Reinforced Soil for Bridge Support Applications on Low-Volume Roads

Abstract

A quick and simple method of bridge substructure construction using geosynthetic reinforced soil (GRS) is illustrated. GRS is used to build abutments and pier foundations for simple bridges. It is a refinement of existing reinforced soil technology used during the last 20 years. The interaction of a closely spaced geosynthetic reinforced soil system and the reasons why conventional design methods are not appropriate for these closely spaced systems are explained. This method is not recommended for all bridge building assignments; for example, it is not suitable for construction of permanent bridges in scour zones. The technique is ideal for remote locations, inaccessible to use of concrete and other traditional materials. A generic style of GRS construction is explained to ensure performance and internal stability. Construction is rapid with conventional equipment. The materials are common, inexpensive, and generally available. An overview of recent full-scale research is provided. The results of two full-scale prototype tests are presented to demonstrate performance and limitations and to confirm the design of such systems. A case history is presented that shows the versatility of the technology in a bridge support application. A procedure for prestraining or preloading the reinforced soil to enhance performance is provided. For bridge support applications, preloading of the GRS has the benefit of limiting postconstruction creep settlement. Preloading also proof-tests the structure and verifies the quality of construction. Additional sketches are included to show its potential for common applications. A brief discussion about design considerations to limit potential problems is offered.