Sinkhole Repair on Council Agenda for January 17th

IMG 0020January 13, 2012

If you have traveled north of the courthouse lately, you're probably aware that there is a sinkhole at the corner of Spanish Oak and North Court Street. Pending City Council approval on Tuesday night (January 17th), work will begin to correct this problem.

Once Council approval has been given, a Notice of Award and the construction contract will be prepared and delivered to the contractor. The contractor will, in turn, provide bonds, insurance and signed contracts back to us. Our City Engineer and City Attorney will review the contract for completeness. Upon successful review, Mayor Gillespie will sign the contract on behalf of the City of Prattville. A conservative estimate of 4 weeks will be required to accomplish these tasks.

A pre-construction conference will take place after the contract signing. Within two weeks of this conference, actual construction will begin. The construction contract is limited to 90 days. Closure of North Court Street is scheduled for a maximum of one week.

The sinkhole was caused by the deterioration of a corrugated metal pipe under Court Street. The metal pipe is deteriorated by the constant flow of water over the life of the pipe. This water carries sediment and sand which, when moved by the water, are abrasive and cut into the pipe material. Eventually, as is the case here, the bottom of the pipe fails completely and the loss of soil around the pipe begins. When it rains, the soil above the pipe falls into the failed pipe and causes a cavity or void above the pipe. When this void becomes large enough and the weight of the overlying soil is heavy enough, the overlying soil caves in. The caving in of the soil leaves the appearance of a sink hole. Once the sink hole has made it to the surface, rain causes the soil to enter the failed pipe easily and maintenance becomes a constant necessity. The solution to this sink hole is to replace the old, failing corrugated metal pipe. The pipe will be replaced with reinforced concrete pipe which has a useful life expectancy of 50 or more years.

This project will cost $48,601.00.