Designing and Constructing Earthquake-Resistant Homes: Best Practices

A beautiful apartment with stunning views – this is a dream most of us cherish. This prompts us to invest in apartments on higher levels or floors of high rises. Apart from the allure these tall buildings and towers have for homebuyers, these projects make optimal use of the land availability in major urban centres like Mumbai. According to a recent news report, Mumbai has nearly 77% of skyscrapers in the country with a height of over 150 metres. While this adds beauty to the city skyline, the data also brings concerns about earthquake resistance and structural safety.

Let us take a look at some of the best practices followed by the developers of Mumbai when designing earthquake-resistant buildings and what you should look for while buying an apartment.

Building earthquake-safe and resilient homes

Here are some of the techniques and practices that are commonly used in India to build earthquake-resistant buildings. 

• Focussing on foundation - One of the main focus areas when building earthquake-resistant buildings is creating flexible foundations. Base isolation is a technique most engineers and architects rely on to create a foundation that is capable of absorbing the shockwaves caused by seismic activity and preventing them from ascending to the levels above. This involves creating a pad of rubber, lead, and concrete that acts as a cushion and prevents the quake from affecting the structure. Another method involves creating a sandwich structure with alternating belts of sand and reinforced steel and concrete, allowing the foundation to absorb most of the impact.
• Shock absorption technology - The framework of buildings and towers, which are highly earthquake-resistant, are designed to distribute the shocks and reduce the vibratory impact. In most modern high-rises, specialised shock absorbers, or dampers, are placed on each floor. These are large pistons placed inside cylinders. These cylinders are filled with silicone oil. When an earthquake occurs, the mechanical energy prompts the pistons to push against the oil and the mechanical energy is converted into heat energy, creating hydraulic fluid. This action is similar to that of a piston in a car and its shock absorbers.
• Core walling - Core walling is a system which uses a wall core in the interior of the building and has a ventilated gap between this wall and the cladding. This air gap acts as insulation and buttresses the transfer of shocks, minimising the impact on the structure. Similarly, the use of shear walls in designing a high rise can help prevent the transfer of lateral forces such as seismic shocks and heavy winds. This keeps the building from swaying and sustaining damages during an earthquake.
• Using earthquake-resistant materials – Using earthquake-resistant materials is important. Most modern projects use reinforced steel, wood, and concrete, which offer excellent seismic-resistant properties. Newer innovative materials such as resistant polymers, memory alloys, and flexible bricks are being developed. Apart from these, most developers are using innovative designs such as steel mesh facades to offer increased protection against earthquakes.

Homebuyers' guide to choose earthquake resistant buildings

Unfortunately, despite being largely in the belt with high seismic activity, India does not have a stringent earthquake code for skyscrapers and high-rises. Most homes comply with the National Building Code and local building laws, but no specific earthquake-resistant building codes exist. This makes it important for homebuyers to ask questions and research the techniques used.  

• Invest in apartments and flats built by trusted and reputed builders.
• Ask the developer for the soil test and soil investigation report, which details the type of foundation, materials used, local water table, etc.
• If you are buying into a high rise, look for the Indian Standard Code (IS Code). IS1893 is an earthquake-resistant design. Concrete buildings and steel buildings may have other codes. All buildings above 50 metre height must comply with IS16700.
• It is also a good idea to find out about the structural designer's credentials and find out about the materials used in the construction.

 Investing in a lovely home must also entail being confident of the safety and well-being of your family. This may require asking several questions and making a real estate investment decision only when you are confident of the construction quality.