Experimental study on seismic behavior of bottom enhanced composite shear wall with CFT column frame and concealed reinforcement bracing

In order to study the seismic behavior before and after damage of bottom enhanced composite shear wall with CFT column frame and concealed reinforcement bracing, bottom enhanced and normal shear wall specimens were tested under low cyclic loading. In the first stage test, the specimens were loaded to reach 1/50 drift ratio and yielding phenomenon was obvious. After the first stage test stopped and the horizontal displacement was unloaded to its initial status. The second stage test was conducted under low cyclic loading until the specimens were seriously damaged. Failure features, hysteretic behavior, bearing capacity, stiffness degradation, ductility, energy dissipation ability and strain were all analyzed. Simplified bearing capacity calculation formulas were presented. Research shows that when the concrete wall suffers no damage, the bottom enhanced composite shear wall gets slighter damage and higher bearing capacity by 8.6% than normal composite shear wall, but the other behaviors of the two walls are close. After a big part of the concrete wall is damaged, the bottom enhanced composite shear wall has higher residual bearing capacity, larger deformation capacity and stronger energy dissipating capacity than the normal one. Thus, seismic performance degradation speed of the bottom enhanced shear wall is relatively low and the anti-collapse property is good. The presented bearing capacity calculation formula can well estimate the bearing capacity. ©, 2015, Science Press. All right reserved.