page_title: Harvard Bridge
section_title: Maintenance and events
hierarchical_section_title: Harvard Bridge / Maintenance and events
caption_attribution_description: English: Harry Houdini jumps from the Harvard Bridge.
context_page_description: The Harvard Bridge is a steel haunched girder bridge carrying Massachusetts Avenue over the Charles River and connecting Back Bay, Boston with Cambridge, Massachusetts. It is the longest bridge over the Charles River at 2,164.8 feet.
  After years of infighting between the cities of Boston and Cambridge, the bridge was built jointly by the two cities between 1887 and 1891. It was named for Harvard University founder John Harvard. Originally equipped with a central swing span, it was revised several times over the years until its superstructure was completely replaced in the late 1980s due to unacceptable vibration and the collapse of a similar bridge.
  The bridge is known locally for being marked off in the idiosyncratic unit of length called the smoot.
context_section_description: In 1898, 3-foot (0.91 m; 0.54 sm)-wide bicycle lanes were installed next to each curb.  In 2011 (113 years later), the City of Boston finally connected these lanes to its own bike lanes.
  A marker near the southeast end of the bridge memorializes one of Harry Houdini's "well known escapes", during which he jumped from the bridge on May 1, 1908. (Other sources give the date as April 30, 1908.)
  The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced.  The draw was elevated slightly and the trolley rails were replaced as well.
  When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure.  They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails.  Structural steel hangers replaced wrought iron.  The swing span was converted into two 75-foot (23 m; 13.4 sm) fixed spans the same width as the rest of the bridge.  The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.
  Heavy traffic at the Mass Ave and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931.
  The bridge was formerly referred to as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it.  This decking was replaced in 1949 with 3-inch (76 mm; 0.045 sm) concrete-filled "I-beam lok" grating topped with a 2.25-inch (57 mm; 0.0336 sm) thick bituminous wearing surface.  At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks.  The trolley car poles were reused for street lights.  Ramps between the bridge and the under-construction Storrow Drive were added.
  The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.  The fifteen expansion dams were replaced or repaired in 1969.
caption: Harry Houdini jumps from the bridge (1908)
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