Des Moines bridge is set for implosion

An interstate bridge in Des Moines will be blown to pieces this weekend. Demolition experts will implode the southbound Cottage Grove Bridge that crosses I-235 northwest of downtown Des Moines early Sunday morning. It’s part of a massive project to replace all the bridges along the I-235 corridor in the Capitol City. Thom Doud of Controlled Demolition Incorporated says they’ll place explosives in some 800 holes in the spans and pillars of the bridge. He says it takes more explosive to bring down a bridge than it does a building as the larger structures are pulled down by gravity. Bridges don’t have as much weight.Doud says they’ll try to keep the blast under control as the entire structure will be covered in fabric and chain-link fence to keep debris from flying.He says there’ll be a lot of dust as there always is with an explosion, but not as much dust as when a building implodes.Doud says it’ll take about three seconds to bring the bridge down, and showed a folder dropping from his hand to a desk as an example of how quickly the bridge will fall.A spokesman for the Iowa D-0-T says they’re discouraging spectators from watching the implosion. He says traffic will be re-routed around the bridge for about 13 hours. The northbound bridge will be dropped a week from Sunday.