When High Concrete Group was asked to help bring an 8547 sq m (92,000 sq h) office building at 1200 Intrepid Avenue to life, it was up for the challenge. Later, they were also rewarded for their work as this project received the 2016 Harry H. Edwards Industry Advancement Award from the PCI Institute. Located at the Navy Yard's Corporate Center in Philadelphia, a master-planned development within the Navy Yard encompassing approximately 125,400 sq m (1.35 million sq h), the Intrepid building is constructed entirely of flat concrete planks. Each piece is set at an angle, so the composition gradually becomes a curving wall with mesmerizing optical effects that make the front wall appear as though it is falling to the ground like a row of dominos. Three sides of the structure are conventional flat walls, while the east facade has a variety of radii, ranging from just over 98 m (320 h) at the ground floor to just over 2,713 m (8,900 h) at the parapet of the roof.
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Location: Cincinnati, Ohio
Type of Precast: CarbonCast® High Performance Insulated Wall Panels and Hollowcore Plank
Size: 85,599 sq. ft. (42,100 sq. ft. walls; 70,000 sq. ft. plank from Hollowcore, Inc.)
Speed without sacrifice at Ohio school
In sports, it’s a common tenet that there’s no substitute for speed. The same can be said for construction. The ability for major building components to be erected quickly and properly translates to a multitude of benefits during and after construction.
That precept held true with the Cincinnati Public School District’s Academy of Multilingual Immersion Studies World Languages (or Academy of World Languages). The citywide magnet school attracts preschool to eighth-grade and offers immersion and partial immersion curriculums aimed at fluency in French or Spanish. With a tight deadline, the architect turned to a total precast concrete system from High Concrete Group LLC.
And with the use of innovative precast insulated wall panels, the school did not need to sacrifice performance for speed. Project Architect Randy Merrill from McGill Smith Punshon, Inc. said, “We tried to keep the design simple, sleek and high-style. It’s truly an international style, in keeping with the school’s mission. It could be built anywhere in the world and still fit in.”
Precast means savings in any language
Academy of World Language's 173 precast sandwich panels and 633 hollowcore planks were fabricated off-site and delivered in a parts kit for immediate erection. The building took shape piece by piece. The panels varied in size from 15’-7” to 41’-0” in height and 11’-4” to 12’-7” in width.
Because precast concrete is manufactured in a controlled factory environment, the wall panels achieved a level of uniformity unmatched by field construction. For example, precast delivered consistent door and window openings, which eliminated the need for costly fieldwork to correct gaps and irregularities.
Precast accrued several other advantages. Weather delays and other setbacks were virtually circumvented with factory fabricated precast elements, which helped keep the project on schedule. Precast reduced the need for on-site material and equipment storage compared to other conventional building systems. Scaffolding (and its cost) was avoided. Fewer people were required on the job site, reducing the risk of accident or injury as well as the associated insurance expenses.
Precast helped maintain aesthetic consistency
The strikingly attractive building features several complementary finishes within each panel. Exposed aggregate provides bold texture and an earthiness that befits the school’s wooded surroundings. A subtle, uniform sandblast finish appears alongside an acid etched treatment that deepens colors for contrast and imparts a stone-like appearance. Horizontal lines of vibrant ruby red tiles below crimson-framed windows add contrast across the façade, while vertical lines of blue tiles almost make the seam between panels an aesthetic feature. Finally, insets of alternating yellow and blue tile provide a visual counterpoint to the exterior light fixtures directly above them. Overall, it’s a colorful, vibrant exterior that reflects the energy and discovery of learning.
Merrill praised the aesthetic versatility of precast. “It allowed us to play with colors and textures, maintaining a simple yet still attractive building,” he said. “We were able to gain economies through repetitive patterning and use scale and massing to keep the building interesting and not overwhelming to the kids.”
The benefits extended to the interior walls as well. The precast sandwich wall panels were prefinished on the inside with paint filler and institutional grade paint. Durable concrete will withstand decades of heavy use and abuse from energetic children. Furthermore, the prefinished interior eliminated the expense and time that a field-constructed interior would have entailed.
Insulated wall panels provide excellent building envelope
CarbonCast High Performance Insulated Wall Panels use high-strength C-GRID® carbon fiber grid for shear transfer between the 3” outer and 6” inner wythes of concrete. The wythes act together as a single structure because the carbon fiber grid creates fully structurally composite action. The load-bearing walls provide a lower-cost alternative to non-composite wall systems because they eliminate the need for other structural elements. This results in thinner panels and less internal structure, which allows for more usable interior space.
The sandwich panels used 2” of extruded polystyrene (XPS) insulation between the two wythes. C-GRID’s relatively low thermal conductivity virtually eliminates any hot or cold spots on wall surfaces, cutting back significantly on heating and cooling costs. Conversely, brick-and-block cavity wall construction often suffers from temperature fluctuation: cold in the winter, and hot in the summer. It can create an uncomfortable learning environment, especially around the perimeter of the building. And with skyrocketing energy costs and heightened public awareness of sustainable construction practices, Academy of World Languages and Cincinnati Public Schools will reap the benefits of the green, energy-efficient CarbonCast system for years to come.
Precast sandwich panels on the Academy of World Languages also provide two levels of protection against mold and mildew, an all-too-frequent problem with masonry cavity walls. First, concrete’s high density renders it virtually impermeable to vapor. Second, eliminating drywall removes a potential food source for spores. The school’s precast system will deliver decades of insurance against the unpleasant realities of a mold-related problem: irate parents followed by facility shutdown and remediation.
Overall, the CarbonCast High Performance Insulated Wall Panels and the entire precast system from High Concrete Group saved time, reduced cost, improved durability and enhanced aesthetic options among other benefits. Subsequently, precast has readily become a preferred building system in the Cincinnati Public School District. The Academy of World Languages joins magnet schools Roberts Paideia Academy and Fairview – also High projects – as monuments to the versatility, efficiency and effectiveness of precast concrete.
CarbonCast is a registered trademark of AltusGroup, Inc.
C-GRID is a registered trademark of Chomarat N.A.