Fast bridge construction helps keep drivers moving
As the manager for the largest road project in Tennessee right now, Marc Rothwell goes a lot of weekends without sleep. From Friday night until Monday morning on 13 weekends, his crews are racing to demolish and replace interstate overpasses. They must finish just before rush hour. And that gives Rothwell a jolt of adrenaline.
“Because you’re worried about, ‘How’s everything still going? Where are we at?’ You’re getting a text message every five minutes,” Rothwell said. “But it’s exciting. It’s the most fun you can have doing this type of work, I can guarantee you that.”
Rothwell’s crews are working with Kiewit contractors. They’re using a method that’s been tried across the country to repair crumbling old bridges faster than ever. It’s called “Accelerated Bridge Construction,” or “A.B.C.” and it’s popular with state officials and with drivers.
The bustling work site in Nashville, Tenn., shows why transportation leaders are turning to this approach. Eight bridges from the 1960s needed replacing. Tennessee’s Department of Transportation (TDOT) turned to ABC in large part because it cuts down on lane closure times. The state shaved its project from three years to two by pre-fabricating the spans and then sliding them into place during a dozen epic weekends. “Now, there is a cost associated with that,” said TDOT Construction Director Will Reid.
Eight spans along Interstate 40 in Nashville are being replaced with accelerated bridge construction methods, which require a total shutdown of all lanes, but only in focused time windows.
The building materials and necessary machinery are more expensive. And the tight time window to get the bridges in place requires additional engineering, minute-by-minute planning, and the use of large construction cranes.
So less time doesn’t mean less work, but it causes less strife for drivers. “We have made the decision, that in this case, with I-40 in downtown, in a city that is absolutely boomin’, that it made sense for us to be aggressive,” Reid said.
State officials estimate the new method reduces the cost of closing lanes by about a third. And that translates into $5 to $10 million in productivity — time that drivers otherwise would have spent in traffic.
Reid said the calculation won’t always come out in favor of accelerated bridge construction. Built into the math are considerations of traffic volumes, the efficiency of nearby detours, and the share of traffic taken up by trucks hauling goods.
In this case, TDOT’s overall budget of $61 million reflects a potential savings of 12 percent compared to a traditional approach, officials said. They credit the shorter project for making that possible, even when the materials are more costly.
Successful efforts like this one have led to “exponential growth” in the use of ABC methods since 2011, according to the Federal Highway Administration. Many states have tried it at least once, and federal grants have encouraged ongoing use of the approach.
Tennessee has also seen a public relations benefit, with officials practically bragging about the savings and the methods. TDOT gave the project a zippy name — the Fast Fix 8 — and promotes it with time-lapse videos. Department spokeswoman B.J. Doughty says the videos have been seen more than 45,000 times.
The Tennessee construction effort has a name and a logo, seen here on the project manager’s phone.
“People are getting into watching this, when they see what looked like a bunch of chaos, all of sudden, you’re like ‘Oh my God there’s a bridge sitting there,’ ” she said.
The project managers even came up with a logo. It appears in videos and on bumper stickers with the slogan: “Failure is not an option.”
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