A spokeswoman for a hospital in Rio de Janeiro confirmed his death to the Associated Press but did not give a cause of death. Mr. Niemeyer was hospitalized in May 2012 for pneumonia and dehydration and more recently for kidney failure.
During a long career in which he received top professional honors, Mr. Niemeyer also helped plan the United Nations Plaza in New York and, as a lifelong communist sympathizer, designed the French party’s head office in Paris while in exile from Brazil’s military rulers.
Through his designs, Mr. Niemeyer protested the “orthodox functionalism” of modern building style that he thought left little room for sensuality. A bikini admirer, he often chose to link his work with Brazil’s shapely beach women. “Form follows feminine,” he said, twisting architect Louis Sullivan’s famous remark about function.
For inspiration, he drew on Brazil’s colonial heritage with its ornate, baroque architecture, and applied new building materials and methods of construction.
He favored reinforced concrete in an economy lacking in steel and created works of voluptuousness and space-age allure: smooth ramps leading to broad esplanades, domes shaped like soup bowls and entire buildings resembling flying saucers.
“This character that his work assumed is identified with the modern Brazilian identity. He’s not the only figure, but he’s the most important,” architectural historian Kenneth Frampton of Columbia University said of such graceful designs.
Much of Mr. Niemeyer’s reputation rested on the monumental Brasilia project. The city that emerged in 1960 from a barren savanna in central Brazil, thus abandoning Rio as the country’s administrative center, was more than a works project, President Juscelino Kubitschek said at the time.
Mr. Niemeyer was not only symbolizing a nation on the rise, Kubitschek said, but dealing in destiny by being for him “what Michelangelo was to Pope Julius II.”
Lucio Costa, once Mr. Niemeyer’s mentor, planned the cross-shaped city structure with its wide boulevards, and Mr. Niemeyer was left to create many of the “city-of-the-future” buildings that caught the popular imagination.
After the initial praise, functional problems arose. The buildings were burning hot in the tropical sun, and the cost of upkeep became a recurring concern. Poor ventilation systems made Brasilia’s presidential residence all but uninhabitable for years.
Diplomats assigned to live in Brasilia often fled to Rio for color and nightlife on the weekends. The city grew far beyond its expected capacity, creating pockets of poor shoved into ill-planned suburbs. Mr. Niemeyer said the satellite shantytowns were not his concern as the initial designer, calling such hovels a result of “the injustices of the capitalist society.”