Noida twin-tower demolition: Implosion to take just 9 seconds

Up to four tonnes of explosives could be used to raze down the illegal Supertech twin towers in Noida and the implosion of the nearly 100-metre tall structures on May 22 would take just nine seconds, according to officials.

Also, around 1,500 families living in close vicinity to the towers located in sector 93A would be moved out of their homes for around five hours when the implosion takes place at 2.30 pm on May 22, they said.

A stretch of the Noida-Greater Noida Expressway close to the site would also be shut for traffic for an hour, while security personnel would be deployed in the area in large numbers on the day, according to the demolition plan shared by Edifice Engineering, the company which has been handed the job.

The Supreme Court had ordered the demolition of Supertech's Apex (100 metre) and Ceyane (97 metre) on August 31 last year as the twin towers had come up in violation of building norms.

The top court had also rapped the local Noida Authority for approval of the project under its watch.

Sharing a presentation with media on Monday, Utkarsh Mehta, partner at Edifice, said Ceyane (31 floors) will collapse to the ground first followed by Apex (32 floors).

The building will fall inwards in multiple stages, floor by floor. Ten levels will act as primary blast floors and seven as secondary blast floors. The primary blast floors will have explosives in all columns. In the secondary floors, explosives will be in 40 per cent of the columns, Mehta said, explaining the technical aspects of the process.

The company had previously demolished the 108-metre tall Bank of Lisbon in Johannesburg, South Africa in 2019 with an implosion.

The gap between the structure and an adjoining building there was around seven metres, while in Noida the space is around nine metres, according to officials.

South Africa-based Jet Demolition is providing expertise on the blast for safe implosion and a trial blast would take place ahead of the actual implosion.

"Explosives between 2,500 kg and 4,000kg will be required. A test blast has been planned in the last week of March or the first week of April to optimise the use of explosive vis- -vis safety measures, Mehta said.

While the actual implosion would take only nine seconds for the towers to be razed, the ground work preparation is already underway.

This includes removal of structures like electrical fittings, plumbing items, doors and windows. Walls are also being demolished to reduce the amount of rubble the implosion would create.

He said the company is also preparing two to three layers of wired mesh around columns which would be filled with explosives and laying 'geo-textile fabric' on the ground to stop debris from flying off in an uncontrolled manner.

The implosion, he said, would induce a pull away from the premises of Emerald Court, the group housing society where 600 families live and on which the twin towers are located.

According to Noida Authority officials, experts will examine Emerald Court and the buildings in the vicinity for damage assessment after the implosions.

They said locals have been assured of no damage to other buildings due to the implosions and in case of any damage, there will be an insurance cover.

The specially-prepared cushions on the ground would reduce the impact of rubble falling on it and minimize vibrations.

Residents from the exclusion zone (the blast radius) will be asked to move out at least three hours ahead of the implosion and they can return at least two hours after the action.

The exclusion zone includes entire Emerald Court, nearby ATS Greens Village and parts of Parsavnath Prestige, a park and the road in the front of the towers as well as a portion of the Noida Expressway.

Traffic on the expressway would be stopped for an hour, even as security personnel, including police, would be deployed in the area.

"We will need people to evacuate the entire area during the implosion. We have given a report in this regard to the Noida Authority, but a final evacuation zone will be decided in consultation with the police," Mehta said.

"At the time of the blast, only five persons two foreign experts, one police personnel, one blaster, and the Edifice project manager, will be present in the exclusion zone to execute the demolition," Mehta added.