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Above & Beyond Roof covers new ground by bringing unique elements into play By DAVID BARRON Copyright 2002 Houston Chronicle As you drive at night along the South Loop and gaze at newly built Reliant Stadium, you may think that you see one building that, in the words of its designer, twinkles like a giant jewel box amid Houston's skyline. What you really see, in the orderly, mathematical world of David Manica and his colleagues at HOK Sports, is two projects -- the stadium, which is impressive in its own right, and the roof, which is unlike anything in the history of American sporting palaces. Roofed stadiums are, of course, almost old hat in Houston. Reliant Stadium, after all, towers over the building that broke -- and redefined -- the mold, the Reliant Astrodome. From the upper regions of Reliant Stadium's north side, it is possible to see downtown Houston and the baseball complex now known as Minute Maid Park. Reliant's roof, however, is unique in the small circle of retractable-roof stadiums. It has two retractable panels, as opposed to three at SkyDome in Toronto and six at Bank One Ballpark in Phoenix. The panels retract in opposite directions, similar to the BOB's roof but unlike the two moving panels at Minute Maid and Safeco Field in Seattle, which travel in the same direction. Miller Park in Milwaukee also has two moving panels, but they retract in a fan-shaped pattern. Manica's first challenge in designing what would become Reliant Stadium actually came back in the days when the NFL's return to Houston was little more than a pipe dream. In 1997, the stadium-to-be was a decidedly different project. For one thing, the roof was fixed, not retractable. "That was the initial design," he said. "But the tenant requirements between the football team and the rodeo were such that the rodeo would require the roof to be closed. They were not interested in being a part of an open-air facility. INS & "Houston was competing with Los Angeles at the time to get the team, and there is no doubt that the NFL prefers an open-air stadium with natural grass. So the best way to solve that problem was to design the new building here with an operable roof." Manica's first drawings of a roof that would open and close began in the summer in 1997 and proceeded in fits and starts for the next two years as Texans owner-to-be Bob McNair wooed and eventually won the rights to the NFL's 32nd franchise. HOK's original plan for the roof called for an "accordion-style" roof -- one that, in visual terms, would simply "fold up and go away" when opened. That plan, Manica explained, would prevent the roof from "overpowering" the stadium by setting too heavily, in a design sense, over the rest of the building. "But that started to present some interesting engineering complications and cost and maintenance worries," he said. "And so we moved away from the accordion to the simple roof panel." To be exact, two roof panels -- each 240 feet long and 385 feet wide. From midfield, one panel slides to the north and one to the south along a set of tracks placed along the 967-foot long "super trusses" that frame the roof structure. When the roof is fully retracted, the open space above the playing field is 350 feet wide by 500 feet long -- 175,000 square feet. Unlike Texas Stadium, which has trusses that span the open portion of its roof, the Reliant Stadium roof is completely open to the elements when the two panels are retracted. And, unlike the roof at Minute Maid Park, which whether open or closed is easily the defining element of that stadium, the Reliant roof is just that -- a top that doesn't overwhelm everything beneath. Smiley N. Pool / Chronicle Reliant Stadium is completely open when two of the roof panels are retracted, a process that takes only seven minutes. "We keep the visual weight of the roof down by not stacking panels, like they do with the roof at Minute Maid Park," Manica said. The second unique element -- at least as it applies to retractable-roof stadiums in the United States -- is that the roof material is made of fabric. Specifically, a Teflon-coated, fiberglass fabric manufactured by Birdair Inc. of Amherst, N.Y. "We wanted to have the feel of an open-air stadium, even with the roof closed," Manica said. "When you walk around the Astrodome, you walk through circular, dark concourses. We wanted to have more light with the comforts of climate control, and the fabric was an important part of that design." Birdair fabrics were used in the United States for the Georgia Dome in Atlanta, the Metrodome in Minneapolis, the Edward Jones Dome in St. Louis and Tropicana Field in St. Petersburg, Fla. Elsewhere, the company installed fabric roofs on the Millennium Dome in London, Olympic Stadium in Rome, Hiroshima Stadium in Japan and Shanghai Stadium in China. "We used a high-translucency version of the fabric, which requires a lot of special care to install as opposed to the standard fabric," said Clark Martens, project manager for Birdair. "It allows 24 percent to 25 percent of the outside light to get through. The Georgia Dome roof, by comparison, allows maybe 10 percent." As with all projects, there are tradeoffs in using fabric, Manica said. "Fabric is more expensive than using a hard roof surface of decking and membrane," he said. "However, we found that not needing the additional amount of structural steel to hold up the weight of the roof would offset the cost of the fabric. So we came up with the most cost-effective roof that could be designed for this building." This particular element of architectural haute couture cost about $10 million. However, Martens said, it is engineered to carry full hurricane loads, including winds of more than 100 mph. Try that with your garden-variety Armani frock. The fabric also creates a vaulted frame over the roof frame to help shed water and to "give a sense of space for those inside inside the seating bowl," Manica said. A series of 10 steel cables, each two inches in diameter and capable of exerting 200,000 pounds of pressure, secure the fabric to the roof structure and create the series of peaks and valleys. "This is relatively new for the United States, but if you go to Europe, fabric roofs are much more of the norm," Martens said. "The next domed stadium that will be built in this country will be the football stadium in Phoenix, and that also will be fabric. We think it is a cost-competitive system, and it gives you a lot of nice attributes, such as that feel of natural daylight." The job of making the roof panels and their giant fabric swatches move to and fro fell to Cyril Silberman, president of Uni-Systems Inc. of Minneapolis, who also designed the transport system at Minute Maid Park. This system, however, is as different from Minute Maid's as football differs from baseball, Silberman said. For one thing, the Reliant Stadium roof is lighter -- 3,000 tons, as opposed to 9,000 tons at Minute Maid, including the sliding glass wall that runs along Crawford Street. That difference made for some, as Silberman gingerly described it, challenging design problems. "The Reliant roof could depart the stadium under a number of different circumstances if we didn't do something special with it," he said. "In winds of 50 mph from the right direction, in theory it could sail away if you didn't have a retention system. And you have 50 mph winds at least 10 times a year during thunderstorms. "Consequently, this roof has a very complex electrical and mechanical system that measures the wind and keeps the roof gripped firmly on its rails and moves it with timers and sensors that make it absolutely impossible for the roof ever to get away." Another challenge in designing the transport system, Silberman said, is that buildings are subject to lateral defractions. In other words, they wiggle. "To build the trusses strong enough so that they wouldn't have had any movement would have required 400 to 600 extra tons of steel and concrete," Silberman said. "But, by allowing this to be a semi-flexible structure, they saved a lot of money and complexities and erecting hazards." The roof is designed to allow 21 inches of lateral wiggle room as the building expands and contracts. To cope with those changes, Uni-Systems installed what it calls a four-bar linkage system on the north roof panel that keeps the roof on track as the building breathes. The south edge of the roof is on a rigid series of transports engaged to a rail that does not allow movement. "We only needed (the release mechanism) on one side," Silberman said. "The other side has to be rigid. Otherwise, the building could fall over sideways." The roof track also has a series of what Silberman describes as hurricane hold-down clamps that are not present on any other transportable roof in the United States. "It's like a series of giant scissors with teeth under the railroad track (on which the roof moves)," Silberman said. "There's enough clearance for the roof to move, but not enough for it to leave the track. When the roof comes to a stop, they clamp on tightly." If you're concerned about leaks, don't be. When the roof panels come together, it activates a system of inflatable seals, powered by a system of six to eight 15-horsepower air blowers, to keep fans protected from the elements. Silberman's transport system can close the roof in seven minutes, as opposed to 12 minutes for the one-way system at Minute Maid Park. He estimates the total cost of the roof, including the transport system, the fabric and the structural steel, at about $48 million. Reliant Stadium is completely open when two of the roof panels are retracted, a process that takes only seven minutes. Even at night, it's clear that the Reliant's fiberglass roof shaped up to look very different from the fixed-glass one that covers the Reliant Astrodome. The retractable roof rides this rail when it is set in motion.
The Texans lost their first game to San Deigo 27-20. What I feel about the texans is two words, BAD LUCK! Even the city of bad luck, and now the texans. Next week they face the Lions, at Detroit. Yes, you could say another lost if they come out and play like they played today against the Chargers. After this season, they need to get another head coach, cause next is going to be the same if he still around. I guess Cowboys will always be Texas team to go to. The crowd at Reliant Stadium wasn't proud of their texans today, why cause they hurt their own selves by alot of turnovers. I say next week game against Lions, texans will fold again to a 20-7 lost. My pick Lions.