In the storm's wake

Harrah's Poydras Street Hotel relies on ready-mix, precast to erect structure

By Angelle Bergeron

The $100 million Harrah's Poydras Street Hotel in New Orleans was on the fast track to be completed by March.

"We poured the core mat at the end of October and were at 27 floors, pouring the roof by the end of August," said Chris Watermeier, project manager for Broadmoor LLC, one of the subcontractors on the job. "I'd say that's pretty fast-paced."

Then Katrina came to town.

For the most part, the building fared the storm rather well, but the contractor's original completion date has been pushed back to Aug. 31.

"That includes not only missed days but also removing and replacing what was damaged," said Jeff Blanchard, project manger for NOW2, the joint venture comprised of New Orleans-area contractors Carl E. Woodward and Walton Construction.

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The only damage suffered by what owners specifically planned to be an airtight and moisture-resistant structure was insulation, water-resistant sheetrock and the specially designed exterior cladding.

Broadmoor's $30 million contract to NOW2 includes the steel superstructure, concrete work and design-build plan for the GFRC and curtainwall/window exterior cladding system. Broadmoor tested its exterior cladding system design by constructing a three-story mock-up test wall at Construction Research Laboratories Inc. in Miami, Fla.

"Then we put it through both positive and negative pressure water tests," Watermeier said. "That was done to ensure that no water would get into the system and the system would withstand storm debris and wind."

In another attempt to ensure the system would meet the stringent design specifications, Broadmoor even hired an engineer with GFRC, who worked hand-in-hand with the structural engineer, Jon Sofranko at Morphy Makofsky of New Orleans.

When Katrina hit, Broadmoor was about 90% complete with its portion of the job, having installed glass up to the 20th floor and GFRC almost through the entire 24th.

Only one panel fell off of the building (inside the site) during the storm, but Broadmoor opted to replace all of the panels on the top four floors rather than invest the time and money in extensive testing.

"They were exposed to stresses they weren't designed for," Watermeier said. "The panels were designed for forces from outside to inside, but wind got in the building and was pushing on the back side of the panels. Those panels were not designed for that."

Broadmoor also replaced 30 panels that were on site waiting to be installed that took quite a beating.

Because owners had emphasized waterproofing the building, a good portion of it was effectively sealed off, Watermeier said. "NOW2 had some moisture consultants come in and (per their advice) the contractor replaced all the insulation and sheetrock down on the north path of the building," he said.

Construction began back in April 2004 when Broadmoor demolished a two-story structure on South Peters Street and began excavation in preparation for the hotel's core mat foundation.

"First we drove sheeting and enclosed the entire hole (109 by 175 ft.), then dug about 4.5 ft. to remove the old footings, backfilled with sand and began driving pilings," said Joseph Gioe, vice president of field operations and field supervisor for Broadmoor. The 220-ft.-long, 285-ton capacity, 20-in. pipe piles had to be driven in two, 110-ft. segments.

"We had to put them on steerable dollies to get into the site," Gioe said. NOW2 was required to preserve a nearby three-story historic structure that would serve as the low-rise portion of the completed hotel.

"When we were digging footings for the new tower, the common wall between the tower and the existing building was moving, so Broadmoor secured it with steel reinforcing," Watermeier said.

Broadmoor then excavated the tower footprint to 17 ft. below street level, poured a dry bottom and the pile cap - requiring 2,700 yds. of concrete - for the core mat foundation. The pour lasted from 7 p.m. on a Friday to 4 a.m. Saturday.

"For the first part of the mix, we used super plasticizer, which makes the mix flowable around a significant amount of re-steel," Gioe said. The rest was a standard, pumpable mix.

Broadmoor used a 6,000- to 5,000-pound high early mix, a special form system and completed each of the post tension decks in two-part pours.

"The mix achieves its design strength quickly so we can move on to another floor, and this is the first time this form system has been used in this area," Watermeier said.

The rolling form system on castellated beams is commonly used in Las Vegas, Gioe said. Basically, two "W" sections are welded together to create a hollow 28-in. beam, which is lighter and has more carrying capacity.

The system is set on key points. Then the rollers are bolted into the structure's columns, which help bear the load all the way down to the foundation, he said. "We had to upgrade the cranes to carry the forms, which are 27 by 52 ft, weigh between 20 and 24 thousand pounds," Gioe said.

Apart from the damage previously detailed by Watermeier, the new hotel "didn't have a heck of a lot of damage," Blanchard said. NOW2 is working on the project "full speed ahead," he added, averaging 350 workers on the job daily.

"The thing that has kept us going is Harrah's has been really instrumental in helping a lot of our subcontractors with housing," Blanchard said. Temporary trailers on site and vouchers for nearby hotel rooms are some of the accommodations provided by the owner.

"Also, for about three months they provided breakfast and lunch for all of the workers on site. They made it the best environment possible, under the circumstances, for people to work. Harrah's has been an unbelievable client to work for. Not that many owners have the capability to do what they've done."