REPAIR, RETROFIT & STRENGTHENING OF PIPES WITH CARBON FIBER REINFORCED POLYMER (CFRP); SYSTEM
Since 1998, QuakeWrap, Inc. has served water utilities and the power industry for repair and retrofit of large diameter pipes with Carbon Fiber Reinforced Polymer (CFRP). The conventional wet layup technique involves saturating the carbon fabric in the field and applying it to the inner surface of the pipe. QuakeWrap, Inc. has been awarded the International Concrete Repair Institute (ICRI) 2008 Award of Excellence in the Water Structures category for its Restoration of Large Diameter Prestressed Concrete Pipelines.
Although the conventional wet layup system has proven effective over the years, it has several shortcomings:
1. The installation is very time-consuming. An experienced crew of 5 to 6 workers can install about 80 square feet of fabric per hour. This is a costly obstacle for larger projects for which miles of pipeline require retrofitting.
2. The quality of installation depends on the crew responsible for mixing the resin, saturating the fabric, and ensuring that the fibers in the carbon fabric remain aligned during the installation.
3. Both of the above shortcomings become even more problematic when the project requires installation of multiple layers of fabric.
Latest Technology: Fiber Reinforced Polymer
In the innovative patent-pending Fiber Reinforced Polymer system developed by Professor Mo Ehsani (University of Arizona) the carbon fabrics of any design (up to a width of 60 inches) are saturated with the resin and run through a special press; the result is a solid laminate with a thickness that can be set from 0.02 to 0.08 inches.
The advantages of the FRP system are:
1. The installation process is very fast. Depending on the number of layers of fabric required, the new system can require as little as 1/10 time compared to the conventional wet layup system.
2. The plant manufactured plates offer much higher quality control and uniform products.
3. Multiple layers of fabric can be incorporated into a single laminate, further reducing construction time and improving quality.
4. When applying to steel or iron pipe, a thin fiberglass barrier can be incorporated into the carbon laminate to avoid direct contact between the carbon fabric and the pipe surface (galvanic corrosion prevention).
5. FRP fits all cylindrical structures (e.g. pipes, tanks, silos) that are 12-inch or larger in diameter -- one size fits all!!
Below is a listing of some of the activities related to FRP:
September 12, 2011 SuperLaminates are Industrial Surgery for Failing Infrastructure: University of Arizona's College of Engineering Publication highlights Prof. Ehsani's latest invention for repair of deteriorated natural gas pipelines. To read the online article, please click here.
October 2011 Trenchless Technology Rehab Project of the Year Award: The very first field application of PipeMedic was to repair a leaking high pressure cast iron main for the gas industry in New Jersey. The project received the coveted Trenchless Technology Project of the Year Award for 2011. Please click here to read more about this project.
November 2011 SuperLaminates Bolster Broken Pipe The website of the American Society of Mechanical Engineers covered a story about the development of PipeMedic laminates and how they can be used to strengthen deteriorated pipelines for the gas industry. Please click here to read the full story.