Problem

A Public Works department in southern Texas needed to replace 110 LF of cast iron pipe running underneath a heavily traveled highway. The 10” wastewater pipe was located inside a steel casing and had suffered extreme deterioration from prolonged exposure to hydrogen sulfide gas. Some sections of pipe were missing entirely, and voids riddled the aged horizontal asset. In this situation, the traditional dig-and-replace method was ruled out as a viable option due to the impact on the traveling public. Additionally, other trenchless methods could not be considered because the voids in the pipe would require point repairs to be done on the existing host pipe.

Solution

Fuquay was able to meticulously clean and televise the pipe in preparation for the lining process. During preparation, areas of severe corrosion were noted to avoid the threat of having equipment get damaged or lost down the large cavities of missing pipe directly under the highway. This is important because the retrieval process would have required a mass excavation effort—counterintuitive to the trenchless rehabilitation method. Fuquay crews successfully pulled the Alphaliner product into place and introduced air to the liner for expansion into the failing host pipe. With less than 8% elongation, the Alphaliner product was a perfect solution for this project. 

Result

The liner was successfully cured in place without expanding into the pipe voids and mitigating the threat of a thinning liner that would lack structural integrity. Within 48 hours of Fuquay crews arriving on-site, the pipe was rehabilitated and returned to service without any trenches or a single-lane closure.