The Elasto-plastic Seismic Response Analysis Of Shear Wall Structure With Weak Linking-slabs

As the development of society and economy,the configuration of buildings becomes increasingly complex.The functional requirement of big space in the lower part of tall building results in big changing of axis and it is necessary to set a transfer story to meet the requirement.The most widely used transfer type is frame-supported transferring structure.The upper load is transferred to the substructure by frame-supported beams,but the lateral stiffness of structure is prone to sudden change,which is negative to earthquake resistance.Meanwhile,large slab openings and slab partial discontinuity are widely existed in modern buildings.If the large openging is set on waist area of structures with wasp-waisted plane,two sub-sturctures will be linked by weak linking-slabs.Once fracture,the linking-slab would be incapable to transmit horizontal force and coordinate the deformation of vertical members.The integrity of structure will loss.Considering that the frame-supported transferring structure and weak linking-slabs are both critical members to determine the seismic performance of the whole structure,the seismic performance of frame-supported shear wall structure with weak-linking slabs is studied in this paper.The tower A1 and A4 of a plaza in Foshan are both partially frame-supported shear wall structures with weak linking-slabs.In order to investigate the seismic performance of these structures,a shaking table test of 1/35 scaled models is carried out.The dynamic characteristics and failure mode are studied,as well as the seismic response.After elaso-platic analysis,the seismic performances of these structures are evaluated based on the deformation of structures and structural members.Furthermore,the seismic fragility of these structures is calculated based on IDA(Incremental Dynamic Ananalysis)and seismic performances are evaluated again in terms of pobability.Several conclusions are drawn as below.(1)The main seismic deformation of the models is translation,accompanied with torsion and the reversed-phase motion of sub-structures on both sides of the linking-slabs.The whipping effect is obvious.The reversed-phase motion cause a failure of weak linking-slabs and beams on the inside area of wasp-waisted plane.The internal forces of the weak linking-slabs increase with the height of models.(2)The deformation-based seismic performance evaluation and the IDA-based seismic fragility analysis both indicate that these structures can satisfy the Three-Level performance objectivity except “undamaged under frequent earthquake”.In order to focus on the effect of weak linking-slab on the seismic performance of shear wall structures and reduce the influence factors such as frame-supported structure,typical models of shear wall structure with weak linking-slab are established according to Chinese code.The design parameters include the effective width of linking-slab,the ratio of the effective width of linking-slab to the width of typical slab,the distance between linking-slabs,the ratio of shear stiffness of sub-sttructures along the vertical direction of linking-slab’s span,as well as the density of linking-slabs along the height direction.After the seismic response of each model is calculated,the parameters’ s effects on whole structure as well as linking-slab and its connecting members are analysized.Several conclusions are drawn as below.(1)The mass and stiffness of the structure increase gradually with the increase of the effective width of linking-slabs,which will enlarge the earthquake action and the displacement.Meanwhile,increasing the effective width of linking-slabs can improve their ability to coordinate the deformation of sub-sturctures on both sides.A reduction of stress and probability of cracking will also be caused.(2)A difference between the stiffness of sub-structures on both sides of linking-slabs will lead to a torsional effect of the whole structure,thus the displacement increase along the vertical direction of linking-slab’s span.They may crack under rare earthquake due to the significantly increase of stress.Attention should be paid to the seismic design of themself and the members on their corners.(3)Both the increase of the distance between linking-slabs and the density of linking-slabs along the height direction can reduce their stress and probability of cracking,but have little effect on the sesmic response of whole structure.