Collapse of a 100-year-old sewer line created a substantial problem for the City of Ansonia, Connecticut recently.  The aging infrastructure of brick lined pipes failed in a downtown municipal area requiring a costly around-the-clock emergency by-pass pump configuration to divert the raw sewage around the leak to the treatment plant.    Additionally, as the collapse was near a local river, significant environmental risks were possible.   Brennan was subcontracted for immediate emergency repairs to the line necessary to mitigate these problems.

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Due to a major flood in 1955, the original lines had been covered when the nearby roadway was elevated an additional 15’, resulting in the need for a 30’ trench to reach the leak.  A complex shoring system was designed and engineered to expedite the repair using a crane for the installation of the walers necessary to do the job.   Due to the seriousness of the situation, for nearly four weeks, crews worked long days and weekends to get the job done.  It would take several days to get the shoring built to the required engineered standards.   Underground boulders and rocks requiring excavation caused additional time to drive the sheets to the necessary depth.   Hundreds of tons of materials needed to be hauled in and leveled to build a ramp necessary to get the heavy equipment down to the level necessary to complete the repair.    A temporary by-pass was built to divert the raw sewage from the newly formed trench and allow the crews to make the repair.

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The collapsed sewer was a clay-tile pipe accessible by 25’ deep manholes.  Once accessible, the repair included replacements with 12” DI pipe.  Additional repairs were made to existing clay fittings by adding concrete and steel to provide structural support.  During the repair process, the city took the opportunity to use a camera to photograph surrounding lines to determine if there were any additional problems needing immediate repair.

While none this complex, the City of Ansonia experienced a total of three such breaks during the previous four-month period.  Along with Brennan, the overall repair project required significant efforts from a multi-member team, which included engineers, the WPCA, the City of Ansonia, Frank Pepe Construction as well as various equipment rental firms.  It is this team approach that allowed for the development of an efficient and pragmatic solution to this serious problem.

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