Minimising the shakes

In this week's edition of Open House , I shared my thoughts on the student housing market. To read the full editions in your inbox every Wednesday, subscribe for free?on my website (https://ashwinderrsingh.com/ ).

Now that we are almost halfway through the year, I want you to hazard a guess as to how many earthquakes we have witnessed so far in our own country this year. <5? <10? >10? Nope, 678! And these are just the ones above the magnitude of three.

While earthquakes are unpredictable, their impact on life and property is huge. However, it can be significantly mitigated through robust earthquake-resistant construction practices. Today, I’ll talk about the world of seismic engineering and explore how buildings can be designed to withstand these forces of nature.

Global challenge

India isn't alone in facing seismic risks. Countries like Japan, which experiences frequent earthquakes, have become pioneers in earthquake-resistant construction. Following a devastating earthquake in 1923, Japan implemented stricter building codes and innovative engineering techniques. Today, their high-rise buildings can sway and flex during tremors, minimising structural damage. This serves as a powerful testament to the effectiveness of seismic design principles.

Foundation: The bedrock of resistance The first line of defence in any earthquake-resistant building is its foundation. A strong and stable soil thus becomes crucial. If the ground itself is prone to liquefaction (where soil loses its strength and behaves like a liquid during an earthquake), additional steps like ground improvement techniques become necessary. Buildings are then anchored to this foundation using specially designed piers and footings that can absorb and distribute seismic energy.

Flexible strength Moving beyond the foundation, the building's structural design plays a critical role. Imagine a building as a skeleton, the goal is to create a flexible yet robust framework. Here's where materials and design come into play:

• Reinforced concrete (RC): This is a common choice, as concrete offers compressive strength while steel reinforcement provides tensile strength. RC columns and beams are designed to absorb and dissipate seismic energy through controlled cracking.
• Shear walls: These are strategically placed vertical walls made of RC or other materials like masonry. They act as a barrier, transferring lateral forces (those pushing the building sideways during an earthquake) down to the foundation.
• Bracing systems: These are diagonal steel beams that provide additional support against lateral forces, especially in buildings with large open spaces.

Other considerations

While these core principles form the foundation of earthquake-resistant construction, several additional factors contribute to a building's seismic resilience. Non-structural elements like ceilings, partitions, and cladding must also be secured to prevent them from becoming falling hazards during an earthquake. To prepare for the aftereffects, buildings should be designed to ensure critical utilities like water supply and electricity remain functional after an earthquake.

India has also established building codes like the National Building Code of India (NBC) developed by the Bureau of Indian Standards (BIS) that define earthquake-resistant construction practices. Following these codes and ensuring proper enforcement is also crucial.

Seismic safety culture

Earthquake-resistant construction is not just about the technical aspects, it's also about creating a culture of seismic safety which can be done in two major ways:

• Public awareness: Educating the public about earthquake preparedness and the importance of living in earthquake-resistant buildings is essential as sometimes corners might be cut from the customer’s end as well.
• Retrofitting existing structures: Many existing buildings, especially those in older parts of a city, may not be built with earthquake resistance in mind. Retrofitting, or strengthening these structures can then significantly improve their seismic resilience as these are generally the buildings most likely to be affected.

Building a safer India Earthquakes are a natural phenomenon, but their impact on our lives doesn't have to be devastating. By adopting and implementing earthquake-resistant building practices, we can create safer communities and we all have a role to play in it - developers by constructing buildings that meet or exceed seismic codes, homebuyers by inquiring about a building's earthquake resistance before purchase, and investors by supporting projects that prioritise safety. By working together, we can build a future where our structures stand strong, even in the face of tremors.