Ysrael Seinuk | Skyscraper engineer, 78

Ysrael Seinuk, 78, a structural engineer who made it possible for many of New York's tallest new buildings to withstand wind, gravity, and even earthquakes, died Sept. 14 in Manhattan.

He lived in the Forest Hills section of Queens.

The cause was cancer, said his daughter, Beatrice Seinuk-Ackerman.

New Yorkers may not know his name, but they certainly recognize Mr. Seinuk's work and its mark on the skyline. Among the many projects that he made structurally possible, usually working with his partner, Irwin G. Cantor, were the 70-story Trump World Tower near the United Nations and the 48-story Conde Nast Building in Times Square. He also helped plan the Lipstick Building, an elliptically shaped office tower on Third Avenue at 53d Street.

Structural engineers analyze forces, such as seismic events, that can affect buildings, especially tall and sleek ones. They must determine the strength and flexibility of the construction materials, including the floor slabs, beams, and columns.

Mr. Seinuk's "real genius was the design of high-rise buildings using reinforced concrete as the structural material," Elizabeth O'Donnell, associate dean of architecture at the Cooper Union for the Advancement of Science and Art, said Tuesday. "I think of him as the person who brought reinforced concrete to New York City," O'Donnell said, "because this was primarily a city where its high-rises were structured in steel."

Ysrael Abraham Seinuk was born in Havana on Dec. 21, 1931, the only child of Jaime and Sara Seinuk. His father had emigrated from Lithuania. When Fidel Castro came to power, Mr. Seinuk fled to the United States.

He was soon hired by what was then called Abrams, Hertzberg & Cantor. Ten years later, he was promoted to partner, and in 1992, he was named chief executive officer of what became the Cantor Seinuk Group.

- N.Y. Times News Service