Study On Shear Behavior Of Coupling Beams And Shear Wall Of Steel Fiber Concrete Based On The Modified Compression Field Theory

With excellent seismic behavior, reinforced concrete shear wall structure is widely used in high-rise buildings. As the transmission link of walls in coupled shear wall and the first line of defense to the shear wall structure at the time of the earthquake, the seismic performance of coupling beam is also crucial. In high-rise building, in order to meet the functional requirements of the building or guarantee enough lateral stiffness, it often use low shear wall or coupling beam with low span-depth ratio,which often occurs generally shear destruction and then its seismic performance has been greatly weakened. In recent years, to improve the ductility and energy dissipation capacity of shear walls and coupling beams and avoid brittle shear failure,is the main research direction of shear wall structure.Because of the high tensile strength and excellent deformation ability, steel fiber reinforced concrete has been used in study of shear walls and coupling beams for improving the seismic performance of the shear walls and coupling beams.Previous experimental research show that, the coupling beams and shear walls of steel fiber concrete can effectively improve the bearing capacity, ductility and energy dissipation capacity,which transform from brittle shear failure to bending failure.But now, the research of steel fiber reinforced concrete shear wall is mostly concentrated in the experiment, and the theoretical analysis is not perfect. Especially in view of the complexity of shear resistance, the theoretical analysis of shear wall of steel fiber reinforced concrete is very limited.Modified compression field theory considering the tensile capacity of the cracking concrete, can well predict the shear performance of reinforced concrete members. So it is considered to be one of the most accurate and effective models.The biggest characteristic of steel fiber reinforced concrete is the improvement of the tensile strength. Therefore, the MCFT is used to analyze the shear resistance of steel fiber reinforced concrete members more accurately.The modified pressure field theory can be used to calculate the whole process from cracking to failure, so it can be used to analyze the seismic performance of members steel fiber reinforced concrete under cyclic loading.In this paper, based on the modified compression field theory, seismic shear behavior of steel fiber reinforced concrete coupling beams and shear walls are analyzed. And this paper mainly completed the following job:On the basis of the MCFT and stress characteristics of the steel fiber reinforced concrete coupling beams, two simplified sectional analysis models in the beams under static load are established. By using the two kinds of analysis model to analyze other test, the calculation of shear capacity has a good agreement with the test, which can be used for analysis of shear resistance of steel fiber reinforced concrete beams very well.Based on the MCFT, the constitutive relationship of steel fiber concrete and steel under cyclic loading were used to establish the section analysis model of steel fiber reinforced concrete beams under repeated loading. Compared with pre experiment test results of steel fiber reinforced concrete coupling beams, and discussed the influence of steel fiber content, strength grade and span ratio on the bearing capacity.Based on the MCFT and stress characteristics of the steel fiber reinforced concrete shear wall, the P-A analysis model of the steel fiber reinforced concrete shear walls under cyclic loading was established. Using this model to analyze others’ test, the analysis results of P-△ hysteretic curve and skeleton curve are in good agreement with the experimental results.