Engineered Ecoroof Systems: Geotechnical Considerations

Abstract

AbstractEcoroof systems are proliferating to meet the need for reducing peak storm discharge and improving habitat in urban environments; however, no coherent set of standards exists for the engineering of these systems. Necessary questions that remain regarding engineering performance range from hydraulic to structural to geotechnical in nature, as exemplified in a series of recent ecoroof failures. As a first step, this paper describes a field exploration and laboratory characterization program conducted to develop a necessary geotechnical engineering baseline for ecoroof soils currently used with sustainable green-roof technologies. A series of low-stress (i.e., 10–30 kPa), static drained, simple shear tests were conducted on both reconstituted and relatively undisturbed specimens derived from three target gradations. The volumetric response of the undisturbed specimens exhibited contraction, and developed significantly larger magnitudes of volumetric strain than that of the reconstituted specimens, wh...