Patton Chest Creek Bridge
PennDOT District 9-0 retained Gibson-Thomas for the design of the replacement of the structure carrying SR 0036 (Magee Avenue) over Chest Creek in Patton Borough, Cambria County. The existing reinforced concrete closed spandrel arch bridge, originally constructed in 1910, was listed as structurally deficient and had exhibited signs of deterioration.
The initial scoping of the project identified half-width construction as the preferred traffic control alternative. However, upon review of the structure and project context, Gibson-Thomas noted several significant safety and constructability issues with removing a portion of the existing arch while maintaining traffic on the remaining section. With no viable detour route and the potential for bisecting the borough of Patton, Gibson-Thomas proposed the use of a temporary bridge and roadway around the existing structure. This alternative was ultimately used for construction.
Within the project site, Chest Creek is located within a flood control levee system that is owned by the Borough and managed by the Pennsylvania Department of Environmental Protection (PADEP). The presence of a levee offered several key challenges to the project. The ownership of the levee and its associated rights-of-way were not formally recorded in the County courthouse and eventually had to be established from the original mapping. An access road down the face of the levee was necessary to place a streambed protection system consisting of rock and geotextile under the existing structure for demolition. The final bid package included PADEP specifications for the levee backfill material and provisions that limited the types of shoring. Emergency stockpiles of sandbags were specified in case of flood waters reached the excavated areas near the temporary and proposed structures.
A railroad line owned by RJ Corman was located approximately 35 feet off the edge of the existing structure. It was identified early in design that the existing crossing was in poor condition and would be replaced concurrent with the bridge replacement. The overhead signals would also be replaced and interconnected with the adjacent traffic signal. A temporary railroad crossing and signal system was placed for the temporary roadway and the permanent crossing replacement was installed using short term flagging. A short section of concrete pavement was placed between the shortened approach slab and the concrete railroad crossing tubs. Additionally, railroad flagging was provided to protect the projected traffic of four trains per day.
The proximity of the railroad crossing, Birch Street, and an adjacent residence also presented difficulties when attempting to design crashworthy end treatments for the structure barriers. This problem was solved by utilizing radial barriers in all four quadrants of the structure. These barriers, supported by moment slabs, allowed for tangential installation of guide rail end treatments or shifted the barrier end outside of the clear zone.
Hazardous wastes were identified within the project site during the design phase. These included asbestos materials within a building that was to be demolished as part of the project, as well as an underground storage tank on the parcel. Samples from geoprobe borings along the railroad property indicated contamination from former auto service stations nearby as well as the former railroad yard area. A material stockpile area was coordinated with PennDOT at a nearby maintenance shed. The final bid package included provisions for the safe handling, testing, and disposal of materials.
PennDOT identified the adjacent signalized intersection of SR 0036 (Magee and Fourth Avenues) with SR 4008 (Magee Avenue) and Fourth Avenue as being in need of upgrading. The scope of the project was expanded to include replacement and redesign of the traffic signal, drainage upgrades, and installation of ADA-compliant sidewalk curb ramps. The traffic signal was interconnected with the railroad crossing signals due to their proximity.
The proposed structure was a steel multi-girder bridge with a span of 84’-0” and supported by integral abutments. The structure was designed to exceed the hydraulic opening of the existing arch bridge to prevent impacts to the 100-year water surface elevation within the levee system.
The project was completed in Spring 2017.