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Is your apartment really earthquake resistant? Here is what you should know

India doesn’t have a definition of earthquake-resistance buildings and higher safety levels do not exist but there are a few steps you can take to ensure that the home you are buying is the sturdiest possible. 
Nov 7, 2020 / 09:27 AM IST

Ajay Sharma, an IT professional, finally found his dream house. It met the requirements of his family, the location was perfect and the biggest of it all—it was within his budget, thanks to the discounts being offered. But then the fine print in the developer’s brochure that said the project was earthquake-resistant caught his eye.

Noida, like most of the National Capital Region, is a high-damage risk earthquake zone, also known as earthquake zone 4 or seismic zone 4. Sharma had to look at quake safety as the apartment was on the 22nd floor.

But the problem for the IT professional and millions like him is that India doesn’t have a definition of earthquake-resistant structure even though building collapse and earthquakes are reported regularly. The building design codes and the Real Estate (Regulation and Development) Act, 2016, are silent on it.

In India, most high-rises are built as per local bylaws and the National Building Code that is considered safe to withstand earthquakes. As most of India is located in seismic zones, it is important for builders and authorities to ensure that construction prescribes to earthquake standards, say experts.

Those who claim to build and sell quake-resistant buildings simply mean they have followed standard regulations.

Buildings are expected not to collapse. The building should not have a “pancake collapse”, which means even if “contents” are destroyed, the structure should remain intact so that the building can be rebuilt after being demolished. This will enable the occupants of the building to survive. It is called “collapse prevention” in design term and that is the nearest that India comes to when it comes to quake resistance.

“You will be surprised to learn that India is the only seismic-prone country in the world that does not have a specialised design code for hospitals,” says Sandeep Donald Shah, a structural engineer from Miyamoto India, told Moneycontrol. Miyamoto India advocates better designs for quake engineering.

In other countries, a structural engineer carries out design checks to ensure that the building can withstand a large earthquake. “This is a day’s effort for the structural engineer who uses specialised guidelines to assess building performance,” Shah says.

In India, buildings are sold, leased and rented by just mentioning that the structure is quake-resistant, without specifying the “category of resistance, ie fully operational, immediate occupancy, life safety or collapse prevention”, he said.

The difference between the four categories is so wide that keeping a customer in the dark is a blatant breach of a consumer’s right to be informed and to consumer education, he says.

“There should be strict rules that all buildings, both new and old should have engraved metal plates of size not less than one feet by two feet, mentioning that the building is earthquake resistant, collapse prevention or any other category or ‘earthquake-resistance unknown’,” he says.

Having said that, there is no substitute for due diligence. Buyers should ask questions about structural safety before buying or renting and ensure the earthquake-safety promise is more than a promotion gimmick.

Before booking a flat, a buyer should find out who the structural designer and the soil consultant of the project is.

“An architect is not responsible for the durability and the strength of the structure,” says Abhay Gupta, director at Skeleton Consultants Pvt Ltd.

Dig dirt

Questions about floor area and other amenities can come later. The first thing a buyer should ask a developer is for the soil report of the building. The strength of the foundation is best gauged through the soil report.

It is often observed that builders undertaking small projects do not go for a soil investigation to save money. A developer in Noida was found to have passed off the soil report of the adjacent building.

“Soil investigation for a small project generally costs around Rs 50,000 and Rs 10 lakh for a large apartment block but the test costs less than a percent of the entire project cost. It provides details of the soil’s water table, the foundation, depth among other things,” Gupta says.

If a developer shares the soil report, the buyer can rest assured that the builder has adhered to structural norms.

It should be mandatory to submit structural drawings along with floor plans with the sale deed at the registration office, say experts.

A board or the plate carrying information about a project at the entrance should be a must and carry the names of the architect and the structural designer and the IS code under which the building has been designed.

Do the coding 

Advertisements that claim that a project is earthquake resistant should mention the name of the structural designer, the IS code number and declare that the building has been designed for earthquake zone 4, says Gupta.

As with other products, construction, too, follows the Indian Standard (IS) codes. For instance, IS456 is the code for design of concrete buildings, IS800 for steel buildings and IS1893 is for earthquake-resistant design.

Also,  check the construction quality for which a buyer or a group of them can together hire a structural expert. The cost can vary from Rs 25,000 for a single buyer to around Rs 2 lakh for the entire building.

Regular health check

Generally, concrete buildings have a life of 50 years but considering the quality of materials used, the buildings start rusting within 15 to 25 years.

This is why RERA should call for an examination of the structure of a group housing project after 10 years and then every five years, says Gupta.

Check the minimum column dimension of a building, which should ideally be 300 mm or 1 ft. Buyers should also make sure that floating columns have not been used. What this means is that often there are large columns constructed on the lower floors and another set of columns constructed on the upper floors.

Column design should be continuous and not floating, says Gupta.

Planning, too, should be symmetrical and buyers should ensure that they are not buying into projects that are “architectural fantasies”— large cutouts, buildings with elongated rectangles or protruding features.

Remember IS 16700  

If you are planning to buy into a higher floor make sure that IS code 16700 has been adhered to. It is the code for the safety and construction of buildings that are higher than 50 metre.

If you are buying an apartment above the 20th floor, make sure you get the building movement tested. The wind force is extremely important, especially in the event of an earthquake. During an earthquake a building undergoes lateral movement and that is why loose furniture is often not recommended for higher floors.

Buyers should also check the quality of windows and the first test is to ensure there is no humming sound, say experts.

Remember to tick these boxes as you go house hunting:  

1 Do not shy away from asking questions on earthquake safety from the seller. Written records of the questionnaire sent and responses received should be saved. This will give legal teeth if anything goes wrong.

2. Don’t get confused with statements like “the building has been designed to Zone 5 or Zone 4 standards”. Zones depict the seismic hazard and the earthquake-resistance category talks about the seismic performance of a building.

3. There are four types of earthquake-resistant buildings. Type A— operational, Type B–immediate occupancy, Type C– life safety and Type D–collapse prevention. Type A is the best and Type D the lowest. Occupants need to know which category their building falls in.

4. Almost all buildings in India are designed and constructed under the Category D or “Collapse Prevention” standard. These buildings will get severely damaged and will not be habitable or repairable after an earthquake.

5. A Type B building will typically cost approximately Rs 350 per sq ft more than a Type D building. A Type B building will have minimal structural damage and will be structurally safe to occupy and use even after a major earthquake.
Vandana Ramnani
first published: Nov 7, 2020 09:27 am

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