Seventh Street Bridge 1885-1925 - Bridges and Tunnels of Allegheny County and Pittsburgh, PA

View toward North Side

Elevation drawing looking downstream

View toward North Side, Sixth St Bridge at left

OFFICIAL NAME:
Seventh Street Bridge

OTHER DESIGNATION:
Irvine (Irwin) Street Bridge

LOCATION:
Pittsburgh

USGS 7.5" Topo Quad - UTM Coordinates:
Pittsburgh West - Zone 17; 0584 4477

CARRIED:
motor vehicles

BETWEEN:
-- Sandusky St on right descending bank of Allegheny River
-- Seventh St [Irvine/Irwin St] on left descending bank of Allegheny River

CROSSED:
-- Allegheny River at mile 0.6

TYPE OF CONSTRUCTION / DESIGN:
Suspension - - catenaries were steel eyebar chain arranged in concentric pairs connected by lattice girders
steel eyebar suspenders

LENGTH OF MAIN SPAN:
two main spans, 320 ft; two side spans, 165 ft

TOTAL LENGTH (including longest elevated ramp):
970 ft

HEIGHT OF DECK:

YEAR ERECTED / ENGINEER:
1885, Gustav Lindenthal; replaced 1925

ADDITIONAL INFO:
A two-span suspension bridge which had truss-bracing on catenaries holding two eyebar-chain cables in concentric arcs. This bridge was designed by Gustav Lindenthal three years after he built the Smithfield Street Bridge.

Declared a toll-free bridge 16 March 1911.

Seventh St was formerly Irvine St (or Irwin St) in Pittsburgh; it aligns with Sandusky St in the former city of Allegheny (Northside).

view page - "Three Sisters" Bridges -- Historic American Engineering Record document

FIELD CHECKED:

INFO SOURCES:
HAER; Lorant, "Pittsburgh"; Smith, "Pittsburgh: Then and Now"

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Introduction -- Nearby Structures

Page created:
Last modified: 07-Dec-2000

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