PA Engineering Firm Wins Award for Frazier Covered Bridge Rehabilitation
Frazier Covered Bridge Rehabilitation

The Frazier Bridge, nestled among the rolling farmlands of Moreland Township in rural Lycoming County, is a covered bridge that was originally built in 1888. The landmark has majestically overlooked the calm waters of Little Muncy Creek for nearly a century and a quarter, until structural deficiencies threatened its future.

Covered bridges have a cult-like following among rural nature enthusiasts. Pennsylvania alone is home to nearly 200 covered bridges, with three owned by Lycoming County. The majority were built in the 19th century, before the advent of preservative treatments for timber. Covering the structures protected the timber trusses from deterioration by the elements, and provided the secondary benefit of sheltering travelers caught in storms. The Frazier Bridge is 78 feet long, constructed of timber burr arch trusses and pierced with a window, the purpose of which is uncertain, but which is thought to increase visibility for approaching traffic.

By 2008, the timber truss members were in a deteriorated condition due to severe decay and insect infestation, seriously compromising the bridge’s integrity. Renovations were crucial to ensuring the longevity of the structure. Mark Murawski, Lycoming County’s Transportation Planner, called on Larson Design Group (LDG) to perform the design of the necessary rehabilitative work. LDG’s challenges included improving the structural deficiencies and increasing safety for vehicles. Paramount to both of these tasks was retaining the historical significance of the structure, as the bridge has been listed on the National Register of Historic Places since 1980.

LDG began working on the project in 2008. Brad James, PE, Project Manager for the Frazier Bridge restoration team, says that the most challenging aspect of the renovation was “determining the extent of the rehabilitation necessary. With historic structures, you have to make sure that you replace enough of the damaged structure to ensure the quality of the renovations, but retain as much of the original material as possible in order to preserve its unique history.” Although the structure was severely deteriorated, complete replacement of the existing timber with a new reinforced concrete structure was not an option, due to its historical significance.

Ultimately, the truss was rehabilitated to accommodate a 3-ton live load, its own dead load, wind loads, and snow loads. Approximately 67% of the existing deteriorated timber members were replaced with new, full-sawn timber members. James says “Only timbers that were severely deteriorated were replaced. The exterior look of the bridge was also maintained. The new concrete substructure features architectural surface treatment on the concrete to mimic the look of natural laid stone.”

The true test of LDG’s work came with the floods of September 2011. During the renovation, LDG placed properly designed rock protection along the upstream channel banks, armoring the banks during large storms. According to James, “If this had not been done, the bridge would have been washed away in last September’s flooding.”

On August 8, 2012, the Frazier Bridge Project received the Road and Bridge Safety Improvement Award, an honor bestowed by the County Commissioners Association of Pennsylvania in conjunction with the Pennsylvania Highway Information Association. James expressed surprise upon receiving the award, stating “I would have expected a new, modern-looking structure to win over the rehabilitation of an existing covered bridge. For a preservationist, it’s the ultimate compliment to defeat new projects in competition.”

The preservation effort ensures that the Frazier Bridge will continue to guard the Muncy Creek for another 50 to 100 years.

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