Nakagin Capsule Tower construction process
The process of the construction of NCT was very unique. Two concrete core structure was standing at first, then they put 140 capsules one by one, from the bottom to the top.
The structure system is designed as much simple as possible regarding this construction process, as you have to hang each capsules by crane. (Since the site is in Ginza, in the center of Tokyo, there were already so many buildings around and in such high density downtown, you could not keep enough space to stock capsules. So they have transported each capsules every day on trucks.)
The weight of a capsule is about 4.1t and it is connected to the concrete core structure with two blacket on the bottom and four bolts on the top.
With crane, it was not so easy to do with such very simple connection, at first you had to control very precisely a capsule to the right position and to joint at the bottom to the blacket. Then you will slightly turn the capsule up to connect four bolts at the top.
They did not understand the problem because of this process at that time. The problem is: it is not easy to take a given capsule to change, since they put all the capsules from the bottom to the top of the building, you do not have enough space to take that given capsule. It is constructed from the bottom to the top, it should be taken off from the top to the bottom. Hmmmm...not so flexible.
The plumbing is damaged in a long day exposed in the outside around the capsules. But it is difficult to change any given plumbing at NCT, again, with the same reason of construction process.
All the plumbings are put into a frame to consist an 'equipment capsule'. But the shape of the frame is very narrow and they put this equipment capsule to the concrete core structure before than capsules. So it is not possible to take off the equipment capsules without taking off some capsules. Also it is not possible to change plumbings when they are behind some, you cannot reach them.
With these reasons, a feasible way of renovation is not changing capsules one by one but to do it at once, including the change of the equipment system.