New government center in Minas Gerais - in concrete suspension

For over 70 years, Brazilian architect Oscar Niemeyer has constructed eye-catching buildings made of concrete. He is now working in his favorite medium to create a new masterpiece - the administrative center in the Brazilian state of Minas Gerais. The seat of the government will be suspended from the world's largest reinforced concrete cantilever construction, and Holcim is providing the concrete.

"Architecture consists of dreams, imagination, curves and empty spaces", Oscar Niemeyer once stated. And, for Oscar Niemeyer, there is almost always another ingredient to be added to the architecture - reinforced concrete. Since the 1940s, he has been the doyen of modern Brazilian architecture. Born in 1907, he has repeatedly developed new possibilities for using concrete. For instance, in his daring and unconventional design for the public administration building built between 1957 and 1964 in Brasilia, the capital city of his native country. Niemeyer's unmistakable sculptural language full of curves and soft contours was made possible thanks to the continued development of reinforced concrete.

Figure 1: The new administrative center includes the seat of government, two buildings for the ministries and the auditorium.

Four large buildings

Niemeyer, the "master of curves", is still full of ideas even after completing 600 projects and continues to create milestones of contemporary architecture. One of these is in Belo Horizonte, the capital of the Brazilian state Minas Gerais. A new administrative center based on his plans is currently under construction and will be completed by early 2010.

This state, an economic powerhouse in the southeastern part of the country, is investing some 880 million reals (about 400 mio. USD) in a 800,000 square meter site to merge its large administrative staff to a well developed location. The site will be characterized by four striking buildings. Two gently curving buildings measuring 65 meters in height will accommodate 17 of the state ministries. The buildings - which are each around 250 meters long - will provide space for 10,000 workstations. The auditorium, with capacity for 540 guests, has a vaulted roof that is reminiscent of a legendary Niemeyer building - the "Capela de São Francisco de Assis" - inaugurated in Belo Horizonte in 1943. The small church with its curved roof is considered an icon of contemporary architecture as it was the first building to demonstrate the new possibilities for reinforced concrete.

Suspended central building

The most spectacular building at the new administrative center is the Palácio do Governo. The 37-meter tall building sets new benchmarks in terms of architecture, engineering and the use of concrete. The six-storey cubic building, which will house the government of Minas Gerais, is suspended above the ground. The building will be suspended from the world's largest reinforced concrete cantilever construction on 30 steel ropes cast in concrete. Oscar Niemeyer, who loves to work in concrete, has now designed a building that showcases his talent. The gigantic roof is supported by four columns, each of which bears a load of over 4,000 tonnes. It is 150 meters long. The overall impression is that of a very bold project. It will be made a reality thanks to state-of-the-art building technology - and thanks to expertise that Holcim has built up over decades and is now contributing to the project as a supplier of concrete.

Figure 2: "I advocate an unlimited freedom of form which does not slavishly bow to technical or functionalistic arguments, but is first and foremost a challenge to the imagination to create new and beautiful shapes." Oscar Niemeyer, Architect

The basis is high-quality cement

Holcim will deliver a total of 40,000 cubic meters of concrete for the government building and auditorium. The company has two concrete plants close to the building site each with production capacity of 50 cubic meters per hour. In terms of logistics, Holcim will use 15 trucks, 25 drivers and three pumps with nine machine operators. Three consulting engineers and four lab analysts will also offer support. The two ready-mix concrete plants will process 17,000 tonnes of Ari RS cement, a high-early-strength cement, and 15,000 tonnes of Duracem cement from the nearby Holcim Pedro Leopoldo plant. Duracem, which is used to mix concrete that is particularly strong, hard and durable, was developed in 2004 by Holcim Brazil.

Figure 3: The project demands maximum performance from everyone involved.

First-class support always guaranteed

In addition to a consistently high quality of concrete mix, Duracem also has another key advantage - it is self-leveling and hardens on its own. As a result, there is no need to use vibration energy. This considerably reduces the work on the thin prestressed concrete structures. "It is largely thanks to Duracem cement that we were able to participate in this project", says Carlos Telles, National Sales Manager at Holcim Brazil. Another key factor in Holcim's favor was its technical support. "Our team of technicians, production and sales specialists developed the right concrete mixes for the entire project in a very short time."