It doesn't take an engineer to figure out how to blow up a bridge.
Bentley got in position near the bridge to begin bombing it, while Sly and Murray took their positions inside the ballroom. Bentley began placing charges on the lower cleats. Doing so caused the structure to destabilize, popping off the retainer rings on the upper cleats. Right before the lower platform fell apart, Bentley bounced up to the upper cleats and began bombing them. Once they were destroyed, the bridge began to crumble. Within seconds, the second platform collapsed, and the entire bridge fell down with it. Bentley then went off to warm up the van and prepare his RC chopper for the final phase.