Monongahela Bridge 1818-1845 - Bridges and Tunnels of Allegheny County and Pittsburgh, PA

Elevation drawing looking downstream

OFFICIAL NAME:
Monongahela Bridge

OTHER DESIGNATION:

LOCATION:
Pittsburgh

USGS 7.5" Topo Quad - UTM Coordinates:
Pittsburgh West - Zone 17; 0584 4476

CARRIED:
Smithfield Street

Pedestrian walkways on upstream and downstream sides

BETWEEN:
-- Water St
-- Carson St (West Carson and East Carson split is marked at this intersection.)

CROSSED:
-- Monongahela River at mile 0.7
-- Monongahela Wharf

TYPE OF CONSTRUCTION / DESIGN:
Burr arch truss - covered (see HAER article for details)

LENGTH OF MAIN SPAN:
8 spans, 188 ft each

TOTAL LENGTH (including longest elevated ramp):
1,500 ft between abutments

HEIGHT OF DECK:
37 ft est

YEAR ERECTED / ENGINEER:
1818; Lewis Wernwag, engineer
burned in Fire of 1845; replaced 1845-46

ADDITIONAL INFO:
The current structure is the third bridge on this site. Lewis Wernwag built the covered wooden Monongahela Bridge in 1818, the first river crossing bridge in Pittsburgh. It replaced a ferry and cost $102,000. It was destroyed in the Great Fire of 1845 and replaced the following year.
John Roebling, creator of the Brooklyn Bridge, designed a wire rope suspension bridge which used the 6 piers and abutments from the earlier bridge (8 spans, 188 ft each). Roebling's first highway bridge operated as a toll bridge. Increasing live loads from added traffic resulted in excessive deflections and swaying, leading to its closure and replacement with current structure.

view page -- Historic American Engineering Record (PA-2) article.

FIELD CHECKED:

INFO SOURCES:
Historic American Engineering Record (PA-2)

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Introduction -- Nearby Structures

Page created:
Last modified: 05-Oct-2000

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