Behavior of steel box girder bridges under blast loads and the possibility of reopening the bridge immediately following the explosion

Bridges play a vital role in transporting inhabitants and goods both within and outside of cities, making them vulnerable to explosions.Therefore, understanding how bridges perform under blast loads is crucial for the safety of infrastructure and urban societies.This research investigates the dynamic behavior of steel box girder bridges when exposed to blast loads, focusing on factors like explosive weight, blast standoff distance, and blast location.It also explores the possibility of partially reopening the bridge to traffic immediately after an explosion.We used the ABAQUS nonlinear finite element analysis software to model the bridge.The study shows that reinforced concrete slabs and steel girders completely collapse when subjected to an explosive weight of 5000 kilograms (equivalent to a truck filled with explosives).This indicates that these structural elements cannot withstand such a large explosion, leading to their total failure.Reinforced concrete slabs are more likely to collapse when an explosion occurs in the middle of the span, whereas steel box girders tend to collapse at the ends of a span.The detonation's standoff distance correlates with the explosive weight.Explosive weights of 50 kilograms (motorcycle) and 200 kilograms (medium car) damage specific areas of the bridge, allowing for the potential partial reopening of other sections immediately after the explosion.In contrast, explosive weights of 300 kilograms (large car), 1400 kilograms (pickup truck), and 3000 kilograms (van) cause extensive damage, making it impossible to reopen any section partially.