Oct18

Behind the Scenes of the South Meridian YMCA Elton Family Aquatic Center

For two years, I worked with an incredible team to design and oversee construction of the South Meridian YMCA Elton Family Aquatic Center – an addition to the existing Tomlinson South Meridian YMCA. Throughout the project, we encountered a number of unique challenges due to the complex pool systems and construction limitations. Problem solving and coordination with specialists led us to some innovative solutions that were implemented on the project. Walking around, most people would never notice these intricacies in the facility – but I can’t help but think about them as I tour the finished product.

Project Background 

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The South Meridian YMCA Elton Family Aquatic Center is an addition to the existing Tomlinson South Meridian YMCA (another KPFF Mountain West project). This facility provides the surrounding population with a place to relax, learn to swim, exercise, celebrate, and enjoy community. The center will also provide local swim teams a place to practice and compete in a state-of-the-art facility.

The project consisted of the construction of a competition pool, a kiddie pool, a recreation pool with rock climbing wall, a hot tub, an outdoor splash pad, a water slide, a lazy river, an attached mechanical and pump room, updates to the existing locker rooms, and a hallway connection between the new facility and the existing building. KPFF provided the structural design for the exterior concrete masonry wall (CMU), concrete foundations, metal deck roof, interior concrete slab on grade, the mechanical room and pit, and interior renovations to the existing building.

Challenges and Innovation

Due to the confined nature of the site, the contractor’s construction schedule, and the unique challenges for the pool infrastructure, extensive coordination was required between KPFF, the rest of the design team, and the contractor.

Constrained Site

The site for the aquatic center was located in between two existing buildings. The building’s walls were constructed only four inches away from the existing CMU walls of both Hillsdale Elementary School (another KPFF Project) and the “dry” side of the South Meridian YMCA. This required the existing footings to be extended to accommodate twelve-inch-thick CMU walls and provide enough bearing capacity for the additional loads. The contractor needed to excavate down low enough to install the new footings while not undermining them to maintain stability of the existing structures. This portion of construction took place during the summer to minimize the disturbance to the elementary school and its students.

Contractor’s Schedule

Some of the challenges faced during construction were due to the contractor’s schedule. To avoid digging the pools during the winter when the ground would be frozen, the schedule required constructing the entire exterior of the building and installing the roof and all overhead mechanical equipment, lighting, and fire protection systems to provide an insulated and weather-protected site for the construction of the pools through the winter. The contractor had to dig out the site to roughly thirteen feet below the final grade to form and cast the foundation footings and walls. Once the foundation was cast, the site was backfilled and compacted to three feet below final grade, which provided the platform for the other trades to finish the construction of the structural walls and roof and installation of all the mechanical equipment. Once everything was installed, the contractor had to re-excavate to begin the installation of the pools. KPFF designed the foundation walls to serve as retaining walls during this phase of the pool construction. This required additional reinforcing as well as the addition of keys to the bottom of the footings.

Pool Infrastructure

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Although KPFF did not provide structural design for the pools, extensive coordination between the pool design engineer and KPFF was required. At its deepest end, the competition pool reaches down ten feet and was separated from the building’s foundation wall by only eight feet. The building’s footings were required to be stepped along with the slope of the pools to a depth of ten feet below final grade to avoid surcharge loading of the pool walls and to accommodate the contractor’s schedule. 

Coordination was also required to accommodate almost ten miles of underground pipes and numerous penetrations through the foundation walls and into the mechanical pit. The pipes ranged in diameter from a few inches up to almost fourteen inches and turned some of the foundation walls into what can only be called “Swiss Cheese.” Other coordination items with the pool contractor included specific admixtures for the concrete used in the water retaining structures to improve its resistance to deterioration due to exposure to chlorinated water, as well as increased clear cover for reinforcing bars in the concrete.

Pool Circulation Systems

On top of the miles of underground pipe, dropped footings, and pool walls, KPFF was also required to coordinate with the mechanical engineer on the project, as a chloramine evacuation system was being utilized under the slab on grade around all the pools. The system consists of a continuous drain around each pool that collects overflow water as well as chloramine, a byproduct of the chlorine in the pools, which can cause skin and eye irritation. The drain then moves the chloramine into a duct system that is almost two feet in diameter which wraps completely around the pools and takes the chloramine up a chase and out through the ventilation system of the building. The drain and ducting system all had to fit in the cramped space between the pool and foundation walls and footings. In some locations there were merely inches remaining once everything was accounted for and installed.

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An Engineer's Perspective

My favorite part of working on this project was seeing all the bits and pieces that go into making such a unique facility possible. From an engineering perspective, all the cool and exciting things in this project were buried. From the dropped footing system to the miles of pipe and mechanical systems, everything is underground. When you are walking around the complex, all you see are simple pools, walls, and a bare bones roof system. It’s what you don’t see that provides the pools with clean, safe water, operates the water fountains and sprayers, allows the lazy river to meander around, and provides thrill seekers the opportunity to take an exhilarating ride down the slide. Being able to walk around and know what’s going on behind the scenes (and under the floor) is a really awesome feeling.

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