| dc.description.abstract | Bridges supported on deep foundations constitute the conventional and standard construction practice. While deep foundations provide several advantages for bridges with respect to their stability and performance, they also have some important drawbacks including higher costs, and long construction time, in addition to the recurring problem of “bump at the end of the bridge”. However, over the last decade a new technology has developed that would be specifically suited for comparatively low volume and short span bridges which is termed as Geosynthetic Reinforced Soil-Integrated Bridge System (GRS-IBS). GRS-IBS has been promoted by the Federal Highway Administration (FHWA) over the last few years as a viable and cost-effective bridge supporting system for low volume and short span bridges across the United States. So far, more than 250 completed GRS-IBS projects have been documented and reported across the United States.
The purpose of this study was to carry out an extensive survey of GRS-IBS projects across the United States and monitor and document the performance of new GRS-IBS projects in the State of Oklahoma. An extensive database was developed to document different specifications, cost, instrumentation, monitored performance, lessons learned and recommendations for 140 GRS-IBS projects from across the U.S. (as available) including five (5) recent projects in Oklahoma. Additionally, a numerical model was developed to simulate the performance of GRS-IBS abutments during construction and when subjected to service loads from the approach roadway and the bridge superstructure. Material properties for the GRS abutment fill, reinforcement and facing blocks were determined through laboratory tests and/or manufacturer’s specifications for the bridges in Kay County, OK. A parametric study was carried out to investigate influences of selected design parameters such as the reinforcement and backfill properties on the predicted performance of model GRS-IBS abutments with respect to settlements and facing deformation. The simulation results for different cases examined suggest that performances of the GRS-IBS abutments in Kay County are expected to be satisfactory with small settlements and lateral deformation.
The review of all GRS-IBS projects across the U.S. with reported performance measures has indicated that they have all been performing well so far with reported settlements within the set tolerance limits. These bridges are located in a wide range of geographical locations and weather conditions, and have been built with different types of facing and geosynthetic reinforcement materials. Four GRS-IBS projects in Kay County, OK successfully withstood a historic flooding event in May and June 2015. Also noteworthy are several multiple-span GRS-IBS projects in Colorado and Maine which constitute pioneering cases beyond the single-span categories in the current FHWA guidelines, and two GRS-IBS bridges in Puerto Rico which were built on heavily trafficked highways with traffic volumes significantly greater than those included in the FHWA guidelines.
The database and the simulation program developed in this study together with the analysis of results presented in this thesis are expected to be beneficial to the department of transportation and counties in Oklahoma and other states in determining the expected cost and comparative performance of future GRS-IBS projects in their respective localities. | en_US |
