Thalle Construction Company celebrated reaching 500,000 labor hours without a lost time accident in constructing a larger navigation lock on the Tennessee River. The U.S. Army Corps of Engineers Nashville District recognized the remarkable milestone last week and thanked construction workers for their role in delivering a project of national significance.
Lt. Col. Robert W. Green, Nashville District commander, spoke during a special lunch Oct. 17 provided by the contractor for the workforce, and addressed the contractor and resident office team about safety and what it means moving forward without delays.
“To have a milestone like this on this project where we are meeting and exceeding production goals, but also keeping each other safe, is an exceptional milestone,” Green said. “I really appreciate that this can’t happen without a team effort.”
Green stressed that safety is also an individual responsibility requiring workers to look out for each other, and that ultimately makes it possible to keep the $380 million downstream lock monoliths contract on track. More importantly, leaders, safety officials and the folks on the ground make safety part of a culture and make it possible for people to go home safely each day, he added.
The Nashville District and its contractor, Thalle Construction Company, are building a larger 1,200-foot by 110-foot navigation lock chamber about 22 miles upstream of where the Tennessee River flows into the lower Ohio River. It’s a massive project with a lot of moving pieces and involves a lot of heavy equipment and conveyer systems placing concrete overhead.
Peter Tully, Tully Group president, recognized the complexity of the project and praised the construction leaders, the coaches and the captains, that care about the team.
“Just keep doing what you are doing. I appreciate it,” Tully said.
Steve Kohler, Thalle Construction president and chief executive officer, said that half a million hours are considerable and very meaningful because injuries can have huge impacts on the construction team and the project.
“The fact that we are tracking so positively here is truly impressive. I appreciate the safety group here. I appreciate the way they take care of the business and take care of people,” Kohler said. “My hope is that when everyone comes to work that each person intends to do their best that day.”
As workers ate their lunches, Kohler also drew attention to a sign inside the bay that noted how the team is bound together for the singular purpose of safely constructing, on time and on budget, a high-quality navigation project in support of the USACE civil works mission. He said it takes hard, dirty, sweaty work, and he appreciates the focus on safety in these conditions to meet these objectives.
Bill Ryan, Tully Group vice president of Risk Management, said leaders make it a point to engage the workforce from a perspective of education and encouragement, so everyone understands the importance of safety, to avoid injuries, and recognize that fatalities have negative impacts on people foremost.
“This is a very worthwhile project, one that you should be proud to be part of,” Ryan said. “My message to you is thank you and congratulations.”
Brian Sharpe, Thalle Project executive, said he is on site regularly and sees what is going on, and realizes that this is a very positive achievement.
“The one thing I want to talk about safety is that everybody here can help the safety program by looking out for the people working with you,” Sharpe said. “So be your brother’s keeper. Look out for one another so we can all go home safely.”
Jeremiah Manning, Nashville District’s resident engineer for the Kentucky Lock Addition Project, said the work is currently estimated for completion in May 2027, which will continue to require close coordination between the Corps of Engineers and contractor to ensure operations continue safely.
The project involves constructing 51 monoliths, which will require an estimated 375,000 cubic yards of concrete to complete the lock chamber. This is enough concrete to fill up more than 114 Olympic swimming pools. Thalle Construction Company has placed about 10 percent of the concrete as of September 2023.
(The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at www.lrn.usace.army.mil, on Facebook at http://www.facebook.com/nashvillecorps and on Twitter at http://www.twitter.com/nashvillecorps. The public can also follow Kentucky Lock on Facebook at http://www.facebook.com/kentuckylock.)
The Upstream Approach Walls for the Chickamauga Lock Replacement Project got a solid start when work crews placed 148 cubic yards of tremie concrete Sept. 20 into the drilled shaft on the bottom of the Tennessee River.
Allen Malcomb, contracting officer’s representative at the Chickamauga Lock Resident Engineer Office, said the U.S. Army Corps of Engineers Nashville District team worked closely with the contractor, C.J. Mahan, to ensure the smooth operation that required putting concrete trucks on a barge and into position to place concrete.
“I was there to monitor that the contractor was performing the work safely and address safety issues if they came up,” Malcomb said. “No major safety issues were observed due to the contractor’s communication and planning prior to making the placement.”
The contractor tested the concrete at the on-site batch plant to ensure fresh properties met contract requirements. After batching and testing, the three trucks were loaded onto a barge and pushed out to the placement site on the upstream side of Chickamauga Dam. At the placement location, the team tested the concrete again for quality, then each truck placed 10 cubic yards of concrete into a 91-foot-deep pipe into the shaft.
“As the concrete pumped, the contractor’s quality control team and the government’s quality assurance team monitored the concrete placement to verify the concrete rose as expected, embedment was maintained, and concrete quality was visually acceptable,” Malcomb added.
Matthew Curvin geologist in the Quality Assurance Section at the Chickamauga Lock Resident Office, said the first delivery of concrete had changed properties, so the contractor adjusted the concrete proportions and mixing time at the batch plant and improved concrete quality for a successful placement. The contractor began placing concrete at around 9:20 a.m. and completed the first of 14 shafts for the upstream approach wall piers by around 2 p.m., he said.
The amount of work performed on this drilled shaft is not visible at the surface of the lake. The size of the rebar cage in the shaft and its complexity in placing concrete is hidden by the water and casing. The contractor and Corps of Engineers worked closely to address safety concerns and placed concrete with no incidents or injuries.
“The Tennessee River is not an easy environment to work in due to the flow of the river and the geology of the bedrock that they are building on,” Curvin said. “C.J. Mahan leadership and staff worked in tandem with good communication and teamwork.”
To build the piers, the contractor must drill 14 eight-foot diameter shafts up to 35-feet into the bedrock, which is up to 135 feet below the surface of Chickamauga Lake. The shaft is drilled through a permanent steel casing. After the drilling is completed, a pre-constructed rebar cage is lowered into position. Up to 300 cubic yards of tremie concrete is placed in the shaft.
Capt. Joseph Cotton, Chickamauga Lock Replacement Project manager, said each shaft will anchor the approach wall beans in place that will be visible on the surface of the lake that will guide vessels into the new navigation lock. As shafts are completed, C.J. Mahan will begin work on the piers that will hold the approach wall beams in place, he explained.
“Approach walls act as a guide for barge operators when maneuvering their vessel towards the lock chamber,” Cotton said. “It provides a location to tie off barges that are waiting to move through and provides a water break to reduce the effects of current and wave action from the dam spillway or during inclement weather.”
Work on the approach walls is expected to continue through December 2024 and is integral in bringing the new Chickamauga Lock to an operational status. Once the new lock is commissioned, a tow system, commonly referred to as a mule, will be installed allowing barges to be moved in and out of the lock chamber without a boat.
“The new Chickamauga Lock will allow the passage of up to nine barges at a time compared to the single barge that the existing lock can pass. This greatly increases the speed that barges can move through the lock and helps create a safer work environment for mariners,” Cotton added.
(The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at http://www.lrn.usace.army.mil, on Facebook at http://www.facebook.com/nashvillecorps, and Twitter at http://www.twitter.com/nashvillecorps. The public can follow Chickamauga Lock on Facebook at http://www.facebook.com/chickamaugalock.)
The U.S. Army Corps of Engineers Nashville District announces a base contract award to Brasfield & Gorrie, L.L.C., of $16.8M for the Dissolved Oxygen facility. This is a sustainability project funded by the Section 212 Program to install an upstream diffuser system at Wolf Creek Dam on the Cumberland River in Jamestown, Kentucky.
The district is partnering with power preference customers, the Southeastern Power Administration, and Tennessee Valley Authority to construct a cryogenic facility downstream of the dam and install 50,000 linear feet of oxygen diffuser lines that reach into Lake Cumberland.
When constructed, the cryogenic facility will be capable of converting 300 tons of liquid oxygen per day to gaseous oxygen through four 15,000-gallon tanks and eight vaporizers. Daily deliveries of liquid oxygen will be required during the low dissolved-oxygen season for operation. Onsite construction of the facility is anticipated to begin in 2024 after fabrication of the liquid oxygen tanks has started.
Installation of polyethylene piping has begun. TVA has mobilized to the site to begin assembling the diffuser lines. Construction is underway downstream of the dam and then the lines will be trenched under Highway 127 and through Halcomb’s Landing in late fall after the peak recreation season. Lines will then be installed in the forebay. The system is similar to those TVA operates at Norris Dam and Watts Bar Dam and is scheduled to be operational in the fall of 2025. Highway 127 and Halcomb’s Landing will remain open or partially open throughout the construction period.
“The award of this contract will improve generation at Wolf Creek Power Plant by mitigating the need to sluice water during the late summer/ fall low dissolved oxygen season,” said Chris Stoltz, project manager, U.S. Army Corps of Engineers, Nashville District. “Without this system, power production can be limited to 30% of its design capability throughout the season. The Project Delivery Team is excited to begin this phase of the project and continue supporting the region with reliable and renewable electricity.”
Installation of an upstream diffuser system, in conjunction with auto-venting turbine runners, reduce or eliminate unit restrictions during the low dissolved oxygen season. When these capabilities are achieved, the Nashville District can provide more environmentally friendly releases while maximizing hydropower generation.
The Nashville District continues use of funds granted under the Section 212 Water Resources Development Act of 2000 for hydropower plant rehabilitation to bring generators up to date through the Hydropower Modernization Program.
Project managers managing Nashville District 212 projects include Sam Jaser, Chris Stoltz, Omar Acevedo, Austin P'Pool, Mason Carter, and Mike Lee. Dana Sexton is the 212 Program Manager. All Hydropower managers can work on 212 projects within the Nashville District.
Section 212 authorized the Corps to accept and expend a portion of hydroelectricity revenues to perform rehabilitation work on hydropower equipment throughout the Nashville District in Tennessee and Kentucky. The rehabilitation of nine hydropower plants, 28 units and aging equipment ensure the production of more hydropower into the future to energize local cities and towns.
Sexton said these rehabilitation projects bring the hydropower plants up to date and they also ensure the Nashville District can reliably produce power that can quickly come online during periods of peak usage and critical energy shortages, like the Christmas Eve blackouts that swept across Nashville last winter.
“Hydropower is very helpful during power shortage situations, because we can quickly come online and produce the power needed during emergencies and fill that gap, so people aren’t as greatly impacted,” said Sexton.
Most hydropower units in the Nashville District began operating between 1950 and 1977, making these units outdated and challenging to find replacement parts for repairs.
“Most hydropower equipment has met the service life at Nashville District plants in the Cumberland River system. The objective for the Section 212 Program is to replace old equipment with more modern equipment so these plants can continue to produce power and increase the amount of power they produce,” said Sexton.
The hydropower plants in the Nashville District have been operating for over 50 years, exceeding their typical design life of 35-40 years. As a result, the risk of component failure increases every day.
Memorandum of Agreements between the Army Corps of Engineers, Nashville District, Department of Energy Southeastern Power Administration, and power preference customers provides Section 212 rehabilitation funding for these rehabilitation projects.
“Wolf Creek and Old Hickory have substantial turbine generator rehabilitation work upcoming. Taking care of these upgrades now will ensure a more cost-effective hydropower impact on the region in for the future,” said Sexton.
The projects are complete turbine generator rehabilitations, consisting of replacing and upgrading the main generating equipment. The direct current exciter replacement projects help power the plant while engineers get a generator online. These projects are done in preparation for the larger turbine generator rehabilitation projects.
“Wolf Creek turbine generator rehabilitation is currently in the design phase and is expected to be rewarded to a hydropower construction contractor in 2024,” said Jaser.
The design process for Wolf Creek turbine generator rehabilitation is currently ongoing at 90% complete, meeting the September deadline for this step of the process.
Jaser, who also leads the Generator Step-up Unit transformer replacement project, said the Nashville District will meet with contractors who are considered industry expects to review the design plans.
“By reviewing the specs beforehand, the solicitation process happens a lot easier. We want to ensure there’s nothing that needs to be modified before the acquisition and solicitation portion of the process is completed,” said Jaser.
With a technical background in electrical engineering, Jaser is a huge asset to the hydropower team. His experience with the electrical equipment used at hydropower projects helps with planning the work and understanding the challenges, so teams can prioritize the necessary work.
Sexton said Jaser’s unique engineering knowledge helps him manage the projects he’s working on and serve as another layer of review on the project.
“Jaser’s background strengthens the Nashville District on several levels, one being the ability to review certain steps ahead of time and make any necessary changes before we move to the next phase,” said Sexton.
The Wolf Creek Hydropower Plant Rehabilitation Project design phase started in 2022. Jaser works closely with the quality control team and technical teams during this phase.
“As a project manager with an electrical engineering background, I’m glad to put these skills to work. I help create functional and critical ways to improve the processes we use to get these projects done quickly and efficiently,” said Jaser.
The project is expected to take approximately 10 years and will enter the acquisition phase in 2024, then contractors will bid for the contract and eventually begin construction.
The Old Hickory turbine generator rehabilitation project will replace three out of four turbine generator units. The Corps rehabilitated the fourth generator under a separate Section 212 funded contract.
Stoltz, project manager for Old Hickory Dam Turbine Generator Rehabilitation Project, said the new generators will be rated at 40,500 MW and contractors will replace three turbines with new Kaplan turbines, rewind existing generators, and refurbish associated equipment and components for three units.
Before starting the turbine generator rehabilitation work, the Corps completed a Hydropower Rehabilitation Analysis Report in 2022, where engineers studied different alternatives to complete the necessary repairs.
“This report helps the design team leading the engineering and design phase to know which alternative will yield the most benefit once completed,” said Stoltz.
The Corps awarded the construction contract in January 2023 and the project is currently in the engineering during construction and supervisory and administration phase. Repairs are scheduled to begin in March 2025 after the contractor submits and gets approval for their construction plans.
“The contractor will be off-site for two years planning, designing, and manufacturing before mobilizing and removing the first unit in 2025. This off-site time is critical and lays the foundation for the successful replacement of the first unit. It gives the team an opportunity to look over the contractor’s plan and ensure it meets the requirements of the plans and specifications,” said Stoltz.
Sexton said Stoltz has done a great job leading the Old Hickory rehabilitation project, he's been actively involved with the contract from the beginning.
“Stoltz and his team had a technical site visit with the contractor and our technical staff early in the contract ensuring everyone was on the same page to meet deadlines successfully. He’s committed to being as cost effective as possible through this entire process,” said Sexton.
The Corps awarded the Old Hickory Dam Turbine Generator Rehabilitation Project to Andritz Hydro, a global supplier of plants, equipment, and services for hydropower stations, in February 2023 and is expected to complete the work by August 2029.
The Nashville District power plants produce over 3.2 billion kilowatt-hours per year on average. Based on an average annual household consumption of 10,715 kWh, as provided by the U.S. Energy Information Administration, that is enough energy to support 304,000 homes annually.
(The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at www.lrn.usace.army.mil, on Facebook at http://www.facebook.com/nashvillecorps and on Twitter at http://www.twitter.com/nashvillecorps.)
A monumental feat of engineering and progress stands tall in the heart of the Cumberland River basin. Dale Hollow Dam and Lake, authorized by the Flood Control Act of 1938 and the River and Harbor Act of 1946, emerged to control the floodwaters of the Obey River and contribute to the reduction of flood levels at municipal, industrial, and agricultural areas along the Cumberland, lower Ohio, and Mississippi Rivers.
Contractors completed the flood control project in 1943 but suspended the construction of the powerhouse. In July 1946, construction of the powerhouse resumed, and Dale Hollow Dam became the first of nine U.S. Corps of Engineers power plant erected within the Cumberland River basin.
Stanley Carter, power plant superintendent, described the planning of Dale Hollow Dam and the subsequent dams as a "holistic" approach to taming the Cumberland River system. "The Corps created each of the dam sites to work in harmony with each other," he explained, pointing out the distinct roles played by non-river run plants like Dale Hollow, Wolf Creek, Laurel River, Center Hill, and J. Percy Priest, which primarily served as storage facilities for flood control. In contrast, the river run plants along the Cumberland and Tennessee Rivers focused on navigation as their primary mission, with minimal water storage capacity.
From 1948 to 1953, contractors added three Francis power-generating turbine units to the power plant. Each unit can produce 16-18 megawatts of power. Together, the turbines generate up to 54 megawatts of power, enough to supply the needs of a town with approximately 45,000 people.
For the town of Celina, with a population of 1,400, that's enough power to keep the entire town powered in the event of a complete or partial energy loss.
The powerplant does more than generate power. Since hydropower is an immediate source of energy, hydropower turbines work as backup generators. Dale Hollow's turbines stabilize the 69-kilovolt electrical grid system it connects to, providing a reliable and steady electricity source during increased demand or emergencies. By increasing the voltage on the turbine units, the voltage on the entire electrical grid system receives a boost.
"We're like the Red Roof Inn. We keep the lights on," said Steven Crawford, journeyman electrician.
To keep the lights on, Carter relies on a strong, highly competent, and professional team to maintain the aging equipment. The team includes Office Attendant Amanda Matheny, Senior Electrician Paul Drinkard, Journeyman Electricians Waylon Hackett, Steve Crawford, Stanley Theisen, Senior Mechanic Brian Perry, Journeyman Mechanics Kyle Cross, Josh Marcum, Chris Boone, and Maintenance Workers Jeremy Bilbrey and Elijah Garrett.
Mechanics and electricians must complete a rigorous four-year training program in addition to the education they receive before coming to the Corps.
Carter described the training program as a testament to the field's commitment to safety. "We have a great responsibility to intimately know every aspect of our job and the equipment so we can operate in a safe environment while ensuring the safety of those around us."
The highly skilled maintenance staff work hard to keep the equipment operating at the same efficiency it did 80 years ago but go above and beyond. "They're innovative thinkers who find creative ways to do more with less," said Crawford.
At the power plant, creativity and innovation are on display. Garrett and Bilbrey have spent time applying fresh and updated coats of paint around the plant, giving it that 'new plant' glow. Marcum, a multi-talented individual, inspires a sense of pride and professionalism within the plant through his work. He has created custom light features projecting the 'Essayons' logo and a wood-framed elevator car shaft with the Corps Castle.
Creativity and innovative problem-solving are a theme at Dale Hollow. For 80 years, the generator turbine floor has been without a restroom. Maintenance workers have had to traverse the plant to clean themselves up after a job or utilize the bathroom. Additionally, access to drainage from a toilet was non-existent. Employees found an area on the turbine floor where they could create a washroom and install a toilet that can pump drainage to the existing sewer and assist in pumping the sink drain water to the sewer. When it's finished, employees will be able to use the sink for clean up and direct the wastewater to an appropriate method to be treated.
Carter described how mechanics and electricians recently rehabilitated the drive component of the tail deck crane for a fraction of the cost and now have another skillset. "Dale Hollow has become a reliable source of sustainability and reliability due to the professionalism of these people," said Carter.
Thanks in part to the pioneering efforts of Dale Hollow Dam and the people who keep it running, the Cumberland River Basin has been a steadfast provider of sustainable power to Tennessee and Kentucky for the past 80 years and will continue to provide power well into the future.
The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at www.lrn.usace.army.mil, on Facebook at http://www.facebook.com/nashvillecorps and on Twitter at http://www.twitter.com/nashvillecorps.
Follow us on LinkedIn for the latest Nashville District employment and contracting opportunities at https://www.linkedin.com/company/u-s-army-corps-of-engineers-nashville-district.
Lt. Col. Robert W. Green took command of the U.S. Army Corps of Engineers Nashville District today during a change of command ceremony at the Tennessee National Guard Armory. He becomes the 68th commander of the “twin rivers” district, commonly referred to as the jewel of the Great Lakes and Ohio River Division.
Green comes to the Nashville District from the Memphis District in Memphis, Tennessee, where he served as deputy commander. As commander of the Nashville District, he assumes responsibility for managing the water resources development and navigable waterways operations for the Cumberland and Tennessee River basins covering 59,000 square miles, with 42 field offices touching seven states and a work force of over 800 employees.
During the change of command, the new commander thanked past mentors, soldiers, NCOs, Army civilians and teammates for being a part in his successes, and said he now looks forward to working alongside the great people in the Nashville District, the most professional and distinguished district in the Corps.
“I’m excited to see what we will accomplish as we pull together with our partners from across the region and the nation,” Green said. “This district has an incredible history and tradition of delivering to meet the nation’s most difficult challenges going back over 130 years, but I am excited to join this team in building on those traditions as we continue to deliver for the American people for the next 130 years.”
Brig. Gen. Kimberly A. Peeples, U.S. Army Corps of Engineers Great Lakes and Ohio River Division commanding general, officiated the change of command and said Green comes to the Nashville District as a seasoned professional with a great reputation in the Army.
“He is the perfect fit – the right leader at the right time – to carry on the legacy of this proud district,” Peeples said. “Rob, I am confident in your ability to successfully lead this district and deliver. You will deal with new challenges and old, but I am confident you will bring great energy and new perspectives to achieve continued success. You have the full support of the division, and you are joining a winning team!”
Peeples also welcomed his wife Krystal and family to the Great Lakes and Ohio River Division and Nashville District. Krystal previously served in the Army on active duty more than eight years as an aviation and UH-60 Blackhawk pilot before becoming a full-time mother to their three kids Jacob, Taylor, and Autumn.
Green is a native of Michigan. He received his U.S. Army commission in 2005 and has served in leadership and staff positions in the United States during his Army career. He has deployed in support of Operation Enduring Freedom, Operation Freedom Sentinel, and Operation Resolute Support in Afghanistan, Operation New Dawn in Iraq, and Operation Spartan Shield in Kuwait.
His awards and decorations include the Bronze Star Medal with oak leaf cluster, Defense Meritorious Service Medal, Meritorious Service Medal with oak leaf cluster, Joint Service Commendation Medal, the Army Commendation Medal with oak leaf cluster, the Navy Marine Corps Commendation Medal, Army Achievement Medal with oak leaf cluster, Joint Meritorious Unit Award with oak leaf cluster, Meritorious Unit Commendation (with two oak leaf clusters), National Defense Service Medal, Afghan Campaign Medal, Iraqi Campaign Medal, Global War on Terrorism Expeditionary Medal, Global War on Terrorism Service Medal, Army Service Ribbon, Overseas Service Ribbon, NATO Service Medal, Pathfinder Badge, and Bronze Order of the de Fleury Medal.
Green holds a Bachelor of Science degree in applied engineering sciences and Master of Science degree in construction management from the Michigan State University. He also holds a Master of Arts degree in civil engineering from the University of Washington. He holds his professional engineering license in the state of Michigan and is certified as an associate constructor from the American Institute of Constructors. His military education includes the Engineer Officer Basic Course, Aviation Captains Career Course, and Command and General Staff College.
Peeples had high praise for the outgoing commander, Lt. Col. Joseph M. Sahl, and noted how this caring officer led the district out of the pandemic, provided stability, purpose and connection to the workforce while allowing the district to solve the nation’s toughest engineering problems without interruption.
“He understands that the success behind mission execution is through our most valuable resource of all – our people. Joe is one of the most caring leaders I have ever met,” Peeples said. “Joe has displayed unwavering commitment to the USACE mission through his continual focus on the people who make up the Nashville District and has been recognized for his leadership at the highest levels of the Corps.”
The general added that Sahl demonstrated exceptional leadership and dedication in the response to the tragic flood in Waverly, Tennessee, by leading the creation of the Waverly Flood Task Force with the state, and coordinated efforts across multiple state, local, and federal agencies.
“Through Joe’s collaborative efforts, he established a strong partnership between the district and the local community, contributing significantly to informing the public about the risks of flooding and the measures they can take to protect themselves and their properties,” Peeples said.
During Sahl’s command, he executed a federal civil works program exceeding $300 million, while managing regulatory and emergency management activities. He also led the creation of the Waverly Flood Task Force with the state of Tennessee to coordinate efforts across multiple local, state and federal agencies. The close relationships he developed with the Tennessee National Guard and Tennessee Emergency Management Agency ensured the Nashville District would be integrated into planning and provided value during emergency responses.
Sahl is also credited with spearheading efforts to improve project delivery by implementing a comprehensive project governance structure that more efficiently forecasted, programmed, and monitored projects. Under his watch, the Nashville District awarded $109 million to replace the spillway Wolf Creek Dam spillway gates in Jamestown, Kentucky, and $91 million to replace the Center Hill Dam spillway gates in Lancaster, Tennessee. His leadership and effective communication with USACE and national leaders secured more than $500 million in funding for the Chickamauga Lock Replacement Project and Kentucky Lock Addition Project.
In saying farewell, Sahl thanked Nashville District’s senior leaders, corporate board, and employees for taking on and tackling the toughest challenges.
“I have enjoyed getting to work with you for two years,” Sahl said. “You are the reason for any success I highlight today and represent all that is great in America.”
Sahl also thanked his wife Kathy, expressing his love and pride for her and appreciation for her support through his tenure as commander. He also gave credit to his parents, siblings, and sons Joey and Cody for their incredible support. He is now set to attend the U.S. Air Force Air War College at Maxwell Air Force Base in Montgomery, Alabama.
Peeples presented Sahl with the U.S. Army Meritorious Service Medal prior to the change of command recognizing his outstanding service as commander of the Nashville District. The commanding general also presented a certificate of appreciation to his wife Kathy highlighting her dedication and support to the district while balancing community and family responsibilities.
The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at www.lrn.usace.army.mil, on Facebook at www.facebook.com/nashvillecorps and on Twitter at www.twitter.com/nashvillecorps. Follow us on LinkedIn for the latest Nashville District employment and contracting opportunities at https://www.linkedin.com/company/u-s-army-corps-of-engineers-nashville-district.
Construction of a new navigation lock on the Tennessee River reached a monolithic milestone yesterday as crews and officials held a topping-off ceremony to mark the completion of the first concrete monolith.
Officials and employees from the U.S. Army Corps of Engineers Nashville District and its contractor, Shimmick, assembled near the construction site to celebrate the occasion and highlight partnering efforts as construction of the lock chamber progresses.
Shimmick Chief Executive Officer and President Steve Richards gave the signal and Crane Operator Patrick Harrison lifted the last concrete form from monolith L13 to mark the official completion of the first of 36 monoliths. Crews placed more than 4,000 cubic yards of concrete into the 87-foot monolith, which is enough concrete to construct the foundations of approximately 150 homes.
Lt. Col. Joseph Sahl, Nashville District commander, thanked and congratulated the USACE construction team and the contractor for achieving this great milestone and for having the commitment to work through challenges without sacrificing safety or quality.
“As the project encountered challenges, I have been impressed by this team,” Sahl said. “We’re here today because you all dedicate yourselves daily to safely delivering this quality project.”
In addressing the Shimmick team, Sahl noted the continued commitment to quality and lauded the efforts of their on-site workers and engineering team.
“Their ability to proactively engage our engineering and construction teams has helped identify many issues early and we appreciate the approach they have taken to being a partner with us in this project,” Sahl said.
Richards said the completion of L13 is the culmination of two years of hard work by the 450 craft workers that Shimmick employees, which has overcome lots of challenges.
He noted that Shimmick and legacy companies have been involved with building landmark projects like Hoover Dam, Dale Hollow Dam, Olmstead Dam, and the Tennessee-Tombigbee Waterway.
“Simply put, Shimmick builds America’s infrastructure,” Richards said.
With the Chickamauga Lock Replacement Project, Shimmick has spent $112 million on payroll to date, $12 million on contracts with local small businesses, and $17 million on contracts with local large businesses. The contracts include five veteran-owned businesses, seven women-owned small businesses, four disadvantaged-owned businesses, and two historically underutilized business zone companies.
Delivering a project that will last for generations is only accomplished with close partnerships, Sahl added, which includes close interaction with Shimmick and with the Tennessee Valley Authority, which is a close federal partner that is involved with ensuring the new navigation lock is integrated safely into the current dam structure.
The base dimensions of the L13 monolith is 51-feet long by 31.5-feet wide at the base. At the top it is 20-feet wide and 51-feet long. The Corps of Engineers is nearly two thirds of the way complete with concrete placement for the lock chamber and is approaching the halfway point for all contracts associated with the project.
The new lock chamber is expected to be completed in the fall of 2026, and the majority of the site work to be completed by the end of 2028.
In looking forward to the completion of the lock chamber, Tennessee District 3 Rep. Chuck Fleischmann provided a statement for the ceremony congratulating Shimmick, and reinforcing his commitment to the U.S. Army Corps of Engineers in the development of infrastructure in the 3rd District.
TVA completed construction of Chickamauga Lock and Dam in 1940. The lock has since experienced structural problems resulting from alkali aggregate reaction between the alkali in the cement and the rock aggregate, which results in a physical expansion of concrete structures. Even with costly advanced maintenance procedures, the concrete expansion threatens the structural integrity of the lock and limits its life span.
With significant annual maintenance, Chickamauga Lock has frequent and lengthy lock outages as a result of downtime for repairs. Up to now, Corps maintenance crews have kept the lock open as the concrete continues to expand and hinder operations.
Chickamauga Lock remains one of the most important current construction projects in the Corps of Engineers because it is so critical to the economy, commerce, and recreation in East Tennessee. It passes approximately one million tons of commodities annually and is the most active lock on the Tennessee River for recreational vessels. If the current lock were to close prior to completion of the replacement lock, the direct impact would be closure of 318 miles of river and associated movement of traffic upstream of Chattanooga.
The active navigation lock is 360-feet long and 60-feet wide and only fits one barge. When constructed, the new lock will be 600-feet long and 110-feet wide, and will handle nine barges per lockage. It will reduce commercial transit times by 80%.
The project to construct the lock chamber is cost shared between the federal government and with navigation industry through the Inland Waterway Trust Fund, which generates its revenues from a 29-cents tax on marine diesel fuel.
(For more news, updates and information please follow the Nashville District on Facebook at http://www.facebook.com/nashvillecorps and Twitter at http://www.twitter.com/nashvillecorps. The public can also follow Chickamauga Lock on Facebook at http://www.facebook.com/chickamaugalock.)