Victory in the race against time

With 65% of progress made, work on the Arena Corinthians addresses the challenge of tight deadlines through planning, well-structured logistics and large scale use of prefabricated concrete elements and structures

Interview with Frederico Barbosa, engineer at Odebrecht Infraestrutura and Operations Manager for the Arena Corinthians construction project

Construction Expo 2013 – the 2nd International Trade Show of Building & Infrastructure Construction, to be held by Sobratema in the city of São Paulo from June 5th to 8th, will feature an attraction that is sure to draw the interest of the public at large: the Corinthians Sports Arena Hall (or ‘Arena Corinthians Hall’, for short) - a large thematic area with architecture based on the lines of the new stadium that is scheduled to host the opening ceremonies and game of the 2014 FIFA World Cup, in addition to several games throughout the championship. At the Arena Corinthians Hall, visitors will be able to follow - via display panels, videos and photos - the sequence of phases in the construction of this project; from the beginning of construction until its scheduled completion. Thanks to the presentation of the many methods of construction, solutions in engineering and logistics adopted, visitors will learn and understand why this initiative is, today, a case of success in the race against time.

With over 65% of physical progress, construction work is currently at the stage of placement of the metallic (steel) structure modules for the covering of the stadium’s west building. A super-crane manufactured by Liebherr, with a  lifting capacity of 1,350 tons, has already begun to position and place the steel structures for the mezzanine which will sustain the central part of the west roof. Work has also commenced on the placement of 11 modules of the main structure and on the preparation of the land for the playing field. Today, the Arena Corinthians project employs 1,849 professionals split into three work shifts.

The expectation of Odebrecht Infrastructure, the construction company responsible for executing the project, is that the arena - which is expected to cost R$ 820 million (US$ 410 million) - will be ready to welcome the public in December of this year. The stadium, which will have a constructed area of 189,000 m2 on 198,000 m2 of land, will be able to receive 48,000 fans. But, as required by FIFA to host the opening of the 2014 World Cup, another 20,000 temporary seats will be installed for a total of 68,000 spectators. These additional seats will be removed afterwards.

Also foreseen in the project are 89 private boxes (suites); 59 shops; 502 restrooms; one auditorium; four restaurants and bars; one industrial kitchen; 15 elevators; 10 escalators; one covered parking area for 990 vehicles and another outdoor parking lot with 1,943 spaces.

One of the features of the design developed by architect Aníbal Coutinho is a skin of glass making up the façades of the east and west buildings and measuring over 200 meters in length and 25 meters in height. On the east side, the glass façade will be flat so that it can become one of the largest, very high-resolution LED screens in the world and exhibit plays of the games and messages from sponsors. On the west side, the surface of glass skin will be irregular so as to depict an organic, undulating movement and will require complex assembly. Each pane of glass will have its own distinctive shape and therefore must be mounted in a specific place in the panel, as if it were part of a giant jigsaw puzzle. Assembly is scheduled to begin in the middle of the year.

In this interview, engineer Frederico Barbosa, Operations Manager for the Arena Corinthians construction works, tells us about the challenges of the project, the solutions adopted and the next steps toward the conclusion of the work; within the scheduled deadlines.

Grandes Construções – One of the greatest challenges in this endeavor was the time frame for its accomplishment - 30 months. How was this challenge addressed by Odebrecht Infrastruture?

Frederico Barbosa – First of all, as soon as we received the order to perform the work, we made an effort to mobilize and get started very quickly. In just two days, we kicked off the work. There was already a study that had been analyzed for almost one year until the proposal was prepared for submission. Therefore, this project had been dissected by the staff of engineers; by the company’s technicians. Upon arriving at the work site, we made minor adaptations to the minimum structure that existed there - the location was the site of a training center that belonged to Sport Club Corinthians Paulista – and we began production on May 30th 2011. About fifteen minutes after we arrived, we were already producing.

Grandes Construções – How were you able to do that?

Frederico Barbosa – Initially we convened a discussion on the issue of safety with the participation of the operators of the few machines that were already here - excavators, bulldozers, trucks, roller compactors, etc. - and with this minimal fleet of equipment and very, very few people, we began to clear the land and perform surveying. It was all immediate. We did not require the usual three or four months to mobilize, which would have been expected. Concurrently, we drew up the project, the preliminary collection of data.

Grandes Construções – But wasn’t there already a project for the arena?

Frederico Barbosa – There was a basic project for the stadium, its size, dimensions, etc. and a study for the work site. But there wasn’t an executive project, neither for the foundations, nor structure, installations/facilities, etc. Therefore, parallel to mobilization for the execution of the work, we set up the whole work site including centers for production, carpentry, rebar tying/imbeds, precast preparation sites, mess hall, administrative area and all the rest. It was a very harmonious mobilization which added to the assignment of the right people to each of their roles and each type of activity. The training center was adapted to serve as an office, kitchen, etc. This enabled us to move fast. And we didn’t waste one minute, from mobilization until today, as regards production. But the greatest difference was, mainly, having studied the project thoroughly and in depth, and begun immediately. People here started calling it ‘planinactioning’ which means planning and taking action at the same time (laughs)….! Besides that, we scored high in deciding right. We made very few mistakes.

Grandes Construções – In the last two years São Paulo has had season after season with a lot of precipitation. Didn’t that affect the progress of work?

Frederico Barbosa – At the moment we are going through our second rainy season. When To cope with the first one we invested a lot in surface drainage, in directing of water; in the protection and covering of embankments with hydroseeding, with the utilization of aggregates and gravel; compacting and in everything involved with accesses for the movement of pile drivers to execute foundations. For example: the excavation we did for the foundations of the West building, which is over 30 meters tall, were executed with gutters in mind, the ramps for water, tubular and cellular sewers, everything tied in so that the rainwater runoff was already getting channeled.

Grandes Construções – The land on which the arena is being built was traversed by Transpetro company pipelines utilized in pumping fuel oil and other petroleum products. These pipelines were buried under the Transpetro right-of-way and, therefore, did not allow any type of construction on the surface. Didn’t this have an impact on the project’s timeframe?

Frederico Barbosa – At the beginning, until the pipelines were relocated, we had to circumvent and learn to live with this problem. We rescheduled the part of the construction referring to foundations and assembly of the precast elements until we were able to detour the pipelines, which were positioned to go around the arena project’s land. But of course, this caused us concern, in the beginning, since it exceeded our jurisdiction, our power to decide.

Grandes Construções – Did you already know the type of soil you would find here and, therefore, the technology that would be adopted in building the foundations?

Frederico Barbosa – The normal series of soil probes had already been performed - a wide ranging web of analyses. But the initial solution, which was considered for adoption, was to execute the foundations with excavated piles; in a few points through boring. But that would take a long time. Then, we invited a company with specialists on the subject to study, along with us, what to do regarding the foundation and wound up opting for precast piles. We used high-quality precast spun concrete piles in practically all of the construction. But we also used root piles (pali radice) for high traction loads, in a few places, especially in those places that are strongly affected by the wind. And we used a hydraulic pile driver. That was very helpful to us because, besides the speed with which the pile driver gets the work done, it can move around more easily on its tracks, it has greater stability and is safer, and provides greater precision in performing the work. That’s why we engaged about 12 hydraulic pile drivers, simultaneously, thereby doing an immense amount of driving. That’s over four thousand piles driven into the ground absolutely on schedule as planned. We were soon done and free of all the foundation, which was spectacular for the progress of the work; for our performance.

Grandes Construções – Were these piles cast in loco, at the actual work site, or brought ready made from somewhere outside the project site?

Frederico Barbosa –They were prefabricated by supplier companies and transported to the site. We engaged a company that provided us with this support, with high quality piles, enabling very high performance.

Grandes Construções – Besides these piles, a substantial part of the structures employed in the works were prefabricated. This also ensured greater speed for the works, didn’t it?

Frederico Barbosa – Precisely. Generally in works with very tight timeframes, as was the case here, the use of prefabricated concrete elements is appropriate. Here we adopted them not just because of the deadlines but also because they were suited to the type of structure. We also installed a plant to manufacture precast elements at the site. This plant produced the heaviest parts of up to 40 tons, such as pillars and raker beams (support beams nicknamed locally “vigas jacaré” or ‘alligator beams’). But light parts, such as steps and slabs with around 2, 4, or 5 tons, were manufactured not too far away, in the metropolitan regions of São Paulo and transported to the site by trailer truck. In the area reserved for the playing field, we installed a protective covering and used it to store and keep a stock of a good of portion of the parts. We kept a stock of some 20% of the parts. This contributed to the movement of the cranes to launch the parts, thereby ensuring excellent performance.

Grandes Construções –The movement of these parts, from the manufacturer’s facilities to the work site, as well as of the large construction equipment through the metropolitan area must have required complex logistics. How did you handle this challenge?

Frederico Barbosa – Even though we’re talking about São Paulo, which has such well known problems regarding mobility, this issue did not cause us trouble. The transportation of parts was done at times of the day when heavy traffic was in the opposite direction. The parts always came to the work site, in the city’s East Zone, in the middle of the night and arrived in the very early hours of the morning. And they were the lighter parts that did not require special transportation. This also helped us to reconcile their transportation with their assembly.

Grandes Construções – What was the production capacity of the precast element manufacturing plant that was set up at the work site?

Frederico Barbosa – At times we produced here as much as 150 m3 per day. Of a total 20 thousand parts foreseen for the project, we manufactured about 40% here. The remaining 60% were manufactured off the site. The slabs, for example, were made off the site in a very significant quantity.

Grandes Construções – For such production to be possible, did you install a concrete plant near the work site?

Frederico Barbosa – Yes, we set up a concrete plant with a small capacity for some 40 m3 per hour. But it succeeded in providing for our needs well, with a continuous supply. We concentrated our production of concrete in the morning period.

Grandes Construções – The construction of this project happens at a time when the construction market is very heated, very active. Did you have trouble assembling the fleet of equipment you needed?

Frederico Barbosa – No. It was only at the stage of doing the foundations that we had some trouble arranging hydraulic pile drivers, but we succeeded. As regards the rest of the fleet, the high degree of activity in the market did not result in greater difficulties for us. Proof of this is that we have here, in operation, the largest crane in Latin America (Editor’s note:  the Liebherr, model LR 11350 tracked crane, with a load lifting capacity of up to 1,350 tons and a 60 meter main boom capable of reaching a radius of 12 meters). It was used in the installation of the spectator stands and is now in use in the installation of the stadium’s metallic roof covering. This was the piece of equipment that concerned us most and it required a long period of negotiations.

Grandes Construções – In order to accelerate the process of assembly of the precast and prefabricated parts, what resources did you utilize?

Frederico Barbosa – One of the measures that we adopted to gain speed in the joining or splicing of pillars was the bolted systems called ‘Trejor’ in which the connections between the parts of the pillars are bolted and filled in with concrete. The essence of the system consists of highly-resistant metallic elements that are bolted into the ends of the parts of the pillars to be joined and then grouted, establishing a splice between them. This reduced the time required for one such assembly from three hours to 30 minutes. Prior to adopting this technology, we studied the possibility of performing the splices by welding, or by pre-fastening, but we realized that the Trejor solution would benefit us much more.

Grandes Construções – Was this system used in all of the work or in specific spots/situations?

Frederico Barbosa – The system was applied when we had to splice pillars together. Here we have a building with over 40 meters in height whose pillars would have to be split into two or three sections. With this system, you practically don’t even notice a splice in these pillars. The performance of this type of splice, furthermore, is interesting when it comes to resistance to traction, in pillars that are subject to a very high load, or that are part of a splice in a very high position.

Grandes Construções – At what point did the team reach the peak of work in the construction?

Frederico Barbosa – We’ve already passed that bend in the road. That point was reached in November of last year when we had as many as 2,300 employees working three shifts. Today we have around 1,800 workers.

Grandes Construções – At what point would you say the construction is at this time?

Frederico Barbosa – In the evolution of the timetable, we are presently concluding the concrete structures and the execution of the metallic (steel) structures supporting the stadium’s roof covering is in full swing. We have already begun the excavation of the playing field and rest is the part referring to the installations and finishing.

Grandes Construções – What are the main characteristics of the stadium covering?

Frederico Barbosa – That involves a certain degree of complexity. In fact, we have two buildings to be assembled with sets of steel trellises, with a rectangular configuration, that weigh close to 150 tons. First, the east and west buildings, opposite to each other, are assembled separately and then we have to unite these two coverings. The union between the two is done with a cabled structure, a tie rod, which will balance itself when the structure is completely ready. Before then, it will go through a period when it is shored. Today it is stayed without the freedom it will have in the future. This shoring will be removed when the structure is all assembled thus taking on its proper degree of deformation, its equilibrium. (Editor’s note:  each structure will be propped on two cantilevered points, on the pillars of the East and West buildings which will transfer the loads directly to the foundations. The trellises will not be supported by any pillars in the spectator-stand areas in order to not compromise the visibility of the playing field). Upon this structure, all of the stadium’s roof covering will be assembled, with panels and the membranes, as well as the lighting system. The assembly of this structure is, without a doubt, a challenge. We have already completed around 30% of this structure and we are moving ahead at a very satisfactory rate.

Grandes Construções – Where did you bring this technology for the covering of the stadium from?

Frederico Barbosa – This technology is German, with a structural project by engineer Werner Sobek. But we adopted a process of ‘tropicalization’. We hired Brazilian designers and consultants to verify the project and monitor its development from start to finish. We conducted wind tunnel tests to study vibration, wind deformation, expansion/dilatation caused by variations in temperature. All overloads must comply with Brazilian standards. The shape of the tie rod is also very new and innovative to us. That’s why it will also be monitored. The companies are being hired to handle that task.

Grandes Construções – What are the characteristics of the membrane that will make up the roof covering?

Frederico Barbosa – The lower membrane is tensioned and partially opaque because it will conceal the metallic trellis. It will provide closure of the underside of the roof covering, comparable to a ceiling. It will only have openings where the floodlights will be placed. Besides providing protection, the membrane will compose, along with the structure, a very interesting geometric form. The aesthetic result will be very good.