| Key Facts |
| Bridge Name | Facility Carried / Feature Intersected | Location | Structure Type | Construction Date / Builder or Contractor |
| Tunnelton Bridge | Tunnelton Road over Conemaugh River | Rural: Indiana County, Pennsylvania and Westmoreland County, Pennsylvania | Metal Multiple-Type-Connected Pennsylvania Through Truss, Stationary | 1938 By: Unknown |
| Technical Facts |
| Structure Length | Roadway Width | Bridge Width | Main Spans | Approach Spans |
| 402 Feet (122.5 Meters) | 21.6 Feet (6.6 Meters) | 22 Feet (6.7 Meters) | 1 | None |
This bridge has a long span that soars over the river via a magnificent single 402 foot span, when most other historic bridges in the area crossing this river do so in a multi-span format. Indeed, this bridge is one of the more unusual bridges to be featured on this website. The bridge features a combination of riveted and pinned connections. Pinned connections were not usually used in the 1930s, and had been largely replaced by riveted connections for nearly 30 years by that time. The bridge features a combination of rolled and built-up beams composing the truss structure. The top chord and end post is a built-up box beam and the underside of the box beam is assembled with plate steel that features holes cut into it... this is a design that would become quite common by the 1950s on truss bridges, but the appearance of this design on a 1930s bridge makes the Tunnelton Bridge an early example of this design. The bridge also features an unusual design of railing, which appears to be original to the structure. Finally, the bridge is significant simply as an example of an uncommon truss configuration, the Pennsylvania truss. The bridge should also be considered significant for its span length.
Information and Findings From Pennsylvania's Historic Bridge InventoryDiscussion of Bridge The one span, 402' Pennsylvania thru truss bridge is supported on ashlar abutments with flared wingwalls from an earlier bridge. The trusses are traditionally composed. The upper chords and inclined end posts are built up box sections, and the verticals are rolled I section. Bracing members are built up. The upper panel point connections are riveted, but the intermediate connections and the lower panel point connections throughout are pinned with the exception of the end panels of the lower chords, which are riveted. The bridge is long, but it has no innovative details. It utilizes technology that was well established in 1910, and is not uncommon in the region. The bridge is not historically or technologically significant. Discussion of Surrounding Area The bridge carries a 2 lane road over a stream in a sparsely developed, rural area with scattered 20th century residences near Tunnelton at the Indiana-Westmoreland county line. Buildings adjacent to the bridge include a junk yard, a cinder block building, and altered early 20th century houses. The setting does not have historic district potential. Bridge Considered Historic By Survey: No |
