Bridge work is typically a predictable undertaking, even if complex – but the recent replacement of a bridge in East Stroudsburg was anything but typical, as it runs through a concrete tunnel that supports railroad tracks and couldn’t be disturbed by construction. In providing alternate engineering services for the project, Larson Design Group (LDG) had to get creative to address these unique challenges.
LDG became involved in 2018 as the contractor’s engineer, when PennDOT advertised a construction contract for the rehabilitation of the Stites Tunnel and the SR191 bridge structure that runs through it needed rehabilitation. The bridge carries the roadway over Paradise Creek inside the tunnel, which itself supports a section of the Delaware Lackawanna Railroad. The approach span structures of the existing bridge had the unique arrangement of the overflow channel of the creek taking two 90-degree bends under the spans.
To accommodate this, a precast concrete deck was designed to be supported by new integral abutments under the outside shoulder, as well as new 94’-long post-tensioned concrete edge girders lengthwise on the creek side. The combined concrete slab and edge girders were precast in 8-foot segments and post-tensioned in place after being erecting on temporary supports. This alternate precast concrete design was an innovative technique for the structures and facilitated the timing and scheduling of the multiple site activities required for this complex project.
“This project was challenging, but it helped us look at how we can use precast concrete more efficiently and effectively,” said Quentin Rissler, Program Manager in LDG’s Lititz office. “We were pleased to partner with H&K Group and PennDOT Engineering District 5-0 to develop these innovative applications of precast concrete, segmental design and post-tensioning.”
Founded in 1986, Larson Design Group is an award-winning national architecture, engineering and consulting firm with 12 offices in five states and a vision to elevate client relationships, enrich the careers and lives of its employee-owners, and enhance the communities in which it operates. For more information, visit www.larsondesigngroup.com.
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