BRIDGES AND
TUNNELS OF
ALLEGHENY COUNTY,
PENNSYLVANIA
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HAER
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 13
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Superstructure "The roadway is at present 22 feet 10 inches wide in the clear, and two sidewalks each 10 feet in the clear. The full width of the bridge on the deck spans of approaches is 43 feet 6 inches, and on the channel spans, which are through spans, 48 feet. "The bridge can be widened out, if ever required, to 64 feet. This made it necessary to erect the present superstructure nearer to the down-stream end of the piers. It detracts much from the appearance of the bridge, which is unsymmetrical at present. "It was important not to stop travel during the rebuilding of the bridge. Passengers and freights from and to the Pittsburgh and Lake Erie Railroad must pass over it. Besides, there is a heavy traffic in coke, iron and other mill material, which would have been compelled to take a long, roundabout way. The construction of the superstructure had to be arranged to allow of the erection first of one track and then of the other. "If the new bridge had really been built 15 feet instead of 20 feet higher than the old one there would not have been left height enough near the ends of the channel spans for teams to pass under on the old bridge. It was therefore intended to erect the channel spans about 5 feet higher than their proper grade, and to complete the floor and tracks of the same. "The pier posts would have temporarily rested on sand jacks, by means of which both spans, weighing about 1600 tons when completed, could have been simultaneously lowered in a few hours to their proper grade. One track and sidewalk on the plate girder approaches on the down-stream side would have been meanwhile prepared for use. In this way travel would have been interrupted only for one day. But this operation became unnecessary when the new grade was raised 20 feet above the old bridge.
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Introduction Last modified on
30-Sep-99
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