Post demolition, he said they need to control the dust and debris on site with water sprays.New Delhi: The “extremely robust” nature of the construction of the now-demolished Noida twin towers posed a challenge for the historic demolition, Jet Demolition Director Joe Brinkman told NDTV. He added the Supertech towers were built to withstand a category five earthquake. Jet Demolition was the agency responsible for bringing down the illegal towers.Mr Brinkman said the demolition went off as expected. “Our main objective was to get the buildings down and not cause structural damage to anything around it and we’ve achieved that,” he said.The construction was “extremely strong” and the shear walls, which are difficult to blast anyway, “were full of steel reinforcement, extremely resistant to blasting”, he added.The other challenge was to make sure there were no spillbacks of debris to the residential flats nine meters north of the site. “That worked out very nicely according to plan,” he said.About the “waterfall implosion”, he said that during this event they don’t blast everything at once “and then the whole building sits down with a thump”. It happened in a sequential collapse mode, so it started at one end of the building and the blast worked its way through the building.”So what you want to do is make sure that you get the building to behave the way you want it to, in terms of which way it’s collapsing. How it’s going down to the ground. And then you also want to spread out the impact over time. You don’t want one big thud, you want to have a stream of particles hitting the ground over a period of time,” Mr Brinkman explained.Post demolition, he said they need to control the dust and debris on site with water sprays. “It’s not a huge health hazard,” he said, adding that it’s all-natural materials from the earth which are going to be recycled and put back either to the earth or used in new projects.