Heated reinforced concrete slabs subjected to blast load: Experimental and numerical results

Ferry-free coastal route E39 is a project that aims to design a coastal highway without ferry connections. Wide and deep fjords along the Norwegian coast make submerged floating tunnels (SFT) an alternative to conventional structures. In the unfortunate situation of accidental events, the SFT reinforced concrete (RC) structure may become damaged, affecting its load carrying capacity. RC shells can be a representative component of the SFT concrete structure, and it is relevant to study if RC shells can carry the combination of fire and subsequent blast load. An experimental program has been performed in conjunction with numerical simulations in order to enable the risk analysis and the feasibility study of SFT in the E39 project. A shock tube equipment has been used to evaluate the influence of high temperature on the blast load carrying resistance. In addition, static and material tests have been performed for further understanding of the slab behaviour. Nonlinear analyses for static loading and preliminary dynamic analyses have been performed, in combination with standard fire curve load effects. Temperature-dependent material properties have been used based on the results from the material tests. This paper gives an exemplary overview of (sometimes preliminary) results. Both the experimental and numerical results have revealed that high temperature leads to a significant internal damage of the material, affecting the response of RC slabs. In addition, statics tests results for slabs subjected to high temperatures show a significant reduction of the load carrying capacity.