Experimental and numerical study of stiffened steel plate-concrete composite panels under explosion

Stiffened steel plate-concrete composite panels (SSCPs), consisting of a stiffened steel plate and a concrete wearing layer, are commonly used in bridge engineering. However, it has been proven that SSCPs are vulnerable to blast loads resulting from accidental explosions and weapon strikes. This study investigated the damage characteristics and mechanisms of SSCPs exposed to explosive-induced blast loads. Field blast tests were performed on two specimens SCP-1 and SCP-2. The tests involved detonating 5.4 kg of TNT at standoff distances (SoDs) of 87.7 cm and 52.6 cm, respectively, to generate the blast loads. A numerical model was established and validated with experimental results to analyze the damage progression of the panels. SCP-1 and SCP-2 exhibited circular compressive damage due to the compressive shock wave front, with plastic damages near the edges caused by the reflected waves. For SCP-1, the stiffened steel plate absorbed more explosion energy than the concrete layer, while the reverse was observed for SCP-2. SSCPs were also subjected to varying explosive masses and SoDs. The results showed that explosive mass had minimal impact on the energy absorption ratio between the stiffened steel plate and concrete layer when detonated at a SoD of 0.877 m. However, at a SoD of 0.35 m, the energy absorbed by the steel plate increased with the increase of explosive mass. Additionally, for panels subjected to a fixed explosive mass and varying SoDs, the energy absorption of the concrete layer initially increased as the SoD decreased but later decreased as the SoD continued to decline. These findings provide insights into the energy absorption mechanisms of SSCPs under blast loading conditions.