Three mistakes that led to Shahberi building collapse in Greater Noida
An exodus of sorts is happening in Shahberi with residents preferring to move out rather than take a chance with their lives. Experts attribute these primarily to three cost-cutting measures.Updated: Aug 16, 2018 05:34 IST
Hindustan Times, Noida
The twin building collapse on July 17 in Greater Noida’s Shahberi that killed nine persons was a tragedy that also served as a wake-up call for builders, residents and the authorities. In the days that followed, many more buildings, most of them built illegally, collapsed or are near collapse in Greater Noida villages, prodding the authorities to look into reasons why they are crashing like Jenga blocks.
An exodus of sorts is happening in Shahberi with residents preferring to move out rather than take a chance with their lives. Experts attribute these primarily to three cost-cutting measures.
Divya Kush, president of Indian Institute of Architects (IIA), said, “Cost-cutting is always done in what is not visible, as what is visible, sells. Unfortunately, what is not visible, such as structural stability, is most important and all buyers needs to understand this.” Kush said the basic structure of a building is not visible and hence, more money is spent on fittings to make the finish more appealing to buyers.
He said the approximate going rate for a building of sound construction is about Rs 2,000 per square ft, excluding land cost. Of this, the cost on the building structure should be Rs 1,100-1,200 per square ft, and the rest on fittings and finishing. However, small-time developers are ready to sell flats for as little as Rs 1,000-1,500 per square ft in the NCR.
Experts said cost-cutting becomes imperative in such cases and developers get away with it as unauthorised buildings have no quality checks. All construction needs to follow the guidelines of the National Building Code (NBC), 2016, prepared by the Bureau of Indian Standards (BIS), based on which many states also have framed their own rules. However, there are three crucial areas where a builder should not cut corners. HT explores each of them in detail.
Apart from big infrastructure and commercial projects and some high-end housing projects, most constructions invariably do not have a soil investigation report. The test is done to check the load-bearing capacity of a construction and determine the size and type of the foundation on which the building can stand.
“There are different kinds of foundations for different kinds of soil. There are also different kinds of foundations based on dead load, live load, wind, vibration, temperature, etc., and all these are determined by the soil investigation before starting construction,” Sanjay Pant, civil engineering department head of BIS, said. He also headed the committee that revised the NBC.
Based on this, borewells are dug to check the kind of construction and design specifications required for the area. Investigation cost is nominal at Rs 15,000-20,000 per borewell. Based on the topography, a one acre plot for a house may need one or two borewells, whereas for bigger projects such as a Metro line, an investigation is done for every pillar. “A multi-storey building is possible in a desert or even in the middle of the sea as long as proper soil investigation is done. However, that is the first casualty of most construction projects,” Kush said.
Design is the real foundation of every building, according to engineers. All experts agree that the right design ensures strength and quality. Structural engineers and architects conduct soil investigation and prepare the design for a building. Most small-time builders do not employ architects or structural engineers.
Kush said, “Builders don’t realize that the job of an engineer or an architect is much more than making a map and getting it approved. The map is based on very specific design principles that ensure the life of a building.”
The design for a building mentions where the load should lie, how many floors and in what manner it can be built. However, in unauthorised constructions or cheaper flats made without required permissions, the map or layout does not follow any design guidelines. Most often, the layout only shows the total space divided into rooms.
“We went to Shahberi last week to see the construction and realised that no design was followed. The buildings are weak and were made with no consideration of topography,” Charan Bhandari, an independent structural engineer, said.
He added that the stilt parking pillars for most buildings are so thin that they are bound to collapse. Additionally, the foundation strength is just about 30%-40% of what is required in the area. “Only buildings next to each other, possibly sharing a wall — we saw a few such in Shahberi— will survive a little longer as the walls support each other. But all building erected in isolation have very thin stilt parking pillars. That is why some buildings are tilting,” Bhandari said.
According to Pant, the life of a building depends mostly on the skill of the structural engineer and one should not pinch money in this area.
The Council of Architects (COA) mentions 5% of the construction cost as the fee of the architect. However, in most cases, it is negotiated to a lower share. Some developers also use junior engineers and architects and pay them 0.5%-1% to draw a working map.
When the design is not scientific, the construction quality will suffer. The basic structure of a building requires mortar, brick and reinforced steel bars. Mortar is made of cement, aggregate (small stones or gravel) and sand. The National Building Code, 2016, mentions that the standard ratio for mortar is one part cement, one and a half parts aggregate and three parts sand.
However, builders mostly cut down the quantity as well as quality of cement and steel bars— the two components that cost higher.
“There are 14 kinds of cement, but only a few are best suited for construction. Similar is the case with reinforced bars. Both are very important for safety and therefore require mandatory ISI mark.
However, cheaper cement without ISI marking is used to save money,” Pant said.
To build a strong structure in the plains, one needs at least four or five kilos of TMT steel bars per square ft, which is reduced to about two kilo to cut cost. Similarly, builders save by using low quality cement.
“In some cases, contractors also save on sand and gravel. They buy sand with more mud and less silt content. They also use bigger gravel, while the NBC mentions use of not more than 20mm size aggregate. The final concrete mix becomes weak and doesn’t bind well. The concrete should be M25 grade, but some contractors use as low as M15 grade that was used over 25 years ago,” Bhandari said, adding that good quality workmanship also ensures safety.
First Published: Aug 16, 2018 05:33 IST