Sectional CIPP of Sanitary Force Main Preserves Historic Hull Waterfront


Sectional CIPP of Sanitary Force Main Preserves Historic Hull Waterfront

Author:

Charles N. Tripp, P.E., Project Manager, Kleinfelder, Westborough, MA 01581

Abstract: The Nantasket Avenue force main in Hull, MA was constructed in the mid 1970’s. The 14” diameter ductile iron force main conveys wastewater from a pumping station in the southern portion of the Town to the start of the gravity interceptor sewer. In early 2016 the Town realized through an investigatory CCTV inspection of sewerage infrastructure that the force main had deteriorated significantly due to hydrogen sulfide attack brought on by decreased flow velocity. The last 15 feet of the force main, which was pitched in a downward gradient, had become pitted with visible holes and voids behind the pipe. The issue however, was that excavation and replacement was not a viable option. The portion of roadway above had recently been paved using Massachusetts Department of Transportation (MassDOT) funding and a moratorium existed on the finished pavement and intersection work. An additional issue was that the only means of access to the deteriorated portion of the force main was through a 60” diameter epoxy lined manhole where the force main discharges to the gravity interceptor system. A second force main service manhole could not be accessed even remotely close to the point of repair and was reported to have been removed during a time when the upstream section of interceptor collapsed and was replaced. Installation of overlapping 14” diameter sectional CIPP repairs utilizing the 60” downstream manhole as the only means of access was the proposed solution to rehabilitate the approximate 15 linear feet of deteriorated ductile iron force main piping. This paper/presentation will describe the planning, logistics and construction involved to improve the reliability of the subject sewer infrastructure. The technique and lessons learned from this project will be applicable to other communities knowing that force main renewal is one of the growing areas of interest in our industry.

Publication Date: 2018

Presented at:
NASTT’s 2018 No-Dig Show Palm Springs, California
March 25-29, 2018 | Paper Number: MM-T3-02


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