The historic Missouri River bridge at Rulo will come down — not in one big bang but in a carefully choreographed series of them.
No charges will be set until workers remove a nearly half-mile-long span of concrete decking, dismantle handrails and cut iron trusses to place the dynamite.
"It could happen toward the middle or end of December," said Mike Habegger, who's in charge of removing the 74-year-old bridge for the Nebraska Department of Roads.
The state dedicated the new $32 million bridge in the southeast corner of the state Sept. 1, leaving the old one connecting Nebraska to Missouri via U.S. 159 a hazard to river navigation.
Built by the Kansas City Bridge Co. for $760,000 in 1938, the bridge — with its arching metal trusses — was added to the National Register of Historic Places in 1993. It was featured in the movie "Paper Moon" and in the BBC's "Stephen Fry in America."
Because of the historical designation, the Roads Department needed approval from the Federal Highway Administration and historic preservation offices in Nebraska and Missouri, spokeswoman Mary Jo Oie said.
The old, narrow bridge sits 650 feet to the north of the new four-lane highway bridge and about 50 feet from a BNSF Railway bridge. That proximity creates a unique situation for the Roads Department and Jensen Construction Co. of Des Moines, Iowa, which has the $1.73 million demolition contract.
An average of 43 trains — most carrying coal — cross the railroad bridge daily, so demolition must be coordinated with the railroad, Habegger said. They've also had to consult the U.S. Army Corps of Engineers, which manages river flows, and the U.S. Coast Guard, in charge of river navigation.
Workers have started sawing off the bridge deck, which is more than a foot thick, and will haul it away in 10- by 10-foot slabs. Local residents and the corps have expressed an interest in them.
Next, handrails will come off and the iron cut for directional dynamite charges, so the three trusses can be dropped precisely.
"Burlington Northern's concern is the actual blasting," Habegger said.
Workers will drop the center truss first because it is in the navigation channel, then have 24 hours to remove the iron using barges and tugboats outfitted with cranes.
The job shouldn't be difficult, Habegger said, because the charges will shear the trusses — like slicing a loaf of bread in midair.
Then, the iron scrap should stick out of the river, which will be about 10 feet deep because of winter controls at Gavins Point Dam on the Nebraska-South Dakota border.
Once the center truss is removed, workers will tackle the pair on the Missouri side, which will come down in separate blasts. Workers will have 48 hours each time to remove iron — more time, because they're not in the navigation channel.
No blasting will be done on the bridge approach on the Nebraska side because homes are nearby, Habegger said. There, the metal will be cut, picked up with cranes and trucked away.
Plans call for blasting the concrete pier in the river's center. One charge will shear off the top, allowing workers to drill holes, set charges and blow up the rest. Everything must be removed down to 4 feet below the riverbed to eliminate navigation hazards.
Once finished, crews will sweep the channel with sonar to check for stray pieces. Altogether, workers will remove 12 piers and two abutments.
The public may get an opportunity to watch some demolition, with the contractor determining the size of the blast safety zone. No dates have been set, but public notices will be sent.
Flag boats will be on the river half a mile upstream and downstream to keep boats away. Because it’s winter, there shouldn’t be many.
Still, the project is a little nerve-wracking, Habegger said.
In addition to the other bridges, a 24-inch natural gas pipeline lies along the Missouri side of the river. It will be depressurized before blasting takes place.
Habegger has experience with bridge demolition. In 1986, he was an inspector when a Missouri River bridge at Nebraska City was torn down with explosives.