The Effects of Infilled Walls on Seismic Performance of RC Frame Structures with Eccentrically Placed Open Corridor

Abstract

In this paper, an RC frame model with infilled walls was built and tested, including by a modal test, percussion test and shaking table test, the prototype of which was a collapsed teaching building with an eccentrically placed open corridor during the Wenchuan Earthquake in Xuankou Middle School. The natural frequency of the model was obtained by microseism testing, and the contribution of the infilled walls with different openings to the lateral stiffness of the model was discussed. In addition, the damping ratio, strain responses and internal force distribution of the columns were analysed by knocking the roof of the RC frame model, and then a shaking table test was conducted to study the seismic performance of the model. The results show that the value of longitudinal fundamental frequency increased from 1.88 Hz to 6.65 Hz, and the transverse one increased from 1.90 Hz to 13.40 Hz. The torsion frequency was increased by 6.65 times compared with that when the wall was not built. Furthermore, the damping ratio of the model was significantly increased after the infilled walls were built. When the floor moves longitudinally, the strain at the end of the columns restrained by semi-high continuous infilled walls is 2–4 times that in the unconstrained columns, and the shear force in the restrained columns is 4–8 times that in the unstrained columns. As a result, plastic hinges would form in the constrained columns; then, the columns would lose their vertical load capacity.