Membrane action of unrestrained lightly reinforced concrete slabs at large displacements

摘要: Following full-scale fire tests on a steel-framed building, together with observations from real fires, it has been shown that membrane action, at large displacements, of composite floors comprising steel deck, concrete, and anti-crack mesh, is extremely beneficial to the survival building. It was therefore decided review previous research conducted unrestrained concrete slabs, under normal temperatures. found assumptions used develop theoretical predictions for load-carrying capacity, given vertical displacement, are only valid square slabs do not conform test rectangular slabs. A new approach presented which both conforms mode behaviour observed in tests. The design method give excellent correlation published data. prediction ultimate collapse slab due fracture reinforcement also presented, limits allowable mechanical strain reinforcement. Comparison available data shows this always conservative.