partitions and vertical partitions in both gaps between the embedded steel plate and the covering concrete slabs,respectively.The buckling-restrained steel plate shear walls with transverse partitions and with vertical partitions specimens have been tested under cyclic loading at the scale ratio of 1/3.The experimental comparison has been carried out between the buckling-restrained steel plate shear walls with partitions and the buckling-restrained steel plate shear wall with out-of-plane deformation spaces to reveal the seismic behavior of the buckling-restrained steel plate shear walls with partitions.The research shows that the overall buckling of the embedded steel plate will be constrained by installing the partitions in both gaps,and the local buckling of the embedded steel plate can only be occurred in independent cell.The damage of the covering concrete slabs has been eased,and there is no large area peeling of concrete.The initial stiffness and the shear bearing capacity of the buckling-restrained steel plate shear walls with partitions can be accurately predicted by the calculation formulas of the initial stiffness and the shear bearing capacity of the buckling-restrained steel plate shear wall with out-of-plane deformation spaces,whicn can be applied in engineering practice.(5)The simplified analysis model,which is suitable for steel plate shear walls to simulate the strength degradation,stiffness degradation,and pinching effects,is proposed based on Pivot hysteresis model of the polyline plastic connection element.The performance targets under the frequent earthquake,fortified earthquake,rare earthquake and extremely rare earthquake levels have been established.The seismic responses of steel frame structure,steel frame structure with flat steel plate shear walls,and steel frame structure with buckling-restrained steel plate shear wall with out-ofplane deformation spaces were studied by using the performance-based design method,which is based on fortified intensity and simplified analysis model for steel plate shear walls.The research shows that buckling-restrained steel plate shear wall with out-ofplane deformation spaces owns stable energy dissipation capacity,and can effectively reduce the structural seismic responses,such as the maximum acceleration of top floor and the maximum layer displacement angle under the action of fortified earthquake,rare earthquake and extremely rare earthquake.