Summary
The lateral stiffness and strength required of supporting beams and exterior panels of continuous reinforced concrete slab-and-beam floors in order to ensure membrane action in the panels at ultimate load is considered. It is shown that tie reinforcement may be required in the supporting beams to carry the membrane forces. Tests on twenty small-scale mortar models of idealized nine-panel slab-and-beam floors with the interior panel uniformly loaded are described. The tests illustrated the modes of failure of exterior panels with insufficient reinforcement to resist the reactire forces due to the membrane action of the interior panel. The ultimate loads of interior panels of the slabs with adequately reinforced exterior panels showed good agreement with theory derived previously (which included the effect of axial strains in the panel and lateral movement of the edges due to extension of the tie steel) once the concrete had cracked.
