The Iowa D-O-T’s chief structural engineer says Interstate bridges are designed to withstand heavy-duty collisions. A wreck this weekend on Interstate-80 closed the roadway for hours after a semi struck a bridge near Van Meter and burst into flames. D-O-T engineer Ahmad Abu-Hawash says not only are bridges designed to withstand crashes, they can withstand the heat of some fires.Abu-Hawash says some fires, though, burn too hot and would compromise the structural integrity of the steel beams which support the bridge. The I-80 bridge near Van Meter was re-opened to traffic Sunday, but will undergo some repairs.The deck needs to be resurfaced in some areas, the steel beams that support the bridge need to be repainted and the guard rail must be fully restored.