Post-crack performance of fibre reinforced concrete and its effect on the first peak cracking load of slabs

摘要

Concrete slabs-on-grade and other plate elements have for a long time been designed on the basis of elastic analyses of stress distribution. This typically results in a very conservative estimate of the minimum thickness required to resist design point loads because an elastic analysis does not account for the capacity of even quasi-brittle materials to redistribute stress following initial cracking. Fibre-reinforced concrete (FRC) is a material that can exhibit significant post-crack performance. The existence of a residual moment capacity in a FRC slab allows the slab to redistribute stress such that the peak in load resistance may occur beyond the point of first cracking in the concrete matrix. The present experimental investigation has demonstrated that residual moment capacity in the immediate post-crack range can influence the magnitude of the first peak in load resistance associated with cracking. The results suggest that the method of structural analysis used to design concrete slabs should consider the residual moment resistance in the immediate post-crack range when estimating the first peak load resistance associated with cracking.