Experts, developers speculate on future of high-rise construction
By Jaime Levy
In the aftermath of the attacks on New York City's World Trade Center, construction experts, property managers and developers are wondering whether skyscrapers will remain desirable symbols of US skylines.
"There's a big psychological factor," said Henry Petroski, a professor at Duke University's Pratt School of Engineering who specializes in construction failure. "The reason people wanted space in the skyscrapers is for prestige. Those things are going to be not so valuable anymore if employees don't want to work in skyscrapers or clients don't want to do business there."
In downtown Miami - well-known for its striking high-rises and imaginative bayfront architecture the planned 70-story Four Seasons Hotel & Tower, hailing itself as "the tallest residential building south of New York City," is already advertising its shops, condominiums and hotel rooms. The complex is scheduled to go up on Brickell Avenue between 14th Lane and 14th Terrace and be finished in winter 2002.
The city's tallest building now is the First Union Financial Center, 200 S Biscayne Blvd., at 55 stories. A nearby building at 100 S Biscayne Blvd. and others on Brickell were evacuated last week after bomb threats.
In fact, a spate of fraudulent, copy cat threats in the days following the New York and Washington, DC, attacks forced workers in tall buildings across Miami to interrupt their workdays and climb down dozens of flights of stairs in order to exit without elevators.
Still, said Gloria Hernandez, secretary of Miami-Dade's Building Owners & Managers Association, the practicality of vertical buildings in urban areas may outweigh concerns about unlikely future terrorist attacks.
"I think because of the density in most major cities in the country, you have no choice but to build vertical structures. There's not a lot of land in big cities to build four- or five-story buildings.
"You have to build up," said Ms. Hernandez, property manager of 1221 Brickell Ave, home of Telefonica. "Perhaps we won't be building large, large structures like the World Trade Center. But we'll keep building high-rises to fill demand."
For predictable events natural disasters such as hurricanes, lightning storms and earthquakes tall buildings may be sturdier than structures closer to the ground, said Richard Coble, an associate professor at the University of Florida's Rinker School of Building Construction who specializes in construction safety.
"When you have a hurricane, vertical shelter is what they find is the best protection," Mr. Coble said. "The middle part of it is designed for heavy wind loads. Your house isn't designed for those loads. Houses get destroyed. But even in the eye of the storm, there's no building reported as going down that was American-engineered. People should be wanting more of those buildings, not less.
"When you start putting 12,000 gallons of fuel in a building," Mr. Coble said, refering to the contents of the jets that hit the World Trade Center, "you can't design it to withstand that kind of heat. You could put 10 feet of concrete around it, but it's not practical."
Practicality, said Jose Mitrani, a professor in Florida International University's construction management program, is a key to determining whether theories of engineering skyscrapers will change.
"If we can put people on the moon, we can build buildings that can withstand these types of things," Mr. Mitrani said. "But how expensive? And where do you stop? Can a building withstand the detonation of a small nuclear device? Where do you draw the line?"
Bill Ross, president of Estoril Inc., the company that owns and is developing Brickell's 36-story Espirito Santo Plaza, said "a big building no matter whether it is tall or sprawling is still a big building, making it unsafe in some way.
"Think of the average tenant in a large building. If you need 50,000 or 100,000 square feet, there is no way to do it in a small building. What difference does it make if it's horizontal or vertical? If somebody thinks you're a target, it really makes no difference if it's big or small, public or private."