Hubbards Flats Road Bridge

Information and Findings From Pennsylvania's Historic Bridge Inventory

Discussion of Bridge

The one span, 75'-long, wrought iron, pin-connected, Pratt pony truss bridge was built by Dean & Westbrook using Phoenix sections for the upper chords and inclined end posts and standard design Phoenix Company connecting pieces and bearings along with details that are particular to Dean & Westbrook. The roadway width is 14.9' and the overall deck width is 16'. This is not a standardized design Pratt pony truss bridge, and it represents Dean & Westbrook’s innovative thinking about features intended to provide a stronger bridge with the most economical use of material. The verticals are composed of angles with lacing. Pin plates are used to make their connection at the cast iron upper chord connecting pieces. The deep, built up, steel floorbeams are framed into the bottom portion of the verticals above the eyebar lower chords. There are punched pin holes in each vertical for the lower panel point connection. Placing floorbeams above the lower chords is not common in Pratt pony truss bridges. A triangular-shaped plate riveted to both ends of each floorbeam accommodates connection of an outrigger that meets the vertical at about its midpoint. The diagonals are eyebars, and the counters are bar stock and Dean & Westbrook’s cast open loop heads. The original pipe railings have been lost, replaced by beam guiderail railings set inside the truss lines. The deck is timber planks, and the abutments with wingwalls are fieldstone. Although there is no plaque on the pin connected 1891 Pratt pony truss bridge with Phoenix section upper chords and inclined end posts, it has the same distinctive details and design variations as 40 7217 0482 6006 (Bridge Key No. 24411) that has a plaque identifying it as built in 1889 by Dean & Westbrook, Engineers and Contractors. Dean & Westbrook were the agents for marketing and building highway bridges for the Phoenix Iron Company. They are also noted for innovative designs, including at least six remaining examples of this one in Luzerne and Chester counties and the English Center (Lycoming County) hybrid design placed in 1891. The bridge has high technological significance because of its distinctive details representing the era of experimentation in metal truss bridge design and the use of Phoenix sections, which did as much as any detail to prove the value of metal truss bridges during the last half of the 19th century. The cast- and wrought-iron bridge provides an important snapshot of thinking about bridge design and fabrication prior to steel and standardization. All bridges with Phoenix section members have at least a high historic significance level. This bridge is nearly identical to 40721704826006 (Bridge Key No. 24411) that has an exceptional level of historic significance but was built two years previous. The character defining features include the truss form and method of truss member end connection (pinned Pratt pony truss), Phoenix section upper chord and inclined end posts, and floorbeams to truss connection details (floorbeams are framed into the bottom portion of the verticals above the eyebar lower chords and triangular-shaped plate riveted to both ends of each floorbeam accommodates connection of an outrigger that meets the vertical at about its midpoint).

Discussion of Surrounding Area

The bridge is located on a one lane unimproved road east of a T intersection with SR 4006 in a rural setting with woodlands, active agriculture and scattered houses. Immediately east of the bridge is a large active farm on the north and south side of Hubbards Flat Road with the residence located at the northwest quadrant of the intersection of Hubbards Flat Road and High Bridge Road. The scattered residences further east on Fords Hill Road or on High Bridge Road can be more directly accessed from SR 239 or SR 4010 (Sunshine Road). The 14'-9" wide bridge roadway is wider than the 12'-wide maintained travelway. The bridge and road have a very low reported traffic volume.

Bridge Considered Historic By Survey: Yes