Trasvases Manabi Water Project, Ecuador
By replacing traditional "form and pour" methods with high production shotcrete, the massive Trasvases Manabi Water Project in Ecuador finished months ahead of schedule. Contractor Norberto Odebrecht in conjunction with Shotcrete Technologies, Inc., and Commercial Shotcrete, Inc. of Phoenix, AZ placed over six thousand cubic meters of shotcrete in less than half the time it would have taken by the specified method, and put the project a whole rainy season ahead.
Centre de Rehabilitacion (CRM) of Manabi, chose Norberto Odebrecht to construct the two hundred twelve million dollar project that would provide a constant supply of water for drinking, irrigation, and industrial use by optimizing Ecuador's seasonal rainfall patterns. Having been on site since May of 1999, by July of 2001, the project was five months ahead of schedule and Danilo Abdanur, construction manager, began to realize that he could perhaps complete the entire project by the Rainy season (late November), if he could come up with a much quicker method to complete the spillway walls of the Conguillo Dam. At twenty five meters high, sixty and one hundred centimeter thick walls with a 1" tolerance and a minimum of six thousand cubic meters of concrete, the specified "form and pour" method would not meet Abdanur's aggressive schedule.
Kristian Loevlie, of Shotcrete Technologies, Inc. was called in to meet with Odebrecht, the Owners and Engineers to discuss the possibility of erecting these massive walls using shotcrete. Having done high volume shotcrete projects all over the world, Loevlie explained that good shotcrete is a high quality "in-place" concrete, often with much higher compressive strengths. The Group was convinced that this innovative solution would allow them to meet their aggressive schedule.
With the decision made to shotcrete the massive walls, time was of the essence and Shotcrete Technologies quickly pulled in Commercial Shotcrete Inc. of Phoenix, Arizona for the application expertise and supervision. Mix designs and testing using local materials, and training local laborers were fast-tracked. Once the shotcrete pumps arrived on site, the first two weeks were spent on training and testing. Alberto Medina, of Commercial Shotcrete and his various supervisors managed the entire process. When the shotcrete application went into production mode, the crews (using the' "hand-held" nozzling technique) reached a daily rate of more than one hundred eighty cubic meters of shotcrete using two pumps on two shifts.
The very workable "wet shotcrete" mix was placed through heavy rebar and mesh directly onto a twenty-five meter high dirt excavation requiring extensive temporary support. By using shotcrete, the initial support and final one meter thick structural walls were done simultaneously. ST-ALKALI FREE ACCELERATOR was used for water control and temporary ground support./p>
This continuous process of excavation, reinforcement, initial support, and final structure was very fast, efficient, cost effective, and shaved months off the time traditional methods would have taken. By the end of November, the spillway walls were finished and ready for the rainy season.
According to Danilo Abdanur, Construction Manager for Odebrecht, the key to the projects success was choosing the proper expertise, with the proper equipment, an efficient working site, adequate support equipment, a well-trained crew, a consistent mix design, and adhering to a daily maintenance schedule. However, the biggest factor in the success of this project was taking the perceived risk on a technology that he had not used for this specific application.
