Chicago took a big step today toward reclaiming bragging rights to the world's tallest building as the City Council voted to approve a $500 million, 112-story office and residential skyscraper planned for the downtown Loop.

The 1,537-foot-tall tower would surpass by 54 feet the Petronas Towers in Kuala Lumpur, Malaysia, which in 1996 dethroned the current U.S. titleholder, the 110-story, 1,454-foot-high Sears Tower that dominates the Loop.

Chicago's new entry in the feverish "world's tallest" race is designed with twin 463-foot antennas that would push it to exactly 2,000 feet and over the top of the widely recognized measurement charts in the lofty hubris sweepstakes.

Being home to the world's tallest building is no small thing in Chicago, whose Home Insurance Building was considered to be the first "skyscraper" when it was erected in 1885 at a then-imposing 180 feet in height.

"It looks like something for the next century," a smiling Mayor Richard M. Daley said after the council unanimously approved the silvery, futuristic-looking tower. Alderman Burton Natarus said, "People from all over the world are going to come and see it."

Although the highest occupiable floor of the Sears Tower is more than 200 feet higher than the top floors of the 88-story Petronas Towers, the Council on Tall Buildings and Urban Habitat, the world's preeminent arbiter of building height, counts uninhabited architectural features like the decorative spires that cap the Malaysian skyscrapers when it considers record heights. If antennas were counted, New York's World Trade Center would top the skyscraper list at 1,728 feet.

The Guinness Book of Records, which the Tall Buildings Council and most architectural authorities look down their noses upon, claims the CN Tower in Toronto is the world's tallest building. But because it is only an observation needle, the best it can legitimately claim to be is the tallest freestanding structure.

The plans approved by Chicago's aldermen today call for 350 condominium apartments selling for an average of more than $450,000 each on 42 upper floors--the highest residential units in the world--and 29 floors of office space below that. There will also be 11 floors of parking space and a two-level retail concourse below the entrance at 7 South Dearborn St. in the heart of the downtown business district.

Scott Toberman, president of Chicago-based European American Realty Ltd., the developer, said that the four groupings of upper floors in the thin, needle-like tower will be separated by distinctive notches that not only will funnel wind and relieve pressure on the structure, thereby reducing swaying for the residents on top, but also highlight the building's function as the city's premier broadcasting tower.

Toberman said his firm had reached preliminary agreement with a consortium of local television and radio stations on lease terms for use of the building's antennas and uppermost office floors for digital broadcasting.

He said his first consideration in determining the height of the tower was not to set a new world's record but to meet the demands of high-density digital television engineers who said the structure's antennas would have to be the tallest in the market with a clear line of sight over the Sears Tower, the Amoco Building (1,136 feet) and the John Hancock Center (1,127 feet).

"Did we make sure we met the criteria of the Council on Tall Buildings? Sure we did. But we don't know that down the road somebody else is not going to build a taller tower. We'll just be pleased to be on top as long as we are," Toberman said in an interview.

A number of developers around the world have said they are trying to raise money to build taller buildings, but their futures are far from certain. One is a 1,600-foot, pyramid-shaped building that would house the World Center for Vedic Learning in Sao Paulo, Brazil, and another is a 300-story, 3,702-foot-tall residential tower in Hong Kong that would be built on "bionic principles," according to its Madrid architects.

Acknowledging that there often is many a slip between cup and lip in the world's tallest tower business, Toberman said his firm, which already has a real estate portfolio estimated at $600 million, has solid backing from "financial institutions from the Asia and the Pacific Rim," which he declined to identify now but promised to name within a month.

Chicago's Planning Commission, in giving its approval last week, imposed the unusual requirement that Toberman must reveal the specifics of his funding sources before he can raze an 18-story office building on the proposed site.

"Skepticism is natural, because even in Chicago some developers have announced plans with nothing more than an artist's rendering behind them," Toberman said. He said he owns the one-acre prime Loop site, has invested $35 million already and has "$500 million in debt equity arranged, period."

Toberman said construction of the new building will begin in April and take about 40 months to complete.

He said the architectural firm of Skidmore, Owings & Merrill, which designed the Sears Tower and John Hancock Center, had addressed the safety issue not only by providing the wind-dispersing notches in the stainless steel and green glass facade, but by designing a new damper system utilizing a concrete pendulum held in place by steel cables that will act as a counterbalance and minimize sway. The top of the new tower is expected to sway two to four times less than the Hancock Center, Toberman said.

Sky's the Limit

The planned 7 South Dearborn building would be more than 50 feet taller than the current record-holder.

7 South Dearborn

Space: 1.86 million square feet

Cost: $500 million

Architect: Skidmore, Owings & Merrill

Use: Primarily offices and condominiums; two-level retail concourse

Parking: 950 cars

SOURCES: "Skyscrapers," Council on Tall Buildings and Urban Habitat, European American Realty

Structure Location Height, feet Stories Finished

7 South Dearborn Chicago 1,537* 112 2003

Petronas Towers Kuala Lumpur 1,476 88 1996

Sears Tower Chicago 1,454 110 1974

Jin Mao Building Shanghai 1,379 88 1999

World Trade Center New York 1,368 110 1972

Empire State Building New York 1,250 102 1931

Central Plaza Hong Kong 1,227 78 1992

Bank of China Tower Hong Kong 1,209 70 1989

*An antenna not included in the structural height would raise the total to 2,000 feet.