Utah Demonstration Project: Geosynthetic Reinforced Soil Integrated Bridge System on I-84 near Salt Lake City

As part of a national initiative sponsored by the Federal Highway Administration (FHWA) under the Highways for LIFE program, the Utah Department of Transportation (UDOT) was awarded a $1 million grant to demonstrate the use of proven, innovative accelerated bridge construction technologies to deliver this $5 million project in substantially less time than conventional construction. The project involved replacing twin bridges located on the westbound and eastbound routes of I-84 over Echo Frontage Road in Summit County. The structure to be replaced was constructed in 1971 and carried a designation of D-783 in UDOT’s bridge management system. The project limits extended approximately between milepost 118 and milepost 120. The innovative construction techniques adopted were as follows: Use of the geosynthetic reinforced soil-integrated bridge system (GRS-IBS) method of design and construction; Use of prefabricated bridge elements and systems (PBES); and Use of a lateral bridge slide. This was the first GRS-IBS project in Utah and also the first GRS-IBS project on an interstate in the U.S. It was also the first GRS-IBS project in the U.S. to incorporate a lateral bridge slide. On this project, UDOT used a price + time or price + time + lane rental bidding process. To estimate the cost savings for the GRS-IBS method, the total costs were computed for both the as-built and baseline (cast-in-place) scenarios by adding the agency costs and user costs (delay + safety costs). The results indicated around 7 percent cost savings during the as-built scenario compared to the baseline because of significantly reduced user costs.