Smithfield Street Bridge in Pittsburgh, Pa

Jake Neal and Jay K

OFFICIAL NAME:Smithfield Street Bridge

LOCATION:Pittsburgh

LENGTH OF MAIN SPAN:2 main spans, 360 ft each (344 ft clear)

TOTAL LENGTH (including longest elevated ramp):1,184 ft

HEIGHT OF DECK:42.5 ftEmsworth Dam normal pool level 710 ft

Carries 4 lanes of roadway 2 pedestrian walkways. TRUSS LENGTH: 34 Inches, 246 scale ft. (32 % reduction)

TRUSS HEIGHT: 6.5 Inches, 47 scale ft. (7% reduction)WIDTHS:

BETWEEN:The bridge connects Smithfield Street in Downtown Pittsburgh with Station Square.

CROSSES:Monongahela River

Cost: 16.3 million

PARTS COUNT: Estimated 8,000 - 9,000

WOOD TIES: 1,100 (rail side)

MAN HOURS: Estimated 2,000 minimum

RAW MATERIALS USED: C-V bridge girders, Plastruct Structural Shapes and Cement, Evergreen strips and sheet stock, 36 ft. code 100 rail.

YEAR ERECTED / ENGINEER:1881-83; Gustav Lindenthal, engineerupstream side added 1889; widened to match downstream span 1911

The bridge has been designated a National Historic Civic Engineering Landmark, a National Historic Landmark, and has a Historic Landmark Plaque from the Pittsburgh History and Landmarks Foundation.

The bridge also served the Pittsburgh Railways streetcar system with a rail line

Thursday, January 24th, 2008

There was an icy spot on the Smithfield Street Bridge and that people were falling who crossed it.

From an office overlooks the bridge and a few of us took a gander. Sure enough: we saw a beautifully executed pratfall. As if we were watching a circus performance, we ohhed and ahhed as about one out of every ten people who crossed the spot fell.

A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders.

In a lenticular truss, the top and bottom chords are curved in such a way that the top chord functions as an arch, and the bottom chord functions as a suspension cable.3 Vertical and diagonal web members are necessary to divide the top and bottom chords into manageable lengths and to transfer deck loads to the top chord and the bottom chord. They also redistribute nonuniform loading, which cannot be resisted by arch and cable action alone. The deck can be placed above the top chord, supported by posts; below the bottom chord, supported by hangers; or in between the two chords.

A holiday card featuring Pittsburgh's historic Smithfield Street Bridge. The inside greeting is "Wishing you peace and joy this holiday season

In 1845 half of Pittsburgh burns

to the ground including the Smithfield Street

Bridge.

The present bridge is the third bridge at the site and remains the oldest steel bridge in the United States.

The bridge also has the distinction of being the most heavily walked pedestrian bridge