Anchored Bridge Abutments and Soil Nail Walls in Upper Coastal Plain Soils: College Street Bridge, Macon, Georgia

This paper presents a case study of a bridge replacement project over a railway in Macon, Georgia. The existing brick arch was deconstructed, and a new single-span concrete girder bridge was erected to provide increased vertical clearance. The site is located in a railway cutting aligned through a residential neighborhood. The physical and environmental constraints influenced the design of the abutments. Subsurface explorations revealed a variable sequence of inter-bedded sand and clayey soils. The piles on this bridge were designed to provide both axial and lateral support for full height abutment walls. This innovation eliminated significant temporary support of excavation. Four rows of double corrosion-protected tiebacks and walers were used for lateral support of each wall. Tieback grout-to-ground bond stress values are presented from preproduction load tests. Wingwalls were retained using soil nails. Lessons learned for future design and construction practice are discussed, including pre-bore constructability challenges in loose sands.