Experimental investigation of the load–displacement behaviour under catenary action in a restrained reinforced concrete slab strip

When a support of a statically indeterminate concrete slab is lost due to an accidental event, tensile membrane or catenary forces can be activated at large deflections. This effect can considerably increase the load-carrying capacity compared to predictions obtained from small deformation theories neglecting membrane and catenary forces. Thus, these actions can prevent a progressive collapse and hence increase the robustness of concrete structures. A novel experimental large-scale test set-up is described which allows the testing of continuous, longitudinally restrained, reinforced concrete slab strips exposed to a simulated accidental failure of the central support and subsequent vertical loading until collapse. The details of this test set-up as well as the measurements related to the load–displacement behaviour are explained. Within this investigation the development of catenary action associated with the formation of large displacements was found to increase the ultimate bearing capacity significantly.