Instrumentation and 5-Year Performance Monitoring of a GRS IBS in St. Lawrence County, NY

One of the first Geosynthetic Reinforced Soil—Integrated Bridge System (GRS-IBS) projects to be instrumented and evaluated under the Federal Highway Administration's (FHWA's) Every Day Counts program was a replacement bridge along County Road 47 over Trout Brook in the town of Stockholm within St. Lawrence County, NY. This GRS-IBS is aligned on a 30-degree skew with a 3.65-percent superelevation and a 0.5-percent grade. The new superstructure consists of 105-ft steel multigirders and prefabricated-concrete deck panels. The heights of the north and south geosynthetic—reinforced soil abutments were 11.0 and 11.6 ft, respectively. To evaluate the performance of this bridge, FHWA instrumented and monitored the bridge for over 5 years. This report details the results of the instrumentation installation and findings from this bridge evaluation. Overall, performance has been excellent, well within the expectations based on previous structures. Key results include measured vertical and lateral earth pressures, lateral deformations at the face and behind the backwall of the superstructure, and vertical and differential settlements. This FHWA report is available online at https://www.fhwa.dot.gov/publications/research/infrastructure/structures/bridge/20040/20040.pdf