It's Not a Pipe Dream—Crossing the St. Johns River with One of the Southeast's Largest Directional Drilling Projects

This paper provides a general overview of the steps JEA has taken to meet future water supply needs in Jacksonville, Florida, while protecting the environment through the total water management plan (TWMP) and highlights the Segment 2 36-in. river crossing design/build project. The river crossing is a key component of the TWMP and one of the longest horizontal directional drills ever completed using 36-in. pipe. The goal of this presentation is to provide utility planners, project managers, and designers with information on the engineering and design/build aspects on this very large and high-profile directional drill. The $80 million dollar TWMP is a capital improvements program to transfer significant amounts of potable water from JEA's North Water Grid to the South Water Grid. It includes six large-diameter pipeline segments. Segment 2, one of the pipeline segments, involved crossing the St. Johns River with a massive horizontal directional drill (HDD) to install more than 6,500 ft of 36-in. steel pipe. The crossing required a full complement of cutting-edge technology and techniques in the HDD field that included the largest horizontal directional drilling equipment available, using the intersect method for the pilot hole with state-of-the-art guidance and survey and utilizing a 300-ton pipe thruster in tandem with a drill rig for pullback. The project also required other trenchless technologies including pipe ramming to install conductor casing at both entry points and auger boring to install a casing for the water main below a major downtown expressway. The 36-in. steel pipe was welded into six intermediate segments along a congested, limited access right of way. Just prior to pullback the segments were maneuvered and welded into one complete pipe string, requiring a heavily coordinated closure of a travel lane and seven ramps along the Arlington Expressway, a major commuter route through downtown Jacksonville. An extensive multiphased maintenance of traffic plan was required. The design/build project required a very compressed schedule and was completed in 10 months, including design, permitting, and construction.