Grate Inlet Hydraulic Efficiency with Varying Porous Asphalt Aprons

Abstract

Grate inlets collect surface runoff from the roadway and other land surfaces and connect to a drainage network. Surface runoff that does not discharge to a drainage system because of insufficient inlet capacity can cause flooding and excessive hazards to pedestrians and motorists, as well as diminished roadway durability, safety, and efficiency. To minimize these risks, this paper suggested a new drainage inlet by surrounding the conventional grate inlet with porous asphalt referred to as an efficient grate inlet. Testing was performed on a 1∶1 scale road model with simulated runoff of various inflows. Various geometrical parameters were simulated, such as discharge rate, longitudinal slope, cross slope, and the dimensions of porous asphalt. This paper investigates the drainage efficiency of the efficient grate inlet (EGI) and comparing it to that of the conventional grate inlet (CGI). An empirical relationship is proposed for the inlet efficiency as a function of the width of porous asphalt and roadway flow characteristics.