Stormwater pipe culverts may consist of concrete, metal, plastic, or a combination of these or similar materials. The pipe culvert structure, regardless of the pipe material used, is made up of the pipe, the foundation, the bedding materials, and the backfill materials that work in conjunction to support the loads imposed on the culvert.
Proper installation of pipe culverts is crucial to the overall performance of the culvert structure. Various problems associated with pipe installation can occur early on in the process. If the trench width is either too narrow or too wide, improper placement and compaction may result in a failure of the pipeline. If sections of pipe are not properly jointed or joints are not properly sealed, exfiltration or infiltration may result in a reduction of the pipe's capacity and voids may occur within the embankment. Damage to pipe during handling and installation may result in premature deterioration of the pipe and the pipe being unable to support design loads leading to failure during its service life. In addition, crossing pipe culverts with heavy construction equipment before adequate cover has been placed can lead to damage of the culvert. These and other problems associated with improper installation of pipe will increase maintenance costs and otherwise limit the design life of a culvert.
This manual is devoted to the proper materials selection, storage, handling, installation, and inspection of pipe culverts. It is intended to serve as a tool to aid NCDOT personnel in performing their duties during construction and maintenance activities. It is also intended to serve as a general guide for private industry involved in construction of roadways that may receive future acceptance onto the North Carolina Highway System.
This manual is not intended to serve as a design guide for pipe culverts used by NCDOT. Although several design references are contained herein, they are used only for clarification purposes.
The information contained within this document is not intended to alter or replace the Standard Specifications, but is to serve as a reference guide to fulfill the requirements set forth by the Specifications.