BRIDGES AND
TUNNELS OF
ALLEGHENY COUNTY,
PENNSYLVANIA
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Smithfield Street Bridge, Pittsburgh, PA
01 Cover Page
02 Foreword
03 Ferries
05 Monongahela
Bridge and
Fire
12 Masonry
17 Removal
of Old and
Erection of
New Bridge
18 Flooring
19 Ornamental
Towers and
Painting
22 Alterations
23 Footnotes
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Smithfield Street Bridge, Pittsburgh, PA Historic American Engineering Record PA-2 page 22
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Alterations (1890-1974) In 1890-91 the bridge was widened by utilizing the provisions built into the original bridge. (34) Lindenthal was both designer and contractor for this change. A third truss was added to each span on the up-stream side of the bridge which increased the width of the structure by twenty feet, eight inches and provided a second roadway. When this was done the street railway tracks ran on each side of the center line, but twenty-one years later the up-stream trusses were moved four and a half feet to the eastward and the additional width made it possible to put both the electric car tracks on that half of the bridge and devote the opposite roadway to other vehicular traffic. Sidewalks eleven feet wide projected beyond the truss work. The floor system, beneath the car tracks, was also modified in 1911, but the other half remained essentially the same as in 1883. Between 1911 and 1915 the elaborate wrought-iron bridge portals were removed and such simpler gateways of cast-steel, designed by Stanley Roush, were substituted. Here we can see the old ideas of the monumental bridge portal in process of disappearing, but even these later portals are highly ornamental. (35) In 1895 the City of Pittsburgh determined to secure title to the bridge and throw it open to the public, an action which was in accordance with the trend of the times. After the appointment of viewers and the taking of testimony on both sides, the Commissioner's Report was filed in Court, and no exception being taken, the City assumed complete ownership of the Corporation through purchase of the outstanding stock. (36) The purchase price of the bridge was $1,000,000. (37) After 1911-15 there were few changes in the bridge, but by the early 1930's it began to be in need of repair. In order to lighten the load on the structure, it was proposed to install an aluminum deck on the vehicular roadway and this was carried out in 1934. According to The Engineer of London -- "This is, as far as we have been able to ascertain, the largest bridge undertaking in aluminum that has yet been carried out. It has afforded engineers an opportunity to gain experience in the use of aluminum on a large scale. Regarded as an experiment in bridge building we suggest that its importance cannot be overrated." (38) In the early 1960's the bridge was once again exhibiting signs of wear and stress. The Pittsburgh Post Gazette of April 10, 1964, announced that "Approximately $700,000 will be spent next year to rehabilitate the Smithfield Street BridgeÉWeight limits have been placed on the bridge." The Pittsburgh Press for May 7, 1967 stated that the bridge would close in June to permit the installation of a new deck -- "the contract for the repairs had been awarded to the Mosites Construction Company in July, 1966, and since that time substructure work has been completed as well as the fabrication of new aluminum deck panels. A polyester non-skid coating is to be applied to the panels". The Post Gazette of November 16, 1967 announced that the bridge "closed since last June will reopen today at three o'clock. The total cost of repairing the structure was $712,615". In 1970 the Pittsburgh History and Landmarks Foundation placed one of its historic landmark plaques on the structure, and on May 28, 1974 the bridge was named an official city landmark by the City Planning Commission under the city's landmarks ordinance. (39) Perhaps the most famous double lenticular truss span in the world is the Saltash Railway Bridge spanning the River Tamar in Cornwall which was designed by the great engineer Isambard Kingdom Brunel and built in 1857-59 just before his death. (40) Perhaps the Smithfield Street Bridge deserves no lesser fame. Impressive as is the Brunel Bridge, the former is at least the more graceful and beautiful. According to David Plowden -- "The Smithfield Street Bridge was the first and largest bridge in the New World to employ the Pauli system of lenticular trusses, it remains the only example of this type in America". (41) The Monongahela Bridge at Smithfield Street is now within a few years of attaining its centenary, that magical state which should ensure its veneration by all who care about our technological monuments. Rumors of demolition still trouble the local air, but our great bridge, now the oldest on our three rivers at Pittsburgh as well as the oldest steel through-truss span in America, if it cannot continue to bear increasing burdens, should be, like the great bridges at Wheeling and Cincinnati, eased into an honorable quasi-retirement. Lindenthal's splendid spans have served long and well, they are now an almost indissoluble part of the city-scape, and it is profoundly to be hoped that this tough, but graceful structure will, as it begins its second century, enter upon a new period of usefulness.
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Introduction Last modified on
30-Sep-99
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