Clean Cuts Needed to Repair 97 Miles of Aqueduct

84 Concrete Cutting and Demo Crew Members Join Forces to Repair California Aqueduct

The Colorado River Aqueduct (CRA) is one of the largest aqueducts in the United States and supplies drinking water to millions of residents in Southern California. Constructed over six years from 1933 to 1939, it was the largest public works project in Southern California during the Great Depression. The aqueduct carries water west from the Colorado River at Lake Havasu on the California-Arizona border across the Mojave and Colorado Deserts to the east side of the Santa Ana Mountains. The CRA runs for 242 miles and is composed of two reservoirs, five pumping stations, 62 miles of canals, 92 miles of tunnels and 84 miles of buried conduits and siphons.

The Colorado River Aqueduct (CRA) runs  for 242 across the desert landscape of Southern California.

The Colorado River Aqueduct (CRA) runs for 242 miles across the desert landscape of Southern California.

Over time, the concrete canals and reservoirs deteriorate, with concrete spalling and cracking. Rebar is exposed and rusts with exposure to air and water, which then leeches into the water supply. The damaged concrete also compromises the structural integrity of the canal liner, and therefore the supply of safe drinking water. It was determined that the canal needed to be repaired, no small feat considering the sections in need of repair spanned a total of 97 miles and would require the complete shutdown of the canal, a clean removal of the damaged concrete and a successful pour-back. Due to the massive scope of this project, an experienced professional with the expertise and manpower to get this job done on time would be needed. CSDA member Penhall Company and their team of over 1,500 concrete professionals were called to action to cleanly remove the canal and reservoir liners in a short timeframe.

This wasn’t the first time Penhall has tackled this challenging job – a similar project was undertaken 15 years ago on the CRA. “The sun and concrete are not best friends!” stated Keegan Clemens of the Metropolitan Water District of Southern California, and with much of the canal exposed to the hot desert sun on a daily basis, the elements won. In 2003, Penhall anticipated set-up and tear-down time to take three weeks, however, operators had only seven days to complete the work on 97 miles of the aqueduct while drained. It was a challenge accepted, and successfully accomplished.

Two-man Penhall crews worked on a concrete slope using vertical and horizontal wall and hand saw cuts to remove the canal liner.

Two-man Penhall crews worked on a concrete slope using vertical and horizontal wall and hand saw cuts to remove the canal liner.

Further complicating this project was the location – project headquarters was the Iron Mountain Pumping Station, over 60 miles away from any kind of civilization. All personnel, equipment, generators, supplies, fuel and other resources had to be brought in and stored in the desert. Penhall carefully coordinated for over a two-month period leading up to the project to ensure all logistics were in place. Furthermore, a team of 84 Penhall employees from 15 West Coast Branch offices were needed to be brought in to ensure project success and an on-time completion.

Crews worked 12-hour shifts each for seven days straight, with shifts occurring back to back, and were driven in and out of the jobsite before and after each shift. Once all equipment and supplies were in place, the Penhall crews could get started on breaking down and removing the reservoir liner. The canal was drained of water for seven days so crews could complete the work. The project commenced on March 6, 2019 with the first wall and hand saw cuts made. The liner was cut into sections, first with two vertical cuts then followed by a horizontal cut. Longer cuts were made using wall saws, while the smaller cuts were made with hand saws. All cuts were of carrying length, so crews had to approach each section individually. Once the liner was fully cut through, the Penhall demolition team used excavators to remove the damaged concrete section so it could be hauled offsite by the general contractor.

Operators had to be rigged with harnesses while working on the sloped canal wall.

Operators had to be rigged with harnesses while working on the sloped canal wall.

Next, the canal liner needed to be removed. The same pattern of wall saw cuts were used to break down the canal liner in 117 locations over 97 miles. Then, 15 head walls were removed using hand saws along the same 97 mile stretch of canal. Once all the cuts were made, the Penhall demo crews removed the cut concrete and it was hauled offsite.

The work was completed with the use of equipment and diamond blades from Diamond Products, K2 Diamond, Hilti, ICS/Pentruder and Husqvarna. Two, two-man crews worked at one time during each 12-hour shift, with crews hopscotching each other when needed. Also at work were two Penhall concrete removal crews to lift out the cut sections. The team ran eight wall saws during the day and eight at night to complete all 117 cutting locations over 97 miles.

Besides the hot, dry desert heat during the day and cold temperatures at night, there were several other factors that made this project physically challenging for the Penhall team. Operators were required to wear body harnesses due to the slope of the canal. The sloped working surface challenged their bodies and legs with constant movement and balance required to stay in position. Days and nights were long, and operators were exhausted after seven consecutive days of 12-plus hour shifts. Finally, the team had to contend with dangerous desert residents, including poisonous scorpions and rattlesnakes.

Penhall wall saw operator Ted Post monitors a horizontal cut.

Penhall wall saw operator Ted Post monitors a horizontal cut.

The safety of not only the wall and hand saw operators but all Penhall team members on this job was overseen by the safety team of Tim McElroy who monitored log hours and Jason Sellers who kept an eye on the operators in the field to ensure breaks were given when needed and all employees followed standard PPE guidelines and safety protocols.

Wall and hand sawing with diamond tools was the only choice to make this project a success. The precise and clean cuts required to leave a clean surface for the pour-back could only be accomplished by using diamond tools. Any other method would have compromised the integrity of the canal substructure and jeopardized the drinking water supply to millions of Southern California residents and businesses.

In all, 20,000 cubic feet of concrete was removed from 97 miles of the CRA. The project was completed on time and within budget, due largely in part to the success of pulling together 84 Penhall “Red and Gray” team members, who worked around the clock to ensure project success and safety. “I was extremely satisfied with the outcome of this project,” said Brandon Salazar, Penhall Project Manager. “Penhall Company completed a very demanding project on time, within budget and most importantly, injury free,” he continued.

84 Penhall “Red and Grey” crew members from 15 branch locations across the West Coast teamed up to successfully complete this challenging job.

84 Penhall “Red and Grey” crew members from 15 branch locations across the West Coast teamed up to successfully complete this challenging job.

Penhall was selected for this massive project due to their experience, manpower and resources. No other single cutting contractor could have brought together this many operators and team members to make this job a success. “I believe Penhall Company was selected for a project of this magnitude because of the sheer manpower that we can provide. Secondly, for the knowledge, experience and skill set that Penhall brings to the project. Lastly, Penhall’s reputation in the concrete cutting and demolition industry,” stated Salazar.

Water through the CRA is once again flowing cleanly and millions of Southern California residents and businesses can be assured that their drinking water is safe, thanks to the clean cuts of diamond tools and the teamwork and manpower of an outstanding CSDA contractor.

Company Profile

Penhall Company is headquartered in Irving, Texas. They were proudly established in 1957 and have grown significantly from a single flat saw to 40+ branches across the United States and Canada, and over 16,000 customers served by a staff of over 1,500 professionals. Penhall continues its growth in leading the nation with their full spectrum of diversified services. They are the largest and most trusted provider of concrete services in North America, offering concrete cutting, coring, demolition, grinding and grooving. Penhall Technologies is a division of Penhall Company specializing in GPR scanning, digital x-ray imaging, utility locating and fiber reinforced polymer. With a national footprint, they bring together teams from throughout the company to get the job done. Penhall Company has been a CSDA member since 1999.

Author: Russell Hitchen

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