(The Missourian will have extensive coverage of the bridge implosion including photos and videos from multiple vantage points on Facebook and emissourian.com just minutes after the event.)
When the copper charges are detonated and the old Highway 47 bridge over the Missouri River is dropped into the water, the green barrels sitting atop the span will lead demo crews to the pieces.
The bridge demolition is scheduled for this Thursday, at about 10:30 a.m. The new Highway 47 bridge will be closed to traffic starting at 10:15 a.m. and will remain closed for up to two hours after the blast. The public can watch the demolition from the Washington Riverfront Park.
On Tuesday, Tim Hellebusch, Missouri Department of Transportation (MoDOT) resident engineer, briefly explained to The Missourian the process from when the charge is detonated and the bridge deck is recovered.
“A cap will be at the end of the copper charge and the copper charge will be on the steel,” he said. “The copper charges will blow and cut that steel in half.”
Hellebusch said the charges will be covered with a plywood box to prevent copper shrapnel from being blasted from the site. There is a total of 750 charges on the bridge beams.
“The only purpose of the plywood box is when the charge goes ‘bam’ it deadens the copper pieces from being flying projectiles,” he said.
According to Hellebusch, the green barrels, which some passersby have assumed are the charges, actually will be buoys to help locate bridge pieces. A cable attaches the barrels to the bridge sections.
“The green barrels will pull the cable to the top of the water, which will allow for the contractor to attach a crane to it and then raise the bridge out of the water,” he explained.
Hellebusch added that people likely will still see bridge pieces protruding from the water, but the buoys will aid crews in finding pieces under the river’s surface.
The demolition and all work associated with the bridge deck removal will be conducted or supervised by Marschel Wrecking LLC, Fenton.
Following the implosion, Marschel crews will wire saw the piers into blocks so they can be picked up with a crane, according to Judy Wagner, MoDOT area engineer.
“They will use this method all the way until they hit water,” she added. “Then they will implode the sections of the piers in the water later. Everything will be removed from the river.”
Wagner explained that a wire saw uses a long rope with diamond blades attached which is used to saw concrete. It uses a drive wheel and a series of pulleys to keep it taunt.
“The first priority after the blast is to get the new bridge cleaned off and opened to traffic,” Wagner noted. “Secondly, is to remove all debris from the river to open the navigational channel. Then work on final pier removal and trusses over the railroad.”
Highway 47 will be closed from Fifth Street in Washington to the Augusta Bottom Road intersection in Warren County.
Most local drivers should be aware of the closure, but out-of-town travelers will be redirected to the Hermann or Boone bridges.
Soon after the blast, inspectors will check out the new Highway 47 bridge to ensure there is no structural damage before allowing traffic to cross.
The Mercy Hospital Washington emergency room will be kept open and law enforcement officers will be at the closure sites to allow for ambulances to get through in the event of an emergency.
There is expected to be 14 Washington police officers dedicated to the bridge demolition. The Franklin County Sheriff’s Office will assist Washington police the morning of the blast.
Warren County deputies and the Missouri State Highway Patrol will control traffic on the north side of the bridge.
Additionally, there will be fire and ambulance crews stationed on each side of the bridge in the case of emergencies.
The Washington Municipal Airport will not allow air traffic there for about two hours before and after the demolition. The no-fly zone includes drones.
The Washington riverfront boat ramp will close at 6 a.m. All river traffic will be stopped 15 minutes before the blast. The channel crossing will remain closed for up to 48 hours after the blast so boaters should plan on staying on the side of the bridge where they put in.
There will be a strictly enforced 1,000-foot radius zone surrounding the bridge in which people must remain indoors when the blast occurs.
The blast radius extends to Third Street to the south. Mercy Hospital is just outside of the zone, but the subcontractor will be working with the hospital and is asking that no surgeries be scheduled during the blast.
There will be a 10-second “all clear” alarm sounded prior to the blast. Also prior to the blast, there will be a “sonic discharge” that will sound to scare wildlife away from the area.
Washington firefighter Matt Coleman, who was the winner of a drawing to push the button detonating the bridge, will be at the control center in the Highway 47 and Third Street area. The control center and packaged explosives will have tight, round-the-clock security in the time leading up to the blast.
Washington police determined the areas to be closed for pedestrian and vehicles traffic.
The following streets will create a perimeter where no pedestrian or vehicles will be allowed from 8:15-9:45 a.m.:
• Third Street from Boone Street to Washington Avenue;
• Boone Street north to Missouri Avenue;
• Washington Avenue north to River Pilot Point; and
• Rotary Riverfront Trail 1,500 feet to the east and west of the bridge, including the railroad right of way and tracks.