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In this interview, Professor Raúl Alvarez Medel, a structural engineer at the Pontifical Catholic University of Chile, explains the science behind the construction of resilient structures capable of withstanding seismic shocks. As Chile's representative to the International Platform for Reducing Earthquake Disaster, Prof. Alvarez Medel has been working with UNESCO to promote the advancement of international knowledge related to seismology and earthquake engineering to strengthen building codes worldwide. 

Hello! My fascination with buildings, designs, and engineering began in my childhood. From a young age, my mother, who was a teacher, introduced me to the wonders of structures, bridges, and mathematics. She would read with me, write with me, and play mathematical games. 

My mind was always occupied with mathematical concepts - whole numbers, fractions, everything. I developed a love for subjects like chemistry, physics, and maths. 

On the other hand, my father was an artist. He loved shapes and lights. He was a photographer, painter, and a writer. I think I managed to merge both these influences. I saw the beauty in combining mathematics and art. 

From as early as 13, I was determined to become a structural engineer, a profession I continue to love after many years. Concurrently, I nurtured a strong affection for the arts and pursued acting. Balancing my daytime job as an engineer with my nighttime passion for acting. 

Nowadays, I no longer have the opportunity to act, but my love for it endures. As a professor at the Pontifical Catholic University of Chile, I use acting techniques into my teaching approach. This strategy has proven effective in maintaining student engagement in class and vivifying even the most mundane topics. Moreover, it's an excellent means to foster dialogue among students. 

When teaching my students, I always start with what they already know. At this point in their studies, they have a solid grasp of individual structural engineering concepts. They can design isolated elements like beams, columns, or slabs, but they often struggle to see how these elements connect to form a comprehensive structure, such as a building. 

I emphasize that understanding this interconnection is the most critical aspect of structural engineering. It's not just about designing isolated elements, but constructing a complete, interconnected body. Just as a body reacts to environmental conditions like wind, a building must be designed to withstand external factors like rain, wind, or earthquakes. If we don't consider these, we risk creating unsafe structures. 

I often use analogies to help illustrate this point. For example, when discussing the importance of a building's foundation, I compare it to human legs. Maintaining balance when pushed is more challenging when standing on one leg than on both. Similarly, a building with a wider foundation offers more stability, much like how a clown's large shoes make it harder for them to lose balance.

The location of a building is another crucial factor, much like how it's more challenging to walk on sand than on solid ground. Constructing a building on soft clay or sand can lead to foundation issues during an earthquake, while building on solid rock ensures more stability. 

We also discuss the concept of ductility, or flexibility, in our structures. Just like flexible plants that bend in the wind and revert to their original position once the wind stops, our buildings need to incorporate this flexibility to resist damage from forces like wind or earthquakes.

In essence, I encourage students to grasp the interconnectedness of concepts and view the entire structure as a body. This is important as it illustrates the importance of constructing safe, flexible structures that can withstand external environmental factors, much like a well-adapted organism in nature. 

Absolutely, the selection of construction materials is crucial, especially when we're dealing with regions that are prone to earthquakes, like Chile. In our experience, for larger structures, we tend to lean towards steel or reinforced concrete because it provides the perfect balance of strength and flexibility. When it comes to smaller structures, we opt for masonry, mainly due to its cost, robust nature and durability. 

Now, a key part of our process is evaluating how these materials will perform in the event of an earthquake. Our main goal here is to mitigate the impact as much as possible. Materials such as reinforced concrete and steel have the potential to have very good resistance, and at the same time be very ductile, so they can better withstand large earthquakes. However, other materials, such as confined masonry, may not offer the same level of performance, so they are used in lower structures. 

It's worth noting that certain materials, take glass for instance, can become quite hazardous during earthquakes due to their fragility and lack of energy dissipation. On the flip side, a structure made of steel or reinforced concrete has the ability to gradually deform, thereby providing sufficient time for evacuation. So, you see, the choice of materials can really make a huge difference in construction and design, especially in earthquake-prone areas. 

When an earthquake occurs, it transfers energy into a building through the ground. This energy needs to be dissipated, and how is it released? Through destruction. The breakdown of the building's components, like beams, columns, slabs, walls, and the structure, releases this energy, much like how the breakdown of glucose in our body releases energy when we're hungry. 

Buildings that are poorly designed or composed of substandard materials can collapse under this energy, leading to possible fatalities. As structural engineers, we aim to prevent building collapse during earthquakes by designing for strategic damage, prioritizing the sequence of destruction of some elements over others. This is complemented by ductile connections that deform gradually, allowing for evacuation. 

It is like a car crash: the car deforms to protect you, and though it might be destroyed, you survive. While this approach may result in extensive structural damage, it's acceptable as it prioritizes human lives. 

Recently, our philosophy has been shifting. We've discovered that by strategically placing certain devices in some places of the structure, we can filter or dissipate the earthquake's energy through means other than destruction. For example, incorporating seismic isolators or hydraulic jack in a building can filter or release the energy entering the building as heat and thus decrease the energy the building is directly exposed to. These methods are more efficient and less destructive. 

A significant obstacle in my field of work is the insufficient dissemination of critical information. Imagine if doctors didn't inform their patients about the existence of life-saving antibiotics; the consequences could be fatal. Similarly, many homeowners, unaware of seismic protection designs and technology, purchase houses without these in high-risk areas. It's akin to buying a car without brakes or airbags. Promoting knowledge of seismic protection is as such crucial, not only for constructors and structural engineers, but also for the general public. 

This is crucial given the indiscriminate nature of earthquakes. They affect everyone, and their impact on areas with weak infrastructure can be catastrophic.  

I often see homes built with materials typically used for earthquake-safe structures, like reinforced concrete and steel. However, due to a lack of knowledge, these materials are often applied incorrectly. This results in vulnerable structures susceptible to significant damage during earthquakes.  

By spreading essential structural engineering knowledge, we can lower this risk and help in constructing safer buildings with little to no additional costs.