A 48-inch diameter reinforced concrete pipe installation has been observed in order to evaluate the performance of both types of bedding conditions as currently used by the Kentucky Department of Highways. A portion of the pipe was laid using Kentucky's Standard B Bedding. The remainder of the pipe culvert was laid using the B1 Bedding (imperfect trench); the design height of the fill (36 feet) was sufficient to require the imperfect trench construction. The embankment was primarily of a rock fill material, with the largest particle size limited to a maximum of 3 feet. The portion of the pipe with the Standard B Bedding exhibited stress in relation to each additional height of embankment placed. For every fill increment, there was a corresponding change in the length of the vertical and horizontal diameters of the pipe and in the pipe distress as exhibited by cracking. The absence of signs of distress in the B1 Bedding portion indicates that the imperfect trench performed its purpose of relieving load on the pipe.

Report Date


Report Number

No. 262

Digital Object Identifier