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| Clyde N. Baker Jr. |
Baker is a strong foundation of experience, having spent 54 years at Vernon Hills, Ill.-based STS/AECOM applying soil theory, in-the-ground testing, instrumentation and careful observation to bring up the science of soils from a crying baby to a responsible adult.
When Baker left college in 1954, soil mechanics was still very young. Prior to the early 20th century, engineers relied on formulas developed in the 1700s as well as their own pseudo-scientific gut feelings to predict settlement. Mistakes and unknowns led civil engineers toward a conservatism that still prevails in many cities today. Baker isn’t afraid to question the status quo to learn more, and because of his work, building settlement doesn’t keep structural engineers awake at night.
For firming up the science of soil to support the skyscrapers of tomorrow, the editors of Engineering News-Record have selected Baker to receive this year’s Award of Excellence.
The bearings of deep foundations are transcending the ultra-conservative safety factors of yesterday to support the extreme skyscrapers of tomorrow. Baker is engineering natural earth, with inherent cost savings, more in line with manufactured materials, such as steel and concrete. For bored piles founded on soil, Baker has pushed bearing pressures in Chicago 400%, while rock-socketed caissons have increased 50%. This track record has made Baker useful in cities building super tall. In design or peer review, Baker has worked on seven of the 20 tallest buildings in the world. Many new tall structures, such as the 2,000-ft Chicago Spire, are planned or just getting in the ground thanks to Baker’s support. As skyscrapers grow taller, heavier and more slender, Baker’s groundwork will continue to hold them up.
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Test methods that Baker implemented in Chicago have helped prove what geotechs have believed all along, that soil and bedrock can safely support big loads. Bearing pressures are advancing to the point where the limiting factor is not soil and rock but the strength of concrete, says Baker. Not all tall buildings require super-high bearing pressures, such as when extra foundation stiffness is required to keep wind loads under control. But extreme options, when needed, are now available.
Baker has taken lessons learned on Chicago buildings, tunnels and other structures and applied them overseas, having recently consulted on the supertall Burj Dubai. Engineers call Baker’s support a boon to tall buildings. “That capacity sometimes is the difference between you can add that extra story or you can’t,” says Bill Baker, Skidmore, Owings and Merrill partner and the Burj’s structural engineer.
Owners also understand the value of an efficient foundation. “The key thing is leaving sufficient flexibility for the superstructure design but not making it so robust that there’s a factor of safety that’s unnecessary,” says Niall Collins, project director for Dublin-based Shelbourne Development Group, Chicago Spire’s owner.
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 STS/AECOM Barrettes bearing on grouted subgrade support Petronas.
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It doesn’t hurt that Baker’s settlement predictions are usually right on. “He’s a very practical guy,” says Bill Baker, who hired Clyde Baker to review the Middle East behemoth. “His calculations for the Burj Dubai were less than one page of hand calculations. Some other engineers did complicated computer models [and] got about the same answer.”
Clyde Baker calls himself “pre-computer” and prefers to do things by hand before feeding data into a program. The Burj, which will weigh about half a million tons on bored piles drilled under slurry, has settled about 40 mm. Baker predicted about 60 mm at its completion.
Baker’s precision has taken the mystery out of deep foundations. “I go to sleep at night because of Clyde Baker,” says Charles Thornton, founding principal of New York City-based Thornton Tomasetti Inc. He hired Baker to solve one of the most difficult pier problems for the 1,483-ft-tall, twin Petronas Towers, built in 1998. Baker describes the subgrade as “a terrible situation” that required a major soil and rock grouting program to get the job moving, where clamshell-dug barrette piers sit over a 200-m-deep, karstic limestone canyon.
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| Difficult caisson-defect investigation and remediation at Hancock led Baker to a higher calling at Sears . | |
For Baker, projects are coming full circle. Thornton learned about Baker’s soil skills in the late 1980s while designing the Miglin-Beitler Skyneedle, a 2,000-ft-tall footnote in Chicago’s supertall building history.
“It is interesting because we really cut our teeth there,” Thornton says. “The job went down the tank…. We took everything we learned in Chicago, including Clyde Baker, to Kuala Lumpur.” The spiraling Chicago Spire, shooting for a late-2011 finish date and possibly the tallest building in the Americas, is aiming for a reality unlike Miglin-Beitler. Appropriately, Thornton and Baker are on the executive design team.
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 Thorton TomasettiInc.; Shelbourne D'ment GrpInc
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 Michael Goodman / ENR
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 STS Consultants Baker (From Top) supported Petronas, Burj, Spire, Beitler,McCormick Place tunnel.
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Pushing the Envelope
Earthwork contractors, who complain of overly-conservative geotechnical engineering worldwide, appreciate Baker pushing the foundation envelope. “He has just upped and upped and upped,” says John O’Malley, president of Roselle, Ill.-based Case Foundation Co.
Baker also “breaks down the walls” on earthwork jobsites that have gone bad, O’Malley adds. “You could be a part of the problem, but you could be a part of the solution as well.” He remembers when Baker played a supporting role at the site of the supertall John Hancock Center, serving as the geotechnical engineer alongside SOM structural superstar Fazlur Khan. Their relationship cemented during an extensive probe of 20,000 ft of 2-in.-dia. cores of the building’s 239 caissons.
Part of the early steel work had sunk, prompting Khan to shut down the site. He ordered a thorough investigation and Baker and others went to work, discovering a 14-ft-long void in an 8-ft-dia. perimeter rock caisson and identifying other defects before remediating the job. Pulling steel casing to save costs was identified as a probable cause.
Due to delays, the developer fell into bankruptcy and the anchor tenant took over. “Big John” eventually rose up to become a Chicago icon and a major case study for deep foundations. Baker and Khan authored an award-winning paper published in 1971 titled “Caisson Construction Problems and Correction in Chicago.” It never specified Hancock, due to ongoing litigation, but its lessons attracted global notoriety. The two engineers went on to tackle Sears Tower, the tallest building from 1974 until 1998, when the Petronas Towers took the record.
For stamping his high-profile name on a lowly geotechnical paper, Baker credits Khan with jump-starting his career as an international foundation expert. The investigation also resulted in major code changes, as Chicago began encouraging engineers to leave steel caisson shells in the ground by allowing them to be included in load calculations. This lowered the risk of creating voids by pulling the steel casings during construction.
Baker has pushed the field forward to support two more supertall building booms. “He has helped make soil mechanics more of a science,” says R. Shankar Nair of Chicago-based Teng & Associates. It retained Baker for the 1,074-ft-tall Waterview Tower, now under construction on Wacker Drive.
In all, Baker has consulted on seven of the 20 tallest buildings as ranked by the Chicago-based Council on Tall Buildings and Urban Habitat, including the top four Taipei 101, the two Petronas Towers and Sears. In Chicago alone, Baker has...
he heavy job of predicting how far the world’s tallest buildings will sink into the soil falls upon the shoulders of Clyde N. Baker Jr., who carries himself under all that pressure with surprising agility. Engineers the world over credit Baker with an enterprising pursuit of efficient foundations that result in lucrative savings for building developers, while giving builders the confidence to deal with the most troublesome soils. Above ground, Baker’s down-to-earth style builds a relaxed atmosphere of trust that puts people at ease from the conference room to the jobsite.
