Damage detection of lightweight concrete dual systems reinforced with GFRP bars considering various building heights and earthquake intensities

Because of their distinct mechanical, rheological, and physical features, lightweight concrete and glass fiber reinforced polymers (GFRP) bars have a significant growth in the modern building sectors over the past decade. Minimizing subsequent quake damages, particularly in multistory residential or administrative RC structures, is a key concern for governments in earthquake zones. The dual frame-wall system is among the most appropriate structural systems for resisting seismic loads in multistory concrete structures. Therefore, this research aims to quantify the seismic damage of multistory dual frame-wall systems with varying heights of 12, 20, and 25 stories under mild, medium, and severe earthquake intensities. The inelastic damage analysis of RC buildings program is utilized to nonlinearly analyze 54 cases containing various materials such as normal concrete, lightweight concrete, steel reinforcement bars, and GFRP bars. Using lightweight concrete with half the density of normal concrete and pure linear-elastic GFRP bars in floor construction will significantly decrease the geometric nonlinearity effect created by the load-displacement (P-Δ) effect and dissipate a large amount of the kinetic energy generated by seismic excitation, resulting in a significant reduction in post-earthquake damage. When compared to the normal concrete, using lightweight concrete in floor construction reduced the mean story damage index by 14–20% as the building's height increased, while reinforcing these floors with GFRP bars resulted in substantial decreases in the overall damage index, reaching about 57–68% when both building's heights and seismic excitation intensities were considered.