The Pennsylvania Avenue Bridge conveys

Pennsylvania Avenue Pennsylvania Avenue is a diagonal street in Washington, D.C., and Prince George's County, Maryland, that connects the White House and the United States Capitol and then crosses the city to Maryland. In Maryland it is also Maryland Route 4 (MD 4 ...

across Rock Creek and the adjoining

Rock Creek and Potomac Parkway The Rock Creek and Potomac Parkway, informally called the Rock Creek Parkway, is a parkway maintained by the National Park Service as part of Rock Creek Park in Washington, D.C. It runs next to the Potomac River and Rock Creek in a generally n ...

, between the neighborhoods of Georgetown and

Foggy Bottom Foggy Bottom is one of the oldest late 18th- and 19th-century neighborhoods in Washington, D.C., located west of the White House and downtown Washington, in the Northwest quadrant. It is bounded roughly by 17th Street NW to the east, Rock C ...

in Northwest Washington, D.C. Pennsylvania Avenue terminates at M Street immediately west of the bridge.

Original bridge

The original bridge at this site was constructed of large cast iron pipes by the Army Corps of Engineers in 1858 to 1860.

Montgomery C. Meigs Montgomery Cunningham Meigs (; May 3, 1816 – January 2, 1892) was a career United States Army officer and civil engineer, who served as Quartermaster General of the U.S. Army during and after the American Civil War. Meigs strongly opposed sece ...

designed the bridge and supervised its construction as part of the original construction of the

Washington Aqueduct The Washington Aqueduct is an aqueduct that provides the public water supply system serving Washington, D.C., and parts of its suburbs, using water from the Potomac River. One of the first major aqueduct projects in the United States, the Aquedu ...

. It was officially named the Meigs Bridge after it was completed, although name that never caught on and it was often called other names such as the Tubular Bridge. At the time of its construction it was the only bridge made completely of

cast iron Cast iron is a class of iron– carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impur ...

of substantial size in the United States. It was originally intended to be solely an aqueduct bridge carrying water mains connected to the

Georgetown Reservoir The Georgetown Reservoir is a reservoir that provides water to the District of Columbia. Part of the city’s water supply and treatment infrastructure, it is located in the Palisades neighborhood, approximately two miles downstream from the Ma ...

, but the onset of the Civil War necessitated making it a vehicular crossing as well. The level of traffic was such that the wooden deck had to be replaced every three years. The bridge used an innovative design in which the 48-inch water pipes themselves formed the load-bearing arches of the bridge supporting the roadway. A water pressure engine in the west abutment supplied water to a reservoir at the current site of the Georgetown branch of the D. C. Public Library to feed the significant part of the City of Georgetown that was too high to be directly fed by the main Washington Aqueduct. A horse-drawn streetcar line crossed the bridge from 1863 to 1872, when it was rerouted over the nearby M Street Bridge.

Current bridge

In 1913 the D.C. Board of Commissioners opted to build an expanded arch bridge around the existing bridge rather than construct a completely new steel-girder bridge, for reasons of cost. The

United States Commission of Fine Arts The U.S. Commission of Fine Arts (CFA) is an independent agency of the federal government of the United States, and was established in 1910. The CFA has review (but not approval) authority over the "design and aesthetics" of all construction wit ...

, the agency tasked with reviewing architectural projects in the capital, opposed the plan on aesthetic grounds, saying that the arch design would clash with the existing Q Street Bridge upstream, but their recommendations were ignored. The expanded bridge was built of reinforced concrete with a smooth granite facing. The abutments and water mains of the original bridge are encased inside the expanded bridge, which still transports water to this day, although they no longer support the load of the bridge. The new bridge was significantly wider than the original; increasing from 17 feet to 73 feet. By 2015, the bridge was considered to be structurally deficient, with a 15-month rehabilitation planned to begin that summer.

References

External links

* {{Georgetown, Washington, D.C. 1860 establishments in Washington, D.C. 1916 establishments in Washington, D.C. Bridges completed in 1860 Bridges completed in 1916 Bridges over Rock Creek (Potomac River tributary) Deck arch bridges Georgetown (Washington, D.C.) Historic American Engineering Record in Washington, D.C. Road bridges in Washington, D.C. Water in Washington, D.C. Arch bridges in the United States Concrete bridges in the United States

Original bridge

Current bridge

See also

References

External links