Model Study of Safety Grating for Culvert Inlet

Abstract

The design of a safety grating for a culvert inlet as investigated using a physical model. The objectives of such a grating are: (1) To prevent a person who falls into the drainageway from being carried into and through the culvert; and (2) to prevent the person from being pinned against the grating. The basic design of the grating, recommended by previous researchers, was tested using a 1:10 scale model. Testing was performed over a wide spectrum of flood flows, including flows that exceed the culvert capacity. The grating has only a minor effect on the head‐discharge relationship, causing a slight increase‐in the headwater required to pass given discharge. However, the grating may act as a debris control structure and vigilant maintenance may be required to prevent clogging of the culvert inlet. Neutrally buoyant objects were introduced to the flow to assess the performance of the grating. Because of the parabolic shape of the grating, an object carried to the culvert tends to be pushed up the grating and out of the flow.