river walk

8/14/2019 River Walk

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28 August 2009 / C cr r a a Photo courtesy of Mark Menjivar

and the San Antonio River Foundation


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C cr r a a / August 2009 29

Ar a Add

A r J w R r Wa

gro o crea ed of decora ive concre e enhance san An onio landmark

A s ACI was meeting earlier this year in San Antonio, TX,for its Spring Convention, work was well underway on

a 1.5 mile (2.4 km) long expansion of the renowned RiverWalk along the San Antonio River. The new section of theRiver Walk features the work of eight artists who havedesigned 12 site-specific art installations within eightbridge crossings. The Museum Reach extension is a$74 million public/private partnership with the City of SanAntonio, Bexar County, the San Antonio River Authority,and the San Antonio River Foundation participating.

Concrete artisan Carlos Corts was commissioned tocreate the art for an inviting grotto complete with awaterfall dropping into a pool, a bench inside the largestcavern with re-created tree roots coming through the ceiling,realistic-looking stalactites, and dramatic lighting. TheSan Antonio River Foundation ( www.sariverfoundation.org )raised $3.5 million in private contributions to fund theconstruction of the grotto.

Corts works in the faux bois (false wood) style, whichhe learned as a child assisting his father Maximo. Thesenior Corts had learned the craft from master concreteartist Dionico Rodriguez, who had brought his highlyguarded technique from Mexico to Texas in the 1920s.Rodriguez called his workcreating concrete elementsthat look remarkably like wood trabajo rustico or rustic

work. Maximo Corts worked together with Rodriguez(who eventually married into the Corts family) on manyprojects throughout San Antonio, including bridges andpalapas in Brackenridge Park. 1

Like his father and great-uncle, Carlos Corts usessimple, handmade tools to replicate wood grain andcreate other organic effects. We might use a fork withbent tines, or use a trowel made of a wide comb, hestated. And when the concrete is cured, we stain it usingnatural mineral salts. 1

For his latest vision in faux bois , Corts wanted toimpart a fairy tale feeling to the project. It looks like a

natural cave, he explains, with stalactites and sedimentary

deposits of minerals, but it also looks very whimsical,with a tall pinnacle toward the center. Ive also created asculpture of Father Nature, with hundreds of seashellscreating his facial features. I used shells to symbolize thatthis part of Texas used to be part of the ocean. 1

Corts and his crew had to approach the 120 ft (36 m)wide and 30 ft (9 m) deep grotto with a differentconstruction method than usual. In most projects, oncewe have the form, we cover it with wet concrete and thendetail it from the top down, Corts said. But because the

grotto was built 2 ft (0.6 m) at a time, the detail work wasdone from the bottom to the top as the project movedalong. 2 The project also included a palapa-style observationarea at street level, featuring a concrete tree shadingrootlike benches. I love doing benches, Cortes said.Im interested in doing work that is functional. 1

R f r c

1. Moffat, L., Web Extra: In the Grotto, Concrete Artist CarlosCorts, Texas Highways, The Travel Magazine of Texas ,www.texashighways.com, accessed May 18, 2009.

2. Goddard, D.R., Artist Carlos Corts creates Faux Bois Tree

and Grotto, San Antonio Express-News , Nov. 22, 2008.

Carlos Corts at work on the River Walk Grotto (Photo courtesy of Mark Menjivar and the San Antonio River Foundation)


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30 August 2009 / C cr r a a

ConstRuCting the RiveR WAlk gRottoThe following photo sequence shows the progression

of the River Walk Grotto project from the initial site workin September 2008 to its completion in May 2009. Over700 yd 3 (535 m 3 ) of sand were used to build the sandform for the grotto. The back of the grotto was entirelywaterproofed with elastomeric waterproofing anddrainage board. Loose gravel behind that creates agiant French drain.

More than 120 individual LED lighting fixtures wereinstalled in the grotto using housings cast into theconcrete. The light levels and the times that individualfixtures are operated can be varied. (All photos are courtesy of

Steve G. Trevio, LEED AP; and Ford, Powell, & Carson Architects &

Planners, Inc., San Antonio, TX.)

In the foreground, the channel wall forms will definethe edge of the River Walk (September 2008)

The retaining wall (background) and grotto columnwere formed in layers using sand (mid-January 2009)

Work on the walls of the grotto continues asthe sand forms rise(late-January 2009)

The form of the grotto roof can be seen in the curvedreinforcing bars and wire mesh (late-January 2009)

Each layer of sand was restrained using geotextile fabric.The sand was simply compacted and no stabilizing agentswere used. The slopes were gentle enough that displace-ment of sand was not an issue (early-February 2009)


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The upper layer of sand served as the form surface for the grotto roof (mid-February 2009)

Here, the sand has been removed, revealing theretaining wall and grotto roof (late-February 2009)

The face of Father Nature takes its initial form (mid-February 2009)

The reinforcing bars for the face of Father Nature seenfrom inside the grotto (mid-February 2009)

Father Nature realized in concrete (April 2009)


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32 August 2009 / C cr r a a

Excavation of the sand has begun and the undersideof the grotto can be seen for the first time (mid-February 2009)

Sand is cleansed from the concrete (late-February 2009)

Sand has been entirely removed and the pinnacle risesfrom its base (late-March 2009)

The pinnacle is complete and shotcrete texture is being applied (late-April 2009)

Concrete artist Carlos Corts (right) and Zachry Construction Superintendent James Summerville pauseto assess the ongoing work (mid-February 2009)


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Texturing iscomplete and finishwork is underway atthe shell canopy (early-May 2009)

Completed shell canopy with shells andstalactites. The stalactites were wire meshhand-formed around reinforcing bars. Thesewere made in the shop and then attached tothe structure and sprayed with concrete

Waterproofing is applied to the grotto pool (early-May 2009)

The River Walk Grotto completed (mid-May 2009)

Natural shells were attached to the steel mesh. Theshells were affixed to reinforcing bars, which were thenwired to the mesh. Concrete was added by hand tocover the steel mesh where they were attached

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