Panamá, March 2015. Two major projects are being simultaneously carried out for the Panama Canal Authority. This has allowed Meco to continue, after an experience of over 16 years, in the team of global professionals working on the expansion of this mega maritime project with more than a century: The Panama Canal.
MECO is developing the first project in partnership with EPSA for the consortium Grupo Unidos por el Canal (GUPC), who awarded, in December 2011, the subcontract “Construction of Borinquen Dams”. The main objective of this project is digging 1.5 km of the new Pacific Access Channel and the construction of three dams of clay core and rock fill.
The second Project corresponds to the “Pacific Access Channel 4” or, as it is known for its acronym in English, “PAC 4”. For this other project, MECO joined FCC and ICA to form the PAC4 consortium. This contract consists of the excavation of 3.5 km of the Pacific Access Channel and the construction of a 2.3 km-long dam with clay and rock fill.
Once the Third Set of Locks and both contracts are finished, the waters of Lake Gatun will invade the new Access Channel to the Pacific and they will be supported by the four dams. This will allow Pospanamax vessels evade the actual locks of Miraflores and Pedro Miguel, and get to transit the Panama Canal.
Engineering Work. The construction project of the Dams of Borinquén involves the excavation of a 1.5 km Access Channel and the construction of three clay core dams and rock fill. It was a very difficult start because it was right at the old mouth of Cocoli River, plus it is crossed by three tectonic faults.
Hence it is said that the excavation, which exceeds 18,000,000 m3, represented the biggest challenge of the project, since the diversity of materials excavated ranged from sludge, silt and clay, to different rock types, which caused it to become mandatory to handle all rainwater and infiltration with the help of high-flow pumping equipment, ditches and canals, all this to be able to make for excavations and fills in acceptable conditions.
Much of the success of the construction project is due to the equipment for its execution, a total of 110 units. 40 tons articulated trucks and 45 tons excavators for excavations in soft materials were chosen; for higher volume activities such as digging in soil and rock rigid trucks of 50 tons and 90 tons excavators were chosen to do the work.
Borinquen Dams. This project is formed by three dams: One West, Two West and Two East, with a total length of 3.1 km and a total volume that exceeds 9,000,000 m3. They all have the same geometry, and they are composed of five materials: clay, filter, transition, causeway and jetty, all drawn from sources located within the project.
During the digging stage, the material was removed to the bedrock level in the nucleus of dams and weathered rock on the shoulders. When the final levels were reached, ditches and pumping wells were dug to control and manage all rainfall and infiltration.
Once the bedrock levels in the nucleus of dams were reached, it is now the moment for the treatment and preparation of the foundation, and preparing the geometry as regularly and waterproof as possible prior to start with the fillings.
The activities for this task included the removal of all loose material by excavators; concrete placement in cracks and construction of leveling slabs. Finally, the injection curtain was drilled and injected, to guarantee a waterproof sealing of all rock cracks in the foundation.
The construction of dams is made through a chain process where all materials are placed in layers of different thicknesses and they all are dependent on each other; if any are missing or are not placed, this will stop the advance of the fillings. Quality control is the most demanding task; since there must be the required documentation for each layer. Strict controls are done both in the field and the laboratory for each of the materials, all in order to guarantee a life period of more than 100 years.
The contractual amount of the Construction of Borinquén Dams is $ 126 million.