Experimental Investigation into the Seismic Performance of Fully Grouted Concrete Masonry Walls Using New Prestressing Technology

Abstract

In recent years, traditional masonry structures have been widely used in rural areas of China. However, they were found to have a poor seismic performance during earthquakes. In this study, a new prestressing technology was proposed and described in detail, and it was used in fully grouted concrete masonry wall systems to improve its seismic performance. The experimental work involved investigating the seismic response of four fully grouted reinforced concrete masonry wall systems, consisting of two symmetrically arranged reinforced block masonry walls, with different section types and prestressing technologies, when subjected to cyclic lateral force. Based on the test results, a flexure and ductile failure occurred in the specimens with a rectangular section, while a shear and brittle failure occurred in the specimens with a T-shape section. The prestressing technology had no significant effect on the failure state of the specimens, but it influenced the crack propagation, making cracks fine and densely covered. A symmetrical and obvious pinching effect was observed in the hysteretic response of all specimens. The average displacement ductility of the specimens varied within a range of values between 3.34 and 6.92, according to the section type of the specimens, and the prestressing technology improved the displacement ductility of the specimens. Moreover, the prestressing technology significantly improved the initial stiffness of the specimens, and the specimens with prestressing technology experienced a greater fall in the degradation of the normalized stiffness than the specimens without this technology throughout the loading process. In addition, the equivalent viscous damping of the specimens ranged between 8.2% and 10.8%, according to the section type. It could be concluded that the prestressing technology improved the energy dissipation of the specimens at the ascending stage, although it had no marked influence on the equivalent damping ratio of the specimens.