Home Plate Update September 2019 - Page 5

The roof wheels are housed in structures called bogies. The bogies are situated between the roof truss and a large crane rail. At 100 pounds per foot and 1,750 total feet of rail length, the operable roof sits on the second-largest crane rail in the world. The single panel design also affects the weight distribution across the roof panels. To balance the substantial weight of the roof, there are more wheels and a complex suspension system to carry the weight from the roof to the rails and throughout the entire 1.7-million-square-foot structure. "That's also what's unique about this one. Instead of a two-wheel bogie, we have a six-wheeled bogie," Agosto explained. Every bogie features six 6,000-pound wheels, four more wheels than the average retractable roof system. Half the wheels are motorized with 10 horsepower motors, giving the roof a total of 600 horsepower. Moving about 39 feet every minute, the roof will open in an estimated 15 minutes. COMMAND CENTER: As it comes time to open or close the retractable roof, the action requires only the push of a single button. Located in the command center, the roof operator has access to control the actions of the 260,000-square-foot roof. Uni-Systems also designed the computer mechanism and programming for roof operation. The computer checks for faults in the system before allowing the roof to start operation. The operator must keep his or her hand on the button the entire time the roof is in transit, and as soon as the finger comes off the bottom, the roof is programmed to automatically stop. "It operates similar to how your phone senses your finger touch. If your finger leaves the switch, the movement will stop," Agosto said. The operator can track where the roof is located at By the Numbers: Roof Size: 268,800 square feet Travel Distance: 405 feet all aspects of operation. The roof is equipped with a variety of tracking devices, allowing the computer to know exactly where the roof is located at all times. The main operator also connects with several spotters placed along the roof rail. The spotters travel next to the roof rail to watch out for obstacles or any possible problems with the mechanism. The same process is in place when the roof is closing. "The spotters are not only making sure there's nothing in the way, but also monitoring that the roof is moving the way it should be so it's not getting out of alignment," Manhattan Vice President of Operations Jim Cuddihee said. "They're also making sure the roof is moving at the pace it should be. It's more like a safety measure." ROOF PROGRESS: Since June, work on the 5.5-acre retractable roof has been moving at a rapid pace. The first retractable roof truss, weighing 3.3 million pounds, was installed and relocated down the rail in mid-July. One retractable roof truss section is being installed every week, and three sections complete an entire truss. There is a total of five retractable roof sections to complete the 24-million-pound structure, with conclusion of the steel roof structure expected to conclude in October. The roof construction involves more than the track and steel. As soon as one truss is completed, construction will begin on the decking, tying all five of the panels together. "We'll construct one truss, then slide it over on the rail to start the roof deck and the ETFE framing," Cuddihee said. "As everything is tied together, we'll start working on the bulb seals, what keeps the rain out from the retractable to fixed roof." ETFE panels, the transparent material that will help natural light flow throughout the building, will be installed alongside the steel work. Retractable roof construction is expected to be complete by the end of the fall. Travel Speed: 39 feet/minute Estimated Time to Open: 12-15 minutes Operable Roof Weight: 24 million pounds 5