Green Lane Bridge

Green Lane Bridge

The Green Lane Bridge, NBI # 39141, is a  concrete arch bridge over the Schuylkill River on Green Lane and Belmont Avenue. Built in 1928, the Green Lane Bridge still plays a critical role in Philadelphia. It is one of the major arteries into the very popular section of the city, Manayunk. The ADT for the bridge is 24,111 vehicles, and for a rather narrow bridge in being only 36.1 feet wide, the traffic is fairly dense. The total length of the bridge is 564 feet, generating  a deck area of

The Green Lane Bridge was designed by world renowned architect Paul Philippe Cret (1876-1945).  Some of Cret’s most known projects are the Benjamin Franklin Bridge, The National Memorial Arch in Valley Forge, and the Rodin Museum of Art in Philadelphia. His design was a closed-spandrel arch. Arch bridges were far and away the most popular bridges of this time period. The four major types of concrete arch bridges are filled spandrel, closed spandrel, open spandrel, and through arches. Both closed and open spandrel arches carry the load of the roadway to the ribs of the arch.

Reinforced concrete is a very economical and efficient way of constructing a bridge. It combines concrete with steel bar to utilize the compressive strength of concrete along with the tensile strength of steel. However, reinforced concrete does not come without its disadvantages. The tensile strength of reinforced concrete is about one-tenth in compressive strength. And despite its rather low maintenance cost, reinforced concrete is far from cheap to pour. And the results of the pour can be inconsistent, leading to even more discrepancies. As of August 2012, the deck and the superstructure were classified as being in fair condition and the substructure was in poor condition. Despite these negative ratings, NBI still has this as a fairly sound bridge receiving 79.6 of the given 100 points.