Glimmer Glass Bridge

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The Glimmer Glass Bridge is a more than 100-year old bridge located in Manasquan, New Jersey. It is owned by the County of Monmouth and facilitates traffic from Brielle Road over the Glimmer Glass, a navigable tidal inlet of the Manasquan River. It is of the cable lift bascule bridge using a Rolling Counterweight design built in an estimated year of 1898 and maintains the integrity of the original design. It has 17 spans making a total length of 279 feet long with a width of 20 feet.^[1]

The bridge itself is located in a salt marsh lowland surrounded by what was historically considered a seasonal community of small bungalows and cottages. Significant modifications have been made to these structures and in addition to large modern homes that are also present in the adjacent towns of Brielle and Manasquan, the surrounding area near the bridge is not eligible for historic district status as determined by the State of New Jersey.

The rolling counterweight single-leaf bascule bridge with a deck girder movable leaf is the only example of the late 19th century bridge type in the state of New Jersey and possibly the entire country.^[2] The designer and builder are unknown as determined by the Monmouth County Engineer's Office. The undocumented bridge represents a little-used technology that was developed prior to 1895. It was a popular design for railroads in New Jersey for spanning canals. Although the Glimmer Glass Bridge was modernized in 1957, it still operates in the original manner and is thus historical and technological significant as determined by the New Jersey Department of Transportation by use of Criterion C under the National Register.

When the design was developed and by whom can not be identified, but an 1896 article in the publication Scientific American described a recently completed example by the Erie Railroad on its main line over Berrys Creek near Rutherford, New Jersey (currently non-existent) that "although the principle behind the design is not entirely new, the Berry's Creek Bridge is the first application of this system of counter weighing for a structure of this magnitude." The principle is to use a curved track and rolling counterweights where the work expended in raising the leaf is equal to the energy released by the falling counterweight. The toe end of the moveable span is linked by cables to cylindrical rolling counterweights. The connecting cable passes over a tower column with a curved track. Moving the counterweights along the curved track thus raises or lowers the bridge<sup id="ref_<name>_<A.G. Lichtenstein & Associates, 1995 NJDOT Bridge Survey>">[<A.G. Lichtenstein & Associates, 1995 NJDOT Bridge Survey>].