It is essentially a gigantic ditch, packed with equipment, concrete, rebar and thousands of laborers from many countries. It is a hotbed of construction challenges and a momentous sequel to one of the world's engineering epics: the original 1914 construction of the Panama Canal. The $3.1-billion third set of locks, the centerpiece of the $5-billion expansion, is taking distinct shape even as an international workforce continues to wrestle with tough materials, geology and logistical issues.

"You can see the progress," says Gerardo Delrio, construction manager for CH2M Hill, program manager for the Panama Canal Authority (ACP). "We've seen the contractors struggling a bit, but they've eventually overcome the learning curve." The "name of the game" for the job is its 100-year design life, he adds.

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The bulk excavation will be substantially complete by the end of this year. "Then, the focus will be on the concrete works for another year, followed by electro-mechanical," says Delrio. The design-build consortium for the locks, Grupo Unidos por El Canal (UPC), is striving to overcome a six-month delay due to concrete mix problems.

As of the end of June, almost 24 million cubic meters of excavation had been completed, with about 9.8 million cu m remaining. The last of four major dredging projects on the Pacific side of the canal is nearing completion, says Jorge Quijano, ACP deputy administrator. That leaves the lock construction as the last remaining major civil job to finish. "From then on, it's concrete placement. They have to come up with a high production rate to meet the deadlines," he adds.

UPC would earn up to a $50 million bonus for early completion. "I hope they'll get it, but it's not likely," Quijano says. The consortium faces late penalties of $300,000 per day for a maximum of $54.6 million. After the locks are tested and accepted, Grupo will have a maintenance contract of $40 million for three years. "After that, we'll assess their job and decide how to proceed," Quijano says.

The complexity of the job goes far beyond the concrete-mix issues. "Just getting the equipment here and maintaining it is a big issue," says Greg Ohrn, ACP quality-assurance engineer. "We're in a country without a lot of [equipment] resources. Everything has to be shipped in."

Logistics are an ongoing challenge that will continue when the lock chambers—three per side and each about 427 m long, 55 m wide and 18 m deep—are ready to be topped out this fall. "How to get the material down there in a controlled manner, how to compact it, how to get the equipment down there—it's all about size and logistics," Ohrn says.

A system of trucks, barges, conveyor belts, stockpiles, crushers and coolers complement two concrete batch plants that operate 24 hours, six days a week. Eight thousand tons of aggregate a day are transported from the Pacific side of the locks to the Atlantic side by barge, then by up to 60 trucks a day, says Giovanna Carrion, spokeswoman for the UPC. A crusher operates at 3,000 tons per hour, and the aggregates, ranging from coarse rock to fine sand, are added to various types of concrete mixes, which are applied to different sections of the locks.

The team installed an on-site quarry-mining operation because not all the basalt reclaimed from existing excavation was up to par, Carrion adds. "We thought the quantity of basalt from excavation of the new locks would be enough for aggregates, but we need about 1.5 million cubic yards from the quarry."

Each batch plant has 10 dedicated scales to handle the five aggregate types required by the primary concrete specifications, says Alan Krause, president and chief executive officer of MWH Global, the design leader for the consortium.

Concrete is produced at 16 cu m every five minutes from the batch plants. "We're sampling all the way through the process," says Ohrn. "If you only had one word to describe this job, it's 'concrete.' "

Global Effort

"The original canal, when built 100 years ago, was classified as one of the wonders of the world," says Krause. "We have to believe that this project will make the same list at some stage."

MWH integrated the work of offices from Milan to Buenos Aires to Chicago. Moreoever, MWH is in a joint venture with two partners, Tetra Tech and Iv Groep, a Dutch firm. "When you have up to 400 people, you're going to have challenges, but I'm very pleased with the collaboration and coordination of the design consortium," says Krause. "We operate in a salt-and-pepper arrangement where we don't have one company focusing on one thing. The best people from the three companies are used for the best tasks."

An initial concern for Hill International, which provides project management oversight for the ACP, "was the ability to effectively communicate with the multilingual participants on the project," says Frank Giunta, managing director of Hill's construction claims and consulting group. "While the language of the project is English, we come in contact with people who speak Spanish, Italian, Korean and a host of other languages on a routine basis. However, we quickly learned that the professionals with whom we interact speak English and Spanish across the board."

Pedro Zuloaga, Latin America manager for URS Corp., is one of those multilingual professionals. "Our lead designer is in Oakland but was born in Colombia. I was born in Peru and educated in the U.S.," he notes. "There are subtle cultural differences, such as body language. What we try to do is be appreciative of differences in culture but, at the same time, be very diligent. One thing we try to do is communicate in writing to make sure everybody gets the message."

URS is designing a nearly 6.7-kilometer-long channel to provide navigation access. Two dams with a combined length of 4 km and about 30 m high will form the new Pacific channel's eastern bank. Two more dams, totaling 1.4 km, will flank the western bank. The Borinquen Dam system must be designed to protect against intense wave surge and constant traffic and withstand a potential impact from a post-Panamax ship as well as seismic events, according to Lelio Mejia, URS dam project manager. Preliminary tests included 1,500 existing soil borings, 150 new borings and analysis of a 3,000-cu-m test fill.

For Belgian firm Jan de Nul, a member of the consortium that also holds two separate dredging contracts ( 10/4/10), the challenge is the sheer size. "The activity is not complicated, but the size is," says Dirk Van Rompaey, director of civil works with the firm. "Whatever we do, it is a huge quantity. We have to proof every single activity and prove that it's capable of 100 years. This is also quite time-consuming."

With more than 10 types of materials to be dredged, "very serious soil investigations have been conducted, and the most adequate equipment was chosen to efficiently excavate the material," says Van Rompaey. "We used software to store and analyze geological data and built 3D models of the material profiles. This enabled us to calculate accurate volumes for each type of material that had to be removed. The 3D models were also used on-site for machine control."

The firm also used a 30,000-cu-m hopper dredge—the first post-Panamax-sized vessel to serve on the same project that will allow post-Panamax shipping vessels to traverse the canal, says Alan Lievens, area director for the Americas for Jan de Nul.

There were also very stringent measures regarding the wildlife rescue and reforestation, adds Van Rompaey. "We first had to monitor the kind of animals that are present in the area. Monitoring was partly visual, partly with cameras, both night and day. It defined the type and amounts of traps we had to place in order to catch the animals." Relocated creatures included 200 crocodiles, plus snakes, frogs and other reptiles, adds Rajan Patel, resident civil engineer for CH2M Hill.

Gigantic Gates

The new lock systems will be among the largest in the world, with the largest water-saving basins. "With the old locks, every time they are used, you use 52 million gallons," says MWH's Krause. "That would be 120 million gallons for the new locks. But with the basins, it is reduced to 48 million gallons." The basins will facilitate a 60% re-use of water.

The 16 gates are up to 10 m wide, 30 m high and 58 m long, says Michael Newbery, MWH project manager, noting the Empire State Building could pass through one chamber. "We believe they are the most complicated in the world," Newbery says. "Some locks may be wider, but they don't have to operate in the same conditions."

A series of chambers and basins will control water flowing from Gatun Lake. They include 158 valves of varying sizes, requiring a total of 20,000 tons of structural material. "They will be able to operate as quickly as one minute and as slowly as five minutes," says Newbery. "There are stringent design requirements for how smooth the water flow has to be in the chambers. If you have turbulence and sloshing, then the loads on the vessels would be too large."

The heaviest lock weighs 4,000 tons. Some 190,000 tons of steel will be required for the lock chambers on the Atlantic and Pacific sides. Sourced mainly from Mexico, the steel is trucked in and stored in warehouses, then taken to the site to be installed in concrete with very dense rebar, says Newbery. "We had a major decision to make during design: unreinforced concrete or reinforced concrete," he says. "We decided it would be more efficient to be heavily reinforced."

The backfilling process for the lock structures is "constrained by when you can place material, since it is sensitive to water contact," adds Newbery, noting that the Atlantic side gets more rain.

Once the lock gates, which are being fabricated in Italy, are completed, they will be shipped by barge to a holding point 50 km away, says Newbery. An ocean-going vessel will pick up four at a time to transport to Panama. Then, each gate will be rolled on a multi-wheel computer-controlled transporter down into the dry chambers. Installation is slated to begin by early 2013, with each gate taking several months to arrive and another two to three months to install. The locks will be tested without water around March 2014, then with water in the fall, says Quijano. As with everything on this project, the standards will be stringent: "They will test, test, test until we accept it," he says.

"You can see the progress." "The best people are used for the best tasks." "They will test, test, test [the locks] until we accept it." "Whatever we do, it is a large quantity." "We try to be appreciate of the different cultures."