In just eight milliseconds, 750 explosive charges sent the old Highway 47 bridge at Washington to the bottom of the Missouri River.
Representatives from the Missouri Department of Transportation (MoDOT) and the demolition team from Marschel Wrecking said the implosion was a huge success.
Jeremy Frye, Marschel Wrecking project manager, said his company began planning for the demolition last October and there is still much more to do.
“Everything went exactly perfect,” Frye said. “Each piece fell exactly where it was supposed to and nothing hit the new bridge.”
Frye added there were more than 200 pages of plans for the placement of 145 pounds of explosives packed into 750 linear-shaped charges and metal precuts on the 2,100-foot-long structure.
All of the charges were connected by 8,000 feet of detonation cord.
“To the naked eye it looked like one blast. The detonation cord took eight milliseconds to travel the 2,000-plus feet,” Frye said. “There were only two charges (on the north side) that didn’t cut through the metal like they were supposed to.”
Those pieces will be cut in place and there will not be any need for additional blasts.
Frye added the all clear notice was given about 45 minutes after the blast.
“We had covered all of the explosives with plywood, so we had to clean some of that off of the new bridge,” he said.
Now that the 38 sections of the old bridge are down, subcontractor Budrovich Marine, St. Louis, is assisting Marschel crews with removing the pieces from the river.
“We’ve still got a lot of work to do,” Frye said. “Budrovich has the cranes and barges, we don’t, but we do have some of our equipment on the barges also.”
From the time the first piece of bridge hit the water just seconds after 10:30 a.m., Marschel had a window of 24 hours to get several bridge sections out of the water.
“We have to get the pieces out of the main channel first,” Frye said. “It has to be cleaned and sonar swept.”
The main channel is located on the Washington side of the river between piers one and two of the bridges.
Once all of the metal pieces are out of the river, Marschel crews will begin the task of removing the piers that once held the steel structure by cutting the concrete in to smaller pieces and placing them on the barges.
Frye said Marschel Wrecking has taken down several other bridges, but this was the largest span over water the company has done to date.
The successful blast Thursday was yet another chapter in the decades long book to replace the 83-year-old river crossing for Missouri Department of Transportation officials as well.
Area Engineer Judy Wagner has been deeply involved with both the construction of the new $63 million bridge and demolition of the old.
“Overall, this was a huge success and everything is good to go,” Wagner said. “Everything went smoothly from the coordination on the land and water, and crews are already in the process of cleaning the twisted metal from the river.”
Wagner confirmed no debris from the demolition hit the new bridge, but there was a lot of old paint chips from the trusses that ended up on the new road deck, but they were cleared quickly.
In less than an hour after the blast, the new Highway 47 bridge and railroad tracks were all open for regular traffic.
“I’m thankful for all of the groups involved,” Wagner said. “The FAA, marine patrols, the railroad, highway patrol, department of conservation local authorities and many others.”
The subcontractor on the demolition project, Budrovich Marine, provided all marine support equipment for the retrieval of the bridge, including tugs, cranes on barges, and excavator on barge. The manager of Budrovich Marine, Mindy Brundick, grew up in Franklin County.
Budrovich Marine previously has done the retrieval on Boone Bridge, as well as Chain of Rocks Bridge.