Earth Pressure Reduction System Using Geogrid-Reinforced Platform Bridging for Buried Utilities

Abstract

Construction of new highway embankments in urban areas often requires building over existing underground utilities and lifelines. Embankments constructed over such utilities often induce substantial additional earth pressures causing overstressing and/or unacceptable deformations of the buried pipes, resulting in interruption of service for both the utility and highway. There are several techniques that can be used to mitigate this problem. Geogrid-reinforced bridge platforms are one of the newer techniques to deal with this problem. In order to gain a better understanding of the earth pressure reduction that may be achieved by geogrid bridging, the Ontario Ministry of Transportation (MTO) constructed an instrumented full-scale test embankment over a geogrid-reinforced bridged trench. In this paper, the results of this full-scale test along with a numerical study to evaluate the stress reductions achieved by the use of geogrid bridging platform installation are reported. In addition, results of a parametric study to investigate the soil structure interaction of the proposed stress reduction system and its effectiveness on the reduction of the deformations, moments, and normal forces of a buried culvert are presented.