A View into Stadium Innovation from the Top

A 1.632Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

The new 63,000-seat-plus Lucas Oil Stadium in downtown Indianapolis will no doubt serve notice to sports fans, sports media and industry around the nation that the Circle City is a serious entertainment and convention business player. The facility is designed for multi-purpose use, thanks largely to a first-of-its-kind retractable roof-the design, surveying and construction of which used extraordinary techniques and concepts necessary to overcome some challenges that were unique to the project, which broke ground in September 2005.

As of midsummer 2008, the stadium was on schedule to be completed in time for a mid-August 2008 grand opening and public tour followed by high school football games and the NFL’s Indianapolis Colts preseason games, leading up to the Colts’ nationally televised 2008 regular season opener against the Chicago Bears on September 7th. As was the case in big-time spectator sports starting in the mid-1990s, when a slew of new stadiums were designed and constructed to support new revenue streams, i.e., via corporate luxury suites, Lucas Oil Stadium is replacing a venue which, Colts ownership claimed, was putting it at a relative economic disadvantage to other NFL franchises.

The new structure is replacing the 55,000-seat RCA Dome, the NFL’s smallest stadium in terms of seating capacity. Built in 1983, the old dome had been the home of the Colts since they moved from Baltimore the next year. Significantly, Lucas Oil Stadium will still rank among the league’s smallest stadiums, but the Colts are seeing the number of luxury suites increase by nearly one-third: 137 in Lucas Oil vs. 104 in the RCA Dome.

Aside from NFL football, Lucas Oil was also designed to accommodate the NCAA Final Four, the Super Bowl, concerts, conventions and various other events. Accordingly, the stadium has a flexible design that allows expansion to 70,000-plus seats and a linking of the end zone seating area to adjacent exhibit space. The structure will cover a total of 1.8 million square feet, including 183,000 square feet of exhibit and meeting space. For now, says John Hutchings, principal with HKS Inc. Architecture of Dallas, the football field surface will be in place permanently, with a wood composite surface placed over the football field and more stands rolled into the stadium interior for non-football events. Eventually, the turf may be portable, Hutchings adds.

Of the estimated $715.4 million to $719.6 million it cost to build Lucas Oil, the Colts provided $100 million. The State of Indiana and the City of Indianapolis jointly provided funding and Marion County provided some funding by raising tax rates on food and beverage sales, auto rentals, innkeepers and admissions. Increased food and beverage taxes in six surrounding counties and the sale of Colts license plates also contributed to the project funding. The stadium project is a companion to a $275 million expansion of the Indiana Convention Center and demolition of the RCA Dome that was to begin as soon as the new stadium was completed across the street.

Unique Roof Structure Design
The owner of the project, the Indiana Stadium and Convention Building Authority–a group of civic and business leaders appointed by the governor of Indiana and the mayor of Indianapolis– contracted the Hunt Construction Group, Inc., of Indianapolis to manage construction of the new stadium. The architect, HKS, also designed Major League Baseball’s Milwaukee Brewers’ Miller Park and Cowboys Stadium in Dallas, the latter of which is to be completed in August 2009.

Lucas Oil is the first to use a "SuperFrame Structural System" with a moving two-panel design whereby the roof is supported by five rails. The roof system, gabled and peaked down the middle, will provide 176,400 square feet–more than four acres–of opening when open. With this design, long, narrow panels stack over the building and do not overhang or shadow the façade. Cable drum drives mounted to transporters operate two 600 x 175-foot bi-parting panels.

Each panel has five upper transporters that support two lines of retractable roof trusses on each side and ride on two 36-inch diameter steel wheels. The three interior upper transporters are mounted with four cable drum drives and the two exterior upper transporters are mounted with two cable drum drives. Each cable drum drive is powered by four 7.5-horsepower AC motors and each winds a 1½-inch diameter cable that is anchored to the structure near the peak of the transverse trusses. The cable drum drives let out cable to let the roof panels down the slope and wind cable up to close the roof panels.

Opening and closing the roof takes nine to 11 minutes. Each side of the roof undergoes 10 critical lifts of 200,000-230,000 pounds and, Hunt Construction points out, the roof panels weigh 2,900,000 pounds–the heaviest in any NFL stadium retractable roof. However, the others use two rails to Lucas Oil’s five.

The roof support structure is also unique. A pair of 760-foot-long steel SuperFrames were constructed using traditional rolled steel shapes laced together into box elements, and located parallel to each other about 300 feet apart, roughly along the edge of the football playing area. The valueengineered elements vary the height of the lower chord, changing the frame depth from 58 feet at midspan to 84 feet deep at the column support while avoiding obstruction of any seat views. The SuperFrame column varies in width from 26.6 feet at the support to 61 feet, 2 inches at the truss. The column is 217 feet tall and is supported at street level by 35-foot-high concrete shear walls.

The SuperFrames support five peaked, three-span transverse trusses spaced 144 feet apart. The trusses are 12 feet wide and vary in depth from 40 feet at the midfield apex to 30 feet at the SuperFrame. The outboard sections of the transverse trusses span 170 feet between the SuperFrames and perimeter columns, while the peaked interior section spans 300 feet between the SuperFrames. Each transverse truss supports a steel rail box girder along its length and the girders each support a 175-pound-per-yard crane rail that supports the wheels of the retractable roof panels. Four bar linkages allow for movement between the roof trusses and supporting rails and transverse trusses, allowing for normal structural deflections, differential thermal expansion and construction tolerance variations.

The design of Lucas Oil’s roof is fundamentally different from those of both Miller Park and Cowboys Stadium, points out Hutchings. "[Miller Park] we designed in a radial shape to match the shape of the baseball diamond," Hutchings notes. "Here, we wanted the view on axis with the downtown and Monument Circle. So the entire building is skewed on site and the [north end] window opens so the fans and the media and broadcast television have a great view of downtown Indianapolis, particularly for a Monday night [football] game or a big sporting event. This is the only one in the world that runs all the way down the centerline of the field and nests the two sides of the roof toward the sidelines." In contrast, all other retractable roofs at football stadiums open end zone to end zone-including Cowboys Stadium.

Tolerances were extremely tight on the roof, necessitated by the multipurpose concept of a stadium that will host both open-air football and indoor events such as basketball. As a result, the surveying team, USI Consultants of Indianapolis, had to bring its "A" game to this project. The team also relied heavily upon the accuracy and produ
ctivity of a Topcon GTS-233W total station to meet the tight tolerances.

Surveying Challenges
Tim Brown, project manager for USI Consultants, notes just how tightly the roof engineer, Houston-based Walter P. Moore dictated the tolerances on the retractable roof structure: within an eighth of an inch, or about as close to "zero tolerance" as realistically possible. In mid-July 2008, looking back at the roof surveying process, Brown points out: "Especially on a day like today where it’s cooler in the morning and hot in the afternoon, when they put the steel together, it can move as much as half an inch" due to heat expansion.

USI Consultants has provided surveying and engineering services for a significant number of road and bridge projects since its founding in 1976. Lucas Oil Stadium, particularly the retractable roof, presented some different challenges. When surveying the retractable roof, Jason Deiwert, crew chief, carried a reflector up a stairwell that goes to the seventh and top level in the southwest end of the stadium and Michael Baden, instrument operator, carried a Topcon GTS-233W total station. Then, having gone to opposite sides of the transverse trusses via catwalks, the crew put in a control line across each transverse truss to check the alignment of the panels at each truss. Brown reports that, because the roof operates with multiple motors and they all have to be running at the same speed, USI Consultants put a line across each truss so that the panels could be monitored during movement. The surveyors also aligned the railing system.

"Not even close," Deiwert says with a laugh when asked if he had ever gone through so much to get into position. Like Deiwert, Bader says he has never worked at a similar elevation to the 270-foot height of Lucas Oil’s roof. Using a control traverse that was set around the base of the structure, the crew set the alignment on the ground. After the alignment was checked on the ground, the crew transferred it up at both ends with the use of the GTS233W. After alignment was established at a given level, the crew moved its instruments up to the top and verified the alignment from up above.

Brown points out that the wireless GTS-233W has some user-friendly features that greatly improved productivity on this project. "It is easy to level, and fast to set up with the Laser Plummet," he says. "Its Bluetooth feature allows for a cable-free environment to work in. The Bluetooth range is about 25 feet, allowing you to move about the instrument or even back to your truck without losing the connection. "If you have to go back to the truck to read your plans, you can take your controller with you to aid in additional computations. There are also no cables to lose or get broken. The instrument itself has a simple keyboard without a lot of menus–this means fewer keystrokes."

Inside the stadium, Smith points out the base of the SuperFrame columns, noting that four 25-foot-deep footings supporting the structures in four corners of the stadium used 390 cubic yards of concrete each and were bonded to the footings with 180 4-inch-diameter anchor bolts.

In addition to the roof, USI Consultants surveyed the concrete walls and floors as each of the seven levels were constructed. The plumbness of the south walls was also checked prior to installation of large glass panels. Brown looks out onto the playing field where workers stitch yard markers and end zone lettering onto the grass-like artificial FieldTurf. Here, USI Consultants set control lines for the luxury suites and press box for drywall and plumbing contractors, as well as surveying the field and goalposts. Control points were set in front of the base of the steel SuperFrames on the north end of the stadium and corresponding control points were set at the other end of the stadium, as well as just south of the 50-yard line in the middle of the playing field.

Final Touches
By mid-July 2008, USI Consultants’ work on Lucas Oil is nearly complete. The last task is to survey the position of some concrete planter walls in front of the stadium’s north entrance. Bader sets up the total station on the north side of the street while Deiwert puts the reflector into the ground and levels it near the north building façade. Holding a log book listing the coordinates for one of the planters, Bader peers through the lens on the GTS-233W and verifies with Deiwert via walkie-talkie that they are plotting out the same coordinate. Bader instructs Deiwert to move forward, back or to either side.

When Deiwert’s position is correct, the total station sends a laser beam that bounces off of the reflector and records distance by measuring the amount of time it took for the laser beam to bounce back. The horizontal and vertical angle between the total station and reflector are also measured as this coordinate is "shot" and the location data saved. Later, the data is downloaded into a computer equipped with AutoCAD software used to produce a drawing of the planter and relative measurement data from other structures on the site for the contractor to set formwork and place concrete in the formwork. The wireless feature of the GTS-233W, which USI Consultants purchased from Positioning Solutions Company’s Indianapolis branch office in 2004, boosted productivity on this project, Brown notes. "We just set it up and turn the collector on without plugging any wires in and start going," he says.

Hutchings reports that the major structural work in the bowl area is, for all practical purposes, complete at this time. Contractors doing finishing work inside the concourses and entrance areas are scrambling just a bit, though. When complete, the stadium will have several architectural flourishes, including a six-panel, 88-by-244foot-wide movable window wall system consisting of six mechanized wall panels at the north end. These panels are guided by two telescoping top roller assemblies and two bottom rollers traveling over the bottom tracks, and driven by a 5-horsepower electric motor. Hutchings points out that the wall system will provide impressive views of downtown Indianapolis, particularly at night.

Lucas Oil also was designed to incorporate architectural elements. For example, the SuperFrame concept has an architectural component, Hutchins says. "From the outset, we liked what we saw with the older structures in Indianapolis with the laced steel, so the concept has always been to have the SuperFrames be steel and punch through the concrete frame. Some of the things fans of Indianapolis will see once they come into the stadium is how the steel structure for these SuperFrames, both on the north and south ends, lace through every level that they’re on. This looks like more of a collegiate football field with the arches down low, etc. We picked up on the exterior from the warehouse district, we picked up on some of the skylights and the feel of [nearby Butler University’s] Hinkle Fieldhouse, with some of the structural steel and some of the skylights."

Don Talend of Write Results, West Dundee, Illinois, is a publicity and communications project manager specializing in construction, technology and innovation.

Lucas Oil Stadium Facts

• Seating: 63,000 for football; 70,000-plus for other events such as basketball and concerts
• Cost: $715.4 million­ $719.6 million (est.)
• Seven levels (vs. three in RCA Dome)
• 1.8 million square feet
• 183,000 square feet of exhibit space
• 137 luxury suites (vs. 104 in RCA Dome)
• Retractable roof opening: 176,400 square feet (more than four acres)
• Time to open and close roof: nine to 11 minutes
• Total roof weight: 14,000 tons-plus
• 130,000 cubic yards of cast-in-place concrete
• 16,000 tons of steel
• 700 pieces of structural precast
• 1,440 pieces of architectural precast
• 9,100 pieces of exterior glass
• Operational large north window (six panels, 88 feet tall and 244 feet wide) providing view of downtown
• Public concourses minimum 30 feet wide, up to 80 feet wide
• 148 concessions stands (vs. 80 in RCA Dome)
• 14 escalators and 11 passenger elevators (vs. no escalators in RCA Dome and six elevators)
• Two slightly graded pedestrian ramps inside the building giving access to each level of the stadium (vs. none in RCA Dome)
• No bleacher seats (vs. all bleacher seating in RCA Dome upper deck) 

A 1.632Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE