The 30m-long Furness Bridge was built in 1916 as a focal point for the entrance to the Upper Bank Nursery in the borough of Media, Pennsylvania, 21km west of Philadelphia.
The concrete and stone masonry bridge, which consists of two 5m spans and one 6m centre span, required rehabilitation in order to support the weight of construction vehicles needed for the development of the nearby site.
A preliminary inspection and load rating of the Furness Bridge in November 2014 had revealed settlement, rotation and water freeze/thaw cycle damage, which had resulted in a large crack in one of the arches spanning Ridley Creek.
Pennoni proposed a design that would rehabilitate the 30m-long bridge from the inside out by constructing a new bridge within the existing bridge superstructure.
The project was managed by Pennoni over a period of six months, beginning with an in-depth inspection and load rating, preliminary and final design, and continuing with a collaborative partnership with bridge contractor JD Eckman during the construction process.
The new design called for the removal of the roadway and fill of the concrete arch and masonry walls: the non-structural fill to be replaced with a reinforced concrete slab: and the complete replacement of the compromised arch ring.
As no existing bridge plans were available, high-definition laser scanning was used to capture the 3D geometry and site topography necessary for contract document creation. In 30 days all necessary permits were secured from the Pennsylvania Department of Environmental Protection in order for work to start within Ridley Creek, including the installation of cofferdams, centering and bracing for the third span replacement.
Construction began in July 2015 and was completed in December 2015. The bridge opened to vehicular and pedestrian traffic in mid November while the rest of the stone work and masonry repointing was being completed.
The bridge was reopened for use by the Wirt Thompson family approximately one year after initial structural concerns arose.
Pennoni’s work on the Furness Bridge has received a number of awards including the Grand Conceptor Award from the Delaware Chapter of the American Council of Engineering Companies: Project of the Year for Unique Challenges and Commitment to Safety from the First State Section of the American Society of Highway Engineers: and Small Project of the Year from the Delaware Section of the American Society of Civil Engineers.
Pennoni project manager Joe Spadea and senior engineer William Cameron will present the Furness Bridge project at the Ohio Transportation Engineers Conference, 25-26 October.
