Colombia Earthquake Refocuses Attention on L.A.'s Non-Ductile Concrete Risk

Alpha Structural's Kyle Tourjé says owners of older concrete buildings need to understand how their structures are likely to perform in a major earthquake before determining retrofit scope, cost, and timing.

LOS ANGELES, Sept. 28, 2026 /PRNewswire/ -- More than a decade after Los Angeles adopted its mandatory retrofit program for certain non-ductile concrete buildings, fewer than 15% of affected properties had submitted retrofit plans, according to research published in Earthquake Spectra in July 2026. Researchers found financing was perceived as the greatest barrier, alongside technical, relocation, and governance challenges.

The finding now sits against the backdrop of a magnitude 7.4 earthquake that struck western Colombia in August. A United Nations Development Programme assessment reported that more than 225,000 structures were affected and estimated $13.28 billion in direct physical damage. The scale of the damage offers an example of what can happen when unprepared structures are exposed to severe shaking.

"One of the biggest misconceptions is that more reinforcing steel automatically means better earthquake performance," said Kyle Tourjé, Executive Vice President of Alpha Structural, a California structural engineering and construction firm specializing in foundation repair, seismic retrofitting, and complex structural upgrades. "A building can contain significant amounts of reinforcing steel and still perform poorly."

Older Concrete Buildings Can Fail Under Strong Shaking

A non-ductile concrete building is a reinforced-concrete structure that lacks the seismic detailing needed to deform and dissipate earthquake energy without brittle failure. A ductile structure, by contrast, is designed to flex and absorb strong shaking while maintaining the integrity of critical structural components.

Older concrete buildings may have deficiencies because of horizontal or vertical irregularities in the structural system. They may also have insufficient resilience in concrete elements and connections, including columns, beam-column joints, reinforcement patterns, column and beam confinement, and diaphragms. Tourjé said engineers may also find insufficient lap-splice lengths, where sections of reinforcing steel overlap, or wider spacing of ties and stirrups within columns and beams. "In some older buildings, those components were not designed to handle the intense, cyclic nature of forces we now account for in seismic design," Tourjé said.

Los Angeles Drew a Line at 1977

Los Angeles' retrofit program applies to certain concrete buildings constructed under permit applications submitted before January 13, 1977. The date reflects a period before major seismic-code improvements changed how reinforced-concrete buildings were detailed for earthquake performance.

That does not mean every building from that era will perform poorly. A review may begin with original drawings to understand the structural system, reinforcement patterns, and applicable code at the time of construction. Engineers may then need field investigation because "plans rarely tell the whole story," Tourjé said. "Site investigations, material testing, reinforcement mapping, and selective exploratory work may be needed to understand the structure that is actually there today."

Defining the Retrofit Before the Cost

Non-ductile concrete retrofits can be more complex than programs aimed at a single, well-defined building weakness. A soft-story retrofit, for example, may focus primarily on strengthening one vulnerable level. An older concrete building may require engineers to evaluate how multiple systems and components behave together.

Depending on the deficiencies identified, strengthening may include work on columns, beams, diaphragms, connections, new shear walls, steel bracing, steel/concrete moment frames, or strengthening of other critical structural elements.

The scope does not always require an all-at-once approach. Tourjé said some projects may allow improvements to be prioritized or phased based on the severity of deficiencies, occupancy constraints, available financing, and the owner's broader project goals. The Los Angeles Department of Building and Safety also points property owners to Property Assessed Clean Energy, or PACE, financing as one option for eligible seismic retrofit improvements.

"Owners cannot make informed financial commitments until they understand which deficiencies exist and which solutions are likely to deliver the greatest risk reduction," Tourjé said.

Evaluation Comes Before the Earthquake

Delaying an evaluation can leave owners making structural, financial, and construction decisions under far greater pressure after a damaging event. "Once a potential seismic vulnerability is identified, the most important next step is developing a clear engineering understanding of existing conditions," Tourjé said. "That process helps owners determine the actual level of risk, the scope of potential strengthening, and the options available before a major earthquake forces those decisions."

Meeting compliance requirements, Tourjé emphasized, does not eliminate the structural vulnerability that may already exist. "A deadline is a regulatory milestone. Structural risk is a life-safety issue."

About Alpha Structural, Inc. 

When he saw geological challenges trigger catastrophic building collapses, Dave Tourje, founder of Alpha Structural, Inc., immersed himself in construction repairs and mitigation facing the iconic hillside homes and buildings throughout Los Angeles in the 1980s. He recognized a lack of skilled tradesmen and the need for repairs or upgrades to be engineered and constructed successfully. Today, Alpha Structural is Southern California's premier structural repair and engineering firm. With more than 30 years of experience in foundation repair, hillside stabilization, and seismic retrofitting with challenges of earthquakes, wildfires and landslides, Alpha Structural distinguishes itself by being dual-licensed and authorized by the State of California to both engineer and build in-house—an integration that eliminates miscommunication and cost overruns seen when engineering and construction are handled separately. Alpha Structural is trusted by homeowners, municipalities, and commercial partners alike. For more information visit Alpha Structural.

References:

• Los Angeles Department of Building and Safety. (n.d.). Non-ductile concrete retrofit owner guide. City of Los Angeles. dbs.lacity.gov/sites/default/files/efs/forms/pc17/non-ductile-concrete-retrofit-owner-guide.pdf
• Rhoades, K. R., Liel, A. B., & Dashti, S. (2026). Perceived enablers and barriers of the Los Angeles non-ductile concrete seismic retrofit ordinance. Earthquake Spectra, 42(3), e70100. doi.org/10.1002/esp4.70100
• United Nations Development Programme. (2026, August 28). RAPIDA assessment of Colombia earthquake estimates USD 13.2 billion (COP 42.1 trillion) in structural damage and generated 16.9 million cubic metres of debris. undp.org/latin-america/press-releases/rapida-assessment-colombia-earthquake-estimates-usd-132-billion-cop-421-trillion-structural-damage-and-generated-169

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SOURCE Alpha Structural