Bridge woes prompt need for wider I-81 crossovers

By DAN KEGLEY/Staff

When wrecks block the northbound or southbound lanes on Interstate 81 in Southwest Virginia, officials often set up a detour at the closest exit back up the traffic stream, and traffic is diverted onto Highway 11. Even though that’s a much slower alternative, since the older route passes through towns and nowhere is the speed limit higher than 55, the problem is solved until the interstate reopens, right?
Not quite, according to Virginia Department of Transportation officials, at least not in Smyth County.
Those interstate detours introduce a new problem, because four of the bridges along Highway 11 are not rated to carry the weight of tractor-trailers.
In response, VDOT is building eight crossovers in the interstate median between mileposts 31 and 57 – the interstate’s span across the county’s midsection. Those will allow detours on the interstate itself, by funneling traffic from the blocked lanes onto the inside lane on the other side of the big road.
The cost of the emergency crossovers is $855,000, said VDOT spokeswoman Michelle Earl. The project is scheduled for completion in late August.
Smyth County’s crossover construction is unique along the interstate. “To my knowledge, there are no similar projects along I-81,” Earl said.
The bridges that are posted – those with signs at either end indicating their capacity is lower than the structure was originally designed for – have deficiencies due to age, weather and wear discovered by inspectors.
The state of Virginia’s bridges came to the fore almost a year ago following the catastrophic collapse of a bridge in Minnesota.
Buston sought to reassure drivers in the commonwealth late last summer, saying the state keeps a close eye on its bridges by annually inspecting those on interstates and other primary roads and by giving back-road bridges the once-over every two years.
Eighty-thousand pounds is the legal limit for the weight of a vehicle crossing a bridge, Buston said. When a bridge is posted – that is, a sign is posted at the bridge that gives a lower weight limit—it’s because engineers have lowered the limit due to their discovery of some form of degradation in the bridge.
When a bridge is posted, that puts it in the running for rehabilitation to bring it back to the full legal load limit. But as with almost all highway projects, it takes time to plan the work and find the money to pay for it. The reduced limit says the bridge can remain in service, but only by drivers’ observing a lighter load stipulation.
Buston said two Smyth bridges on Highway 11 are first in line for rehabilitation.
One is the bridge crossing the Norfolk Southern railroad at the west edge of Chilhowie near the Smyth/Washington county line.
“That bridge has been posted,” Buston said. “A project has to be done on it, replacing the deck or the piers. It will be below the legal limit until that’s done.”
At the time, plan designing was under way and Buston could not be sure what year funding would be available.
Earl said that project, which has been advertised for bids and is set to begin in September, will replace the bridge and cost $2.6 million.
Also beginning that month is replacement of the deck on the Route 11 bridge over the interstate at Exit 39, Earl said. The project has also been advertised for bids and will cost $1.1 million.
Next on the calendar for 2011 is the Route 11 bridge at Groseclose over the railroad near Exit 54.  The project to replace the bridge is tentatively scheduled to begin in fiscal year 2011 and will cost an estimated $2.9 million, Earl said.
Finally, replacement of the Route 11 bridge east of Chilhowie is tentatively scheduled to begin in fiscal year 2012 at a projected cost of $2.9 million, Earl said.
A 2005 VDOT traffic report said the Interstate 81 corridor averages 48,000 vehicles per day, up to 60,000 in some places.
Trucks make up 26 percent of this volume, a percentage that rises to 35 percent in some sections.
VDOT said the interstate was designed to handle 15 percent trucks.
Virginia’s bridges are generally a bit newer and in slightly better shape than the national average, a Richmond Times-Dispatch review of highway records shows. Federal highway officials rate fewer than one in 10 of Virginia’s bridges as being in poor shape.
Seventy-six of 13,365 Virginia bridges are in even worse shape. Those have rust, flaking surfaces or erosion eating deeply into or under the main pieces of steel or concrete that hold them up, the Times-Dispatch review found.
One reason the state has fewer structurally deficient bridges may be that Virginia’s bridges aren’t quite as old on average. While 26 percent of Virginia bridges are more than 50 years old, the national figure is 29 percent.