Robustness assessment of precast reinforced concrete structural systems in an accidental design situation

Abstract

The article presents the simplified implementation of the method of alternative load paths based on the energy balance approach. This method should be used to checking the global resistance of a damaged structural system after the occurrence of an accidental event. It is necessary to provide (reserve) enough ties with the required continuity and ductility in the original prefabricated structural system to ensure the integrity of the damaged system. We consider the system of ties as the “second line of defense” of the structural system after the exhaustion of the flexural resistance of its elements. The continuity and ductility of the tie elements provide a resistance of the damaged structural system under an accidental combination of actions by mobilizing alternative load paths after the support or key element has been removed. Ductility is the ability of the tie to obtain significant plastic bond elongation before rupture. The ductility is important properties of the ties for redistributing internal forces and getting large deflections. It is necessary for the realization of the chain (membrane) effect, as well as a measure that provides energy absorption (damping) during the dynamic application of an accidental action after the vertical support losing. The article presents analytical solutions and the working example for the design of horizontal ties in precast hollow-core slabs floor, which are obtained based on the energy approach.