Teams of Trades, Artists, Scientists and Animal Lovers Surface to Build St. Louis Aquarium


(Nov-Dec 2019 Issue of St. Louis Construction News & Review Magazine)

Building a two-story, 120,000-square-foot aquarium within a National Historic Landmark structure dating back to 1894 is replete with design and construction challenges that project partners continue to meet head-on and creatively solve as they prepare for December’s public opening of St. Louis’ indoor aquatic wonderland.

Lodging Hospitality Management (LHM), owner of St. Louis Union Station, is also the owner of St. Louis Aquarium. Construction manager McCarthy Building Companies, paired with attraction designer and master planner PGAV Destinations, have been working with a team of specialty subcontractors and local trades since the project’s start in November 2017 to deliver a world-class family destination that is expected to draw more than one million visitors annually.

“This is definitely a new adventure for us,” said Chad Smith, vice president of design and construction for LHM. “We bought Union Station in 2012 and are continuing to transform this 30-plus-acre development. The big challenge has been the adaptive reuse of this incredible building. At one point, we evaluated the possibility of building all new (aquarium) construction rather than fitting the St. Louis Aquarium within Union Station, but we’re passionate about the rich history of this landmark. Being able to stand in the aquarium, look up and see a 125-year-old structure above you is priceless. We’re committed to providing that level of experience to visitors, incorporating St. Louis’ unique train and river legacy in the process.”

Initial interior demolition in order to open the space for aquarium construction presented a formidable challenge early on, according to McCarthy Project Manager Shawn Brinker. Leaving the historic infrastructure of the original 1894 train shed intact as a Landmark-designated property, controlling noise and dust while working close to the operational 567-room hotel and adjacent restaurants, and working from “as-built” drawings created more than a century ago all contributed to the complexity of the work.

“We had limited access to certain areas, sometimes affording us as little as a few inches of space, as we worked to protect and preserve original columns, footings, foundation, underground piping and more,” said Brinker.

Geotechnology’s purview was front-end engineering and geotechnical evaluation of subsurface conditions prior to the design and installation of structural support systems for the aquarium. “The Union Station property has a lot of geotechnical history dating back to the 1850s,” said Tony Roth, project manager and geotechnical engineer for Geotechnology. “Most of Union Station including the aquarium site was built over Chouteau’s Pond. The nearly 30-foot-deep pond was drained back in the 1850s, some 40 years prior to the construction of Union Station, when foundations for the train shed were then built. Additional foundation systems were built in the 1980s to support the mall. We had maps to indicate details associated with the stacked limestone footings and timber pile foundations underneath the train shed – and the 50-foot-deep driven concrete piles that supported the mall – but the creative challenge was working with PGAV Destinations’ design team to increase loading capacities for the mall’s foundation to support features of the aquarium. Reusing some of the existing foundations while installing additional micropile systems around them became the ideal solution,” Roth added, noting that the aquarium project denotes the third iteration of the classic structure over the past 125 years.

During geotechnical exploration, one remaining tenant operating in the food court of the mall required additional project considerations specific to venting drill rig exhaust fumes, according to Roth. The process was complicated by the existing maze of halls and corridors on what would become the aquarium’s lower level. Direct push sampling using a dynamically driven tube sampler paired with manual auger borings were techniques Geotechnology employed within the historic structure’s tight space constraints.

Jeff Klein, principal engineer in Geotechnology’s materials testing group, said the firm was tasked with special inspections, construction observation and materials testing. “We also employed concrete scanning to locate reinforcing in the existing concrete, which allowed the contractor to make perforations through existing concrete without damaging the existing reinforcing steel,” said Klein. The testing encompassed the foundations, soil, concrete and structural steel for the project, with team member ABNA Engineering providing some of the concrete testing.

Hunt Vac Services served as a subcontractor to McCarthy on the interior demolition of the retail spaces that had been home to shops and restaurants. Susan Hunt and Project Manager Jevon Poncez said the demo spanned two phases. The initial phase was a soft, non-structural demolition removing everything from floor to ceiling. Phase two was more structural in nature, taking out concrete on the first and second levels and removing the HVAC system from the third level. “For Hunt Vac, this is the largest interior demolition project we’ve taken on,” said Hunt.

Helitech Civil Construction installed the deep foundation micropile system capable of supporting exceptionally heavy loads driven by the water-filled exhibits and back-of-house animal life support systems. The system designed for the aquarium includes capabilities to support shear and compression loading.

“There are huge weight issues to contend with in terms of the loading requirements of aquariums,” said Jason Courtney, president of Helitech. “The system we engineered and built allows for that capacity amidst a lot of space limitations and overhead height limitations. Most of our micropiles are designed to hold between 70,000-150,000 pounds per pile, and we installed in excess of 200 piles on this job,” he added, “supporting more than 20 million pounds of structure in all.” Installing a micropile system, Courtney noted, eliminates the need to bring large drilling equipment onto a site, complying with historical landmark requirements and enabling support structures to be built within tight spaces. The micropiles installed at St. Louis Aquarium are supporting the exhibits, river gallery, ocean gallery mechanical pump rooms and other front and back-of-house systems.

Waterhout Construction supplied and installed the wood blocking, hollow metal and wood doors, hollow metal frames, door hardware, custom millwork/casework, expansion joints, exterior benches, fences, restroom partitions and more for the aquarium project. Waterhout Vice President Jeff Bunge said the firm also supplied and installed fiberglass catwalks around the shark exhibit and other exhibits. The contractor also supplied and installed reclaimed barn siding from San Francisco for the Bait Shop, where visitors may acquire food to feed the aquatic animals. Bunge added that the Carpenters assisted Waterhout in the work.

Rock Hill Mechanical performed the HVAC piping and ductwork that will heat and cool the facility. Jamison Bloebaum, vice president, said supplementing the installation workforce of Longhorn Organics – the Forney, TX-based firm specializing in animal life support systems – was also a major aspect of the work that the local MEP contractor performed.

Creating and delivering customized animal life support systems (LSS) is Longhorn Organics’ specialty. Co-Owner Holly Dempsey said the firm provides water filtration and infrastructure systems for aquariums, zoos and theme parks. Animal life support systems are similar in scope to human aquatic systems such as those designed for swimming pools, she said, and yet the layered, sequenced systems that support animals are decidedly more complex.

“Anytime you add an animal to the equation, you add a biological element,” said Dempsey. “Mechanical, chemical and biological filtration are layered to achieve the best possible conditions for the animals,” she added, noting that the St. Louis Aquarium LSS are designed to accommodate animals that live in rivers, oceans, freshwater and saltwater. “A total of 17 independent systems at the St. Louis Aquarium are each tailored to support the particular animal in each exhibit,” she said. For the touch tanks wherein visitors are able to interact with species, Longhorn Organics prebuilt a skid filtration system on a mounted platform for a single point of contact and an on/off button allowing staff flexibility if they decide to change out the specific species of animal at any given time. The system also features easily interchangeable components.

Examples of system components, both in the public exhibits and in the back of the house, are separate holding tanks, quarantine tanks, piping to provide individualized, treated water to each unique exhibit of animal life, ozone and temperature control systems.

Working directly for LHM, Longhorn Organics began as a project partner during the excavation phase. Most of the pipelines connecting the LSS are underground, Dempsey said. Underground systems work took nearly eight months as high-density polyethylene – a material with a longer life than PVC – was welded and fused together. “Our pipe size ranged from two-inch up to 24-inch,” she said, noting that the flow rate for each exhibit dictated the size of piping. More than 10,000 linear feet of pipe was built for the aquarium. The five back-of-house basins alone hold 100,000 gallons of water.

Both mechanical and chemical layers of filtration systems were engineered and built. Large sand filters measuring 96 inches tall and several feet in diameter were installed by Longhorn Organics, each with varying layers of gravel and sand. Dempsey said on-site machines are producing ozone gas as an animal-friendly means of chemical filtration rather than chlorine. The aquarium’s biological filtration system introduces the right strains of bacteria to promote animal health. “They’re the soldiers who are doing the real work,” she said. Local Union 562 Plumbers & Pipefitters, under the direction of Rock Hill Mechanical, assisted the firm in construction of the systems.

The Companies of Nassal is the project’s scenic fabricator for all the artificial rock work both in and beyond the exhibits that visitors will appreciate at St. Louis Aquarium. Nassal Project Manager Jason Ohlsen said the firm regularly works with PGAV Destinations on projects across the U.S. but that PGAV’s headquarters in St. Louis made logistics on this project progress smoothly. “First and foremost, these habitats have to be good for the animals,” said Ohlsen. “Secondly, they need to enhance the visitor experience. The rock work in this aquarium is very stout at 5,000 pounds per square inch, and concrete tanks are built to an even higher standard than that.” Nassal employed a custom concrete mix design that met both the structural and artist needs of the client.

Breckenridge Material Company supplied the aquatic concrete mix for the aquarium exhibits. Ryan Bohon, director of sales with Breckenridge, said the mix included antimicrobial and moisture-mitigating admixtures. The subcontractor worked in tandem with Vee-Jay Cement Contracting Company in pouring more than 2,200 cubic yards of concrete and alongside McCarthy, pouring another 1,800-plus cubic yards, much of it aquatic concrete.

Local trades including Ironworkers Local 396, Plasterers’ Local 3 and Painters District Council 58 worked alongside Nassal on pivotal tasks. One formidable task, according to Ohlsen, was delivering and applying shotcrete – sprayed concrete – through a hose from a longer-than-usual distance. “The closest we could park our (concrete) trucks was along 18th Street, which was several hundred  feet from where the shotcrete needed to be applied,” he said, noting that a lane of traffic on 18th Street at Market Street had to be blocked off from traffic for a full day, with a series of trucks arriving every 35 minutes to convey their loads through a hose that stretched 300 feet from the curb to the project site within the aquarium. “The logistics of pumping exact mixtures and pneumatically projecting it at a high velocity onto the surface, as a half dozen sculptors directly followed the concrete teams and molded the product into place, was an unusual challenge,” said Ohlsen.

PGAV Destinations Architectural Designer Andrew Schumacher said the firm worked closely with owner LHM and construction manager McCarthy to meet the goals associated with theming of the exhibits and overall historical significance of the destination. “Part of the whole concept of working within a historic train station was to really play up that story,” Schumacher said. “Not only will visitors experience a first-class aquarium, they’ll do so via the lens of historic train travel. Visually we’ve worked hard to mimic the city’s rootedness in train transportation and to overlay St. Louis’ significant river history.”

As visitors enter the aquarium lobby, they’ll behold a 14-foot-tall clock tank holding 10,500 gallons of water and a collection of colorful discus fish native to South America. Arched ceilings will add to guests’ sensation that they’re embarking on a train journey, especially as their ticket (which includes a specific “boarding” time) is called out and they enter simulated, life-size train cars to begin their tour of the aquarium. Exhibits include the Mississippi-Missouri River – complete with an enormous underwater tree made of sculpted shotcrete. “Once you set off on your train journey, you immediately gain the sense that you’re at the bottom of the river,” said Schumacher. “One thing about this project that is truly unique is that we did all of our rock work design on a computer. A computer program known as Zbrush allowed us to virtually sculpt and model, similar to how we used to model in clay. We were able to bring it all into BIM, edit it and were then able to 3D print it to see it in the field and bend the rebar to hold the rock work. This method enabled us to create precise models in order to coordinate with the custom acrylic (exhibit-viewing) panels that were fitted into the aquatic concrete.”

River Monster is another exhibit that will entertain aquarium goers, according to Brinker. “The design and construction of this exhibit makes it appear to be the ruins of a South American temple,” he said. “This exhibit will house enormous fish that hail from South American rivers and lakes.” Visitors will then move on to behold the nearby piranha exhibit.

No doubt one of the most talked-about experiences, Brinker said, will be negotiating the ramp running to the side and underneath the 250,000-gallon, exhibit known as Shark Canyon, which will include 60 sharks and rays. The walk leads visitors down below the tank (18 feet, 6 inches deep at its deepest point), where they’ll be able to gaze straight ahead and upward as schools of sharks swim directly over their heads. Installing the oversized, curved acrylic panels into place within a tight space prior to the concrete walls being poured required precise, detailed measurements. Height and sound restrictions also played a role in the complexity, as the exhibit is located directly below and adjacent to hotel rooms.

Designing and building access to and from each of the animal exhibits was critical, allowing staff to feed, shelter and interact with the aquatic wildlife and to clean the habitat spaces, Schumacher and Brinker said. Several of the exhibits span more than one level, adding to the beauty but also the construction complexity.

The upper level of the St. Louis Aquarium plays host to an above-water-viewing otter exhibit, a waterfall feature, several touch tanks, laboratory space, veterinarian quarters, the Bait Shop, kitchens where animal food will be prepared, a power generator and more.

McCarthy self-performed much of the aquatic concrete work, according to Brinker, who said the strength of aquatic concrete is typically in the range of 6,000 pounds per square inch, as compared with standard concrete that has a psi of 4,000. “Working with 120-year-old concrete columns and elevating the (second-story) deck so we could successfully place the concrete without affecting these existing train shed columns was a hefty construction challenge,” he said. “Utilizing cranes and lifts with serious overhead restrictions was another related obstacle that we needed to surpass.”

Hydrotesting the animal exhibits with water to ensure that the pH, oxygen level, temperature and other conditions are exactly as they need to be for each species of animal life – was a vital aspect of the project.

Caring for the 13,000 aquatic creatures who will live in the St. Louis Aquarium, as well as overseeing all operations of the new destination, is San Francisco-based zoOceanarium Group. Founder and CEO Chris Davis’ company operates aquariums, dolphinariums and zoos worldwide.

“LHM brought us into this project at an early stage so we could collaborate with PGAV Destinations to create a top-notch destination that cares for the well-being of each aquatic animal and provides an exceptional visitor experience, too,” Davis said. “A lot of times, aquariums are built without the operators in mind. Not so in this situation. LHM invested generously on the front end and had the vision to enable the collaboration of design, construction and operation that has been taking place for two years. There are nuances along the way where the operations side can provide input into design and construction to make the end product the very best for the animals and for the guests. We’ve been able to do that here.”

St. Louis Aquarium will employ approximately 90 full-time and part-time staff members who are directly involved with aquarium operations, according to Davis, and another 30 to 50 workers staffing the destination overall. An animal care staff includes a cadre of veterinarians as consultants, a curator, on-site biologists and weekly visits from a dedicated aquatic veterinarian who will receive daily records on each animal.

In addition to the aquarium, zoOceanarium is the operator for the facility’s indoor ropes course and mirror maze.

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