Seismic behavior of unreinforced and confined masonry walls using innovative sintered insulation shale blocks under cyclic in-plane loading

Abstract

An innovative masonry unit, sintered insulation shale block, is produced with excellent thermal insulation performance and high compressive strength. In order to provide comprehensive understanding of the seismic behavior of sintered insulation shale masonry wall and promote the application in the severe cold region, seven prototype single leaf wall specimens test under the cyclic in-plane loading corresponding with the constant vertical load, including the unreinforced masonry and confined masonry walls. Previous research has indicated the tie-columns could enhance the seismic behavior of common masonry walls, and we further set out thin reinforced concrete bonds to connect the end tie-columns and hinder the brittle destruction of masonry. The main investigated parameters are axial load ratio, comprehensive effect of construction measures and aspect ratio. Thereafter, the failure mechanism, hysteretic behavior, deformation and strength capacity comparatively conducted between the tested specimens. The axial load ratio significantly impacts the failure modes. Moreover, the higher axial load would result in severe brittle destruction presenting crushed webs and shells for shear effect, which also causes the relatively fast decrease of strength after the maximum strength. The tie-columns corresponding to reinforced concrete bonds play a crucial role to improve the seismic behavior, in particular the maximum strength and ultimate deformation. Nevertheless, the effective constraint would not reverse the brittle destruction failure induced by the SIS masonry. Finally, the formulas propose to predict the critical stress and drift in the skeleton hysteresis curves. For example, the reinforcement yield strength and ductility use as the main parameters to determine the maximum stress and ultimate drift, respectively. Moreover, the formula results are in agreement with the experimental results.