A crane (a big lift in a building) who knows.
The height of the tower is in the column of the tower, with an oil pressure jack, which is used as a climb. When the building is covered by a layer, the height has to reach the tower, and the climb is done. Fixed tower crane tower crane engineer will screw loosening, jack, will cranes rise about one meter, then pillar fixed on the structure of the building, and then narrowed jack and will be at the bottom of the fixed on the building structure, and loosen the upper screw, hold up a jack, rose again one meter, so repeatedly, backwards, a stretched to the desired height, then pillar is fixed. To dismantle the tower crane, when building was completed in tower crane to a small crane onto the roof, then, is the contraction of jack will tower crane fell to the roof, and then decomposed into several segments, with a small crane, then small crane break down into smaller components, take the elevator down. When the tower is removed, the ground will be filled with the structure of the tower crane. There is another way is to own a jack will pillar elongation, reoccupy lets own boom lift a scape in, puckering up jack again, and so the scape is getting longer.
The crane boom can stand up or flat It will be flat when it is lengthened and it will be ready when it is put up.
That should be called tower crane, which is similar to jacking. Below the cab has a thicker than every other segment is, that a top up first, and then under loading section of the tower, tall again, into a again, and so on
Tower crane beam and the stents cross which is below the control room, is a structure similar to the casing, connected to the beam size is greater than the support structure of steel column, is set on columns. Usually below the casing structure, there will be a circle of platforms for workers to stand. In the lower part of the casing, the casing is fixed to the bottom of the casing, not only the connection between the two structures, but also the upward support. In other words, the top of the pillar is not supported. The pillar is made up of a section of steel, which is connected by a large riveting, which is a section of a steel component of 45 degrees. And casing structure usually has section 2.5 is so high, but the connection is only lies in the following section, so the casing can rise to the most in the previous section, and will not rise to stable. When the casing up to the top section, in the bottom of the casing and pillar top there is more than a quarter of the space between, then, can lift the new section, and placed it in the space. The new section, which is neither heavy nor connected, holds it to the top of the pillar. And then the casing can keep going up. Actually this new section is on the rise before hanging up, and there at the bottom of the casing structure, equipped with two slide rail, a new section can hang in the above, when the space is enough, a worker can take it advance along the slide rail. The casing and its connected beams are also heavy,
