Cianbro is using a barge-mounted Manitowoc MLC650 crawler crane to replace two transmission towers on the James River near Charles City, Va. When construction is finished, the towers will help feed energy from a nuclear plant to the surrounding area.
During planning, it became clear that a barge-mounted crane would be able to complete lifts in close proximity to the 425-foot-tall transmission towers. It was determined the 650-ton MLC650 crawler crane with the variable position counterweight would provide the reach and capacity to get the job done.
“In the past, we would have had to build a trestle, cofferdam, or causeway to accommodate a traditional crawler crane with the necessary capacity,” said Mike Berry, lift superintendent for Cianbro. “The MLC650 has the right capacity and a compact footprint that fits securely on a barge, which enables us to lift from an optimal position on the river.”
Cianbro’s MLC650 is erected on a Poseidon P10 portable sectional barge, which measures 132 feet by 132 feet. Once the crane removes the old transmission towers, it will then set the replacement towers into position on the river. The heaviest components of the new towers are their 100 foot by 90 foot bases, which weigh 75.5 tons and will be lifted to a height of 10 feet. The upper halves of each tower weigh 28 tons and will be lifted 435 feet above the water for installation. To dismantle the old transmission towers and erect the new ones, the MLC650 is outfitted with the VPC-MAX attachment, which enhances the crane’s capacity and enables additional boom- and jib-length combinations.
Each tower section will be assembled at Shirley Plantation on the north bank of the James River, nine miles away from the construction site. Once completed, the sections will be moved into position by barge, where the MLC650 will install each one.
“The MLC650 with the VPC-MAX is the only crane that had a load chart that would enable us to complete the project this efficiently,” Berry explained. “Also, you don’t get any listing of the crane on the barge, so you can lift without moving the crane. The VPC counterbalances everything and the crane stays level, even when completing the heaviest lifts.”
The MLC650 isn’t the only Manitowoc crawler on the job. An additional, barge-mounted Manitowoc 4100 RINGER will assist the MLC650 crawler with lifting each tower component. Two Manitowoc 4100Ws and a 4000W are also set up on the river bank to remove old tower components from the river and to deposit them on land for further disassembly.
Cianbro received the MLC650 from Shawmut Equipment. The tower replacement project is being overseen by PAR Electric, which brought Cianbro onboard as a subcontractor.
The transmission tower replacement began in August 2017 and is on schedule for completion in February 2018.