Design, construction and monitoring of concrete roadway pavement at extremely steep longitudinal slopes

Abstract

ABSTRACT Most conventional roadway pavements are not constructed at grades greater than 15% due to construction limitations and/or motor vehicle operator safety concerns; however, there are conditions, especially in the developing world, where roadways must be built at extremely steep longitudinal slopes. Currently, there are limited published design procedures for extremely steep concrete roadways, and little guidance on either the type, shape, or spacing of sliding restraint devices for these pavements. This paper presents an original design methodology for concrete roadways at slopes of 15–60% with integral concrete lug anchors to resist sliding where the design computes a sliding factor of safety of the earth pressure resistance developed by the lug anchors as compared to the downhill forces acting on the concrete pavement from gravity, vehicle loading and vehicle braking. A case study of a concrete roadway construction project, which uses the lug anchor design methodology with slopes of 23–58% and with limited right of way, is also presented. Many valuable lessons were learned during the construction of a roadway at such steep grades, including novel ways to transport and place fresh concrete and the fabrication of specialised equipment to screed and smooth concrete on a steep slope.