How are those really tall construction cranes assembled ???
its a truss... they take each piece and attach it... its no hard
I saw one erected once - it was fascinating. They started out with a big mobile crane - then they added piece by piece until they finished it.
I assume you are talking about a tower crane. From a distance, it looks like a T with one side shorter than the other. First, you need a good foundation for the crane to sit on. Next, you have a large mobile crane. With the mobile crane, you construct the tower (metal framing going up), the cab (where the operator sits and the motors), the boom (the mast out front) and the counter-weights (on the side opposite the boom). For the most part, this will get you a tower crane that will be about 200 feet above the ground. Most tower cranes today are self-jumping. Once you are ready to jump the tower crame (i.e. insert another section of the metal frame) there are hyraulics that lift the boom, cap and counterwieghts. This will create a gap in the metal frame. The tower crane will then pick up a section of frame and hoist it up and the ironworkers will slide it into place. The top section will be lowered down onto the new frame piece. The hydraulic jacks then get re-attached higher up to continue the jumping process. That is how you get a crane to build a 50+ soty building. By the way, once the crane is about 700 feet in the air, (if you have the stomach for it), it is a blast to ride out to the end of the boom.
