This project involved the reconstruction of a portion of SR 0048 in Allegheny County from an existing 2-lane roadway to a 4-lane roadway with an additional turning lane. Tri-State Design and Development designed a replacement structure for an existing 89’ single span, dual-girder steel bridge carrying SR 0048, Section A11 over a private access road in North Versailles Township, Allegheny County. The design required constructing the replacement structure while maintaining traffic at all times on the existing bridge (SR 0048), as well as on the private access road that passes beneath the existing structure.
Maintaining traffic all the time for the entire project was an important task due to very high traffic volume and lack of easy alternate choice of route. Tri-State prepared a multiphase Traffic Control Plan that allowed reconstruction of the entire project (including main multi-span bridge) with minimal inconvenience to the traveling public.
Tri-State proposed constructing a 16’ modified Conspan® arch supporting cast-in-place concrete walls bearing on deep piles. The structure was constructed under the existing SR 0048 structure, allowing embankment to be placed over the completed Conspan® structure. Traffic on the mainline was then diverted onto a temporary roadway allowing traffic to be maintained at all times. The design of the 146’ underpass with 16’ minimum clearance was cost-effective, provided an extremely low maintenance replacement structure, and enabled the replacement of an existing, 2-lane, high volume structure without interruption of traffic.