By Robert L. Reid
As Chicago’s Shedd Aquarium approaches 2030 and its 100th anniversary, the facility is in the midst of a $500 million strategic plan program known as the Centennial Commitment that is scheduled for completion by 2027 and includes an extensive physical transformation of the facility. In addition to creating a new, more accessible entrance, the project will integrate and expand the aquarium’s aquatic science laboratories; add new and expand existing exhibits; and renovate, expand, and improve other attractions in and around the site’s ornate Beaux-Arts building and lakeside setting.
The planned exhibit work will add the aquarium’s first underwater tunnel and essentially double the water volume in certain exhibits throughout the attraction’s historical galleries, which are the six original galleries on the main level of the aquarium.
Opened in May 1930 at a site along the Lake Michigan waterfront, the Shedd Aquarium features a Beaux-Arts structure described on the facility’s website as a “neoclassical temple of white marble and terra cotta that celebrates aquatic life, from the marine fossils in its limestone floor to Neptune’s trident capping its glass dome.” Since opening, the aquarium has expanded twice, first with the modernistic Abbott Oceanarium, which opened in 1991, and then in 2003 with the Wild Reef exhibit that was constructed 25 ft below street level under the original south terrace.
The current project will convert the Shedd’s existing ground-level accessible entrance on the southwestern side of the site into a new main entrance for the building. This enhanced accessible entrance will feature a roughly 1,500 sq ft elliptical building where guests can purchase tickets. This posttensioned concrete structure will be founded on steel H-piles sunk to depths of 90 ft or more, says Bob Wengel, the Shedd’s senior vice president of facilities and security. It will be clad in glass fiber-reinforced concrete that matches the color of the overall building’s marble facades, says Sarah Hezel, the Shedd’s vice president for design and exhibits.
The enhanced accessible entrance will supplement, rather than entirely replace, the aquarium’s original main entrance, a columned pediment structure on the western side of the building. The original main entrance features a wide set of stairs that lead to the aquarium’s main level, which is elevated one level above ground. This columned entrance will remain in use.
The project’s design team includes architect Valerio Dewalt Train, landscape architect site design group ltd., and structural engineer Klein & Hoffman, all based in Chicago. Although Klein & Hoffman is the project’s main structural engineer, New York City-based Thornton Tomasetti is the structural engineer specifically for the new elliptical entrance building. The general contractor is a Chicago-based joint venture of Pepper Construction and BMI Construction.
Inside and out
In addition to the new entrance, the plans for the exterior of the Shedd site will feature enhancements to the 4 acres of green spaces and gardens surrounding the building. The goal is for these areas to serve as a sort of living classroom and habitat for migrating birds and butterflies “to make sure there is a seamless integration with our parkland and that there is one entrance for all, so that everyone can access the same space and begin their journey through the aquarium,” says Hezel.
The interior work for the Centennial Commitment project will involve “a restoration and transformation” of many of the aquarium’s historical galleries and exhibits, including expansions to existing facilities and the construction of entirely new attractions, Hezel says.
One of the most dramatic changes will feature the construction of a new ramp that will lead down from the building’s elevated main level to the ground floor, taking guests past various aquatic habitats. The curving ramp will measure roughly 12 ft wide, varying somewhat depending on location, and will be constructed from steel beams and concrete slabs, notes Michelle Ryland, S.E., a senior associate at Klein & Hoffman.
The ramp will lead visitors directly to the Shedd’s new underwater tunnel, a 40 ft long structure topped by an enormous, curving acrylic roof to immerse guests in an expanded Caribbean reef habitat holding roughly 190,000 gal. of water — twice the volume of the original Caribbean exhibit, says Hezel. The new Caribbean reef exhibit will start on the aquarium’s ground floor. The old exhibit, which had been in the center of the main floor, will be replaced by an exhibit known as the Wonder of Water that features two new habitats — one with saltwater and the other fresh — that will fit within the footprint of the existing Caribbean reef space. Those new habitats “will tell the story of how water is the source of all the biodiversity you see throughout the aquarium,” says Hezel.
Because the Centennial Commitment project will double the amount of water within some of the Shedd's historical galleries, the engineers had to carefully analyze the new load paths and how they would affect the existing structures, especially the building’s deep, composite timber foundations, says Ryland. “In several cases there will be reinforcement to those deep foundations as a result of the added loads of the additional water,” she explains. For example, new micropiles will be installed and the existing pile caps enlarged.
The plans to expand the Amazon Rising exhibit for arapaima — a freshwater fish from the Amazon that can reach 10 ft in length — will involve the replacement of part of the existing concrete joist floor system in that gallery with a more robust steel and concrete composite floor structure to better accommodate the new loads, says Kathleen Strnad, a Klein & Hoffman senior associate. The new floor system will extend from inside the habitat to the visitor areas outside of the 6 ft tall acrylic viewing windows and must be carefully tied into the original structure, Strnad says.
The larger water volumes will also require expanded life-support systems for the habitats, says Hezel. To provide additional space for such equipment, a concrete-framed terrace on the north side of the aquarium building will be extended by about 10 ft and provide occupiable space below. Supported on steel H-piles down to bedrock, the new portion of the north terrace will be constructed with the same materials and appearance — including marble cladding — as the original terrace, says Ryland.
Other changes include the conversion of a former retail area into a new educational space that will provide views across the city and parts of Lake Michigan. Those views will be made possible by uncovering a series of large windows, each roughly 12 ft tall and 4 ft wide, that had been covered up for the last 25 years or so because natural lighting was not desired in the retail area, says Wengel. “But now we are fortunately able to open those up, let the light in,” he says, “and also show a nice view of the Chicago skyline and the harbor that sits to northwest of us.”
This article is published by Civil Engineering Online.