A third hiccup happened on Jan. 25, when wind gusted up to 100 mph. Vertical perimeter safety netting, tied to horizontal safety cable, shredded up from the 44th floor. The cable apparently started oscillating, and the turnbuckles at the cable ends unwound and came loose, says Rechichi. Turnbuckles, netting and some 2-ft-square plywood pieces flew off.

Stronger Netting

There were no injuries, but the Dept. of Buildings (DOB) stopped work and issued two violations to construction manager Kreisler Borg Florman: one for failing to safeguard the site and the other for storing materials too close to the edge. Measures were taken, including installing stronger netting. The DOB rescinded the stop-work order in phases and fully lifted it on Feb. 5. Environmental Control Board hearings regarding any penalties are scheduled for May 20.

Superstructure construction, complicated by the heavily reinforced shear walls, the undulating curtain wall and the changing floor plates, went smoothly. “The Frank Gehry factor only comes into play on the perimeter,” says William Kell, Sorbara’s chief estimator. “It’s painful, it’s time-consuming, but all the planning is a little sugar for the medicine.”

For the curtain-wall units to fit, layout was critical for the 14,000 aluminum embeds, set on the total 50,000 ft of slab edges. Each embed is a 1-ft-square box, 4 in. deep. “Gehry situates the curtain wall and then locates the slab edge,” says Kell. It is typically the other way around, he adds.

Sorbara did a “phenomenal” job on slab edges and bay-window slab projections, which only have plus or minus 1 in. of tolerance, says Budd.

A year in advance of construction, FCRC gave Sorbara a set of schematics to price the job; Sorbara bid the job when documents were 50% complete. Kell did all the estimating and budgeting without BIM. “I can see 3D in my mind,” he says. “Our budget pretty much stayed in line with the estimates.”

Concrete work, which started in April 2008 and was finished last December, was also complicated by the height of the building and the stiffness of the outrigger walls, which are as tall as 26 ft at level 38. Over 50% of the formwork for the 12,000- to 5,000-psi concrete was vertical; the norm is 20%, says Kell. All forms were hand-set because the layout changed too much and because slab edges are segmented and protrude. The curtain wall, installed by PNA’s local sub Tower Installation LLC, is going more smoothly than anyone expected, says Budd.

Occupancy is likely to start in May 2011. Rents have not been set, but the area’s going rate for a new one-bedroom in a luxury building is $3,000 per month. Is FCRC concerned about the economy putting a damper on the demand for high-end rentals? Robert Sanna, an FCRC executive vice president, says, “Once you get through the risk of construction, you are in a good position. The frightening risk is almost behind us.”