2013 Project of the Year - New Install Honorable Mentions
Oct 28, 2013
Hayes-Yorktown 230kv Transmission Line Crossing
This power supply was to extend the electric transmission system by building a new 230-kv line north across the York River, which has a width of 3 miles at the crossing location. The project was completed by the engineering, procurement and construction (EPC) method involving a large group of engineers and contractors to bring together the specialized technical resources required. It included six HDD crossings for the parallel system of 8-in. steel pipe necessitating two temporary platforms constructed in the river to stage HDD operations. The two 50 ft x 150 ft platforms were designed and constructed instead of using conventional barges. This allowed a stable work site that minimized impacts from weather and tides. This resulted in two shore approaches at each side of the river and two water-to-water crossings between the platforms. The crossing lengths were two 7,400 ft, two 6,600 ft and two 3,600 ft — for a total of approximately 17,600 ft. Several of the crossings used the intersect pilot hole method. Challenges associated with the project included tidally influenced currents; shipping lanes; very soft sediment; a relatively narrow, S-shaped right-of-way (ROW) with two bends of 45 and 32 degrees; and Hurricane Irene, which swept through during the mid-way point of the project.
JEA 36-in. River Crossing
The Haskell design-build team, including Jacobs Engineering Group and Michels Construction, successfully completed a challenging and high-profile HDD across the St. Johns River in downtown Jacksonville, Fla. The design-build project was part of a larger Total Water Management Plan (TWMP) for JEA. The HDD was 6,572 ft of 36-in. diameter steel pipe 60 ft below the river, and was installed as a single pipe string. The pipe was assembled along the Arlington Expressway, a major roadway between the Jacksonville beaches and downtown. The crossing is close to downtown and the Jacksonville Jaguars football stadium. To minimize disruptions, JEA developed an aggressive construction schedule of 10 months for design, permitting and construction to ensure the project was complete before the Jaguars’ first home game. Before drilling the 6,572-ft pilot hole, Michels used a TT Technologies Grundoram pneumatic hammer to install two 60-in. surface casings by pipe ramming. Then, after positioning the Atlas 840 and Hercules 1200 drill rigs on opposite sides of the river, pilot hole construction began using the intersect method. During pipe pullback, a 300-ton Herrenknect hydraulic thruster worked in tandem with the 1.2 million lb thrust drill rig to overcome a challenging bend in the bore hole. The final section of piping was installed by jack-and-bore under the Arlington Expressway.