What makes it interesting?
Each of AMPs four hydroelectric power plants along the Ohio River required intricate construction expertise. Concrete must be poured at exactly 55 degrees, and heavy 36-foot turbines must be hung at precise tolerances, leaving only a width of two business cards between the blade and the structure. Ruhlin had to build adjacent to a US Army Corps of Engineers Lock and Dam, with a fault line running through the site Conventional drilling and blasting techniques were not allowed on the sensitive site.
How HCSS Software assisted with this project
The use of HeavyBid was integral to winning this project. The project was bid to AMP, utilizing a specific proposal form. The versatility of HeavyBid allowed Ruhlin to produce an exact copy of the bid form and use that format to determine bid items, holding accounts, and parent-child relationships. Ruhlin estimating staff used the information stored in the vendor/business contact system to reach out to potential material suppliers and subcontractors to request quotes, and then used the bid pricing screen for entering costs. Standard codes were pulled from the activity codebook or made up on the fly for non-standard work items. When the estimate was complete, Ruhlin used the vendor/business contact information to send out material and subcontract quantities for quotation. The quotes received were entered into the quote comparison system for analysis and the low quote selected. This quote was then rolled back into the bid and the plug pricing updated. This project had several owner modifications after the initial bid. Ruhlin was able to copy the old estimate to a new estimate and make updates, preserving the history of changes. After being selected by the owner to build this project, Ruhlin was able to make changes to costs and activity codes and then export from the accounting subsystem. A direct import to Viewpoint was accomplished and the budget complete. To pick one portion of HeavyBid as the reason Ruhlin was low bidder on the project is not possible. It was the complete integration of the estimating process and elimination of duplication that helped win the project.
The AMP Willow Island Powerhouse, though the smallest of AMPs plants in number of turbines, presented additional geotechnical challenges given the jobsite’s tight location. Faced with many complex construction needs, AMP selected The Ruhlin Company to design and build the cofferdam and excavation, and to be their general contractor for the hydroelectric powerhouse project.
The first phase, a $42 million cofferdam and excavation, kicked off in January 2011. To successfully build a hydroelectric powerhouse adjacent to the existing US Army Corps of Engineers Lock and Dam, Ruhlin had to work around existing site challenges within tight constraints. Ruhlin leveraged its team’s technical expertise and proactive problem-solving skills to design the intricate solutions AMP needed.
First, containment of the river and groundwater flow was critical before excavation could begin. Working with a team of skilled subcontractors, Ruhlin constructed a bentonite slurry cut-off wall on the landside, a cellular sheetpile cofferdam on the riverside, and a series of 28 deep dewatering wells around the perimeter to handle up to 3,000 gallons per minute.
Next, the mass of bedrock needed stabilization to support the 40-year-old dam next to the 110-foot deep excavation — especially with a fault zone running diagonally through the site. Stabilization required 28 rock anchors drilled 140 feet deep, each exerting 2 million pounds of force. Excavation was anything but routine. Conventional drilling and blasting techniques were not allowed on the sensitive site, so large bulldozers had to rip out 410,000 cubic yards of fractured rock and slick clay.
By staying in constant contact with everyone involved in the project, Ruhlin collaboratively tackled issues head-on to ensure that challenges did not impede construction progress. The excavation prepared a dry foundation for the construction of the Willow Island Powerhouse, with Ruhlin acting as general contractor.
Slated for completion in May 2015, the $139.5 million construction project consists of 82,000 cubic yards of cast-in-place concrete, 9.5 million pounds of reinforcing steel and 200,000 pounds of other embedded metals. Designed to divert water from the Willow Island Locks and Dam through two turbines, the powerhouse will generate an average annual output of 239 gigawatt hours, with a total rated capacity of 37 megawatts — 1 megawatt of energy can sustain approximately a thousand homes for one hour. Coordinating this volume of material on a tight schedule to precise specifications required that Ruhlin’s staff and subcontractors worked as a cohesive team. Ruhlin is keeping the powerhouse on schedule despite the geotechnical challenges.