Walnut Lane Bridge

40.032297 - 75.199442Koordinaten: 40 ° 1 ' 56.3 "N, 75 ° 11' 58 " W

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Wissahickon Creek

The Walnut Lane Bridge is a concrete arch bridge in Philadelphia, Pennsylvania, United States. She leads the Walnut Lane over the deep Wissahickon Creek and thus connects the districts of German Town and Roxborough in the district of Northwest Philadelphia with each other.

Description

The road bridge has a traffic lane in each direction, separated by a bike path markings and a wide walkway that is externally bounded by a balustrade.

The 178 m long bridge crosses the valley cut with a large double arch with a span of 71 m at a height of 45 m above the water running. The rising height of the double arc is 21.42 cm (70 ft 3 in ). On both sides of this double arches four 6 m wide cost-cutting arcs are sorted elevated to support the bridge plate. The double arches are framed on both sides by strong pillars and a total of 5 double arches on the slopes of the valley, which have a wingspan of 16 m. The bridge plate is a total of 17 meters wide and was originally divided into a 12.20 m wide road for four lanes and 2.4 m wide walkways.

The Walnut Lane Bridge is a true copy of the designed by Paul Séjourné Adolphe Bridge in Luxembourg, apart from slightly different dimensions from and the fact that the Adolphe Bridge, a stone arch bridge with a reinforced concrete slab, but is Walnut Lane Bridge, a concrete arch bridge. The actual construction of the bridge Walnut Lane Bridge consists of plain concrete without steel inserts, only for the bridge plate with two parallel flat girders and walkways cantilevered reinforced concrete was used. It should be noted that under concrete stamped concrete was then to be understood, which consisted of gravel with grain sizes largely random and it was still a long way to today's concrete of broken aggregates whose particle sizes are mixed using a well-defined particle size distribution.

Just as the Adolphe Bridge, the Walnut Lane Bridge was not a huge arch, which would have required an enormous and expensive falsework, but two parallel narrow arches that were built one after the other, so that only a narrow falsework was required. However, not Paul Séjournés ideas were adopted, laterally support the falsework for further material savings to the fighters and stabilize by ropes, but they built a conventional -positioned at the bottom of the valley falsework.

History

On 13 July 1905, the City Council of Philadelphia decided to build a viaduct to connect the neighborhoods German Town and Roxborough, whose residents had to travel long detours to bypass the Wissahickon Creek. The planning of the Philadelphia Department of Public Works, which is the city-owned building administration headed by George S. Webster and Henry H. Quimby was commissioned. On 5 July 1906, with the construction of the bridge, ie initially started with the construction of falsework. The otherwise rapidly progressing construction was overshadowed on December 27, 1907 through a serious accident with one dead and nine injured when the falsework collapsed, with its degradation had just begun. The completed up to the driveways bridge was opened in October 1908 for pedestrian traffic and officially opened after completion of the remaining work on 16 December 1908.

The Walnut Lane Bridge was at the time of its opening, the largest concrete arch bridge in the world, its wingspan of 71 m exceeded that of 1904 finished Grünwalder Isarbrücke by one meter. But the Detroit Avenue Bridge, with a span of 85 m above the Rocky River in Cuyahoga County, Ohio was under construction and was completed in 1910. In 1911, the Ponte del Risorgimento followed in Rome, a reinforced concrete bridge with a flat segmental arch and a span of 100 m.

In a review in 2010, several aging-related defects were identified, which should be remedied in 2013 as part of a major renovation.

Since 1988 is listed as a cultural monument of the Walnut Lane Bridge on the National Register of Historic Places ( NRHP).

Other bridges

The Walnut Lane Bridge is easily confused with the Walnut Street Bridge, a 1900 finished iron girder bridge over the Schuylkill River in Philadelphia, with the nearby, similar-looking Wissahickon Memorial Bridge, a 1931 finished concrete arch bridge or with the Walnut Lane Memorial Bridge, the first prestressed concrete girder bridge the United States, which leads since 1951 as part of the Walnut Lane over a tributary of the Wissahickon Creek.