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California's Largest Carbon Fiber Retaining Wall Repair Project.

Updated: Jun 24

Nestled against the scenic Tachevah Canyon in Palm Springs, this case study explores a significant carbon fiber retaining wall repair project, which might be the largest of its kind in California. Spanning 650 feet, the wall supports the lush backyards of six luxury homes, complete with swimming pools, hot tubs, and towering palm trees. The repair plan showcases a pivotal application of modern engineering solutions in a residential setting.

Leaning and tipping and cracked retaining wall in California prior to being repaired
Panoramic View of 650ft Retaining Wall Facing Major Structural Issues in Palm Springs, California

Originally constructed in 1973, the wall began showing signs of severe structural distress, including significant tilting and cracking. These conditions, exacerbated by the growth of large palm trees whose roots added extra pressure, threatened the stability of these deluxe backyards. The situation was further complicated by the added weight and shifting soils due to newly installed pools, hot tubs, and extensive irrigation systems.

Recognizing the urgency of the situation, a collaborative effort between Helfrich Associates Engineering Consultants, Dalinghaus Construction, and Structural Reinforcement Solutions resulted in a repair plan that utilized both Steel products for support and restraint as well as Carbon Fiber Reinforced Polyment (CFRP) for strengthening and spanning of the sections where the Steel products could not be installed.  There are numerous benefits with the use of CFRP.  It's strength, durability, and corrosion resistance along with carbon fiber's high tensile strength and resistance to environmental factors make it ideal for countering the stresses affecting the wall, including seismic activity—an important consideration in California.

The reinforcement strategy included the integration of tiebacks extending into the soil behind the wall to provide lateral support and restraint for the top of the wall. These tiebacks were strategically placed to secure the wall against the pressures exerted by the soil and potential seismic forces.  The carbon fiber served two purposes, one to strengthen the wall flexurally from top to bottom now that the restraint forces have added and two, to carry the restraint forces between the tiebacks like a waler system. 

It was not possible to install tiebacks along the entire length of the wall due to the multiple pools and their proximity to the wall.  In these areas, CFRP was run horizontally from the tieback locations to carry the loads across these areas.  This approach bolstered the wall against immediate structural threats and ensured long-term resilience, effectively distributing stress and preventing localized failures.

Prior to applying the carbon fiber, the surface of the wall had to be prepared.  This included cleaning and repairing cracks as well as the standard surface preparation required for CFRP to ensure effective adhesion. The carbon fiber was then applied, providing a strength enhancement approximately two times greater than that of a number 5 rebar. This method, being non-invasive, required no extensive drilling or excavation, preserving the wall's integrity and appearance.  

Structural Strengthening and Repair to a large retaining wall in California
California's Largest Carbon Fiber Structural Repair on a Cracked and Leaning Retaining Wall

Carbon fiber reinforcement for retaining walls offers an impressive strength advantage by adding reinforcement to the wall's outer face rather than embedding steel into the wall. When applied externally, this ultra-thin material—less than 1/16 of an inch thick—provides an impressive strength enhancement. This considerable increase in strength arises from how carbon fiber materials distribute tensile forces across the surface of the wall, optimizing structural integrity while maintaining a minimal profile.


unidirectional carbon fiber structurally reinforcing the retaining wall in California
Commercial Grade Carbon Fiber Was Used To Provide aNon-Invasive Surface Mounted Structural Strengthening

The application of carbon fiber is non-invasive compared to traditional methods that involve embedding rebar within the structure. This means there's no need for extensive drilling or excavation, which can disrupt the existing wall structure and surrounding landscape. By adhering directly to the external face of the wall, carbon fiber reinforces the structure without altering its physical integrity. This method not only strengthens the wall significantly but also preserves its appearance and extends its lifespan with minimal disruption.

In this region, known for its clear skies and intense sunlight, the extreme UV radiation levels necessitate special consideration in material choice and protective measures within the reinforcement plan. To address this, it was essential to coat the carbon fiber with a protective layer to shield it from UV radiation and ensure its longevity. This coating not only protects the material but also aids in aesthetically integrating the repairs with the existing structure, maintaining the visual appeal of the residential environment.

The completed project now offers enhanced security and stability, protecting the properties from potential land movement and seismic activity. By employing advanced materials and techniques, this initiative not only preserved the aesthetic and functional aspects of the residents' backyards but also demonstrated the effectiveness of innovative solutions in traditional construction scenarios, marking a significant advancement in the field of structural engineering.

Read More About SRS Retaining Wall Repair Solutions


Explore Past Retaining Wall Projects


Download Past case Studies

Commercial Retaining Wall Reinforcement and Strengthening Case Study
Download PDF • 360KB

School Retaining Wall Strengthening Case Study
Download PDF • 3.82MB

SRS - CFRP Retaining wall Reinfrocement
Download PDF • 659KB

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