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Historic Bridges

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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.  Modern transportation needs place difficult demands on these resources.  Historic bridges are an important focus of PennDOT's Cultural Resources program. Due to the number, history and importance of Pennsylvania bridges, 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.

This topic is explored in the video Pennsylvania's Historic Bridges: Connecting our Past and Future which was developed in partnership with the Pennsylvania State Historic Preservation Office.

Rehabilitation
In some cases, PennDOT has been able to rehabilitate historic bridges so that they can continue to serve their communities. 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 the Interior's Standards for Bridges in Pennsylvania and the accompanying training presentation provide guidance on following the Standards when rehabilitating a historic bridge. 

Minimization
Not all bridges can be rehabilitated 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.

Mitigation
When avoidance or minimization is not possible, PennDOT must mitigate, or make up for, the adverse effect. PennDOT traditionally recorded the historic bridge, at a minimum. 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, in consultation with the State Historic Preservation Office and other consulting parties, is moving towards mitigation measures that foster the preservation of other historic bridges.  For historic metal truss bridges that cannot be rehabilitated, for example, the mitigation may include adding funds to the Historic Metal Truss Bridge Capital Rehabilitation Program. 

Historic Metal 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, in conjunction with the Federal Highway Administration (FHWA) and the PA State Historic Preservation Office (SHPO) developed a Historic Metal Truss Bridge Management Plan (Management Plan). The Management Plan was to address the accelerating loss of historic metal truss bridges within the state. Historic metal truss bridges are those listed in, or eligible for listing in, the National Register of Historic Places. Pennsylvania has, by many accounts, the most distinct population of metal truss bridges in the United States; however, over half the population of historic metal truss bridges have been lost over the last 20+ years. The goal of the effort was, and remains, to take sensible measures to extend the useful life 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, the Management Plan serves an ongoing purpose as a planning tool to help maximize the chances of rehabilitation for historic metal truss brides. The Historic Metal Truss Bridge Capital Rehabilitation Program, explained below, is an outgrowth of the Historic Truss Bridge Management Plan. 

Historic Metal Truss Bridge Capital Rehabilitation Program

In 2021, the Twelve-Year Program (TYP) update included Federal Surface Transportation Program (STP) discretionary funding (SPIKE funds) to promote the rehabilitation of historic metal truss bridges beginning in federal fiscal year 2023 (FFY 2023). This program has since been named the Historic Metal Truss Bridge Capital Rehabilitation Program (Program). The TYP includes $18 million dollars spread over a twelve-year period. $1 million will be allocated during the first two years (FFY 2023 and FFY 2024) followed by $2 million per federal fiscal year (FFY) for the remaining ten years.

As currently envisioned, the Program will focus on county and municipally owned historic metal truss bridges where owners desire to work collaboratively with PennDOT, MPO/RPOs, and historic preservation interest groups and individuals to rehabilitate their historic metal truss bridge for continued vehicular transportation use.

A committee comprised of representatives from: PennDOT's Program Center; PennDOT's Bureau of Project Delivery Environmental Policy and Development Section; the FHWA; and the SHPO is charged with selecting the historic metal truss bridges for rehabilitation through the Program based on several parameters. Outreach to historic metal truss bridge owners and planning partners is ongoing to confirm the transportation needs of these crossings.

More information can be found in the Program Overview and Frequently Asked Questions documents.

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 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 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 PA-SHARE system. PA-SHARE links to the 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.  

Metal Truss Adaptive Use 

PennDOT's Metal Truss Adaptive Use program, also referred to as Bridge Marketing, has succeeded in placing a number of historic metal truss bridges with new owners. Most have been moved to new locations where they serve a pedestrian use. PennDOT primarily markets historic metal truss bridges, many of which came out of the Historic Metal Truss Management Plan, because these structures can be more easily disassembled and moved to new locations.

Bridges available for adaptive use, and more information on this program, can be found on our Bridge Marketing Page. Unless otherwise noted, all these bridges require relocation by the buyer.