Why did the twin towers collapse ,when the planes crashed into the top 4 floors?
There is no simple answer to the question of why the Twin Towers collapsed. Engineers, academics and demolition experts have not found agreement on the subject. Oral Buyukozturk, a professor of civil and environmental engineering at MIT and Mark Loizeaux, president of US demolition company Controlled Demolition Incorporated, suspects a combination of factors caused the towers to fall. When the planes hit the towers, they inflicted major damage on the structure of the buildings. As many as 40 vertical columns at the perimeter of each building were knocked out. It’s likely that the impact damaged columns at the core of the building too – preventing people from escaping down stairwells, which were in the core. However, the towers were – initially at least – able to withstand this damage. Indeed, the force with which the planes hit the buildings was 95% of the wind load which they were designed to withstand. What is not known for sure, is how much damage the planes inflicted on the buildin
