Olmsted Locks and Dams
Olmsted Locks and Dams
As Part of one of the final Phases of the Olmsted Locks and Dam Project, a Putzmeister Concrete Placing system is placing up to 140,000 cubic yards(107,308M³) of Tremie Concrete VIA the In-The-Wet-Mathod, A first in the U.S., for the new replacement locks and dams numbers 52 and 53.
Located on the Ohio River, which begins in Pittsburgh, Pennsylvania and flows west 981 miles (1,579km) to the Mississippi River at Cairo, Illinois, are 20 locks and dams that provide a nine-foot (2.7m) deep year-round channel for navigation, which allows the traffic on the river to descend a total of 460 feet (140m), from 710 feet (216m) in Pittsburgh to 250 feet (76m) above sea level at Cairo, Illinois. The continued increase of waterborne commerce on the Ohio River has ultimately required periodic improvements in the waterways transportation infrastructure.
Two of the current locks and dams, numbers 52 and 53, originally built in 1929 and located on the Ohio River between Paducah, Kentucky and Cairo, Illinois, cannot meet the current and future traffic demands without significant delays because of their age and dated design.
As a result, the U.S. Army Corps of Engineers (the Corps) and the navigation industry are replacing Locks and Dams numbers 52 and 53, as one of the largest civil works projects undertaken by the Corps.
Construction of the 20th and final lock on the Ohio River, known as the Olmsted Locks and Dam Project, at river mile 964.4, was authorized by the U.S. Congress on November 17, 1988, by passage of the Water Resources Development Act of 1988 (Public Law 100-676).
Several phases make up the Olmsted Locks and Dam project:
1. Access Road/ Resident Engineers Office (Completed June 1994)
2. Lock Cofferdam (Completed December 1995)
3. Lock Construction (Completed March 2002)
4. Bulkheads (Completed July 2005)
5. Lock Approach Walls (Completed April 2004)
6. Dam Construction (Construction began spring 2004; completion date of 2015)
7. Demolition of Locks and Dams - 52 and 53 (upon completion of dam construction)
The joint venture Washington Group Alberici (WGA) was awarded the $564 million contract from the Corps for construction of one of the last project phases, which includes constructing a 2,700-foot (823m) long concrete dam across the river. The dam will comprise five 110-foot (33.5m) tainter gates and a navigable pass section with boat-operated wicket gates, along with a fixed weir tying the dam into the Kentucky bank.
The dam is being constructed using the in-the-wet method, a first for the Corps on a dam of this size. The in-the-wet method is the construction of a dam under water. Normally, water is drained out of a cofferdam, and construction work is done in-the-dry. The in-the-wet method was used because the Corps was convinced this method would be cheaper, faster and have less impact on the environment than using conventional cofferdams.
“There is nothing standard about this job,” says James Whitworth, marine engineer with WGA.
“The in-the-wet method required us to think outside of the box to figure out how we would construct the dam underwater. We had to determine which equipment would be the most efficient in this unique job environment.”
As part of the dam construction, precast shells are constructed on land adjacent to the dam location, carried into position and set underwater on a prepared bed of select fill, piles and continuity rebar grids. Once the shells are in place, tremie concrete is tremied under the precast shells to form a continuous bond between the piles, rebar, and surface shell, and provide more strength and fuller foundation overall for the dam. WGA consulted with Putzmeister’s Special Applications Business (SAB) to help decide what equipment would be best suited to deliver the tremie concrete.
SAB is a partnership between Putzmeister America, Allentown Shotcrete Technology, Inc., Esser Pipe Technology and Maxon Industries, Inc. (Maxon).
Because of the importance of everything working correctly for the entire length of every 36-hour pour, the mix design was reviewed and trial-run testing was carried out under cold-weather conditions to determine the level of pumpability of this “sticky” mix.
“We then used the trial-run results to evaluate all of the pump equipment and the project layout prior to equipment being supplied and installed,” notes Jim Bury, engineering director at Putzmeister America, also SAB member. “This attention to detail later resulted in a problem-free full system trial-run and an average output placement rate that has met the customer’s expectations.”
Whitworth explains, “After discussing the specific needs of the project and the environmental circumstances with SAB, we determined that they could provide us a complete concrete delivery system for dam construction. Because they manufacture and provide every component of the system, that’s huge because it means less time I have to search for another company that has the other system components needed.”
The Right Equipment
The equipment that SAB proposed for the project was selected and arrived on site in early spring 2010. It included:
• Two freestanding MX 43/47Z-Meter placing booms mounted on two freestanding pin towers
• One 31Z-Meter placing boom
• Two BSA 2112 skid-mounted concrete trailer pumps
• One 40Z-Meter truck-mounted concrete boom pump
• Four Maxon Maxcrete IV 18-cubic yard (13.7m3) remix hoppers
• Two DVH 5/2 diversion valves
Moving the Mix
The tremie concrete mix being used is a self-leveling mix to ensure that it fills up every square inch under the shell for ultimate strength.
“The mix’s strength is 5,000 psi (34 MPa) at 90 days and has a 10-inch (254mm) slump,” comments Whitworth. “It does not need any vibrating.”
Placing the concrete for each of the 28 shells is a non-stop 36-hour, step-by-step process. First, a Putzmeister 40Z-Meter truckmounted concrete pump, located on the river side of the project, delivers the concrete through slickline across the lock chambers.
“The 40Z not only helps to deliver the concrete quickly through the slickline with up to 210 cubic yards per hour (160m3/h) output, but it also allows for smooth and controllable pumping with its free flow hydraulic system,” notes Whitworth. “And that’s what we need for these long pours.”
In addition, the boom pump works with pressures up to 1,233 psi (85 bar).
At the end of the slickline is the Putzmeister 31Z-Meter placing boom, which delivers the concrete into the four stationary mixer drums on each of the two delivery barges. “The 31Z-Meter placing boom is perfect for customized applications like ours, providing us the utmost versatility in the concrete placement process,” comments Whitworth.
Next, the delivery barges go to the placing barge where the Stationary Mixer drums dump concrete into the Maxcrete Remix Hoppers. Two delivery barges are constantly rotating between the 31Z-Meter Boom and the placing barge to provide the most efficient placement of concrete during the non-stop pours.
The remix hoppers then place the concrete into the hoppers of the BSA trailer pumps. “The remix hoppers offer fast loading, fast discharge and complete remix capabilities,” says Whitworth. “And those characteristics are crucial to the project given our nonstop pour process; it’s almost as if this style of remixer was made specifically for this project.”
“The two BSA 2112 trailer pumps performance has been outstanding,” says Whitworth. “We’ve been averaging 100 cubic yards per hour (76m3) from each pump, but they are capable of pumping up to 142 cubic yards per hour (109m3). The rate of output from these trailer pumps has been vital in ensuring we stay on track, considering how much concrete needs to be placed.”
Two DVH 5/2 diversion valves are hooked up between the BSA 2112s and MX 43/47Z placing booms. “The diversion valves have been an added support of muscle within this system,” explains Whitworth. “They provide the flexibility to use either trailer pump with either placing boom, and provide cleanout routes.
In addition, the valves can easily handle high pressures up to 1,885 psi (130 bar) without leaking.”After the trailer pumps and diversion valves, the concrete travels up to the two MX 43/47Z placing booms. Here is where the concrete is delivered to the tremie pipes that move it underwater to its final resting place underneath the precast concrete shells.
Getting It Right
The two Z-Fold, five-section MX 43/47Z placing booms are the largest placing booms in the industry that do not require a counterweight.
“Not needing a counterweight on these placing booms saves us time and reduces labor costs,” says Whitworth. “Anywhere we can save time and money is a huge benefit to us.”
Both placing booms’ reach proved to be invaluable on site as well. “Their monstrous 138-foot one-inch (42.09m) horizontal reach places concrete exactly where we need to into the tremie pipes,” adds Whitworth. “With these pours being nonstop, we don’t have time for a system that doesn’t place the concrete precisely where it needs to be.”
The concrete placing system has delivered 2,000 cubic yards (1,529m3) of concrete for one percast shell, and the system will deliver up to 5,000 cubic yards (3,823m3) of the concrete for each of the remaining pours, until completion in 2015.
Owner/Developer: U.S. Army Corps of Engineers
General Contractor and Ready Mix Supplier: A joint venture of Washington Group and Alberici Constructors Inc., also known as Washington Group Alberici (WGA)
Putzmeister and Maxon Equipment: MX 43/47Z-Meter placing booms (2), Freestanding pin towers (2), 31Z-Meter placing boom, BSA 2112 skid-mounted trailer pumps (2), 40Z-Meter truck-mounted boom pump, DVH 5/2 diversion valves (2), Maxon Maxcrete IV remix hoppers (4)