The first blast to begin the demolition of the old Hurricane Deck Bridge went off as planned around noon Saturday, Dec. 7, taking down close to one-third of the truss arch bridge with precision.
The blast had been delayed three times due to winter weather this week, giving the old bridge on Highway 5 at the 35 mile marker a reprieve of two days.
But Saturday dawned bright and cold, and the blasting finally went forward after crews had been working for weeks to first remove the deck following the switch to the new bridge on Sept. 9.
Two steel truss spans on the north end of the bridge were blasted with 31.16 pounds of explosives, according to Missouri Department of Transportation officials.
The $32.3 million contract with American Bridge Company, Inc. for the replacement bridge included the demolition of the old bridge. Duane Houkom, Inc. was the subcontractor for the blast.
MoDOT estimated the detonating velocity at 27,000 feet per second. From the trigger to the detonation of the last charge, the shot took place in thirty-two thousandths of a second.
Mostly what could seen were a few small orange lights then quickly lots of smoke as around a million pounds of steel dropped down.
The bridge was eight spans long with three spans of concrete girders and five spans of steel truss girders. Only the steel truss spans — around 2,180 feet — are being removed by blasting.
Designed specifically to cut steel, linear shaped charges sheered the 740 foot section of the bridge into 12 pieces upon detonation, according to MoDOT project manager John Sanders.
Afterwards, a few barrels and debris floated on the water beneath where the old bridge once stood. Crews quickly got busy removing debris.
Residents near the bridge who had been warned to stay inside during the blast could safely come out. On Highway 5, traffic across the new bridge — located just a few feet from the old — had been stopped about 1/10th of a mile away, but the roadway was quickly reopened following the blast.
Attached by cable to the large steel sections sent down into the depths of the lake, the barrels mark the location for divers to hook up the pieces for a crane to pull out of the water and onto a barge over the next couple of weeks. From there, the old steel will be salvaged and recycled.
The second blast will take place in two weeks and will take down the south steel truss span. The third and final blast in another two weeks after that will remove the center steel truss span.
Built in 1934-35, the old bridge was a five span steel continuous cantilevered Warren deck-truss design with two concrete deck-girder approach spans and was the last of its kind in the state, being only one of three of that type built in Missouri. The other two were also located at the Lake of the Ozarks — the old Grand Glaize Bridge and the Niangua Arm Bridge — and have already been replaced.
Page 2 of 2 - The American Institute of Steel Construction named it the most beautiful steel span built in 1936. And that beauty helped make it a landmark at the Lake of the Ozarks since it opened Dec. 28, 1936 and officially dedicated Oct. 3, 1937.
Originally a toll bridge, there are likely few now who remember paying to cross, but the cost was 40 cents for a car and driver and 5 cents for each additional passenger — or a dime for a round trip.
Prior to the old bridge, cars and people were moved across the water by ferry.
The new bridge is a safety improvement as the old bridge was considered structurally deficient and had rust issues.
The new bridge is also wider providing more space on the shoulders.
Drilled shafts and rock sockets, ranging from a few feet long to 100 feet long, hold up the new bridge.
MoDOT has invested roughly $100 million in bridge work in the region over the last 20 years.