Hoop Tendons Reinforce one of the World’s Largest Drinking Water Systems
The Cutzamala System is one of the world’s largest drinking water systems, providing approx. 485 millions of m³ of water per year for several districts and communities in Mexico State. In 2014, CONAGUA started repairing several pipe sections from both pipelines using hoop tendons.
The system includes two parallel, 75km long pipelines. The oldest part of the system was opened in 1982, and it has been continuously expanded in order to supply the growing population of Mexico City and its surrounding districts with fresh water.
DYWIDAG participated in phases three and four of the rehabilitation project, during which the pipelines from Tower 5 (TO5) to the Analco San Jose Tunnel were examined and repaired. Twelve 2.5m Ø Prestressed Concrete Cylinder Pipes (PCCP) had to be reinforced because the prestressing wires underneath the cement mortar coating were found to be damaged.
533 extrusion coated Type 0.6" DYWIDAG Hoop Tendons in lengths of 10.7m were installed around the PCCP pipes in order to re-establish their original design properties.
External DYWIDAG Hoop Tendons have been developed especially for the repair and strengthening of circular structures such as silos or pipes. They are ideal for repairing pipelines in operation because only that part of the pipeline that needs to be repaired has to be excavated. Once excavated, the polypropylene polymer sheathed hoop tendons can then be installed directly around the pipe.
The extruded monostrand tendons are installed in hoops around the pipe, and the strand ends are stressed at a coupler. Using this method, an efficient prestressing is created that can be installed quickly.
The system proved to be ideal for the Cutzamala potable water system: The repair work was carried out quickly and trouble-free in less than 50 hours.