View east (downstream right)
Two views east, downstream parapet and closed spandrel|
Spang Rd over Big Sewickley Creek [SB07]
USGS 7.5" Topo Quad - UTM Coordinates:
Baden - Zone 17; 0572 4499
-- west of intersection with Warrendale & Bayne Rd [Red Belt]
-- Big Sewickley Creek
TYPE OF CONSTRUCTION / DESIGN:
Closed spandrel concrete arch;
Parapet walls: concrete formed modules
LENGTH OF MAIN SPAN:
TOTAL LENGTH (including longest elevated ramp):
HEIGHT OF DECK:
YEAR ERECTED / ENGINEER:
1910, Allegheny County ?
The characteristics of this bridge seem to match many others built between c1910 and c1936 by the Allegheny County Public Works Department.
During years surrounding 1900, Allegheny County, under the direction of County Engineer Charles Davis, was busy throughout the region building stone arch bridges of a simple and similar design. Typically, they featured parapets with rounded top and slightly enlarged parapet endcaps.
Beginning about 1910 -- after Chalfant assumed the position of County Engineer -- new county bridges of this size were being constructed solely in concrete using a design which mimicked the earlier stone arches. On a few of the concrete structures, a builder's plate identifies the bridge as having been constructed by Allegheny County and includes the stream name and date.
Several bridges of this design are found throughout Allegheny County, but usually without the builder's plate to confirm the date or the authority in charge of construction. The similar of design and construction seems to imply that they were all built by Allegheny County, and other sources state construction dates to about 1936. This arched design was phased out and replaced by simpler beam bridges.
The arch portion of the bridge seems reasonably intact, but the parapet walls are severely crumbling. Examination of the other bridges of this design show a similar pattern. The parapets appear to have been constructed by stacking a series of formed concrete modules. The modules were shaped to mimic the rounded caps found on County bridges designed by Davis. Each block seems to have weathered differently and the seams between them allowed further decay. The Old Butler Plank Rd bridge over Gourhead Run is possibly the best preserved example.
The closed spandrel walls and outer faces of the parapets have recessed panels which further echo the designs from the County's earlier stone arch bridges. The parapets are most similar to those created in stone for Merriman Rd over Big Sewickley Creek.
Allegheny County assigns its bridges with an ID number counting from a stream's outflow, sequentially upstream. At time of construction this bridge was the seventh bridge upstream from the outflow of Big Sewickley Creek into the Ohio River (Big Sewickley Creek Number 7 -- "SB07").
Due to the relative seclusion of this corner of Allegheny County, several older bridges can be found nearby. About one-half mile south on Warrrendale & Bayne Rd, a similar concrete bridge carries Markman Park Rd over Big Sewickley Creek. Another half-mile south a pair of 1900 girder bridges by Charles Davis may be found. A little over one-half mile further south off Big Sewickley Creek Rd, Brown Rd spans the East Branch of Big Sewickley Creek with one of Davis' earliest stone arch bridges .
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