Venezuela Earthquakes Spotlight Seismic Design, Retrofits, and Base Isolation for Safer Buildings

In this interview, Raffaele De Risi, associate professor in civil engineering at the University of Bristol, explains why Venezuela’s back-to-back earthquakes led to widespread building collapses and what this reveals about building design, codes, and retrofit strategies. The Conversation highlights how multiple factors, from construction age and maintenance to local soil amplification and proximity to the quake source, combine to shape outcomes. It also discusses practical approaches to reducing risk in seismic zones, including enforcing modern building codes and strengthening existing stock, as well as keeping hospitals and critical infrastructure operational with advanced solutions such as base isolation.

• Venezuela is in an active seismic zone and collapses result from multiple interacting factors
• The importance of enforcing up-to-date building codes for new construction
• Seismic retrofitting and strengthening for existing buildings is essential
• Base isolation and other strategies help critical facilities stay operational after earthquakes

Overview and context

The Conversation interview with Raffaele De Risi centers on the large-scale devastation in Venezuela following powerful earthquakes. It explains that Venezuela’s location in an active seismic zone, combined with factors such as the age and type of buildings, maintenance levels, local soil conditions, and proximity to the quake source, contributed to extensive damage including pancake collapses. The piece emphasizes that there is rarely a single cause; rather, a combination of conditions leads to the observed outcomes.

Key drivers of building performance

De Risi notes that modern seismic building codes are effective when properly enforced, particularly for new construction. However, much of the world’s building stock predates current codes, which have evolved as scientific understanding has advanced. The assessment of risk is therefore twofold: ensure new builds comply with robust standards and address the existing stock through retrofitting and strengthening. Ground conditions, such as soil amplification, and the shallow nature of the main and aftershocks further amplified damage in many structures.

Strategies to reduce risk

The discussion highlights several approaches to mitigating seismic risk. For new construction, the enforcement of modern seismic building codes is central. For existing stock, seismic retrofitting and strengthening are essential because rebuilding everything is not feasible. For strategic facilities like hospitals and power plants, modern solutions such as base isolation can keep them not only standing but operational, a capability demonstrated by recent earthquakes in various regions.

Retrofitting and targeted strengthening

Retrofitting techniques vary by building type (reinforced concrete, steel, masonry). Broadly, retrofits aim to increase strength and stiffness or to reduce the forces the structure must withstand, for example through base isolation or energy dissipation devices. A bespoke assessment is essential before intervention, supported by surveys, material testing, and structural models to pinpoint weaknesses rather than applying generic fixes.

Pancake collapses and prevention

A pancake collapse occurs when vertical support columns fail, causing upper floors to drop onto each other. Older buildings are particularly prone to brittle failure. The preventive engineering principle, capacity design, anticipates where a structure will dissipate damage, typically in the beams, while columns and joints are designed to remain intact. This approach aligns with capacity design philosophy in modern building codes and helps prevent catastrophic multi-story collapse.

Post‑earthquake safety and decision making

When damage is substantial but does not cause collapse, post‑earthquake assessments determine whether a building can be repaired or must be demolished. Rapid inspections classify buildings for immediate use, restricted access, or unsafe entry. A subsequent detailed engineering assessment evaluates residual capacity and repair feasibility. The Christchurch example in New Zealand illustrates a common outcome after major earthquakes: extensive demolition occurs to restore safety, not as a failure but as a deliberate risk-reduction strategy, allowing life safety to take precedence over preserving every structure.

Takeaways

The article reinforces a design philosophy that prioritizes life safety and resilience. Modern building codes, when enforced, and carefully planned retrofits can significantly reduce collapse risk and maintain essential services after seismic events. The broader lesson is that the built environment must evolve with scientific understanding and that protecting life often requires difficult but prudent decisions about repair and rebuilding after disasters.