NOIDA: With the successful demolition of the Supertech twin towers here on Sunday, India has joined the club of countries that have razed buildings taller than 100 metres, Joe Brinkman of South African firm Jet Demolitions said.
The illegal twin towers in Noida's Sector 93A were grounded by waterfall implosion technique in a matter of 12 seconds, Brinkman told reporters.
The Apex (32 storeys) and Ceyane (29 storeys) towers of Supertech had a height of 103 metres each, according to officials.
Mumbai-based Edifice Engineering, which was tasked with the demolition, had selected Jet Demolitions as its expert partner for the job.
The two had together previously demolished four residential complexes in Maradu municipal area of Kochi, Kerala in a similar fashion.
"India and Edifice have now joined the 100-metre club of countries which have buildings over this height that have been demolished and that too with residential buildings standing so close to them, making the project extremely challenging," Brinkman, 62, said, heaping praises on the Edifice-Jet team.
"All credit goes to the entire team," he said.
Jet Demolitions holds a distinguished position globally for demolition works.
In November 2019, the firm had grounded the 108-metre-tall Bank of Lisbon building in Johannesburg within a few seconds in an eye-popping event and ensured that a structure barely seven metres next to it was safe too.
Brinkman said the whole process for demolishing the Noida twin towers took 12 seconds.
He said the team's first priority was to ensure that there were no injuries to people during the implosion and no structural damages caused to any of the buildings around.
He added that very few buildings taller than 100 metres have been demolished in a controlled manner across the world.
Edifice Engineering partner Utkarsh Mehta described Brinkman as the "mastermind" of the successful demolition.
Mehta said around 35,000 cubic metres or approximately 80,000 tonnes of debris was left after the demolition.
Around 50,000 tonnes of it has been absorbed in the basements of the now-demolished towers while the remaining would be disposed of in 90 days, he said.
"We will have to coordinate with the Emerald Court and ATS Village societies for the disposal since the debris would have to be first processed at the site only and then it would be taken to construction and demolition waste processing centres."
"Coordination would be needed for fixing the timing for work at the site to cause least disturbance to residents," said Mehta.
Jigar Chheda, another Edifice partner, said they took a full six months to plan the clean execution of the demolition and the whole exercise was a "very challenging" process.
"Days and nights went into the preparation for this day. Over 9,000 holes were drilled for explosives in the two buildings; they had to be most accurate and all this was challenging," Chheda told PTI.
CHECK OUT VISUALS OF THE DEMOLITION HERE
"Getting permission from all authorities concerned, coordinating with multiple agencies, and convincing residents of safety were key effort areas," he said.
Mayur Mehta, project manager for Edifice, said 9,642 holes were drilled and 3,700 kgs of explosives were used for the demolition.
"The types of explosives used were Solar coal, with 6 gm, 10 gm, 20 gm, and 80 gm mass. Electric detonators, shock tubes and emulsions were also used. The tubes were placed in a way that some had a 0.5-millisecond explosion capacity, while others had a 7,000-millisecond capacity," he added.
Edifice officials said nine metres of the boundary wall of ATS Village comprising some 900 bricks was damaged.
Several window panes in Emerald Court, as well as ATS Village, were cracked and they had started the process to replace them with new ones shortly after inspection at the site Sunday evening.
Meanwhile, around 100 families evacuated from residential buildings near the now-demolished Supertech twin towers in Noida returned to their homes till Sunday night.
Over 5,000 people from Emerald Court and ATS Village societies were evacuated before the demolition of the twin towers.
Apex (32 storeys) and Ceyane (29 storeys) were gone in 12 seconds on Sunday, in the carefully choreographed and meticulously executed demolition, the biggest such exercise in the country so far.
People, who returned home, are relieved that their houses are safe.
Aarti Koppula, Bluestone resident and RWA member, said that four towers in the Supertech society haven't received gas supply yet.
"We returned at 9 pm and there is no damage to our houses. There is just a foul smell in the basement of our buildings most likely of the explosives."
"They have been informed that the gas supply will be restored by tomorrow. Rest is alright. There is no damage at all," Koppula told PTI.
There was the deployment of police to ensure safe passage to people.
Police have barricaded the area around the collapsed building.
Meanwhile, even after several hours of the explosion, people gathered near the demolished towers and were seen taking selfies with the rubbles.
Meet the daredevils behind the operations
Supertech's illegal twin towers were razed to the ground in a matter of just 12 seconds on Sunday in Noida and seven people -- three Indians and four foreigners -- were the only persons inside a 100-metre radius during the demolition.
As was expected, the demolition left behind a whopping mound of debris and a cloud of dust in close vicinity of the structures located in Sector 93A of Noida.
An exclusion zone of roughly 500 metres from the twin towers was created for the demolition.
No human, vehicle or animal was allowed in that exclusion zone while around 5,000 residents of nearby Emerald Court and ATS village societies were also evacuated.
Only seven people were present inside the exclusion zone to trigger the button that set off over 3,700 kg of explosives in a series of blasts separated by microseconds.
Those present inside the exclusion zone were Indian blaster Chetan Dutta, who pressed the button, Mayur Mehta, the project manager for Edifice Engineering, and IPS officer Rajesh S, who is also the local deputy commissioner of police.
Besides them, four members of Jet Demolitions -- Joe Brinkkman, Marthinus Botha, Kevin Smit and Ian Ehlers -- were present there.
The detonation team was stationed about 100 metres close to the 50-acre city park in front of the twin towers.
The final evacuation clearance came around 12.30 pm and the demolition took place at 2.30 pm.