PennDOT’s Interstate 78 Bridge Underclearance Project replaced six overhead bridges, located consecutively along an eight mile stretch of Interstate 78 in western Berks County, Pennsylvania, utilizing accelerated bridge construction (ABC) techniques. Benesch was responsible for the design of three of the six replacement bridges on the project. The bridges were replaced to increase the minimum vertical clearance over Interstate 78 from approximately 14’-0” to 16’-6” and to accommodate future Interstate 78 widening. As part of the project, the approach roadways and ramps were reconstructed to accommodate roadway profile and width modifications.
All six replacement bridges are single-span prestressed concrete beam bridges that incorporate aesthetic features such as an architectural finish and color scheme. The substructure units typically consist of tall cantilever abutments supported on spread footings (one structure was supported on pile foundations). The use of ABC techniques under roadway closures reduced the average construction duration for each structure from a year to 45 calendar days. ABC techniques utilized on the project included prefabricated bridge elements and time-based bidding techniques. Prefabricated bridge elements utilized included precast concrete footings, stems, pedestals, back walls, deck panels, approach slabs, sleeper slabs, and moment slabs. Construction on the project is currently completed, with three bridges constructed in both the 2016 and 2017 construction seasons.
The complexity, uniqueness and successful delivery of this project played a significant role in our winning of the 2018 Project of the Year Award for projects over $20 Million from the American Society of Highway Engineers (ASHE), East Penn Chapter.