Project overview: Callide Dam flood control structures
Callide Dam, located in Biloela, Queensland, serves multiple purposes including irrigation for agricultural industries. Callide also features a series of dam bridges that function as flood control structures, utilising a counterweight system for operation. Reinforced cement pipes, containing concrete REO bars, pump water into large chambers to lift the bridges and release water when levels become critical.
During a routine dam maintenance inspection, the local water authority identified a malfunction in one of the dam bridges – it would open momentarily before closing abruptly. A dye test confirmed water leakage from the cement pipes, necessitating urgent bridge repair as part of the dam’s maintenance program.
However, the challenge lay in the pipes’ location. They were encased in 600m of concrete within the footing walls, making traditional replacement methods unfeasible without significant structural damage. But with Nuflow’s skills and solutions, this could be overcome.
Technical challenges and innovative solutions
Upon inspection, the Nuflow Central Queensland team, led by franchise owner Ben, identified several unique challenges. CCTV technology revealed the concrete pipes were shaped like a horseshoe, extending 17m vertically on either side before bending to span 14m horizontally at the bottom. This configuration meant that the majority of the relining needed to occur vertically, requiring a departure from standard horizontal relining techniques.
Furthermore, traditional pipe cleaning methods using vacuum and water jetting proved ineffective. This was due to fragmented steel from the reinforced pipes and high head pressure (170kPa) in the vertical sections. Their vacuuming equipment was not strong enough to remove the steel from the pipe, so the team had to devise an innovative solution to address this issue.
In response, the team developed a custom magnetic cleaning method. They used 100mm round, high-strength magnets to remove the metal fragments from the pipes. This process, while time-consuming, proved highly effective in preparing the pipes and ensuring proper adhesion of the new lining.
Product specifications and execution
After careful analysis of the head pressure and pipe conditions, the team selected Nuflow Standard Liner with Blueline Underwater Resin for optimal performance in this high-pressure environment. This choice of materials was crucial to ensure the longevity and effectiveness of the concrete repair.
For the relining process itself, the team employed a strategic liner insertion method. Instead of relining from end to end, they inserted the liner at an access point above the bend and halfway down the bottom pipe. This approach allowed for easier manipulation and installation of the liner. For the vertical sections, the liner was suspended and inflated in place for curing, adapting their techniques to the unique demands of the project.
The project was completed over a four-day period. The first day was dedicated to the custom magnetic cleaning process, meticulously removing metal fragments from the pipes. The second day saw a weather delay, but the team used this time effectively to secure the site and prevent water infiltration into the cleared pipes. The final two days were spent on lining installation and curing, bringing the project to a successful conclusion.
Results: a happy client and safer infrastructure
The successful completion of this project resulted in the full restoration of bridge functionality without any structural damage to the existing infrastructure. This not only solved the immediate issue but also enhanced the long-term reliability of the flood control system.
The water authority expressed high satisfaction with the results and the professional approach of the Nuflow team. This positive outcome has led to discussions about potential future projects on additional bridges at the site.
Trust Nuflow with your infrastructure maintenance
Nuflow’s innovative approach to the Callide Dam project showcases our ability to tackle complex pipe rehabilitation in critical infrastructure. By combining technical expertise with creative problem-solving, we delivered a solution that extended the lifespan of vital water management assets, ensuring their continued effectiveness and reliability.
This case study demonstrates how Nuflow can adapt standard trenchless rehabilitation techniques to unique infrastructure challenges, providing cost-effective solutions for complex water management systems. Our capacity to innovate and overcome obstacles positions us as a leader in the field of pipe rehabilitation and infrastructure maintenance.
For more information on how Nuflow can assist with your infrastructure maintenance needs, including dam bridge repair, concrete pipe rehabilitation, or other trenchless pipe repair projects, please contact our team of specialists. We stand ready to apply our expertise to your most challenging pipe rehabilitation projects, ensuring the longevity and efficiency of your critical infrastructure.
