Experimental study on seismic behavior of steel tube confined high-strength concrete shear walls

Abstract

The high strength concrete shear walls are characterized by its high bearing capacity, high stiffness but a poor deformation capacity. In order to improve the deformation capacity of these members, specimens of high-strength concrete shear wall with steel tube confined boundary elements were designed and the quasi-static tests were conducted. The failure mode, failure mechanism, deformation capacity, hysteretic behavior, stiffness degradation and energy dissipation capacity of specimens were researched. The results indicate that the steel tube boundary elements can provide an effective confinement to the wall pier and the horizontal bearing capacity of specimens dropped slowly. Under a high axial force, the vertical bearing capacity of specimens can be maintained, and the deformation and energy dissipation capacity could be obviously enhanced due to the use of steel tubes in the boundary elements. The ultimate displacement and the energy dissipation of steel tube confined high-strength concrete shear walls were increased by 27 % and 81 % respectively compared to high-strength concrete shear walls with the same axial load ratio. According to the experimental results, the calculation formula is addressed for the cross-section bearing capacity of steel tube confined high-strength concrete shear wall. As a result, it is a good practice that the steel tube confined boundary elements can be utilized at the bottom strengthening zone so as to improve the seismic performance of high-strength concrete shear walls.