Supertech towers fall via ‘controlled implosion’ — here’s how it happened – The Indian Express

After much anticipation and a nine-year-long legal battle, the Supertech twin towers of Noida were reduced to rubble on Sunday (August 28). The towers, Ceyane (29 floors) and Apex (32 floors), that are part of the Emerald Court project of Supertech Ltd, were found to be in violation of multiple regulations regarding construction, and were therefore demolished.
The highest structure in India to be demolished, the towers, comprising about 850 flats and located in Sector 93A near the Noida-Greater Noida Expressway, have a height of almost 100 metres — taller than the Qutub Minar. Preparations, from charging the buildings to clearing the area, were in full swing earlier this week. The resident welfare association (RWA) had directed residents of nearby apartment complexes, ATS Greens Village and Emerald Court, to evacuate by Sunday morning. According to the police, Emerald Court has 15 towers and ATS village has around 25 towers and four villas.
The surrounding area of 500 metres radius is marked as an exclusion zone, where no human or animal was allowed except for the members of the team in charge of the demolition. Apart from this, the police, a team of the National Disaster Response Force, eight ambulances and four fire tenders will be deployed at the site.
Supertech was granted approval in 2005 by the New Okhla Industrial Development Authority (NOIDA) to build 14 towers with nine floors each, a shopping complex and a garden area. However, it revised its project in 2009 to include twin high-rise buildings — Apex and Ceyane. Even though the NOIDA authority approved the new plan, the Emerald Court Owners Residents Welfare Association (RWA) moved to the Allahabad High Court in 2012 alleging it was an illegal construction.
In 2014, the Allahabad High Court ruled that the towers were illegal and ordered demolition. The Noida Authority and Supertech approached the Supreme Court challenging this order. On August 31, 2021, the apex court upheld the ruling of the Allahabad High Court and ordered the demolition of the buildings.
The Supreme Court found the construction of the twin towers in violation of the minimum distance requirement.
It said the towers were built without complying with building regulations and fire safety norms.
It said the modification of the plan — removing the garden area to make way for the construction of Apex and Ceyane — was done without the consent of the flat owners, which violated the Uttar Pradesh Apartments Act, 2010.
The top court, in August 2021, while ordering demolition of the illegally constructed towers, said it was built through “acts of collusion between the officers of NOIDA and company”, and sanctioned the prosecution of officials for violation of the Uttar Pradesh Industrial Area Development Act, 1976 and Uttar Pradesh Apartments Act, 2010.
Even though the Court ordered the demolition within three months, multiple delays resulted in setting the final date to August 28.
The Supertech towers will be demolished via a ‘controlled implosion’, which means it will collapse after explosives are strategically placed and detonated to ensure minimal damage to the surroundings. The process behind the implosion includes the gradual weakening of critical supports of the building, i.e., removing the structures that will help resist the gravitational force. This will be achieved by numerous explosives placed within the structure. Usually, the explosives on the lower floors of the structure initiate the controlled collapse of the building.
The technique was used for the first time in 1773 to raze the Holy Trinity Cathedral in Waterford, Ireland, with 68.04 kg of explosives. It was recently used in India in the 2020 demolition of four luxury waterfront apartments in front of Vembanad Lake in Kochi’s Maradu for violating Coastal Regulation Zone regulations. The same technique can be used for the demolitions of bridges, smokestacks, towers, tunnels, and other structures, too.
Mumbai-based Edifice Engineering has partnered with South Africa’s Jet, the same team behind the demolition of the Maradu buildings, to demolish the Supertech towers.
One of the most time taking processes in a controlled implosion is the preparation to place the chemicals. For this demolition, the preparation took nearly seven months, including one month of planning and six months of onsite preparations, said Utkarsh Mehta, CEO of Edifice Engineering.
Around 3,700 kg of explosives have been infused into the two towers. Apex has 11 primary blast floors, where all columns on the floor have explosives, and seven secondary floors, where 60 per cent of the columns will be blasted. Ceyane has 10 primary blast floors.
According to Mehta, the main component used for the explosion is the emulsion that has superior rock crushing quality, generally used underground for heavy blasts and mines. He said they have used a lesser quantity of it in Supertech since the structures don’t require much. Apart from the emulsion, shock tubes that will direct blast waves and simulate actual explosions, and electric and non-electric detonators that will trigger the explosives, are also being used.
The event, which takes around 13 seconds, will leave behind approximately 80,000 tonnes of construction and demolition waste, of which 50,000 to 55,000 tonnes will be used for filling the site and the rest will be sent to a construction and demolition plant for processing.
There are several concerns regarding the demolition of Noida’s Supertech twin towers. The first is the amount of dust the demolition will generate.
The second is the clearing of the debris, even though officials have said the rubble will be cleared within three months.
Third, experts have raised concerns over windblown dust generated in the blast, that can remain in the air for weeks and cause health issues to people in the area. The Noida Authority has said they will provide water tankers, mechanical sweeping machines, and sanitation staff to control the dust menace. Officials have also promised air quality monitoring.
Gaurav Saxena, a resident of the Emerald Court, is leaving Noida for Nainital on Saturday night with his 65-year-old mother as he is worried about the fine particles that may remain in the air. Saxena plans to return to his flat on Monday, but says he and his neighbours are hoping the plastic sheets put up to cover their windows and balconies will protect them. He also hopes rainfall will bring some relief.
Mehta, meanwhile, said, “We are expecting the dust to dissipate in 10 minutes. The moment it does, our team will inspect the site and check whether any explosives are remaining to explode. The settling of the dust is dependent on the wind direction and its strength.”
The impact of dust on the already bad air quality of Noida can’t be ruled out, said Delhi-based environmental activist and co-founder of New Delhi Nature Society, Verhaen Khanna. He said a more scientific method should be used to control the dust other than water spraying.
Another point of worry is the vibration and shockwaves that a demolition of this scale can induce. Mehta says multiple studies by the company predict a travel time of vibrations as 20-34 mm/s. But, on the ground, there will be much less impact, he claims, as the predictions are done without considering the design of the blast. “We call the design a waterfall implosion. The last point of the building hits the ground six to seven seconds after the first point. So, there is no sudden impact on the ground and the vibration will transfer gradually,” he said.
Mehta said the company has assured nearby societies there will be no vibration that can damage any structures, but may cause cracks. He also said officials will monitor the vibrations during the process at various locations to assess the damage.
Residents will be permitted to return to their homes on Sunday evening, hours after the demolition.
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