Noida twin towers: All about the demolition and clearing of the debris

Mumbai-based Edifice to bring down Supertech's twin towers (File image of the twin towers)

Demolition experts are preparing to conduct a test explosion of the Supertech twin towers in Noida on April 10.

Moneycontrol’s Vandana Ramnani spoke to Utkarsh Mehta, a partner with Edifice Engineering about how the buildings will be brought down and the debris cleared. Edifice Engineering is the company selected by the Noida Authority and the Central Building Research Institute, Roorkee, to demolish the towers in collaboration with Jet Demolition from South Africa,.

Need for a test blast

The test blast ahead of the demolition of the 40-storeyed Supertech twin towers — Apex and Ceyane — in Noida will be conducted at 2.30 pm on April 10.

The purpose of the test explosion is to optimise the quantity of explosives to be used for the actual demolition on May 22. An estimated 2,500 kg to 4,000 kg of explosives may be required, but the final quantity will be ascertained after the test blast.

Listen: The Moneycontrol Real Estate Show | The World Will Be Watching The Noida Twin Towers Demolition

It is important not to use too many explosives, which will cause debris to disperse all over. Equally, underutilisation of explosives may result in the building not collapsing. The test explosion is needed to optimise and be sure of the exact quantity of explosives to be used.

This test explosion will be conducted on two floors. Columns have been selected in the basement and on the 14th floor. Two to three layers of wired mesh will be wrapped around the columns, filled with explosives. Geo-textile fabric will be laid on the ground to stop debris from dispersing in an uncontrolled manner.

The test explosion will be a 10-minute activity and residents of the surrounding areas won’t have to be evacuated.

Procurement of explosives, test-blast preparations

Edifice Engineering cannot procure the explosives directly, nor can it store them. The explosives will be sourced from a company called Solar Explosives. The explosives will be brought from the factory to a licensed magazine, where it will be stored before being transported to the site in a specialised van.

The company has selected Alpha Enterprises located in Palwal, 100 km from the site, as the authorised magazine for storage of the explosives. The vehicle will leave the magazine at 8 am and will reach the project site at 10:15 am. Experts will charge four to five columns with the explosives. The test blast will occur at 2:30 pm, following which all roads will be opened.

The final blast scheduled for May 22

For the final blast, 14-15 days will be needed to charge the buildings.

The scheduled date of May 22 may change if preparations for the demolition are not complete. The Noida Authority CEO may then be asked to file an affidavit in court, seeking an extension.

The Ceyane tower with 31 floors will be demolished first, followed by the Apex Tower with 32 floors. Each building will collapse floor by floor. Ten levels will act as the primary blast floors and seven as the secondary blast floors. The primary blast floors will have explosives fitted on all columns. In the secondary floors, explosives will be strapped on to 40 percent of the columns.

An ‘exclusion zone’ will be set up in the area on the day of the demolition and all buildings within this zone will be evacuated. The area is likely to remain cordoned off for about five hours on the day.

About 1,500 families living in the vicinity of the twin towers located in Sector 93A, Noida, will be asked to move out for about five hours on the day of the implosion.

The exclusion zone is likely to include the expressway on one side and the Sector 93A Park on another side. It may include ATS Village, Emerald Court, and the road that passes in front of the twin towers.

The zone will be finalised in concurrence with the Noida Authority and police, and residents will be informed through flyers. Only five people, including a blaster, a police officer, and project manager, will remain within the exclusion zone.

The Noida-Greater Noida expressway is likely to be closed for traffic for about half an hour on the day.

The debris

While the buildings will be demolished in 9 seconds, it may take at least three months to remove all the accumulated debris.

The debris may be processed at a construction and demolition waste plant or disposed of in a low-lying area. However, clearing of the debris has not yet been finalised.

Impact on the environment

Dust and noise levels in the area are being monitored on a weekly basis, the amount of waste generated is being logged and daily water consumption is being accounted for. Dust separators have been installed on the site.

The biggest challenge of the demolition will be in containing the dust cloud, which may be difficult. An attempt will be made to mitigate the dust cloud by spraying, but there is no definitive way to contain it. It may take 7-8 minutes to disappear, depending on the velocity of the wind.

The explosives have been used for mining and can also be utilised in civilian areas. The company is looking at ways to contain the vibrations by deploying impact cushions.

The Indian Institute of Technology (IIT) in Chennai has been brought on board to monitor the vibrations. The institute’s services had been used for the demolition of the apartment complexes in Kochi, Kerala, in 2020 as well.

A structural analysis of the surrounding buildings will be conducted and they will be video-graphed to ascertain their existing conditions. Insurance cover of almost Rs 100 crore is being taken in case there is damage to these buildings.

The company will also deploy drones to record the demolition.

The background

Supertech, the builder, will bear the expenses of the demolition. Mehta of Edifice Engineering did not divulge the amount to be spent on the exercise.

The Supreme Court said on August 31, 2021, that the twin towers must be demolished within three months for violating regulations on the minimum distance to be maintained between buildings.