In general, seals and sea lions in captivity tend to have more eye problems than other zoo animals. Although the exact reason for their ocular ailments has not been pinpointed, some research suggests it is related to the animals’ prolonged exposure to sunlight and the amount of light that reflects off the surface of the swimming pools in their zoo habitats. As part of a complete renovation of the sea lion exhibit at the Blank Park Zoo in Des Moines, Iowa, two large canopies, using metal panels from The Garland Company, Inc., were constructed to provide the zoo’s five pinnipeds – some who already suffer from vision problems – with respite from the sun.
Timothy Korpela, P.E., professional structural engineer and owner of Korpela Engineering Structural Services Company, Windsor Heights, Iowa, was challenged with finding a shade structure with the strength to withstand the varying weather conditions in Iowa in addition to increasing the aesthetic value of the exhibit.
The 1,200-square-foot canopies were designed to resemble large umbrellas and are located on the pool’s island, providing maximum shade coverage over the pool area. The bases were constructed using cylinder steel piping, allowing for an open structural framing system that is both lightweight and aesthetically pleasing.
The structural engineer recommended metal as the canopy covering as a cost-effective material that provides the strength and durability needed to withstand the varying wind speeds and heavy snow in Iowa. The canopy design features Garland’s 24-gauge, 16-inch wide R-Mer® Span structural standing seam panels that were attached to 16-gauge, one-piece clips on the framing system, eliminating the need for exposed fasteners and allowing for thermal movement. The panels, varying in length from 5 feet to 25 feet, provide the industry’s highest wind uplift rating and were engineered to withstand 40 pounds of snow. Additionally, the metal system requires little to no maintenance and was engineered with the goal of reaching more than 30 years of service life.
With the addition of the shade canopies and plans for four more, the zoo now has the opportunity to rescue more seals and sea lions, providing them with a safe and healthy life in captivity.