Comparative studies on blast resistance of precast concrete composite and cast-in-place slabs

Precast concrete composite (PCC) slabs with truss rebars have been widely applied in modern civil engineering attributed to their advantages over traditional cast-in-place reinforced concrete (RC) slabs in constructional industrialization and environmental protection. With the increasing aggravations of blast-induced catastrophic incidents, there is a lack of understanding on the blast resistance of PCC slabs. This study aims to perform a comprehensive evaluation on the dynamic behaviors of both PCC and RC slabs against blast loadings. Firstly, by designing a blast loading test apparatus, the field explosion test was conducted on six PCC and RC slabs with three identical scaled distances of TNT explosive. The incident and reflected overpressures-time histories, as well as damage patterns and deflection-time histories of slabs were recorded. Secondly, by adopting the Multi-Material Arbitrary Lagrangian-Eulerian and Fluid-Structure Interaction algorithms, a finite element analysis approach was proposed and fully validated by comparison to the overpressures of blast wave, deflections and failure modes of slabs in both the present and existing explosion tests. Finally, the prototype PCC and RC slabs in frame building structures were designed, and the corresponding blast resistance against three typical design-based threats of explosion specified by the U.S. Federal Emergency Management Agency was examined. It indicates that, under the near-range explosion of briefcase bomb (23 kg TNT), the maximum deflection at the 1/4 span of the prototype PCC slab is 36 % less than that of the RC slab. Considering the superior blast resistance of PCC slabs, the traditional RC slabs could be replaced by PCC slabs for the prefabricated blast-resistant buildings.