Craftsmen devise ways to work with a pyramid and sloths

From experts in high, irregular glazing projects to riggers typically assigned to large entertainment venues, the National Aquarium Upland Tropical Rain Forest Exhibit project required uncommon breeds of craftsmen.

The project team from Plano-Coudon Construction had been tasked with replacing all the windows in the aquarium’s glass pyramid as well as the bird wire mesh inside the pyramid, which kept birds and animals inside the exhibit.

“There are not many subcontractors in the country qualified to do this kind of work,” said Cliff Milstead, Vice President at Plano-Coudon.

However, Plano-Coudon contracted Super Sky Products Enterprises for the glass replacement and The Crew Works for the bird wire replacement “and they did a really great job figuring out some challenging logistics,” Milstead said.

Craftspeople from both companies won individual Craftsmanship Awards for their work on the aquarium.

To replace the pyramid’s glazing — as well as its flashings, pressure plates, covers, operable windows, tie-off assemblies, screens and ice guards — the team would have to position a crane at the end of the aquarium pier.

“A big challenge was confirming that the size of the crane we needed would fit there and that we would have enough area for setup, deliveries and still be able to reach all three sides of the pyramid,” Milstead said. “We also had to make sure we weren’t overloading the pier so we brought in a structural engineer to review the loading.”

The team decided to use a 400-ton crane, a 75-ton crane and two 185-foot boom lifts for the glazing work. Glaziers, who were comfortable working at high elevations, were selected for the project and faced difficult working conditions, including the physical strain of working on a 45-degree sloped surface, the need to suspend operations in even minor winds, and the intense heat (often over 100 degrees) and glaring sunlight reflected off the glass structure.

Crew members were concerned that the old panes could separate as they were removed and expose both rooftop workers and rainforest animals to broken glass. So, they carefully clamped each piece together before lifting it out of its frame.

When workers discovered the old framing was not sufficiently straight, they also developed a method to modify existing clips to hold the new rail system for the replacement glass. Then to ensure that each window would fit before hoisting it up the pyramid, craftspeople field measured each of the 684 pieces of replacement glass.

Despite all those challenges, the glazing work progressed smoothly. Only a single pane of glass was broken in the process.

Inside the pyramid, the project faced a different challenge. Craftspeople had to remove the old bird wire system and install all new bird wire, replace the misting system, and install new lighting. The need to preserve existing rain forest plantings, however, would prevent the workers from using scaffolding or swing stages.

Expert riggers and certified climbers from The Crew Works, which specializes in theatre and concert productions, devised a plan for climbers to use an ingenious pulley system to remove and install equipment. They meticulously sequenced each operation and even crafted a scale model of the pyramid and the rigging system from LEGO and K’NEX pieces in order to demonstrate, test and revise the operation.

The plan enabled craftspeople to successfully install more than 15,000 square feet of wire mesh while suspended over 70 feet in the air. They used 70,000 hog rings to connect the rolls of bird wire and secured the wire to the existing structure using 4,000 stainless steel straps.

The plan also enabled the team to meet project requirements that no gap in the mesh exceed one inch and that it prove strong enough to withstand encounters with animals, such as several large sloths that eagerly climbed up onto the mesh as soon as they were placed back in the rain forest exhibit.

“This was a project with some unusual challenges but we like challenging projects,” Milstead said. “Sometimes, they keep us up at night but it’s really interesting to figure out the solutions.”