Under contract with the National Park Service, and agency of the US Department of Interior, R. Zoppo replaced the water supply system at the Boston National Historical Park and the Charlestown Navy Yard, Charlestown, MA. The original scope of work required the replacement of a 16” cast iron water main with a 12” ductile iron water main located in a reinforced concrete utility tunnel under the main pedestrian sidewalk that traverses the park from east to west. The existing tunnel carried water, hot water, steam supply and return, fuel, and communications and alarm warning. The contract also included the replacement of all branch lines in the Park with new 4”, 6” and 8” HDPE including hydrants, domestic and fire services, and appurtenances. We installed approximately 5000 lf of bypass water main to facilitate the new installation.

 

     Prior to installing the new 12” DI water main along with a new meter pit, the tunnel had to be remediated due to asbestos insulation on the pipes in the tunnel. Once the tunnel was remediated, the roof was removed and disposed along with the old utilities. The new 12” DI main was installed per plan, and a new precast sidewalk was installed over the existing tunnel with cast in place elements at the wheel chair ramps.

 

     The remainder of the work, however, changed dramatically from the original concept. Our onsite investigations and research of old construction plans led us to develop a VE proposal to accomplish the installation of the 4” through 8” branch water mains using various trenchless techniques. Where existing pipes were larger than proposed, we cleaned and sliplined the old cast iron pipe with the HDPE pipe specified for direct burial. In areas where the existing pipe was the same size as the proposed pipe, we cleaned and lined the old cast iron with a structural liner. Finally, where neither of those options were available, we employed HDD to install the specified HDPE pipe. Each technique served its purpose well, and allowed us to construct the new water system with minimal impact to Navy Yard operations and the many tourists who visit the Park on a daily basis.

    R. Zoppo Corp Project Superintendent Paul Scally and Project Engineer Chris McManus have done yeoman’s work overseeing the project to keep it on time and on budget while coordinating with the National Park Service and the U.S. Navy, to maintain Navy operations and to safely keep the park open and accessible to the public.

 

                     --From CIM magazine