Structural Design Equations for Bell and Spigot Joints in Culverts under Vehicle Load

Abstract

The structural design of joints in highway culverts requires evaluation of expected values of both the shear force across the joint and the joint rotation that result from vehicle loads. This paper describes new design equations that have recently been developed for estimating shear force and rotation in bell and spigot joints for both rigid and flexible culverts. The equations are exact closed form solutions based on the modeling of the pipes as elastic beams, and the Winkler soil model (where the soil stiffness is represented using a series of elastic springs). The kinematic assumptions are explained, and the equations are presented. Comparisons are included between estimates of joint rotations under surface loads and rotations measured during full-scale laboratory experiments. The paper concludes with a discussion of how shear force and rotation depend on pipe diameter, pipe stiffness and burial depth.