Blade

Also known as The Petal Structure, The Concrete Flower.

No. 3 · 1963 / 2003

Blade was Poly Canyon’s inaugural foray into experimental concrete architecture, constructed in 1963 to test the emerging potential of post-tensioning. This technique, which applies compressive force to counteract tensile stress in concrete, enabled daring and elegant designs like Blade's signature petal-shaped structure. The "concrete flower" became a visual and structural feat, showcasing how post-tensioning could support innovative and lightweight forms.

However, its experimental nature came with unforeseen challenges. Rumored to be a favorite scratching post for nearby cattle, the petals endured unexpected upward forces, coupled with the stresses of environmental wear. Over time, these factors led to cracking and structural failure, culminating in the collapse of much of the structure by the late 20th century. Blade remained as a partial and haunting relic of its ambitious origins, with fragments still visible amidst the canyon landscape.

In 2003, a team of Cal Poly students took on the ambitious task of rebuilding Blade, applying lessons learned from the original project alongside modern engineering advancements. The redesign introduced a catenary arch shape, which inherently supports its own weight through compression, significantly improving stability and resistance to wear. Advanced post-tensioning methods and updated materials ensured the structure met contemporary safety and durability standards while honoring the original aesthetic.

The rebuilt Blade preserved the artistic essence of the original while creating a far more resilient structure. The project received national recognition in 2006 with an Award of Excellence from the Post Tensioning Institute, applauding the students' innovative approach to merging historical design with modern engineering.

Today, the Blade stands as an enduring symbol of experimentation and adaptation. Its striking form, blending functionality with sculptural beauty, continues to inspire visitors and serves as a reminder that in the canyon, you always get a second chance.

post-tensioned concrete, catenary arch redesign, structural collapse, sculptural concrete petals, cattle impact, innovative load-bearing, experimental architecture, award-winning rebuild, weather resilience

Photographs