SVCW 48-Inch Forcemain Improvements

The primary objective of this project was to construct a new fused 48-inch diameter high-density polyethylene (HDPE) sanitary sewer pipeline, replacing a pipe that had a history of leakage and damage due to the unstable Bay Mud ground conditions in the area. The existing 2.5-mile, 48-inch force main was constructed in 1971.

The initial phase of Power’s work was the construction of 3,300 linear feet of new pipeline that passed under waterways and land, using microtunneling and other intricate construction methods such as ground probing and jet grouting. To accommodate the microtunneling, jacking and receiving shafts were built. There were two jacking shafts, each 800-ton thrust capacity, and two receiving shafts ranging from 24 to 36 feet in diameter and 45 to 50 feet deep.

An additional 1,000 feet of pipeline required open trench, cut-and-cover excavation at approximately 15 feet below grade and necessitated complex navigation around several existing utilities, including water, sanitary sewer, and storm drain.

The final phase of the work was the design and build of temporary tie-in installations to allow for the continuous operation of the force main while two pump stations underwent reconstruction. This work was very critical as it revolved around existing influent lines and required very time-sensitive force main shutdowns to complete the installations of 48-inch HDPE tees, steel tees, and resilient wedge gate valves.

This project was successfully completed and awarded APWA Project of the Year due to the complex nature of this project and the collaborative efforts put forth by the entire project team and the large number of stakeholders involved.