1931,1989 Boston Cantilever Bridge over Youghiogheny River in Boston, PA

(Archived Bridge Hunter returned too many 429's, Bridge Hunter; Historic Bridges; Satellite)

Street View, Jul 2019

HistoricBridges
This 1,182' (360.3m) long bridge has a main span of 420' (128m).
"This impressive bridge which is considered eligible for the National Register of Historic Places, is a striking and impressive cantilever bridge that is very unlike most cantilever bridges encountered. The bridge was designed to look highly attractive, and as such the sway bracing on this bridge is designed as unusual large arch shapes, and the top chord of the cantilever is carefully designed especially between the towers to have a very smooth curved appearance to the bridge. The curve is designed so that the top chord sweeps far lower that in most cantilever bridges, which is only possible because the bridge has sway bracing only in the vicinity of the towers, yet another unusual feature of this bridge. The bridge is a cantilever bridge, and two hinges at the bottom chord define a six panel suspended span at the center of the bridge, although visually this is almost impossible to see with a casual view. The bridge's diagonal and vertical members are all rolled beams, and the top chord is a built-up box beam with lattice on the bottom, which is the only place in which lattice occurs on the bridge. No v-lacing is present."

This shows the lattice on the bottom of the top chord described by HistoricBridges.

Street View, May 2025

This is a good view of the arched sway bridges that HistoricBridges mentioned.

Coreen Baumann (Th3G1rI), Apr 2019

Maddog4x4, Jan 2025

These are the six center panels or the suspended span. The triangular gusset plates on both sides would be the location of the hinges.

Digitally Zoomed

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