‘2019 Top Plant Award’ for Bagnell Dam Stabilization Project at Ameren Missouri Osage Energy Center

St. Louis – MC Industrial, Inc., a McCarthy Holdings company, which serves the specialized construction needs of the industrial market nationwide, has received a “2019 Top Plant Award” in the renewable category from POWER magazine. The award recognizes MC Industrial’s work as general contractor for the Bagnell Dam Stabilization project, a $53 million investment in major structural and anchoring upgrades for the Ameren Missouri Osage Energy Center in Lake Ozark, Mo.

Completed three months ahead of schedule and on-budget in September 2018, the stabilization project was the first major structural update in over 30 years for the 85-year-old historic Bagnell Dam. The hydroelectric dam holds back 600 billion gallons of water from the Osage River at Lake of the Ozarks and is a source of clean energy for the entire state, as well as the centerpiece of a billion-dollar tourism destination.

When it was built in 1931, the Bagnell Dam, which created the Lake, was the largest construction project in the nation during the Great Depression. Today, it is the largest privately funded dam in the U.S. and produces more than 624,000 megawatt-hours of clean energy that powers 52,000 homes each year.

“This recognition as a Top Plant from POWER magazine is very special for this complicated 18-month-long project on the downstream side of the Dam to improve overall safety, efficiency and reliability, as well as long-term sustainability,” said Michael Hartwig, project manager for MC Industrial.

Work performed to enhance the structural integrity of the Bagnell Dam demanded expertise in heavy civil and major dam rehabilitation. The three-part project included installation of 67 new post-tension anchors to help secure the dam to the underlying bedrock; more than 66-million pounds of the new concrete poured to further weigh down the dam; and a new concrete overlay to replace worn and cracked concrete on the east and west sections.

Notable innovations included the use of Project Tracker, a Lean construction tracking 3D model software developed by McCarthy to allow real-time integration of project data, enabling the project to be completed three months ahead of schedule. In addition, the project is the first in the U.S. to use Duoguard Formtex, a new permeable form liner, to complete the challenging vertical and diagonal concrete pours, ensuring a durable surface free from imperfections.

“This project was focused on keeping this vital asset providing clean energy in the long-term, using the best possible engineering available today,” said Warren Witt, director of hydro operations at Ameren Missouri. “The high-quality work will ensure Bagnell Dam and the Osage Energy Center operate reliably and safely, affording the quality of life for hundreds of thousands who enjoy all that the Lake of the Ozarks has to offer each year.”

For more than four decades, POWER magazine has honored the top performers in the electricity-generating industry with annual power plant awards. Winners are plants that have distinguished themselves by innovative design or engineering upgrades, producing power more reliably or economically than comparable plants, or demonstrating a new generation of environmental controls technology.  More information about the project is available at https://www.powermag.com/successful-dam-stabilization-project-improves-safety-and-reliability.

Facts Sheet 

Background

• MC Industrial, a McCarthy Holdings company, was selected by Ameren Missouri as general contractor for the Bagnell Dam Stabilization project, a $53 million investment in major structural and anchoring upgrades.
• As a significant hydropower project, the scope of work demanded expertise in heavy civil and major dam rehabilitation to ensure a safe and high-quality outcome, as well as the long-term sustainability of the Bagnell Dam to provide clean energy each year to the surrounding 52,000 homes.
• The last major structural update at Bagnell Dam was completed in the early 1980s, when 277 post-tensioned anchors were installed to hold the dam into the bedrock.

Location and Dam History

• Bagnell Dam and Osage Energy Center, Lake of the Ozarks, Missouri
• The Lake of the Ozarks stretches for more than 54,000 acres in southern Missouri.
• The Bagnell Dam, which created the lake in 1931, was the largest construction project in the United States during the Great Depression.
• The dam holds back 600-billion-gallons of water from the Osage River and is the largest privately funded dam in the U.S.
• The dam facilitates a billion-dollar tourism industry for the state of Missouri.

Project Overview

• Project team mobilized on site in March 2017 for the 18-month project and began construction work in April 2017 with the first of three work phases.
• Project comprised of three parts: new post-tension anchors to help hold the dam to the underlying bedrock; concrete added between the highway piers to add weight to the dam; and a new concrete overlay to replace worn and cracked concrete on the east and west sections.

Construction Features

• 17,000-cubic-yards of concrete placement equals 66.2-million-pounds
• Added a total hold back capacity by 200-million pounds
• 67 post-tensioned anchors – each has a 2-million-pound hold back capacity
• 198 foundation drains
• 500-ft. spillway section contains 12 flood gates that spill approx. 200,000 cfs during high water
• Utilized two hydro demolition machines / robots built specifically for this project to climb the wall and remove 3-inches of concrete off the face of the dam using 35,000 psi water over a 100,000-sq.ft. area
• 33 anchors over the spillway that required a large temporary steel work platform
• Overlay – 9-to-12 inches of sloped concrete on the downstream side of the dam; 55,000-sq.ft. area