'Monstrous' steel joists are MVP of high school gym on Grand Cayman | Dump Trucks Charlotte NC

The island of Grand Cayman is well known as a global financial center and vacation hot spot in the Caribbean, but it's also home to a growing mix of international residents. As the population explodes, so does the need for supporting development. One such project is a U.S. $60 million expansion of Cayman International School (CIS), with a multi-purpose gymnasium and performing arts center as its cornerstone.

It's a grand space fitting for the island of Grand Cayman. To create the expansive, unobstructed spans and open floor plan necessary for spectator sports and performances, the facility features nine 110-foot-long, 60-inch-deep joists and an acoustic steel roof deck. 

The gym's design and construction is unique in nearly every way, from delivery of materials and their size to the products and building methods used. Developer Dart, steel fabricator Charleston Steel and New Millennium Building Systems worked closely together to ensure project success, said Christopher Mounts, manager of technical services at Charleston.

Challenges surfaced along the way, however.

• An overseas job site introduced schedule and delivery challenges.  

• The gymnasium's size made for complex joist design. 

• Island building codes complicated specification and design of joists and deck. 

Going the distance for successful scheduling and delivery

Before the joists or steel deck began the 750-mile journey from Lake City, Florida, to Grand Cayman, extensive planning and collaboration took place. Gary Gibbs, senior vice president of design and construction at Dart, says early cooperation between Charleston and New Millennium ensured materials were shipped and delivered on time. It was a complicated process, particularly for the 110-foot joists, which were delivered as two 55-foot pieces.

New Millennium shipped the joists from a plant in Lake City on inland freight to the Port of Miami, where they were placed on flat racks that were loaded onto ocean-going cargo vessels. A week later they arrived in Grand Cayman, where they were offloaded onto another flat rack. They were then transported via inland freight to the job site. From start to finish, delivery takes three to four weeks.

"If you miss a logistics window, it can definitely be a scheduling problem," Gibbs says. 

New Millennium was required to arrange special shipping for the joists. Standard shipping typically involves 40- or 45-foot cargo containers, too short for the 55-foot joist pieces. 

'Exceptional' joist challenges

Steel joists of the size required for the gymnasium are not common on Grand Cayman. 

"This project was exceptional due to the size of the joists," Mounts says. "Even to me, they're monstrous."  

Since they were shipped as two pieces, the joists had to be spliced on site, says Ben Pitchford, engineering manager at New Millennium. The bolted splice was located at the ridge of the double-pitched joists.  

To accommodate the facility's utilities and suspended elements, the joists' chords were engineered to address various integrated loads, including fire sprinklers; basketball goal structures; a dividing curtain; lighting; audio-visual equipment; and rooftop solar panels. 

"It was done in a flexible manner, so loads could be field-located as needed without additional reinforcement," Pitchford says. 

Accounting for tropical weather

Since Grand Cayman often experiences severe tropical weather, Miami-Dade hurricane standards dictated the design and engineering of the joists and deck.

The joist chords were designed to account for wind uplift (60 pounds per square foot), along with axial wind loads in the joist top chord.  

"This required the joists to be built with 5x5 angles for the top chord and 6x6 angles for the bottom chord," Pitchford explains.  

For the roof, Pitchford and the engineer of record specified a 3-inch type NA acoustical roof deck having two different gages. 

"Considering requirements for high uplift and diaphragm shear, we had to use 18 gage deck at the perimeter of the roof to meet this need, then transitioned to 20 gage deck at the interior of the roof," Pitchford says. 

The gymnasium-theater space opened in January 2021, providing the island a much-needed lift physically and emotionally.

"This project was satisfying on several levels," Pitchford says. "We were able to overcome challenges with the help of invested project collaborators. We worked through a pandemic without losing much time. The result is a beautiful gymnasium and theater space for students and the community alike—and that makes you feel good." 

For more information about the steel joist and roof deck systems featured in this article, visit www.newmill.com/education. Want a trackable link?