The U.S. 40 bridge over the Patapsco River, a durable and scenic icon of Depression-era infrastructure that has finally reached the end of its useful life, is being replaced — and it's today's motorists who will endure the resulting delays.
Sometime in the next few months, the State Highway Administration will begin preparations for the demolition of the roughly 75-year-old structure spanning the Patapsco River State Park on the border between Baltimore and Howard counties.
But the $32 million project will not be a routine bridge replacement. Because the bridge is a vital link on a busy commuter route that connects Ellicott City with Catonsville and Baltimore — carrying about 37,300 vehicles a day — highway officials have deemed the corridor too vital to replace with a detour.
Instead of closing the structure, the state will adopt the unusual strategy of building two, two-lane temporary spans to carry traffic over the river while the deck and supporting pillars of the four-lane bridge are demolished to make way for a new, wider structure. Only some parts of the substructure, including the graceful concrete arch that bears most of its weight, will be retained.
To build the temporary bridges, says State Highway Administrator Neil J. Pedersen, work crews will have to take over one lane of the existing bridge. After conducting traffic surveys, officials have decided that the burden will fall on westbound drivers because the homeward evening commute is more spread-out than the eastbound morning rush.
According to early estimates, motorists would have to get by on one westbound lane for about six months while the temporary bridges are built and another six months toward the end of the project. But Pedersen said the highway agency is looking for ways to lessen the disruption.
There's little doubt that the old bridge is in need of replacement. Classified as "structurally deficient," the grades for its condition are low enough that the project qualifies for federal aid that will cover most of the construction costs. Photos released by the highway agency show serious rusting and corrosion of the columns and struts, as well as cracks in its beams.
"There have been several major bridges that our bridge engineers have made very clear to me are the highest priority bridges," Pedersen said. This, he said, is one of them.
The highway chief noted that Maryland, like many other states, built many new bridges in the 1930s as the original federal road system took shape and in the 1950s with the birth of the Interstate Highway System. For many years before Interstate 70 opened, U.S. 40 was Baltimore's principal route to Western Maryland.
He said many of the 1930s-era bridges were actually over-engineered and have held up as well as those built in the Fifties. But many bridges from both decades — resources were diverted by World War II during much of the 1940s — must now be replaced.
"Just as health care costs for baby boomers are going up, health care costs for bridges are going up," he said. The project is expected to extend the life of the crossing by 30-50 years.
Bids were opened last month, and the apparent contract winner is Corman Construction Inc. of Annapolis Junction.
The work is expected to be completed in 2013. Construction money for the project is firmly embedded in the new draft six-year spending plan released this month by the Maryland Department of Transportation.
Pedersen said the strategy of building temporary bridges to handle traffic is an unusual one. He said he can't remember it being done before in Maryland except in the case of relatively small structures.
"We try to avoid having to do it," he said.
The U.S. 40 bridge is far from small. The 334-foot-long span, with a deck almost 50 feet across, carries the highway not just across the river 60 feet below but also across a deep gorge. There are other current Maryland bridge projects that cost as much or more because they involve interchange work, but in terms of the size of the span itself, this will be the largest under construction, Pedersen said.
The new bridge will include 5-foot shoulders, sidewalks and bicycle access — features that are not present on the current structure. Plans call for preservation of the old bridge's historic design features where possible. According to Pedersen, the project will have to be carried out with extra care to protect the park environment from harm.
State records show that the bridge was completed in 1936, though contemporary accounts put the finish date in 1935. The bridge remained virtually unused for many years after its completion because the highway it serves had not been finished.
A 1938 article in The Sun described the structure as "one of the most beautiful bridges in Maryland" but complained that it led nowhere.
"It is the sort of bridge that arouses enthusiasm and excitement in whoever sees it," the article said. "But it is a useless bridge. For more than a year it has made its gallant leap across the valley, but no traveler has yet crossed it. It does no work."
The bridge saw only limited use by local property owners in the late 1930s and early 1940s, but paving of the Howard County side of what is now U.S. 40 was delayed by World War II and not completed until 1949. Eventually, the span would go on to carry generations of motorists over the Patapsco — opening much of then-rural Howard County up to the suburban development that exists today.
History can judge whether the state has recouped its investment on the bridge. The original cost, according to the SHA: $158,410.93.