Traditional methods for the structural design of buried culverts and storm drains (culverts) ignore longitudinal stresses, transverse stresses, and circumferential stresses at the joint. The structural design of the culvert joint assumes only in-plane loading of the pipe’s cross section, that is, in-plane bending and in-plane thrust. Current practice does not consider longitudinal bending moments and shear resulting from non-uniform loading and/or variations in the bedding support along the length of the pipe.
Field observations show that longitudinal effects such as variation in bedding stiffness may be the cause of many culvert failures. Failure of the joint may allow water and soil to seep through the joint, potentially resulting in loss of soil support, and ultimately, collapse of the pipe and pavement damage.
Longitudinal distress resulting from poor bedding alignment and stiffness is a problem that may be solved using tighter standards for construction/installation. Nevertheless, experience shows that most pipe installations are less than perfect. A structural design process that considers longitudinal effects will improve the performance of joints.
The objective of this research is to develop structural design requirements for joints in flexible and rigid culverts to withstand variations in construction, support, and loading conditions. These requirements shall be suitable for consideration for adoption by the AASHTO Highway Subcommittee on Bridges and Structures.