Effect of out-of-plane deformation and varying axial load on sliding shear behavior of reinforced concrete shear walls

Sliding shear failure of reinforced concrete shear wall members has been observed in actual earthquake damage. Sliding shear failure is a failure that reduces the load capacity and energy absorption performance of members. The sliding shear capacity, determined by sectional response, is affected by the lateral bidirectional loads and varying axial force acting on shear wall members during earthquakes. This research aims to uncover the sliding shear behavior of shear walls under tridirectional loading conditions, simulating realistic seismic conditions. The authors employed loading experiments with axial load conditions and O/I drift ratio (defined as the ratio of outof -plane drift angle to in -plane drift angle) as parameters. As a result, only the specimen with a varying axial load of 0 - 1370 kN and an O/I drift ratio of 3.0 showed sliding shear failure, whereas the specimens with constant axial load or an O/I drift ratio of 1.0 showed shear failure. Additionally, the evaluation method of sliding shear capacity proposed by Idosako (2018) was confirmed to be applicable under varying axial load. In conclusion, this study revealed that sliding shear failure is more likely to occur when the axial force decreases due to varying axial load or when the out -of -plane directional drift angle increases. Furthermore, the expansion of the applicability of the sliding shear capacity evaluation method contribute to designing more resilient buildings by preventing sliding shear failures from occurring in shear wall members.