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object:Panama Canal type:shipping canal
location:Panama-City state:Panama
architect:John Frank Stevens, George Washington Goethals materials:concrete
published:BFT 9/2016 page:10 - 11

Panama Canal expansion project

The world's largest continuous concrete structure

The Panama Canal has been expanded by adding a dual three-stage set of locks each both on the Atlantic and on the Pacific side of the canal. Covering a length of over 1.5 km each, these are currently the largest concrete structures worldwide.
Until this summer, the Panama Canal divided international maritime traffic into two classes: Panamax applied to vessels with a length of up to 294.3 m and a width of up to 32.3 m; these were able to transit the 82-km long connection between the Atlantic Ocean and Pacific Ocean in approx. 12 to 15 hours. Larger vessels, called New Panamax, had to circumnavigate South America, thus needing three weeks longer for the journey.
When the Canal was opened in 1914, the existing locks had been designed to include generous reserves for the world's largest vessels; they were no longer big enough, however, for the vessels in use at the turn of the millennium. In 2006, the Republic of Panama decided to expand the Canal and to create a new system of locks. The expansion project began in 2007, its total cost amounting to approx. US $ 5.24 billion (approx. €4.7 billion).
Course of the Canal
As a result of Central America having the form of an S, the canal runs in an almost north-south direction. The Caribbean Sea, which is part of the Atlantic Ocean, lies to the north, the Pacific Ocean to the south of it. The northern entrance to the Canal is Limön Bay, a just over 8-km long natural harbor near Colön where vessels wait to be given their passage date. The passage begins with entering a three-stage set of locks which raises the vessels to approx. 30 m above sea level. They have now reached the level of Gatün Lake, a formerly natural lake, the water of which is retained by a 2,300-m long dam. The lake's water level is the level throughout of this Pan- American waterway.
The huge project was realized by a joint venture of four construction companies: Sacyr Vallehermoso from Spain, Impregilo from Italy, Jan de Nul from Belgium and local Panama-based Constructora Urbana.
World's largest concrete structure
All three-stage sets of locks of the Panama Canal comprise three chambers in each direction of travel, one arranged behind the other, in which the vessels are raised or lowered in several locking steps. The new lock chambers are 427 m long, 55 m wide, and 18.3 m deep. As a matter of fact, the Gatün locks are currently the world's largest concrete structure, their counterpart at Miraflores being only slightly smaller in size. A total mass of 6.6 million m³ of concrete was required for the new construction of both lock systems, which equaled daily production rates of approx. 6,300 m³. lt was produced in four mixing plants from Italian concrete manufacturer Simem based in Minerbe near Verona. The corporate group set up two production facilities each on the Atlantic and on the Pacific side, totaling four. They were in operation non-stop during the entire construction period of well over eight years.
The control systems installed in the highly efficient concrete mixing plants were supplied by Dorner Electronic based in Egg. To ensure just-in-time supply of the required amounts of concrete in the specified quality, Simem purchased ten aggregate scales, eight cement scales, four water scales, eight additive scales, four ice scales, two fiber scales, as well as four mixers with a capacity of 4.5 m³ each from the Austrian plant manufacturer.
Slipform construction for lock walls
Working in two shifts, it took 4,200 construction workers over three years to complete construction of the lock structures. They set up formwork for a total surface of 2.2 Million M2 using the slipform method. In the process, 70 cranes lifted a total of 337,500 tons of steel into the formwork, and in excess of 30 pumping stations were needed to pour the amounts of concrete mentioned above.
The successful completion of this huge project was due in no small measure to Peri GmbH based in Weißenhorn. Between 2011 and 2014, the manufacturer of formwork and scaffolding systems supplied a total of 1,100 shipping containers of material to Panama, which has to date been the largest single order in the company's history. The formwork primarily used in the project was the southern German company's SCS Climbing System for single-face applications. Using the SCS 250 climbing system with a formwork carriage offering a retraction distance of 60 cm allowed the creation of sufficient workspace. The brackets were combined with the "Vario" girder wall formwork or "Trio" panel formwork to comply with the varying design of the different lock sections. Additional scaffolding systems from Peri were used in the Panama Canal project, especially the "UP Rosett" modular scaffold. It was used to create safe access ways especially in combination with slab formwork and slab tables.
The number of larger New Panamax class cargo vessels had increased significantly even prior to the opening of the canal expansion; 96 % of all ships can now use the Pan- American passage. In addition, the construction project achieved a doubling in transit capacities, which is why the Panama Canal Authority is now expecting annual revenues of approx. US $ 3 billion (approx. € 2.7 billion).
Robert Mehl, Aachen