Stability of Slender Wall Boundaries Subjected to Earthquake Loading

Global instability of slender reinforced concrete walls occurs when the concrete section buckles out-of-plane over a portion of the wall length and height. Theoretical and numerical analyses were conducted on axially loaded prismatic members to evaluate the onset of global instability under tension/compression load cycles. A buckling theory suitable for hand calculations is introduced and evaluated using data available in the literature from tests conducted on columns. Computer simulations using force-based nonlinear elements with fibers are used to numerically simulate the tests and to study the influence of non-uniform strain profiles along the height of the member. The study shows that the onset of buckling can be identified using either the proposed buckling theory or finite element models. Furthermore, buckling is affected by gradients of axial load or strain along the length of the member. Design recommendations are made to inhibit global wall buckling during earthquakes.