Overview - The Wood Road Bridge is located in the Town of Campbell, in Steuben County, New York. The bridge was built in 1897 and is a 207-foot, single-span bridge that carries Wood Road over the Cohocton River. The bridge is historically significant as an intact, representative example of a pin-connected, wrought-iron through truss bridge. It incorporates the sub-struts and tension members typical of the Baltimore truss form, a late 19 th-century adaptation of the Pratt truss. The top chord is comprised of the patented Phoenix column, a rigid, built-up member of considerable strength. Manufactured by Phoenix Iron Works, the Phoenix column represented a significant technological advance in metal truss bridge construction. The bridge is one of the few remaining examples of this type of construction.
The years had taken their toll on this bridge. The bridge was posted for a four-ton load limit, and it was imperative the bridge be improved to ensure the safety of the public. The question was, “Should the County rehabilitate the bridge and maintain the historic integrity of the existing structure or completely demolish the existing bridge and start with new construction?”
Realizing the historic importance of the bridge, Steuben County made the decision to favor rehabilitation of the bridge, if feasible.
Rehabilitating a historic bridge presents its own challenges but this project is a success story. Once poised on the precipice of demolition, the newly rehabilitated bridge went on to receive a statewide award and sustain its place in the County’s history.
Wood Road Bridge in Disrepair
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Completed Wood Road Bridge
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Funding - Because of the high anticipated cost to rehabilitate the bridge, the County turned to federal, state, and local agencies to help with the funding. They were turned down once for funding under the Intermodal Surface Transportation Efficiency Act (ISTEA) and once again for the Transportation Equity Act for the 21st Century (TEA-21) Enhancement Program. Looking at the possibility to fund only the deck replacement, grant applications were prepared by the County, and funding was obtained under the FHWA’s Innovative Bridge Research and Construction Program for a Fiber Reinforced Polymer (FRP) deck. However, bids obtained for the FRP deck were twice the expected amount, and the project was temporarily canceled.
The project finally obtained funding as a Locally Administered Federal Aid Project, the consultant was selected, and design proceeded.
T he Right Team - Another important factor in this project process was the right choice of design team. The County chose the Erdman, Anthony and Associates, Inc. (Erdman Anthony) team to provide in-depth bridge inspection, material testing and sampling, load rating, survey and mapping, hydraulic analysis, environmental screening, preliminary and final bridge design, construction support, and construction inspection services. The team consisted of Erdman Anthony as Prime Consultant, with Fisher Associates for geotechnical design and maintenance and protection of traffic, Delta Engineers for additional truss bridge experience, and Abba Lichtenstein for specialized experience with historic structures.
Coordination - The decision was made by the County to contact New York’s State Historic Preservation Office (SHPO) early in the project process. SHPO determined that the existing bridge was historically significant as an intact, representative example of a pin-connected, wrought-iron, through truss bridge. The challenge was to find a method of restoring the bridge’s functionality while preserving the historic elements at a reasonable cost.
In addition, the County coordinated with several agencies to truly enhance the look and feel of not only the bridge, but the surrounding area. A gauging station building at the site, operated by the United States Geological Survey (USGS), was renovated to fit in with the upgrade of the bridge. The County also coordinated with the Chemung Basin River Trail Partnership to build a small public access site for the Cohocton River as part of the project. The site consists of a small parking lot, information kiosk, boat launch, and concrete walkway down to the river.
Listening to the Public - Listening to the public’s concerns can affect the success or failure of the project. In this case, the public’s primary concern was flooding. The bridge was subject to debris during major storms, which worsened the flooding conditions upstream. In response, the bridge profile was elevated to help minimize the hydraulic constraints in future rainfalls. In addition, because the bridge was to be closed to traffic during construction, a town road was repaved to provide a good off-site detour, also making the public happy.
The Process - An in-depth bridge inspection was performed to verify the structure’s geometry and condition. In addition, material samples were collected from several wrought-iron components of the bridge and tensile tests performed to determine the physical properties that were used in the analysis of the structure. The tests also included chemical and microstructure analyses to determine the uniformity of the material. The tests confirmed that all of the material was wrought iron and had similar properties.
A structural load rating analysis was performed of the truss using a combination of finite-element and influence-line methods. The analysis identified that the sub-struts and floor beam hanger members of the truss needed to be strengthened to allow the truss to carry modern vehicular loads.
Erdman Anthony prepared a report discussing the findings of the inspection, material testing, load rating of the existing bridge, and review of several alternatives, including replacing the bridge in its entirety. Based upon the findings of the report, a rehabilitation scheme was selected by the County.
The rehabilitation scheme that was developed included the following work:
- Capping and re-pointing of the abutments
- Rehabilitation of the expansion bearings
- Replacement of the deck, stringers, and floor beams
- Strengthening of 12 sub-struts
- Replacement of 12 floor beam hanger members
- Replacement of 3 lateral struts
- Replacement of the bridge railing
- Painting of the truss
- Installation of new approach railing
The proposed rehabilitation work was submitted to the State Historic Preservation Office (SHPO) for review. The resulting determination was that the project would have “No effect” on the historic bridge.
Plans were prepared for the work, and the project was bid in June of 2003. Vector Construction of Cicero, New York, was the successful bidder with a bid of $820,458.82, approximately 5% over the Engineer’s estimate. Construction was completed in August of 2004.
Conclusion - This project restored one of the few remaining historic truss bridges in Steuben County and demonstrates how the close teamwork of all involved in the process can lead to a truly successful project for all. Steuben County and the Town of Campbell were very pleased with the project and applied successfully for listing the bridge on both the State and the National Registers of Historic Places. The project was awarded the Silver Award for Engineering Excellence by the American Council of Engineering Companies of New York (ACEC, New York).
www.erdmananthony.com
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