Many times, the concrete ring that supports the storm drain from underneath the drain will crack and break up into pieces. Once this occurs, excessive water will wash away supporting gravel underneath the concrete or asphalt. When this happens, the area of asphalt or concrete around the storm drain will sink along with the drain. Typically, for something like this, the concrete ring will need to be replaced, along with the washed away gravel and sunken ground.
The first step in repairing a drain is to saw cut a square line in the pavement around the perimeter of the drain. Typically this would extend 2 feet beyond the edge of the drain in all directions. The material around the drain would be excavated and removed from the site. The casting would be removed so as to assess the damage to the structure.
Broken or damaged storm drain inlets may not only prevent the proper drainage of the pavement, but may also create “trip” hazards as well as potential traffic hazards. Left un-repaired, the broken drains expose the property owner to unnecessary liability.
If the damage is too severe, it may be necessary to remove the existing structure and install a pre-cast concrete box. In either situation, it is important to repair any connecting pipes and permanently seal the connections to the structure. The steel casting is then set on the structure and the area is backfilled. After the material is properly compacted the asphalt is applied as outlined in the full depth repair procedure.