Concrete Pipe & Box Culvert Installation - Shaw Precast Solutions

used (less than 1 1/2 in. preferred but no largerthan 2 in.). If the construction site is located in a regionwhere the ground is frozen, remove the frozenlumps and replace them with designer approvedmaterial.A bedding thickness of no less than 3 in. (75 mm)should be used except when the foundation is rock,in which case the bedding thickness should be 6 in.(150 mm). The width of the bedding material shouldequal the width of the box (span plus twice the wallthickness) and the length of the bedding materialshould equal the length of the box.The box will tend to pull some bedding materialtoward the connection as it is aligned with the previousbox. Excess bedding material trapped in thejoint will prevent a proper alignment and connectionand hence should be prevented. Therefore, atthe connection end, a small trench (a shovel lengthwide and running the length of the bedding material)should be dug. This allows for the bedding materialto fall into the trench instead of the joint whenthe box is pulled into place.All bedding material characteristics should correspondto code and designer’s plans for the specificproject. Correct installation requires that the boxculvert be installed on properly graded bedding.Any discrepancies in the installation of the culvertregarding bedding or grade should be addressedwith the engineer for remedial action.American Concrete Pipe Association • www.concrete-pipe.org 71