Behavior, design, and modeling of structural walls and coupling beams — Lessons from recent laboratory tests and earthquakes

TLDR

Current models of slender structural walls capture nonlinear flexural behavior but fail to account for reinforcement buckling, shear‑flexure interaction, and associated strength loss, indicating a need for further research. Recent earthquakes in Chile and New Zealand and laboratory tests reveal that modern codes underestimate wall damage, with reinforced concrete walls experiencing boundary crushing, reinforcement fracture, and buckling, while coupling beams show limited energy dissipation—diagonally‑reinforced beams tolerate about 6 % rotation before strength loss, whereas conventional beams fail near 4 %, underscoring the need to revise code provisions.

Abstract

Abstract Observed wall damage in recent earthquakes in Chile and New Zealand, where modern building codes exist, exceeded expectations. In these earthquakes, structural wall damage included boundary crushing, reinforcement fracture, and global wall buckling. Recent laboratory tests also have demonstrated inadequate performance in some cases, indicating a need to review code provisions, identify shortcomings and make necessary revisions. Current modeling approaches used for slender structural walls adequately capture nonlinear flexural behavior; however, strength loss due to buckling of reinforcement and nonlinear and shear-flexure interaction are not adequately captured. Additional research is needed to address these issues. Recent tests of reinforced concrete coupling beams indicate that diagonally-reinforced beams detailed according to ACI 318-11 1 can sustain plastic rotations of about 6% prior to significant strength loss and that relatively simple modeling approaches in commercially available computer programs are capable of capturing the observed responses. Tests of conventionally-reinforced beams indicate less energy dissipation capacity and strength loss at approximately 4% rotation.