The Macombs Dam Bridge was named after
Robert Macomb, the son of merchant
Alexander Macomb. It is composed of an over-water span and the 155th Street Viaduct, both of which were designed by consulting engineer
Alfred Pancoast Boller. The bridge's total length is , including its approach viaducts. , the Macombs Dam Bridge carries
New York City Transit's bus routes. In 2016, the New York City Department of Transportation reported an
average daily traffic volume in both directions of 38,183, Between 2000 and 2014, the bridge opened for vessels 32 times.
Over-river span The Macombs Dam Bridge includes a
swing bridge over the Harlem River, pivoting around a small masonry island in the middle of the river. The swinging span is the oldest remaining swing bridge in New York City that retains its original span. According to the
New York City Department of Transportation (NYCDOT), which maintains the bridge, it is the city's third-oldest major bridge still in operation. The roadway measures wide and the sidewalks measure wide. The total width of the deck, including additional space for supports and railings, is . On either bank of the river are pairs of stone
end piers with shelter houses.
155th Street Viaduct At the western end of the over-water span is a long steel viaduct, carrying two sidewalks and two lanes of traffic in each direction. The viaduct stretches from the intersection of
155th Street, Edgecombe Avenue, and St. Nicholas Place, at its western end, to the intersection of Macombs Place, Macombs Dam Bridge, and
Seventh Avenue (also Adam Clayton Powell Jr. Boulevard) at its eastern end. There are traffic lights at both ends of the 155th Street Viaduct. An unconnected lower section of 155th Street runs at ground level under the viaduct. It passes over an unconnected section of 155th Street located at the bottom of the cliff. The fountain—sometimes called the Hooper Fountain after its donor, businessman John Hooper—still exists on the southeast corner of the 155th Street Viaduct and Edgecombe Avenue. Before the viaduct was built, the
155th Street station of the elevated
IRT Ninth Avenue Line, located along Eighth Avenue at the bottom of the cliff, could only be reached from the top by a long staircase. A
Scientific American magazine article in 1890 stated that "To draw a load up the hill a team has to be taken a mile or more to the south".
Seventh Avenue approach The other approach viaduct to the over-water span is from Seventh Avenue and Macombs Place (formerly Macombs Dam Road). Original plans did not provide for a connection to Seventh Avenue, but a curved ramp to Seventh Avenue was added by the time the bridge was opened. The approach was rebuilt in 1931 to provide direct access to Seventh Avenue. , it provides access to southbound Macombs Place and both directions of Seventh Avenue. At 152nd Street, a connecting road descends from the median of Seventh Avenue, connecting to the lower section of 155th Street.
Bronx approach At the eastern end of the over-water span, there are two Warren truss spans, followed by a
camelback span over the tracks of the
Metro-North Railroad's
Hudson Line. Past the camelback span, the bridge intersects with the on- and off-ramps to and from the southbound
Major Deegan Expressway. To the northeast, a steel approach road leads to Jerome Avenue, which extends north into the Bronx and
Westchester County, and there are
cloverleaf ramps to and from the northbound Major Deegan Expressway. The approach road consists of six steel-and-concrete spans across the expressway, as well as six more Warren trusses. These spans are supported by girders located atop granite piers. The approach road contains another intersection, with 161st Street, before terminating at Jerome Avenue. The
grade of the approach road is 1%. ==History==