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.
Keywords: Composite Bridges, Steel box girder, Blast loads, Explosive weight,
Non-linear analysis