Experimental Study On Shear Resistance Of Steel Plate Reinforced Concrete Coupling Beams And Design Method

In the high-rise building structure, the coupling beams which are the first line of defense in seismic design can seriously influence shear wall stiffness, bearing capacity and ductility. The earthquake energy is dissipated through the ductility and energy dissipation ability of the coupling beam. The coupling beam is sensitive to shearing deformation and easy to shear failure while cross section thickness is small and even bear reverse bending effect on both ends of the beam. Through the buried steel plate in the beam, jointly improve ordinary reinforced concrete beam shear performance.In this paper,12 specimens with a span-depth ratio of 1.5 and different ratio of steel plate reinforcement were tested under cyclic loads. Tests results show that due to the existence of the built-in steel plate, the shear bearing capacity of the coupling beam, the displacement ductility and energy dissipation performance is significantly higher than the reinforced concrete beam. Along with the increase of plate ratio, bearing capacity is improved. When the plate ratio increases to a certain extent, the bearing capacity is no longer improved. If continue to increase plate ratio, bearing capacity will declines. Hysteresis curve of steel concrete coupling beams are even fuller than ordinary concrete beams. And with the increase of plate ratio, the area of the hysteresis curve surrounded. Due to the existence of the built-in steel plate, energy consumption capacity significantly increased, stiffness and strength degradation is also not clear than ordinary concrete beams, showing better seismic energy dissipation capacity. But the plate ratio has little effect on energy consumption of the coupling beam. The strain and shear bearing capacity are analyzed in detailed according to the experimental measurement results. Measured strain showed that before yielding of the specimen, the beam inflection point is located in the middle of beam span, the beam section remains as a plane. But after that The beam inflection point moves towards compression zone. The steel plate has great strain among steel section height, steel has a large axial force here. And steel strain is relatively small at section edge. Therefore, the flexural bearing capacity consists of two parts, the steel plate section modulus resistance of bending moment and the axial force to compressive zone of concrete. The shear of steel plate and stirrups are quantitatively analyzed. The steel plate reinforcement ratio effect on the bearing capacity is analyzed. Analysis results show that Before specimen yield, Shear mainly borne by the concrete, the main purpose of steel plate and stirrup constraints the development of cracks; After specimen yield, the original shall be borne by the concrete shear transfer to stirrups and steel plate. Even when the shear ability of steel plate reach a certain extent, the role of shear stirrups relatively weak. Based on this, the formula to calculate the shearing resistance of the steel concrete coupling beam and reasonable plate ratio ranges are put forward.The paper also includes the non-linear finite element analysis using ABQUS. Analysis results are basically in agreement with the experiment results. The specimens with different plate ratio of steel reinforcement are analyzed by finite element simulation. The analysis results verified the calculate formula. The design proposal is put forward so as to provide reference for engineering design.