Tower cranes are ubiquitous in big cities. The only way to construct tall buildings, there are the sign of a prosperous city when there are lots of them. They can be a nuisance when you are taking photos of a skyline of course since they interrupt the flow of a cityscape. You seen them all the time but you don’t often get to see how one is assembled. When we were watching the tower construction across from our building in Chicago, we got to see the cranes being put together.
The first thing that is needed is a big crane! Got to have a crane to make a crane! The base was put in place and then the cab was lifted into place. From this, the elements of both booms were lifted and attached. Then the counterbalance weights could be added along with the machinery to do the lifting work. It was fun to watch it all go together and to see the guys walking around on the structure once it was in place including all of the bracing elements. Once the crane is complete, there is a sleeve section that allows the inner section to be slide up and a new section to be inserted.
Two cranes were built for this project. They were both within the footprint of the building so it grew around them and they grew above it. There was never terribly much of the crane exposed above the building so it was well supported. One of the crane operators on this project used to take his camera up. He had a great selection of images from up there with all sorts of things going on a round him and some incredibly variable weather. I will have to see whether those images are still available online.