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Historic Bridges


No matter where one travels in the Commonwealth, historic bridges dot the landscape. These graceful monuments to Pennsylvania's transportation and engineering history are a tangible link with the past that visitors and residents statewide can enjoy today. To learn more about the role of these historic structures, check out the Commonwealth's video Pennsylvania's Historic Bridges: Connecting our Past and Future.

Historic bridges are a key focus of PennDOT's cultural resources program. Due to the number, history and importance of Pennsylvania bridges, significant efforts are expended to foster transportation projects that are sensitive to the historic character of these resources. A delicate balance is required to design, build and maintain safe bridges, while at the same time seeking to preserve historically significant bridges.

In some cases, PennDOT has been able to rehabilitate historic bridges so that they can continue to serve their communities, and in other cases a historic bridge has been bypassed when it can no longer meet traffic demands and where a new owner is identified. If rehabilitation is proposed for an historic bridge, the process is guided by the Secretary of the Interior's Standards for Rehabilitation. The Secretary of Interior's Standards for Bridges in Pennsylvania and the accompanying training presentation provide guidance on following the Standards when rehabilitating a historic bridge.

Not all bridges can be rehabilitated or bypassed to meet the vehicular needs of the crossing. In many cases, today's vehicular loads exceed what the historic bridges were designed for and rehabilitation would require altering the characteristics which make the bridge National Register eligible. When avoidance of effects is not possible, PennDOT seeks to minimize the effects a project may have on a particular resource. One example of minimization is context-sensitive design, which involves designing replacement bridges in harmony with the original design, paying particular attention to materials, workmanship, and appearance. This approach is typically undertaken where the crossing is within an historic district or urban setting.

When avoidance or minimization is not possible, PennDOT must mitigate, or make up for, the adverse effect. PennDOT traditionally recorded the historic bridge to mitigate the replacement of historic bridges; this typically entailed documenting the bridge according to standards established by the Historic American Engineering Record (HAER) prior to its demolition. This is less common now, as PennDOT is moving towards mitigation measures that foster the preservation of other historic bridges to compensate for the one that must be replaced.

Historic Bridge Inventory and Evaluation

In 2001 PennDOT, on behalf of the FHWA and in conjunction with the SHPO, completed a statewide inventory and National Register eligibility evaluation of all bridges greater than 20 feet in length built, and built prior to 1956, in PennDOT's Bridge Management System (BMS).  As part of that effort, PennDOT developed a Bridge Survey Context and a Bridge Technology Context to provide a framework for determining significance and integrity, as required by the National Register of Historic Places. 

Those determinations were captured in an MS Access database that was later eliminated with the incorporation of the results into the SHPO's CRGIS system. The CRGIS system links to  National Register eligibility fields in BMS.

PennDOT is working with the SHPO to update the 2001 inventory in consideration of the passage of time and the loss of many older and/or historic bridges. To date, PennDOT and the SHPO have completed updates to the population of metal truss bridges and concrete arch bridges.  

Stone Arch Bridge Management Plan

Pennsylvania has the nation's largest population of historic stone arch bridges, many of them in the greater Philadelphia region (PennDOT's District 6-0 region). In that part of the Commonwealth, PennDOT developed and implemented an innovative Stone Arch Bridge Management Plan and an accompanying Maintenance Manual to assist in both transportation decision making and the care for this type of historic bridge.

Historic Truss Bridge Management Plan

As part of our mission to both maintain a safe and efficient transportation network and to care for Pennsylvania's transportation heritage, PennDOT has developed a truss bridge management plan for the Commonwealth's population of historic metal truss bridges. The effort began in 2012 by gathering a list of all extant historic metal truss bridges that are part of PennDOT's Bridge Management System. This was followed by the development of preservation assessments on all bridges that could benefit by an assessment of preservation potential, followed by a planning phase that evaluated the needs of these crossings and sought to determine the likelihood that the bridge could be rehabilitated and/or maintained to meet those needs. Additional components of the plan included an effort to develop a manual on appropriate tools and techniques for the preservation and maintenance of this population of bridges. 

The management plan was completed in the Fall of 2017 following the conclusion of the planning phase. However, implementation of the management plan is on-going and is necessarily a continuous effort. A primary component of the implementation phase is seeking specialized funding to assist in the preservation of these bridges, whether it be for continued vehicular use or for adaptive use in a public setting.

Bridge Marketing

PennDOT's historic bridge marketing program has succeeded in placing a number of historic bridges with new owners. Most have been moved to new locations where they continue to grace the Commonwealth's landscape for pedestrian use. PennDOT primarily markets historic truss bridges (many of which came out of the Truss Management Plan) because these structures can be more easily disassembled and moved to new locations.

Bridges available for adaptive reuse, and more information on this program, can be found on our Bridge Marketing Page.  Unless noted otherwise, all these bridges require relocation by the buyer. There you will also find stories on bridges that have been successfully rehabilitated and/or relocated.