Staged construction analysis of reinforced concrete buildings with different lateral load resisting systems

摘要

Lateral load resisting systems (LLRS) in reinforced concrete (RC) buildings should be adequately determined to control their response under lateral and gravity loads. Practitioners used to select the LLRS using one-step analysis (OSA) by assuming both the lateral and gravity loads are applied at one stage to a complete building. Instead, staged-construction analysis (SCA) should be adopted because RC buildings are constructed in different stages and the gravity loads act sequentially. In this research, a nonlinear finite element model for SCA of RC buildings is developed and validated using a robust commercial software. The developed model is extended to account for time dependent effects (SCAT) such as shrinkage, creep, and strength gain. The model is utilized to analyze eight RC buildings with different heights and LLRS. Design parameters for the studied buildings are proportioned to satisfy both the working and ultimate state design criteria. Differential displacements and straining actions in horizontal elements as well as shortenings in vertical elements are estimated using SCAT and then compared to their counterparts obtained from OSA. SCAT yielded shortening and differential displacements larger than those obtained from OSA by a percentage that reached 143%, 153%, 116%, and 154% for buildings with rigid frame, shear wall, wall-frame, and tube in tube LLRS, respectively. Increase in straining actions obtained from SCAT ranged between 26% and 554% more than those obtained from OSA. Decrease in straining actions obtained from SCAT ranged between 26% and 71% less than those obtained from OSA.