Courtesy FCC
Total diameter of the excavated tunnels was nearly 10 meters.

A design-build team led by Brazilian engineering and construction conglomerate Norberto Odebrecht and the Spanish company Fomento de Construcciones y Contratas (FCC) last month completed the 14-kilometer, $1.8-billion Panama Metro light-rail line. The work featured two earth-pressure-balanced tunnel-boring machines, each 9.77 meters in diameter, dubbed "Marta” and "Carolina."

The Panama Metro route includes seven kilometers of tunnels and more than five kilometers of elevated guideway. The metro will connect the transportation and shopping hub of Allbrook on the city’s south side to residential areas northeast of the urban center.

ENR Transportation Editor Aileen Cho queried Victor Alberola, FCC director of Central American operations, about the four-year project.

ENR: Did the project come in on time and on budget? Do you receive any bonuses or incentives for early completion or meeting other milestones?
Alberola: The Panama Metro project was completed on time, on February 27, 2014, with the first test runs carried out in November 2013, as originally planned. The inauguration took place on April 5, 2014. The contract, which was awarded to FCC—as part of an Odebrecht-FCC consortium—on October 27, 2010, valued the project at $1.446 billion (USD), but three addendums to the original budget, covering a further three stations on a 2.2-kilometer extension line, brought the value up to $2.009 billion.
Along with the Panama metro, what are some other major projects occurring in the area?
FCC is involved in a number of other projects in Panama. We are building two hospitals: Ciudad Hospitalaria Ricardo Martinelli in Panama City, due for completion in 2015, and the Chicho Hospital in Santiago. In 2013, FCC completed the Electoral Court Headquarters, the first building completed in the Panama City proposed master plan, and the Vía Brasil I and II corridor, which are located on Panama City's main avenue. We are also involved in the Panama Canal expansion, on a project called PAC-4, and on a hydroelectric plant project for SN Power.
In addition to Panama, FCC works in other Central American countries, including Costa Rica, where we recently won a contract to build a hydroelectric plant for Enel Green Power and a sewer to improve the environmental situation in the capital, San José. We are also building the Necaxa-Avila Camacho Highway, in Mexico, which is part of the 30-year Nuevo Necaxa-Tihuatlán Highway concession that FCC won in 2007.
What are some of the major project challenges specific to Panama? How about labor and materials availability, competition with other projects and localities' skill sets?
The availability of equipment and materials presents a significant challenge. The metro was the first project of this scale in Panama, and some of the materials for the project had to be shipped in, including two large-diameter tunnel-boring machines and four hydromill trench cutters to build the underground stations. The same is happening on the rest of the large projects taking place in Panama.
What were some major technical feats accomplished on the metro project that could be useful for ENR's audience?
The internal diameter of the tunnel is 8.70 meters, with a thickness of 35 centimeters in the concrete stone and a total excavation diameter of 9.77 meters. The stone is a universal type, 1.6 meters in length, and the ring is formed by six stones plus the keystone. To complete the total excavation we had to use 4,190 rings. Unlike with other tunnels, we used mortar bi-component to fill the gap.
                                Technical Facts and Figures

•      Line No. 1 length: 15.9 km, from Albrook in the south to Los Andes mall in the north
•      Stations: 14, or six aboveground and eight underground
•      Trains: Fleet of 19 three-car Alstom Metropolis trains
•      Daily ridership: 15,000 in 2014, rising to 40,000 by 2035
•      Materials: 420,000 cu m of concrete and +47,000 tonnes of steel

•       Tunneling: 476,938 cu m of ground excavated in the underground stations and trenches
•        Underground stations: 92,650 cu m of concrete walls and almost 27,000 linear meters of piles with diameters ranging from 1.2 m to 2.5 m
•       Workforce diversity: Almost 5,000 people from 30 countries: 91% from Panama, 3% from Spain, 1.6% from Colombia, 1.3% from France and 1% from Brazil
•       Construction: Javier Alañon, project manager, FCC Construction Manager
•      Project Initiators: Panama Metro Secretary, government of Panama
•     Design Firm: Technical Services FCC Construccion S.A. and Odebrecht

What are some major projects that you expect to be vying for this year and in the near future? Will Odebrecht and FCC possibly team again? 

FCC works with project partners across the world, and the on-time, on-budget delivery of the Panama metro project was a great demonstration of how we can do this and deliver outstanding results. Panama will soon be requesting tenders for the second line of the metro, and FCC will be keen to hear the details disclosed to potential bidders.
What was the general geological makeup of the earth through which the TBMs Marta and Carolina excavated? Will the next metro construction project be similar to this one or will it have significant differences in terms of site conditions?
The geological conditions posed a major challenge. There were many kinds of rocks, with varying hardness levels, some of them reaching 100 MPa. However, the most challenging part was not the hardness of the rocks but their fractures, which required changing the tools of the TBMs into hyperbaric form. In the elevated section, the seismic requirements were the most important factor for structural design.
When will the construction boom in Panama slow down? What are the remaining major infrastructure needs?
Residential construction projects will slow down soon, but, in terms of infrastructure, it is a different story. With its rapidly growing economy, the government of Panama recognized the need to invest in the country's infrastructure, and the result of this was the 2009 launch of a $20-billion infrastructure program, including the metro, airports, highway improvements and the Panama Canal expansion. If Panama is to continue growing at its current rate, it will need to ensure that infrastructure developments match economic growth, making the country attractive for investors and citizens alike.