Trenchless Rehabilitation of Large Brick Conduits in Boston

The Boston Water and Sewer Commission is a public agency created in 1977 by the Commonwealth of Massachusetts. Its enabling legislation gave them ownership of the water, sewer and drainage systems within the City of Boston. Since its inception the Commission set several goals for improvements to those systems through a clearly defined annual Capital Improvement Program. Since 1978 the water, sewer and drainage systems in the city have seen substantial improvements in the areas of water quality and reductions of Combined Sewer Overflows to Boston Harbor and its tributary rivers. Hundreds of miles of water and sewer pipe have been replaced or rehabilitated. More than eighty miles of new drains have been installed for the purpose of sewer separation. New larger sewer interceptors have been constructed along the waterfront and many sewer and drain interceptors have been cleaned and inspected. The results of the inspections have revealed that most of the systems large pipes are in good condition with the exception of some of the old brick sewers and drains that have exhibited various minor structural problems or infiltration due to degradation of mortar. Rehabilitation of odd shaped brick conduits presents a difficult challenge to provide adequate and long term repair to the conduit at the lowest cost and amount of disruption to the surrounding neighborhoods. Common rehabilitation methods are often not applicable to large or odd shapes and pipe replacement may not be a viable option. This paper presents the planning, design and construction of two projects in Boston involving the rehabilitation of large brick conduits.