Reconstructing a catch basin refers to the task of refurbishing an existing catch basin structure and raising or lowering it’s casting and structure top to line up in harmony with the adjacent grade, pavement, curb, etc.
Reconstructing a catch basin is different from adjusting a catch basin in that it often requires more structural work will be done to the basin. If a catch basin requires raising or lowering more than 12″, it is often considered a ‘reconstruction’. Reconstructions are also done if the existing structure is deteriorating or for some reason considered unstable. In this case the engineer may require that the structure will be removed down to the nearest sound area, but usually not past the lowest springline (middle of the lowest pipe), and built back up with precast pieces, brick, or solid block and mortar.
Lastly, anytime an existing catch basin casting/top elevation requires considerable lowering, it is typically considered a reconstruction. Lowering a precast concrete structure is commonly approached by:
-removing a precast concrete riser or top
-sawcutting the structure top horizontally
-or making vertical cuts (about 6-10″ apart) along the perimeter of the top of the structure, then jack hammering them off piece by piece.
Lastly, depending on whether the catch basin is within an area with vehicle traffic, a ‘concrete collar’ may be required within the reconstruction scope. This is typically the last task done when installing a catch basin and is often lumped into the overall task of reconstructing a catch basin.
A concrete collar is a cast in place concrete section formed and poured around the casting giving additional strength and reinforcement to the catch basin from vehicle traffic. The concrete collar also helps resist the entire assembly from shifting or moving with vehicle traffic or freeze thaw conditions.