Research to Action: A low-cost earthquake protection system for Cuba

Imagine putting spheres under your house, so that when the ground shakes, the house can freely roll on the spheres instead of receiving the intense ground shaking. This is essentially what seismic isolation does. Flexible devices placed between the building and its foundation act like shock absorbers (or sliders), allowing it to move independently of the ground’s motion during an earthquake. The current go-to devices work exceptionally well, but at a cost prohibitively high for lower-income countries.

About three million people live in the southeast region of Cuba, an area of high seismic activity. While this is not the most earthquake-prone region in the world, don’t let that fool you. Less frequent earthquakes don't diminish their potential threat. In fact, they are often more dangerous due to a lack of previous experience, hindering updates to construction standards and community awareness, particularly in a region with such population density and limited construction regulations. That's precisely why we're passionately working on a low-cost seismic isolation system using elastomeric spheres, tailored to meet Cuban needs. Yes, we're literally trying to make houses roll on spheres—and it seems to work so far.

That’s also the reason I traveled to southeast Cuba last year. I met with local engineers and government entities to discuss the latest breakthroughs from my Ph.D., unveiling the potential for implementing the sphere isolators by the groups our design aims to reach. As I walked through Cuban cities and towns on my trip, the precarious construction standards of dwellings immediately captured my attention. While high-income countries have the resources to set and enforce design codes, many Cubans have built or improved their houses independently, which led to seismically unsafe constructions. This is understandable when you consider that most individuals have lived on less than $35 a month in recent decades, making adherence to a design code much more difficult. In response, the Cuban Seismological Research Center³ released its "Booklet of Useful Tips to Build Seismic-Resistant Houses by Your Own Means," providing simple guidelines for constructing earthquake-resistant houses.⁴ Nevertheless, the document strongly encourages asking a competent professional for the structural design and supervision. This shows that the construction situation in Cuba is unique.

From the beginning, my research team and I recognized that this low-income setting and the specific needs of the local community would be the driving force in developing the isolation system. In line with this, we organized a workshop during the 2023 Annual Earthquake Engineering Cuban Meeting, in which we brought together the Cuban government, construction companies, engineers, students, and professors. This collaborative environment not only allowed us to share our vision for the seismic isolation system, but also provided a platform for our stakeholders to express their perspectives and concerns, taking an active role in the process. The invaluable feedback during the workshop guided us to refine critical aspects of the system with a focus on its practical constructability and to start planning the final shake-table tests.⁵ For instance, some materials, such as PVC, are difficult to obtain in Cuba and therefore cannot be considered in the construction process. The workshop also revealed that the use of cranes considerably increases the cost of construction, so most elements need to be liftable by human power.

In this upcoming stage, we will construct a model structure in the laboratory and subject it to a series of consecutive earthquakes. This rigorous testing will validate the effectiveness of our isolation system under extreme and realistic conditions. Through the workshop, the significance of our work became even more apparent as we sought to bridge the gaps between our research and the practical needs of those who would benefit—the future users in Cuba. As a structural engineer, being part of this project has been one of the most fulfilling aspects of my career. It has been a long and challenging road, but the promise of safer housing for communities in seismic-prone regions like Cuba will continue to drive our dedication to seeing this project through to implementation.