In 2018 alone, more than 14,500 earthquakes of magnitude >4.0 rocked the world causing extensive damage to life and property. While India has been a relatively stable region, scientists now state that there could be an increase in higher magnitude earthquakes in the future. It only makes sense to ensure that you are as safe as can be in these unstable times. One of the ways to do that is to ensure your property follows the National Building Code (NBC) and is structurally capable to withstand a natural disaster.
What is the National Building Code?
India has standards and regulations in place that if followed will ensure that buildings remain safe in the event of an earthquake. In India, the National Building Code of India sets the guidelines for building activities. These govern the design, construction, alteration and maintenance of structures.
Why is it important to check if NBC is followed?
An earthquake of similar magnitude in Tokyo will cause lesser damage than on in Delhi. Most of the damage caused by natural disasters is because of poor building design and unsafe construction practices. Japan has some of the strictest regulations around construction. India – not so much. According to the Centre for Science and Environment (CSE) almost 80% of the buildings violate NBC guidelines. A survey by the National Disaster Management Authority (NDMA) found that more than 25,000 human fatalities were caused primarily by collapse of buildings during earthquakes! That is a lot of lives lost.
Rapid urbanization in India has resulted in poor urban planning and now we are burdened with unplanned construction that is a death trap in the waiting. Ductile materials, robust design, and strategic construction are vital to create homes and buildings that are safe havens for everyone.
Building guidelines must take in to consideration the geography and the types of disasters that the area is prone to. For instance, for earthquake prone zones building structure must be more flexible and symmetrical on horizontal and vertical axes. The foundations must be able to withstand the side-to-side movement that happens during an earthquake. In tsunami prone areas the buildings need to survive high waves, so a hydro-dynamically shaped structure is more suitable.
Builders also need to check and address the potential of soil liquefaction to avoid tilting and cracking in the event of a flood or landslide. In areas near the sea or rivers the construction site must be at the distance of at least 250mts from the bank. A drainage system will help avoid flooding during high tides or rise in water levels. The construction materials also play a big role.
What are some of the stipulations under the NBC?
As per the building code of India, workmanship and the materials used in construction should confirm to the Bureau of Indian Standards specification. NBC stipulates structural loading and design and construction codes relating to wind load, earthquake resistant design of buildings, steel design and foundations. Here are some of the principles of the code:
- Buildings must have a safety certification issued by architects and structural engineers that should be periodically renewed.
- Two stage permits are needed for high rise buildings and special buildings
- Special provisions must be followed for hilly areas and low-income housing projects. If the house is in seismic zone II, III, IV or V, additional safety measures must be followed.
- Tall overhead tanks and heavy reinforced concrete slanting roofs should be avoided
- Light-weight and prefabricated building materials should be used
- Openings should be properly designed to balance brick and concrete load
- The plan should be symmetric – possibly rectangular to balance the load
- Long cantilever and heavy suspended parts should be avoided inside buildings
- Steel should be used in columns and beams to create a stable foundation and a ductile structure
India has out in place seismic codes covering a variety of structures. However, there is precious little done to ensure these codes are followed. The need of the hour is a robust mechanism to enforce these design code provisions in actual construction. If you are buying a house, do check for these certifications to ensure your property meets these guidelines and can keep you safe.