Walls on either side of the stage consist of CMU backup and stone with every two courses recessed to mix the sound, enhancing the acoustic performance. Where split face CMU is used, its craggy texture reflects highfrequency sound in random directions. This high frequency diffusion can be helpful in controlling excess brightness where scattering is desirable.
NOVEL DESIGN ELEMENTS AND TONS OF LIMESTONE BRING NASHVILLE A DOWNTOWN FRONT PROCH
As a multipurpose outdoor gathering space, the 11-acre Riverfront Park is a scenic marvel, anchored by the architecturally extraordinary Ascend Amphitheater.
Integrating the city’s identifying elements proved uniquely challenging in creating a signature amphitheater and public green space for Nashville – a diverse and currently expanding urban center with an industrial riverfront history and a worldwide reputation as Music City.
Three design firms collaborating on the development followed a park first directive where the amphitheater and surrounding buildings were to be as unobtrusive and organic as possible, prompting a concept for site walls and architecture evoking the appearance of being carved out of the earth. Site-wide use of regional Kansas-quarried US Stone Flint Hills grey high-density limestone – roughly 30,000 sf of it, with nearly as much used on the park site as in the buildings – along with approximately 80,000 sf of cost effective high performance CMU. Integral water repellent in the CMU increases durability, especially at ground level for the outcropping effect according to Craig Smith, vice president Better Block. Block design according to ASTM C90 allows for a 15/8" face shell for the 8" CMU which decreases thermal bridging allowing increased thermal performance. And contribution to LEED optimizing energy performance credit.
Mix design for the CMU included pre-consumer cementitious material, a by-product of the aggregate extraction process contributing to this product’s being very environmentally friendly, thus able to increase LEED recycled content credit. According to Alley-Cassetty vice president Tim Pedigo, distributor for the durable limestone, “This building’s stone has a life expectancy of 100+ years.”
Throughout Tennessee, limestone resides a foot or so below ground and crops up in the form of bluffs along the banks of the Cumberland River, which defines downtown Nashville’s northern boundary as it passes through the north central portion of the state. Landscape architect Brian Phelps of Hawkins Partners, local lead designer and project overseer, explains that the river was inspiration for the park’s sinuous forms. Limestone, he says, was a perfect fit for the concept. Adds Andy Berry of Nashville-based Smith Gee Studio, architect of record, “We chose limestone as a reference to bluffs and old stone bridges throughout Tennessee. It serves as a great base from which the park’s contemporary and unique materials emerge. Our goal was to vaguely mimic a rock outcropping.”
The amphitheater and surrounding buildings are designed to be unobtrusive and organic as possible evoking the appearance of being carved out of the earth
Integral pigment to match the limestone was added to the mortar and CMU for a monolithic effect. CMU uses lightweight expanded shale in the production of the block which allows for ease in lifting and setting, thus quicker installation. As well as greater fire ratings and increased thermal performance.
Short, coursed site walls wind around the grounds emulating the Cumberland’s bluffs, using CMU covered with 2'' and 4'' stone. “The idea suggests cutting through the site, exposing stone the way a river would. Coursing was really important because of the sedimentary rock, common within the bluffs and cuts.” The concept, Phelps says, extends to the amphitheater itself – “this large object that was a part of the land that was cut away.”
Craig Hodgetts, principal of Californiabased Hodgetts + Fung, was particularly inspired by the flexibility and visual unity made possible by limestone, a material not commonly used in earthquake-prone Los Angeles, “That was a tremendous aesthetic impact on the entire park and conferred a kind of classic legacy to all the structures on the park,” says Hodgetts, whose design employed limestone in the amphitheater’s podium, proscenium and exterior walls. While Riverfront Park is a visually integrated expanse whose many public amenities offer an earthy appeal, the open-backed Ascend Amphitheater stands out as a stunningly atypical outdoor performance space. Its asymmetrical aspects, which Hodgetts says were intended to imply motion and acknowledge the energy and enthusiasm of Nashville’s musical impact, include a roughly 35' x 55' reverse-battered wall with 6'' and 8'' stone of random lengths creating a non-uniform effect. Flanking the stage’s right side and leaning outward about 4°, the wall is a subtle, but nonetheless notable, design element. Andy Berry recalls that “when the stonemason was installing this, he said, ‘You realize stone shouldn’t do this.’ It’s an exceptional use of stone. This crew did an awesome job of installing it.”
Outward-sloping masonry tower supports Ascend Amphitheater’s rakishly angled, bridge-evoking roof
H-B DW-10 sliding veneer anchors were specified to attach the irregular coursing of stone veneer right through the CMU backup. Stone courses of 2", 4", 6" and 8" were used to replicate the ledges of stone carved from the earth for a natural look.
Stone and metal also work together somewhat unconventionally on the outward-sloping masonry tower supporting Ascend Amphitheater’s rakishly angled, bridge-evoking roof. The vertical piece represents the city’s industrial river history, confirms Hodgetts, who remembers noticing Nashville’s abundant limestone bridge abutments as well as its century-plus-old civic buildings, another influence on the material palette. Comprised of a hollow steel structure with block applied to the outside and given a 3'' deep stone face, the angled form is integral to the dynamic visual effect of the amphitheater shell.
Functional and Aesthetic
The inward-leaning, stone-veneered block wall on the amphitheater’s southern side gives the impression of a retaining wall, Hodgetts explains, “to suggest that it's a landscape element rather than an architectural element.” Serving as further evidence of masonry’s suitability for bridging the functional and the aesthetic, the wall exemplifies the entire project’s design approach: to eliminate the perception of structures encroaching on a prime stretch of green space and provide park visitors with numerous recreation options in a rolling, open environment that maximizes the allure of both the park’s native riverfront scenery and its gleaming skyline view. Tucked unobtrusively beneath the stage, the 2,500 sf Riverfront Room (a community event space doubling as an artist meet-and-greet area) features a 1,600 sf stone terrace enhanced with decorative ground-face CMU with textured aggregate exposed, also used in the artist area’s elegantly appointed dressing rooms.
Limestone and block form an inviting visual foundation throughout Riverfront Park, from the base of its industrial-themed swings and conceptual site walls offering varied seating options to the visually arresting amphitheater standing as a signature Music City identifier. “The client was really looking for this iconic imagery that the park could communicate to the public and to visitors, so the idea that the amphitheater was something very iconic was important to them,” says Hawkins Partners’ Brian Phelps.
“We’re building something that will look great for a very, very long time,” Phelps continues. “We were excited to be able to use so much stone for that very reason. One of the most special things about stone is how long it lasts and still looks beautiful. We expect it to look like that for decades to come, without much maintenance.”
"As the owner of a masonry company, I'm obviously passionate about the trade and the materials we use. On each and every project we get an opportunity to be an instrument in the designer's intent and a voice for the benefits masonry offers. The designer is the artist; our craftsmen are the brush, and the materials are the paint. It's always inspiring to be involved in a project from conception to reality." - Andy Sneed
Andy Sneed, fourth generation brick layer, is president and CEO of WASCO, his family's mason contracting company, headquartered in Nashville TN.
Sneed is president of the Masonry Institute of Tennessee and serves as a GREAT MIND of the Editorial Advisory Board of SMART|dynamics of masonry where industry leaders gather and speak.
He chairs the Mason Contractors Association of America’s Education Committee, sits on an Advisory Board for Middle Tennessee State University Construction Management Degree Program Committee, and is a member of the TN Quality in Construction Committee.
He was previously on the boards at the Associated General Contractors of America and the ACE Mentoring Program
He studied at Tennessee Tech and Nashville State Technology Center, earning his associate degree in Civil Engineering. He is also a certified Masonry Inspector.
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RIVERFRONT PARK & ASCEND AMPHITHEATER
Nashville Metropolitan Government
Hodgetts + Fung, Culver City CA
Architect of Record
Smith Gee Studio, Nashville
Lead Consultant | Landscape Architect
Hawkins Partners, Nashville
Skanska USA, Nashville
EMC Structural Engineers, Nashville
Jaffe Holden, Norwalk CT
River City Erectors, Rossville TN
Alley-Cassetty | Better Block | Gerdau | Heckmann Building Products | Hohmann & Barnard | Laticrete | Quikrete | Ram Tool | Smyrna Ready Mix | US Stone Industries
11 acres, including amphitheater, restroom, concession and support structures $52 million | Masonry $1,000,000+ | LEED Gold Completed 2015