Benesch provided preliminary and final design services for the complete replacement of mainline Bridge No. EB-117 which carries the Pennsylvania Turnpike over Norfolk Southern Railroad (NSRR) in Cumberland County. The existing three-span steel deck I-beam bridge was replaced with a single-span bridge applying Accelerated Bridge Construction (ABC) techniques. The project’s design had to provide sufficient deck width for the eventual total reconstruction of the Turnpike mainline in this area, as well as sufficient underclearance for the NSRR.
The project’s design relied on cast-in-place concrete abutments supported on micropiles which were constructed under the existing structure. Upon completion of the substructure construction, the superstructure was replaced during two weekend closures of the Turnpike. The superstructure consists of two beam deck modules which were joined utilizing UHPC joints.
Constructability was a key component in getting this project off the ground. During the design phase, we utilized our extensive construction experience along with our railroad knowledge to develop a construction schedule that demonstrated the ABC portion of the project could be built over the weekend. Vissim software was used to model impacts to travel to develop a construction schedule and determine the closure window. Traffic was detoured along the busy Interstate Highway system of Harrisburg.
Benesch’s planning efforts also included coordination with contractors, material suppliers and our in house construction staff to set realistic work durations and account for potential schedule impacts that could develop. This also required extensive coordination with PennDOT, the local municipalities and the NSRR. The need to maintain railroad traffic throughout this busy corridor of the NSRR complicated the schedule. Our coordination efforts resulted in the NSRR designating a five-hour shutdown window to permit beam placement. In addition, they provided multiple two-hour windows for work that required fouling of the RR track.