U-shaped walls under diagonal loading

Core walls are often used to provide horizontal stiffness and strength to mid- or high-rise buildings. The design practice is, however, largely based on findings from tests and analysis of rectangular walls subjected to uni-directional loading. The article shows results from two quasi-static cyclic tests U-shaped walls. These tests highlight that the diagonal loading direction is particular critical for U-shaped walls. This is for the following reasons: (1) The strain gradient across the wall width promotes out-of-plane buckling of the boundary elements in the flange ends; (2) Plane section analysis does not yield reliable moment capacity estimates for the diagonal loading direction and (3) under diagonal loading the compression depth in the flange end boundary elements is larger than for the other loading directions, exposing unconfined concrete to large compressive strains.