Historic Uses: Bridge, Pennyslvania-through-truss type
Stylistic Influences: No style
National Register of Historic Places: Recommended Eligible
Previous Designations: National Register Listed (Indiv.)
Other Historic Designations: 2098000143
TxDOT Bridge No.: 091610B00331001
National Register Listed: #98000143
The Washington Avenue Bridge, a pin-connected, steel Pennsylvania through-truss, spans the Brazos River north of downtown Waco, Texas. The bridge is located 200 yards west of the Waco Suspension Bridge (1870). Built for two-way access, both traffic lanes on the bridge now run in one direction (south), carrying vehicular traffic from Elm Avenue to Washington Avenue. The length of the span is 450 feet. Two approach spans measure 67 feet on the east side and 40 feet on the west, resulting in a total length of 557 feet. The total width, including the roadway and sidewalks, is 41 1/2 feet. At its highest point, the truss is 60 feet above the road surface.
The bridge's substructure consists of four piers, 96" in diameter, one under each inclined end post. The piers are poured-in-place concrete, with the top 20 feet clad in 3/8" rolled steel plate. Each pair of piers is braced and clad with 3/8" steel plates and angles, riveted diagonally between them. The bracing is placed only at the top 18 feet of each pier. The inclined end posts are attached to the piers with 6" diameter steel pin. On the west side, the connection assembly is bolted to the top of the pier. To accommodate expansion and contraction, the pinned connection assembly on the east side is allowed to slide on rails that are anchored to the top of the piers.
The loads imposed on the deck of the bridge are supported by two top chords, braced with perpendicular and diagonal struts, constructed of angle and lattice bracing. The top chord is made up of 16 individual girders, all pin-connected. The girders are composed of 13 individual steel members. The overall dimensions of the top chord are 32-3/4" x 26". Braces between the vertical members and the struts feature modest ornamentation. At each end of the bridge, a five-point star is cut out of each metal portal brace. The interior braces feature trefoil and tear drop patterns cut out of the center.
At the time of its construction, the Washington Avenue Bridge was the longest single-span truss bridge in the southwest. Today, the Washington Avenue Bridge is the longest and oldest single-span vehicular truss bridge still in use in the United States. The bridge is an excellent example of a truss system popular at the turn of the century, but now rapidly disappearing from American roads. (Information taken from the National Register nomination for the Washington Avenue Bridge, listed 1998).
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