Shear Lag Effects in Reinforced Concrete C-Shaped Walls

Abstract

Shear lag effects can significantly reduce the moment capacity of nonrectangular reinforced concrete walls. Although this phenomenon is recognized as an important component in the analysis and design of buildings, it is generally not well understood by practicing engineers. Furthermore, a paucity of experimental studies exists that have focused on the seismic performance of reinforced concrete C-shaped walls and virtually no studies that have investigated the shear lag effects for these types of walls. This research investigates shear lag effects in reinforced concrete C-shaped walls using an extensive number of finite element modeling results. The numerical analyses are conducted using VecTor3 version 1.1, a state-of-the-art finite element modeling program, to estimate the vertical strain distributions across the web and flanges of the wall. The results show that shear lag effects are significant and sometimes prominent in C-shaped walls, particularly for the wall sections perpendicular to the loading direction. An expression is derived to estimate the effective width of C-shaped walls and for the different loading directions. Moment-curvature analyses are conducted to illustrate how practicing engineers can implement the effective width method for future analyses and designs.