Research on seismic resistance and mechanic behavior of reinforced lightweight aggregate concrete walls after high temperature

摘要

This study focused on the mechanical behavior of reinforced lightweight aggregate concrete (RLAC) walls under repeated horizontal loads after a standard temperature-rising fire-resistance test and compared the specimen walls' ultimate loads, yielding loads, cracked loads, stiffness, and ductility with those of reinforced normal-weight aggregate concrete (RNAC) walls. Steel reinforcing bar spacing, aggregate types, wall widths, and high temperatures were variables in this study. The experimental results showed that, after the fire-resistance test, the smaller the steel reinforcing bar spacing of RLAC walls, the higher the yield and ultimate loads, yet the worse the ductility and the hysteresis loop's energy, whereas the greater the width of the wall, the greater the stiffness and the higher the hysteresis loop's energy. The differences in terms of stiffness, ductility, and hysteresis between RLAC walls with and without the fire-resistance test were insignificant, indicating that RLAC walls do not lose their basic mechanical behavior during a high-temperature fire. RNAC walls showed, indeed, a significant downward trend for strength and hysteresis after the fire-resistance test, but the decrease was much less clear for stiffness. Therefore, RLAC walls did show better seismic resistance than RNAC walls under the same testing conditions.