Explosives fell old Marble Falls river bridge

Mar 17, 2013 (Austin American-Statesman - McClatchy-Tribune Information Services via COMTEX) -- Seventy-seven years. Then four seconds.

With a deafening series of explosions, moving north to south in a half-second across the U.S. 281 bridge over Lake Marble Falls, most of the 950 feet of metal truss works collapsed into the river Sunday morning.

The blasts produced a mass of black smoke that quickly drifted to the north over downtown Marble Falls with the morning's brisk winds.

The 8:07 a.m. concussions, louder and more forceful than even experienced Texas Department of Transportation officials on hand anticipated, also produced a sustained round of "wow," "awesome," fist pumps and excited chatter among the 3,000 to 4,000 people who public safety officials said gathered in various shoreline locations to watch.

"I didn't expect it to be that impactful," Howard Lyonscq BW, TxDOT's area engineer for the Hill County section of the Austin district, said a few minutes later. "I had pretty much been a party pooper about it not being that big a deal. But I'm glad I was here for that." Officials kept spectators who were on and along the river, including about 20 motorboats, kayaks and rowboats, at least 1,000 feet away from the bridge, and there were no reports of injuries.

But the explosion damaged a sewer line suspended from the new concrete highway bridge located just a few feet downstream of the destroyed bridge, delaying re-opening of traffic of that bridge until after 9 a.m. The sewer line was repaired by 1:30 p.m.cq BW, TxDOT spokeswoman Kelli Reyna said.

Reyna said the concussion also damaged a Verizon phone line that crosses the river at the bridge. That company's phone service, both for cellular and land-line phones, was still spotty Sunday afternoon, Reyna said. Lyons said the phone problems were expected to be resolved Sunday. The cost of both the sewer line and phone line repairs will be borne by TxDOT's bridge contractor Archer Western, Reyna said.

The demolition was part of a $30 million project to remove the existing four-lane bridge, built in 1936 and later expanded, and replace it with two side-by-side, two-lane bridges, each with ample shoulders and 6-foot-wide sidewalks. The original bridge had virtually no shoulder lanes and a single 4-foot-wide sidewalk. The northbound bridge opened in December and will have two-way traffic until the southbound bridge is built along the path occupied until Sunday by the old bridge.

The project should be complete by fall 2014cq BW, Lyons said Sunday.

Most of three sections of steel framing became twisted and obscured beneath the estimated 20 feet of water at that section of the Colorado River, deepened by the Starcke Dam about a mile and a half downstream. But one large section ended up leaning against one of the two concrete piers in the river that had supported the four-lane highway bridge. And on the south bank, another tangled mass of metal came to rest against another land-based concrete bridge support.

Crews with Archer Western moved in aboard a barge within 30 minutes to begin clearing a 100-foot channel through the wreckage so that boats can move unimpeded past that point. That job was expected to be complete by Monday morning, officials said.

Clearing the rest of the wreckage should take four to six dayscq BW, Lyons said, and workers will mechanically tear up the concrete piers down to the water line. Then the explosives crew will be at it again with what is likely to be a smaller show, blowing up the rest of those piers. That second set of explosions likely will take place March 29cq BW, Lyons said.

The explosive demolition, which officials said will cut one to three months off the project time and be safer for workers than taking apart the bridge girder by girder, required approval from state wildlife, river and environmental regulators. Their OK included enlisting Texas State University biology professor Tim Bonner and a boatload of assistants to stun fish in the area of bridge with low-grade electrical charges, and move them before the blast.

Bonner said that in the early morning hours, close to 200 fish and 17 species, including a 32-inch-long-nose gar and 20 large-mouth bass, were released about a mile downstream and had recovered sufficiently to swim away. He said his crews also temporarily relocated two ducks that bridge crews told them have been hanging around the construction for some time, becoming the project mascots.

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