Geosynthetic-Reinforced Soil Bridge Abutments

Geosynthetic-reinforced soil (GRS) bridge abutments have been used on a number of bridge projects over the past decade. This adaptation of reinforced soil technology to bridge structures and their approach fills offers an excellent opportunity to simplify construction, reduce construction time, and reduce cost on structures for which this technology is appropriate. This design concept, in which the actual bridge superstructure rests upon the GRS abutment wall, minimizes differential settlement and eliminates the problematic “bridge bump” found on many structures. The technology has been adapted to both road and trail bridges. The basic design concept of GRS used in bridge abutment applications was evaluated, along with its advantages and disadvantages. Some selected case histories of GRS bridge abutments on low-volume roads and trails in Alaska and California were considered. In addition, the Mammoth bridges, in the mountains of northern California, with high design snow loads and high horizontal peak ground accelerations, afforded an opportunity to design, construct, and monitor GRS-supported spread-footing abutments under difficult service conditions.