Industrial History: 1806+1896,1957 Northampton Street Bridge over Delaware River at Easton, PA

Monday, April 22, 2024

1806+1896,1957 Northampton Street Bridge over Delaware River at Easton, PA

1806: (Archived Bridge Hunter)

1896: (Archived Bridge Hunter; Historic Bridges; HAER; Satellite)

Historic Bridges rates this bridge as 10+10, his highest rating.

The 560' (171m) long bridge has a main span of 300' (91m). [BridgeHunter_1896]

The main span has a 50' (15.2m) suspended span truss. [HistoricBridges]

Street View, Jul 2019

Significance: The Northampton Street Bridge is one of a few extant eye-bar cantilever bridges in the United States. Its 50'-0"-long central span, supported between two 250'-0" cantilever arms, is carefully disguised by superfluous members so as to appear as a smooth catenary. Its appearance is tastefully balanced between Gothic flamboyance and a spartan machine aesthetic — a piece of urban "structural art." Designed by James Madison Porter III, professor of engineering at nearby Lafayette College and an early advocate of materials testing, this bridge is his most important work. Bethlehem Steel Company repaired the structure to its original design in 1957, after it was heavily damaged by a flood two years previous. The Northampton Street Bridge has been designated a National Historic Civil Engineering Landmark by the American Society of Civil Engineers. [HAER_data]

I'm glad I found information about this bridge, otherwise I would have assumed it was a suspension bridge.

Street View, Jul 2019

Street View, Nov 2021

HAER PA,48-EATO,15--1
1. GENERAL VIEW, LOOKING SOUTH FROM WEST BANK OF THE DELAWARE RIVER. - Northampton Street Bridge, Spanning Delaware River at Northampton Street (U.S. Route 22 Alternate), Easton, Northampton County, PA

DRJTBC
"The bridge was designed and built by Timothy Palmer, one of the foremost bridge builders of his time. Palmer’s covered bridge at Easton endured many floods and storms while other bridges fell. However, by the late nineteenth century, when horse-drawn streetcars were replaced by trolley cars, the old wooden bridge could no longer handle the demands of traffic and a new structure was erected. The new bridge was designed by James Madison Porter III, a graduate of nearby Lafayette College with a degree in civil engineering, who hailed from a family long prominent in Easton and Pennsylvania history. The Northampton Street Toll Supported Bridge sustained major damage during Hurricane Diane when floodwaters, 44 ft above normal water level, topped the roadway of the Northampton Street Bridge on August 19, 1955. Repairs carried out over the next two years made the bridge useable but the flood damage left a readily apparent sag in the center span that remains today. Another series of improvements were completed in the Summer of 2002 and included structural steel repair and replacement, painting, and the replacement and installation of sidewalk decking and new pedestrian railings The bridge is currently posted for a three-ton weight limit and a fifteen mile per hour speed limit." [I wonder if the webpage has been updated since the 2023 rehabilitation and if the bridge is still limited to three tons and 15 mph.]

Bob Dover posted

The Northampton Street Bridge connects Easton, Pennsylvania to Philipsburg, New Jersey. The surprising and appealing feature of the bridge is the decoration of the towers and lampposts. Eyebar chains and composite girders are decorative wherever you find them because the individual components can be shaped into complex geometric patterns. Added to these are elongated, lattice-like finials on the tops of the towers. On the top chord over the middle of the roadway, a frieze displays gilded allegorical figures of Liberty and Prosperity on either side of a heraldic shield, which sits over a gilded plaque reading “1795-1895.” Another gilded plaque on the lower horizontal support shows the significance of these dates, with 1795 being the date of incorporation of the Delaware Bridge Company, and the bridge construction in 1895 marking the centenary of the company. The lampposts are nicely-shaped, frosted-glass globes sitting on decorative black iron bases. The bridge carries two lanes of traffic on a steel mesh deck and has wide sidewalks on both sides, outside of the truss.

I provided an extensive description of a tour of the bridges of the upper Delaware River in Chapter 9 of my book, Bridgespotting Part 2: A Guide to Even More Bridges that Connect People, Places, and Times. There are photos of most of the bridges, including the Northampton Street Bridge, posted on www.bridgespotting.com. [Upper Delaware River Bridges]

Note the diagonal member on the left is an eye-bar that can handle only tension whereas the diagonal member on the right is a built-up beam that can handle compression. HistoricBridges explains that is because the left panel is part of the cantilever arm whereas the right panel is part of the suspended span.

Street View, Jul 2019

HistoricBridges_articles

The bridge has been rehabilitated several times, most recently in 2023. The rehabilitation included adding colored lighting to the bridge. Here are five photos supplied by the DRJTBC via HistoricBridges.