July 4, 2022 – by Daniel Picco
In 2018, The American Museum of Natural History, located in Central Park, New York City, announced that one of their most beloved and popular exhibits would be temporarily shut down for a major renovation. The Mignone Halls of Gems and Minerals, at 11,000 square feet, houses over 5,000 precious stones, gems, and minerals from 98 different countries around the world. When the museum was tasked with showcasing a new 18,000 lb fluorescent stone specimen to this already world-renowned collection—they called PICCO.
Rendering: Ralph Appelbaum Associates
A total of seven large specimens required PICCO’s expertise in designing their structural steel frame base. A 3,800 lb labradorite column, a 4,000 lb golden beryl, a 7,300 lb azurite crystal, two massive geodes at 10,000 lbs a piece, and the two specimens we will be highlighting in this blog. An 11,000lb fractured piece of granite that contained multiple crystal-like garnets and an 18,000 lb fluorescent willemite which when exposed to various lighting, naturally displayed vibrant colours of the rainbow. The first five specimens mentioned featured lightweight display cases that housed our structure underneath. The garnet and willemite, however, required an exposed structure that involved both supporting the massive weight and not being an eyesore. Needless to say, we were faced with various challenges!
Caption: Extraction of blocks from their original homes
Our preliminary concepts were straightforward in theory. Visually, the garnet was to be freestanding. Exposed on all sides and able to be touched by visitors, we needed to design something discrete but sturdy. Our plan for lateral support was to thread two rods vertically drilled and through the top of the garnet and anchored to a steel base below. The garnet’s weight would bear onto the steel base that would then be anchored to the floor slab. The engineer of record informed us that under no circumstances were we to anchor to the existing floor slab. The only option for the garnet was to engineer a base wide enough and with adequate ballast to resist overturning with zero attachment to the slab below, while maintaining a footprint that would fit within the exhibit floor plan and still provide patrons the experience to view and touch the specimen.
Caption: Schematic drawing for fabrication and installation
The willemite, being exposed on the front face only and having an adjacent wall to attach to, could easily sit on a steel base and be laterally tied back to the wall behind. However, upon exposing the existing floor and wall anticipated to support the massive willemite, the construction team discovered that the wall directly behind the willemite hid what was once an old window, leaving us with a massive void where we were expecting a full-height wall capable of supporting the new specimen. On top of that, the 153-year-old building featured a concrete floor slab that was not capable of supporting the weight either. A staunch reminder that building codes were slightly different at the time of initial construction in 1869. Back to the drawing board.
Because the slab itself could not support the 18,000 lbs, we investigated the option of using the void in the structural wall as a ‘shelf’ to carry the weight. The large block of willemite was extracted from the mountain face and strategically split into four pieces. The plan was to reassemble these four pieces into their original form to give the illusion of one large piece. Since the pieces were being installed one at a time, our anchoring strategy needed to ensure maximum adjustability for the installers, making precise alignment possible. After considering many approaches, meetings, and iterations, our bases were complete.
During shop handling of the willemite rock sample, one of the four major pieces cracked and broke away, requiring further assessment from PICCO on how to “stitch” the piece back together and repair the break.
After close examination of the cracked pieces, we were able to design a solution consisting of discretely located and strategically placed epoxied threaded rods. We were able to salvage this very important piece for the museum without aesthetic compromise.
Caption: Instruction given to fabricator to repair willemite block
Unforeseen delays caused by the pandemic postponed the grand opening of The Mignone Halls of Gems and Minerals until June 12, 2021. PICCO had the opportunity of visiting the exhibit in early 2022. There is nothing more satisfying than seeing our design solutions and creativity in person. The PICCO team looks forward to solving more unique challenges for the Museum in the future.
We also hope you get to enjoy this beautiful exhibit in person one day too! Until then, enjoy these breathtaking photos!
Caption: Photos by Daniel Picco on his visit to AMNH (April 2022)
For more information contact: firstname.lastname@example.org
Project Coordinator at PICCO Engineering
Daniel has proudly been with PICCO Engineering since 2016. In addition to connection and anchorage design, Daniel works directly with clients ensuring all preferences, site conditions and best practices are met. His keen attention to detail provides our clients with the confidence and comfort to successfully deliver projects. Daniel holds a diploma in Architectural Technology from Sheridan College.