Study On Seismic Behavior Of Embedded Steel Plate Reinforced Concrete Coupling Beams

Coupling beams play important roles in shearing forces transmission and moment's resistance,which are major energy consuming components in shear wall and core tube structures.Previous results showed that the strength,stiffness and ductility performance of coupling beams were critical for the mechanical behavior shear walls.In order to improve the deformation and energy dissipation capacity of coupling beams effectively,researchers intended to substitute steel coupling beams and composite coupling beams of traditional reinforced concrete coupling beams.Among them,steel plate reinforced concrete coupling beams(SPRC)can be used to tackle the previous problems such as deficient shear capacity and ductile deformation due to the advantages including stress uniformity in steel surface,high strength and excellent plastic deformation ability.So this coupling beam is worth popularizing.A total of 5 SPRC coupling beams and 1 reinforced concrete coupling beam(CCB)with diagonal reinforcement was tested under cyclic loading.The experiment investigated parameters of longitudinal reinforcement ratio,plate form and steel plate rate,to analyses performance of the failure mode,hysteretic behavior,energy dissipation capacity,strength and stiffness degradation,bearing capacity and ductility under different parameters.The test results indicated that compared with the CCB specimen,the SPRC coupling beams generally had more superior hysteretic behavior,ductility and energy dissipation capacity,and construction technology is simple as well.The SPRC coupling beams occurred mainly bending failure as the principal modes,and achieve ductility damage.When the beam longitudinal reinforcement ratio was too high,the capacity of specimens improved at the peril of displacement ductility reduction.Under the same ratio of plate,the bearing capacity of a single plate and double plates was similar,thus in practice,double steel plates can be adopted in the practical design to solve other problems caused by the thickness of a single steel plate.The bearing capacity of the specimens enhanced with the increase of the ratio of steel plate,when the ratio of steel plate and the longitudinal reinforcement ratio exceed a certain value,the displacement ductility decreased.TheSPRC coupling beams can effectively improve the bearing capacity and deformation properties,refine the pinch of the hysteresis curve,meanwhile in plastic hinge region,the existence of plate can provide better resistance to bending moment,the rotation capacity of plastic hinge.In general,the SPRC coupling beams had better seismic performance than traditional reinforced concrete coupling beams.This paper analyzed the specimens by FEM analysis software ABAQUS,the simulation results showed that it matched with the experimental results well,which confirmed the FEM accuracy effectively.Based on that,impacts of thickness and height of the steel plate,span-depth ratio and longitudinal reinforcement ratio of SPRC coupling beams were analyzed on failure mode and shear capacity.The computational results stated that the bearing capacity of SPRC coupling beams enhanced with the increase of the thickness of the steel plate while the growth rate decreased gradually.The bearing capacity increased linearly with the height of the steel plate,and the displacement angle of the peak load was larger.The reinforcement ratio of longitudinal reinforcement had a great influence on the bearing capacity of SPRC coupling beams when the span-depth ratio was more than 2.0,that less than 2.0,however,the improvement was not obvious.Finally,the preceding calculation formula of bending and shear capacity along with the relevant problems had been concluded about the steel plate reinforced concrete coupling beams,both at home and abroad.Based on the results of experimental and numerical simulation,the formulas for calculating the bending capacity and shear capacity were proposed.The calculated values were in good agreement with test data.It can provide important design basis and theoretical support for practical construction.