Influence Analysis of Axial Compression Ratio on the Performance of Core-Grouted Assembled Thin-Walled Steel Tube-Reinforced Concrete Composite Shear Wall

As a new type of shear wall system, core-grouted assembled thin-walled steel tube-reinforced concrete composite shear wall avoids the difficulty of core pulling of assembly shear wall. Besides, the amount of steel is not increased much, which means it has a good economy while improving the production efficiency. In order to study the influence of axial compression ratio on the performance of thin-walled steel tube reinforced concrete shear wall, the shear wall specimens with the height are 2 600 mm and the section size is 1 100 mm×200 mm are simulated by numerical simulation. The whole specimens are modeled, and it is assumed that the upper and lower ends of the wall are fixed with the loading beam and foundation beam. The load process is applied to the top of the model with vertical uniform load, and the horizontal displacement at the top of the specimen is gradually loaded from 1.3 mm to 26.0 mm. The whole process from elastic force stage to failure is simulated effectively. The difference between failure modes and hysteresis performance of thin-walled steel tube-reinforced concrete composite shear wall in the range of axial compression ratio 0.3-0.5 is compared.
Through the numerical analysis of different models, it is found that the final failure modes of 5 specimens belong to the bending failure of large deflection members under the action of compression bending. Under the reciprocating load, the model near the bottom has a large horizontal deformation, which eventually results in failure due to loss of bearing capacity. According to the stress cloud diagram of the simulated specimens, the thin-walled steel tube at both ends of the test piece yields first, and then the concrete outside the thin-walled steel tube near the bottom begins to reach its tension strength, so the concrete outside the thin-walled steel tube gradually fails. The concrete inside is restrained by thin-walled steel tube, so the specimen can continue to bear the load. Thin-walled concrete-filled steel tube can bear repeated load. During the simulation process, there is no shear slip between thin-walled steel tube and concrete, to maintain a stable state, which makes the specimen have good plastic deformation ability while being subjected to vertical uniform load. The model hysteresis curves are full shuttle shapes, without obvious pinch up. With the increase of axial compression ratio, the envelope area of the hysteresis curve of thin-walled steel tube core filled concrete shear wall is larger, the shuttle curve presented is more fat, the energy dissipated is more, and the ultimate bearing capacity is improved to some extent. From the skeleton curve, when the axial compression ratio exceeds 0.35, with the increase of axial compression ratio, the ductility coefficient decreases. According to the cumulative energy consumption coefficient of each model, the energy consumption capacity of thin-walled concrete-filled steel tubular shear wall will be improved with the increase of axial compression ratio. Under the condition of axial compression ratio of 0.3-0.5, the ductility coefficient of thin-walled steel tube core filled concrete shear wall is more than 3.0, which shows that the structure has good deformation and ductility performance, which can meet the requirements of seismic design.