If the narrow roads weren't challenging enough, the steep grades of the mountainous terrain added to the project’s difficulties. "We were traveling unusually high grades of up to 17.5 percent," Long said. With its maximum 10 degree gradeability, the Terex CC 2800-1 NT efficiently handled the steep grades, and its Quadro track drive helped with maneuvering by allowing the tracks to counter rotate to make tight turns.
RMT’s crews started at turbine pad site six and worked their way down the mountain to pad 14. When finished at turbine 14, they moved the CC 2800-1 NT up the mountain without disassembling it to pad one and worked their way back to pad six.
Once back to turbine number six in May, they had enough room to disassemble the crane for transport to Oahu. Transport of the crane to and from the port and between Islands was arranged by locally owned general/mechanical contractor American Piping & Boiler Co. (APB), Kapolei, Hawaii. “Moving between islands was logistically challenging, but APB did a fantastic job handling all of the arrangements,” Long said.
When using the narrow track crane at the Kawailoa Wind project on Oahu, Buckner noted one additional advantage the CC 2800-1 NT offered - ease of assembly and disassembly. From June through mid-October, crews used the crane to build 30 of the larger 2.3 MW turbines. "Because of the challenging site conditions, we had to assemble and disassemble the crane three times," says Lusso.
Hayden Murphy was on site each time the crane was disassembled to offer support and consultation. Additionally, the same remote control unit used to move the crane from pad to pad, is also designed to assist with crane assembly.
These large turbines required a maximum lift capacity of 105 tons. The crane was equipped with full counterweight, 334.6 feet of main boom and a 39.4-foot fixed jib offering up to 10-degree offset.
Even with the longer boom configuration and 50 percent higher capacity lifting requirement, Buckner did not need to equip the crane with its optional superlift for the project. Long said this significantly improved crane assembly and disassembly efficiency. "The total disassembly and reassembly process took two to three days," he said. "If we would have needed the (superlift) derrick, this would have added another full day to the process."
To ensure these turbines continue to harness the renewable wind energy at peak efficiency, Buckner will keep the Terex CC 2800-1 NT on Oahu for five years. The company has created a joint venture with APB, American Piping & Buckner, to assist with maintenance and service activities.