Web crushing capacity of high-strength concrete structural walls: Experimental study

This paper discusses the relationship between concrete strength and web crushing capacity based on results from large-scale tests of thin-webbed structural walls with confined boundary elements. Eight walls with concrete strengths ranging from 39 to 138 MPa (5.6 to 20 ksi) were tested to web crushing failure under cyclic and monotonic loading. These tests clearly demonstrated differences between elastic and inelastic web crushing behavior and their dependence on concrete strength. Walls with higher concrete strengths reached higher levels of displacement ductility due to an increase in web crushing capacity. Evidence with respect to monotonic tests showed that degradation of the diagonal compression struts from cyclic loading increases with concrete strength, thus limiting the inelastic deformation capacity gains. Thus, concrete compressive strength does not linearly increase web crushing strength as implied by rational web crushing models; rather, the relationship is nonlinear, with a decreasing limit as concrete strength increases. The ACI shear stress limit considerably underestimated the web crushing capacity of the walls. Test results and observations are reported with the intent of providing physical insight into the web crushing failure mechanism and the inherent limits of thin-webbed concrete members in shear.