Failures of Pipe Culverts from a 1000-Year Rainfall Event in South Carolina

South Carolina recently experienced a 1000-year rainfall event that caused catastrophic flooding and crippled the transportation infrastructure. Initially, almost 400 roadways were closed due to flooding, a majority of which were closed from roadway washouts. Many of these roadway washouts resulted from failure of the pipe culvert soil system beneath the roadway. The culvert infrastructure is critical to not only preventing flooding during normal and extreme conditions but is integral to proper road and highway maintenance. This paper presents the results from a post-flood reconnaissance study aimed to collect perishable data from sites where pipe culverts failed and roadways were washed out. The study included collection of extensive photographic evidence and documentation of descriptive information related to the failure; collection of soil samples; and field and laboratory geotechnical tests.