The plan was never to demolish due to its cost, in the contrary it was planned that the existing tower shall remain but transformed to a core inside the new plan. Casting around with few modification will cost less than demolishing a complete reinforced concrete monolithic tower. This tower was continuously casted from outside to inside there is no block works, it was done by an American Construction company between 1970-1974 It’s the system we do today for high rise buildings core.