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Historic Dorrington Road Bridge in Collier Threatened: Requires New Site

Landmarks met with PennDOT and Collier Township officials today and discussed the possibility of saving and relocating the bridge. Collier Township is open to having the bridge moved to a new park it is creating near Nevillewood, but funding would be needed to support the project.

Landmarks member and 2002 Scholarship winner Todd Wilson prepared a presentation on the behalf of Landmarks that was presented at the meeting. The content below.

Dorrington Road Bridge

Dorrington Road Bridge


Within the next 20 years, the upgrade from the truss bridges of the 19th century to modern post World War II bridges will likely be completed.

It is crucial to carefully select significant bridges to preserve in order to represent and exemplify the rest of the demolished truss bridges.

The Dorrington Road Bridge, being one of the last of its type in the country, is one such bridge.

PHLF wants to work with PennDOT and Collier Township to find a suitable owner for the relocated bridge.

Bridge Information:

  • Pin-connected
  • Pratt pony truss
  • Single span
  • 60 feet long
  • 19 feet wide
  • Built in 1888 by the Pittsburgh Bridge Company
  • Composed of cast and wrought iron (according to the Pennsylvania Historic Bridge Inventory)
  • Endposts of bridge are vertical instead of diagonal

Historical Significance:

  • Rare cast and wrought iron Pratt pony truss with vertical endposts
  • One of 15 truss bridges identified as cast and wrought iron in
  • Pennsylvania (as of the 1997 Historic Bridge Inventory)
  • Last remaining cast and wrought iron bridge in PennDOT District 11
    One of 5 iron truss bridges remaining in District 11
  • Only remaining iron pony truss in District 11
  • Eligible for the National Register of Historic Places
  • Maintains historical integrity
  • Retains builders plates from prolific bridge company
  • Unique among the other 861 bridges on

According to December 2006 data from the Federal Highway Administration:

  • 3.3% of PA bridges are trusses (2006), down from 5.5% in 1992; a loss of 40% (482 bridges)
  • 2.2% of bridges nationally are trusses, down from 4.3% in 1992; a loss of 47% (11,380 bridges)
  • 21 states have 100 or fewer truss bridges; 5 states have 25 or fewer truss bridges
  • If that trend continues, all historic truss bridges that have not been preserved or rehabilitated will be demolished within the next 16 years
    According to the PA Historic Bridge Inventory, 12% of truss bridges surveyed in 1997 were built before 1890 and 30% were built before 1900
  • “Over half the historic bridges identified by statewide surveys have disappeared over the last twenty years” – Winter 2003 Preserving Pennsylvania Newsletter

Expert Evaluation:

Eric DeLony, former Chief of the Historic American Engineering Record (HAER) and author of Landmark American Bridges.

  • On January 31, 2007, Eric made the following evaluation regarding the Dorrington Road Bridge:
  • Despite the wealth of HBs in Pennsylvania, I’m confident the bridge will be at the top of the list regarding its value, significance, condition and preservation potential.
  • The outriggers (buttresses) look like they might have been added to increase lateral stability, but this was well done, and in my view doesn’t diminish its integrity.
  • The bridge has many things in its favor for preserving: significance, condition and relatively short span – a structure easily moved to another location.

Nathan Holth, creator of

  • On January 24, 2007, Nathan Holth wrote:
  • The Dorrington Road Bridge will only become more rare and significant as time passes and more truss bridges elsewhere are demolished.
  • The Dorrington Road Bridge is a pin-connected Pratt pony truss bridge that is technologically noteworthy for having vertical endposts, giving it a distinct rectangular shape that in uncommon in truss bridge design.
  • The bridge retains a significant level of historic integrity, meaning features that were present on the bridge in 1888 still remain today. Among the elements that remain in their original form are original lattice railings and a builder plaque, which are elements that are often missing from other truss bridges.
  • I strongly feel that relocating and rehabilitating the historic Dorrington Road Bridge is a wise course of action.

Other Reasons to Save Bridge:

  • Educational tool
  • Tourist attraction
  • Community identity
  • Feature of a park
  • Bridge for a trail

Local Rails to Trails:

  • Last 7 miles of the Great Allegheny Passage Trail in Allegheny County to be completed in 2008 at a cost of $7 million
  • Montour Trail Council’s Panhandle trail ends in Rennerdale, about a mile away from the Dorrington Road Bridge
  • “About 40 miles of the [Montour] trail are completed; but completed miles are not all connected, being isolated by a few large uncompleted sections, as well as some missing bridges requiring at-grade crossings of public roads.”
  • $10.1 million conversion of Hot Metal Bridge underway for trail use

Cost Effective Solution:

Funding up to the cost of demolition is available for bridge preservation
With that funding, the cost of relocating a historic bridge is comparable to the cost of a new bridge
Dorrington Road Bridge in better condition than many comparable bridges

Case Study: Bollman Bridge:

  • 1871 cast and wrought iron Warren through truss bridge
  • 81 feet long by 14 feet wide
  • Closed to traffic in 1999
  • Bridge currently being relocated to Great Allegheny Passage Trail
  • Total cost of project about $200,000
  • $80,000 funded by government
  • Bollman Bridge

Case Study: Henzsey’s Bridge

  • 1869 wrought iron bowstring arch truss
  • 96 feet long by 17 feet wide
  • Closed to traffic in 1986
  • Feasibility study and drawings prepared by a civil engineering professor and students
  • Restored and relocated to serve Central Pennsylvania College in 2002
  • Cost for a new bridge would be “slightly less” than the cost to reuse the old bridge
  • Cost approximately $250,000
  • Project won 2003 Historic Preservation Award
  • Henzey's Bridge
  • Henzey's Bridge

Michigan’s Historic Bridge Park:


Dorrington Road Bridge

The Dorrington Road Bridge has served Collier Township for over five generations. Dating from a time before the automobile was invented, it is a rare surviving piece of transportation history. By relocating the bridge to a park or trail, we can preserve this structure and create a “bridge” to the past for many more generations to enjoy.

Dorrington Road Bridge

Pittsburgh History & Landmarks Foundation

100 West Station Square Drive, Suite 450

Pittsburgh, PA 15219

Phone: 412-471-5808  |  Fax: 412-471-1633