NCHRP Synthesis 581: When Culverts Need Rehabilitation

This article, drawn from the National Cooperative Highway Research Program (NCHRP) Synthesis 581: Rehabilitation of Culverts and Buried Storm Drain Pipes, presents current and emerging culvert repair and rehabilitation methodologies, as well as factors affecting their selection and implementation. The synthesis collected and analyzed information from a variety of sources including: a literature review of relevant standards, best practices, and guidance documents; a web-based questionnaire that was completed by 42 state departments of transportation (DOTs); and follow-up interviews to develop case examples. Four major culvert types were examined: corrugated metal, precast concrete three-sided or box structures, precast concrete pipe or arch, and thermoplastic pipe. The survey questionnaire and case examples focused on: culvert types and frequency of their rehabilitation, critical factors affecting the rehabilitation method, local and spot repairs, repair of joints between pipe pieces or metal plates, invert paving and invert lining rehabilitation methods, system-level rehabilitation methods for the entire culvert lining, existing structural capacity, in-house rehabilitation, and quality assurance. This article discusses key findings, spot and joint repair methods, system-level methods, consideration of existing structural capacity, and case examples from various state DOTs.