County officials agreed this week to post signs limiting speed and weight on the Brighton Dam bridge, which links Howard and Montgomery counties, because of the 48-year-old bridge's crumbling concrete.
The signs limiting truck weight to 10 gross tons and speed to 25 milesper hour will be in place within two weeks, said James I. Irvin, director of the county Office of Public Works.
Thomas A. Stumm, operations bureau director for the Washington Suburban Sanitary Commission, said the commission, which owns the dam beneath the road, was making the request of both Howard and Montgomerycounties as a "precautionary measure." The counties share responsibility for road maintenance.
After a 155-pound chunk of concrete fell 80 feet and severely damaged one of the commission's service truckslast month, the manager of the dam sent a memo to his superiors calling for the bridge to be closed immediately.
Stumm said the erosion of concrete "is not life-threatening." He said the commission sought the lower weight and speed limits to lessen the impact on the bridge. The reductions may mean the difference between another "chunk falling and not falling," he said.
Six barricades and 22 cones on the bridge sidewalk have also been put in place as a precautionary measure to keep people from stumbling or tripping, Stumm said. The cones mark places where the curb has crumbled along the 0.1-mile-stretch of bridge. The barricades mark places on the railing where the concrete has fallen away to reveal steel structural rods.
The worst of the damage is on the reservoir side of the bridge, although there is also heavy crumbling on the dam side. The dam itself is structurally soundand is inspected frequently, Stumm said. It is the bridge on top of the dam that is the problem, he said.
The bridge had been used further up the river before the dam was built in the early 1940s. It wasmoved to the top of the dam after the dam was finished and the reservoir created.
The lightly traveled road leading to the dam begins in Clarksville and meanders though wooded hillsides populated with homes priced at $600,000 and more. The top of the dam offers one of themost scenic views in the county. The foot of the dam on the Montgomery side has been set aside as a picnic area by the commission.
Thequestion of further repairs is being negotiated by commission officials and their counterparts in Howard and Montgomery counties. At issue, Irvin said, is whether to make intermediate or "full-blown" repairs to the bridge. Meanwhile, traffic continues to cross the bridge unabated.