Super Dome

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At the gaming hotel of Harrah’s Atlantic City it’s not all about the gambling. It’s also about the swimming pool.

Forget the chain-link girded postage-stamp swimming holes of yesteryears. This past Memorial Day Weekend, Harrah’s unveiled its expansive 23,500 square-foot, eye-popping pool and multipurpose entertainment venue. For $35 million, it transplanted the tropics and created an island destination of lush foliage, towering palm trees and azure water, all housed under a soaring glass dome that tops out just shy of 94 feet above the pool deck.

“It exceeds our expectations,” says R. Scott Barber, senior vice president and general manager of the hotel. “It truly is a must-see destination.”

The pool complex is part of a $550-million renovation and expansion of Harrah’s existing facility scheduled for completion in February 2008.

The half-acre atrium facility boasts an 86,000-gallon sinuous swimming pool, six Jacuzzis and 12 curtained, pool-side cabanas each outfitted with a daybed, a 26-inch LCD TV, an iPod hook up and service provided by personal attendant. It sports an exercise center, a 50-seat bar, a mezzanine that overlooks the pool, a 15,000-square-foot outdoor sun deck and an Elizabeth Arden Red Door Spa with 23 treatment rooms. The indoor and outdoor spaces in the pool complex can accommodate 900 to 1,000 guests at a single event.

Still, it’s the hot-house flora that makes the space a “tropical oasis” says Julie Brinkerhoff-Jacobs, president and chief financial officer, Lifescapes International Inc., Newport Beach, Ca. Harrah’s imported plants from California, Arizona and Florida, investing roughly $2 million to plant 52 palm trees of five different varieties.

“This is one of the largest gardens in the New York area,” says Architect Steve Anderson, at the architectural firm of Steelman Partners in Las Vegas, “and it wouldn’t have been possible without the glass dome and glazed façade.”       

The dome
The $5 million dome guarantees that, no matter the season, guests and the permanently residing flora will experience what Harrah’s calls its “endless summer.” In this giant terrarium temperatures hover between 76 degrees and 80 degrees and the air maintains a comfortable level of 50 percent to 60 percent humidity. The air—tinctured with a tropical blend of mango and coconut scents—is refreshed eight times a day by five air handlers, Barber says, compared to a single turnover a day in most buildings of equivalent size.

The dome’s size, aesthetics, cost and scheduling presented seemingly conflicting design requirements for the design-build team at Novum Structures LLC, Menomonee Falls, Wis.

Its 208-foot span across the diameter “is very, very large,” especially when it had to be built to sustain for both hurricane wind loads and snow loads, says Ian Collins, Novum’s president. Normally, such an expanse would demand a double layer support structure superimposed with a heavy glass skylight system, he says.

However, the solution would have looked massive and undermined the aesthetic goal of an envelope that would appear seamless with the sky. Rather than making a statement in its own right, the dome’s job, so to speak, is to be as transparent as possible, pulling the sky itself into the space.

One alternative was a single-layer geodesic structure using triangular glass to stabilize the system, but the small triangular glass “would have doubled the cost,” Collins says. Instead, Novum designers opted for a trapezoidal grid and determined how to support the 42,000-square-foot single-layer dome.

Novum officials have developed proprietary software that electronically generates fabrication drawings based on structural analysis. It specifies the exact size and placement of each member and piece of glass in the edifice.

The automation delivers dramatic time savings. For example, just two and a half months after Novum officials secured the dome contract it began fabrication.

Eight triangular struts, or ribs, run from the top of the dome to its base and stiffen the webbing, while three triangular rings maintain its shape. The compression ring at the apex applies down forces and the tension ring at the base prevents the dome from flattening out.

Novum engineers used pre-finished structural members—its KK and BK systems—that “positively impacted speed of installation, economics and the quality of the end product,” says Terry Peterson, vice president.

A conventionally engineered approach would have relied on field-welded connections and created a heavier structure, he says.

Welding would have been time consuming and the necessary requirement for touch-up field painting would have compounded the time invested. Moreover, field painting “results in a much lower quality finish system,” Peterson says. 

He considers the issue of particular importance given the high-humidity conditions of the swimming pool environment. “Wet field paint applied over mild steel would result in a long-term maintenance issue,” Peterson says.

By comparison, the KK and BK systems employ easy-to-handle, lightweight tubular members that dramatically reduced the dead load of the structure, Peterson says. Both systems attach via concealed, mechanical fasteners. As a result, “connections can be made at a much faster pace than field welds,” he says.

The mechanical connections also allowed Novum engineers to pre-finish the members with a hot dip galvanized undercoating followed by a factory applied, powder coat colored finish. The resulting finish “is of much higher quality than you could get in a field applied situation and maintenance in this difficult pool environment is reduced substantially,” Peterson says.

To save on shipping costs and because of the ease of assembly of the modular systems, Novum workers assembled everything on site.

The project employed no scaffolding, a significant time and money-saver, and instead had a custom designed temporary support system 70 feet square at its base and stabilized by cables. The temporary structure supported the top of the dome until the ribs were in place. Once the struts were secured, the support structure was disassembled and a crane lifted parts into position where workers in cherry-pickers connected one to the other.

The glass
Novum Structures Co. in Beijing fabricated the clear, 1.5-inch thick, insulating glass units in the dome. They consist of a low-emissivity coating on the second surface, a laminated glass interior layer with clear polyvinyl butyral interlayer and a tempered outer layer.

The glass is used structurally, point fixed at the edges with clamps that allow it to float over the supporting structure. A silicone gasket was inserted between each unit and the remaining gap filled with a wet silicone seal.

“Harrah’s represented [Novum’s Edge Clamped Glazing system’s] first significant application,” Peterson says. Novum introduced the system this past year.

Structural use of the glass eliminated the requirement for aluminum framing realizing a huge cost savings while increasing transparency, Collins says. The easy-to-use clamping mechanism for attaching the glass made installation simple and fast.

Designers concerned about the build-up of condensation on the glass inside the dome knew the issue could be controlled by increasing air flow over the surface. Vented duct work threads through the dome’s vertical ribs and the mullion-free glazing facilitates unobstructed air flow.

A circular 36 inches wide by 48 inches tall reinforced concrete wall, built into the roof framing 35 feet above the pool, supports the dome. At the juncture where dome tension ring meets the concrete wall, the struts connect to the wall and align with steel, wide-flange columns below. “[These] columns are backed up by an additional row of columns about 35 feet beyond the diameter of the concrete wall to form an internal radial buttress system built into the roof framing,” says Anthony Volonnino, a structural engineer at Paulus, Sokolowski & Sartor, LLC, in Warren, N.J. A steel-pipe pile foundation system supports the columns, he says. Each pile can bear 65 tons of load, and groups of up to 12 piles support just one column.

Not all the glass in the project is in the roof. Bronze reflective, insulating glass glazes the two-story, low podium entry way to the casino hotel and pool complex and clear, 6-foot-by-9-foot, low-E, tempered insulating units form the façade between the mezzanine and outdoor sun deck.

Guthrie Glass & Mirror Inc. of Egg Harbor Township, N.J., installed both curtain walls as well as the glass storefronts along the interior corridor and buffet. Arch Aluminum & Glass Inc. of Bridgeport, N.J., fabricated the reflective units and Erie Architectural Products Inc. of Ontario custom-fabricated the curtain walls using the Kawneer 1600 curtain wall system. Oldcastle Glass’ Moorestown, N.J., facility fabricated the tempered units for the exterior mezzanine wall and General Glass International in Secaucus, N.J. supplied the 1⁄2-inch tempered, butt-glazed storefronts.

A 14-foot high glass wall sits on a 2-foot knee wall and encloses much of the pool’s perimeter, Anderson says. It allows guests walking through the hotel’s interior promenade, in the buffet, exercise room or spa to feast their eyes on the tropical oasis. 

CMS Glass of Atlantic City hung the 700 linear feet of 6-foot-by-14-foot, 3⁄4-inch cleared tempered glass manufactured by Oldcastle Glass in Toronto, says Stephen Strauss, CMS vice president. Butt glazed, a structural return fin runs perpendicular to the glass, separating the panels and stopping any lateral motion, he says. Five floating glass doors in the wall provide access to the pool.

Incredibly, Oldcastle Glass took only two weeks or less to turnaround the glass, Strauss says, a product that by his estimate normally requires three to six weeks for delivery.

Patrick Gelineau, general manager at OldCastle Glass, said his crew worked three straight weekends in order to deliver enough glass to CMS on Mondays. “We pulled rabbits out of our hats,” he says.

The project
The entire project operated on a “very, very tight deadline,” says Nicholas Moore, project executive, T.N. Ward Co., Ardmore, Pa. Workers at R.E. Krugg Corp., North Tonawanda, N.Y., began erecting the dome in August 2006, completed the webbing in January and the glazing in February. In less than a year, the dome went from the drawing board to completion. 

The project’s progress was tracked by a Web camera and can be viewed at http://harrahs.oxblue.com/baytower2/.

The accelerated pace required extended hours. “We needed to erect a piece of the dome every other day in order to maintain the schedule,” says Brad Swegles, Novum’s project manager. Three field crews of local iron workers kick-started the assembly process during which they tag-teamed two shifts a day for three weeks. One team clocked in at 7 a.m. and left at 3:30 p.m. The second crew arrived at 3 p.m. for a smooth turnover and stayed until 11 p.m. The night shift was dropped, but from November through Jan. 5, people were on the job seven days a week.

CMS Glass’ crew followed suit. They worked “steady 10-hour shifts,” Strauss says, and a couple of Sundays, including Mother’s Day, to keep pace with the schedule. 

Since the pool opened, Harrah’s has used the venue to host happy hours, island luaus and late-night events with live entertainment. “We have created something that can’t be easily replicated,” Barber boasts.