Failure of Concrete Walkways Across Alluvial River Channels

摘要

Concrete walkways are relatively low cost alternatives to bridges and culverts. They provide good and dependable ways across streams and rivers. This article discusses failures of concrete walkways in selected locations in Nigeria. The selected locations in Katsina state were visited before raining season started and during raining season. Concrete walkways across selected rivers (streams) were examined and their failures were assessed. Soil samples at the location of the walkway were collected and classified. The study revealed that earlier failures of culverts/bridges led to the construction of these concrete walkways in 1985 because the walkways were cheaper and required lower technology than construction of bridges. The soils at the site were mainly sandy–loamy soil with an average of 75.5% sand, 9.85% clay, and 14.65% silt. Failures of the concrete walkways were due to rapid and varied flow in the middle of the river channel, the presence of a hydraulic jump, the lack of resistance to turbulent flow, the presence of impulse forces, high Froude number (F r), and the lack of cohesion between the soil and concrete materials. It was then concluded that provision must be made against turbulent flow and cohesive materials must be provided in the construction of walkways to prevent failure of walkways.