Non-Planar Reinforced Concrete Walls: Assessing Effective Stiffness and Influence of Axial Load Ratio and Eccentricity with Simplified Beam-Truss Models

This study investigates the effective stiffness of non-planar reinforced concrete walls, a key parameter in seismic design. By assembling a database of experimental cyclic tests, it highlights how effective stiffness varies with wall geometry, loading direction, and axial load ratio and eccentricity – factors often neglected in current code formulations. Using pushover analyses with a simplified beam-truss model (BTM), the study demonstrates good agreement with experimental data and supports BTM use for estimating effective stiffness. The findings underscore the need to revise effective stiffness definitions in design codes and promote further research for better seismic design of non-planar walls.