【Daily Discussion】Utilities - Civil Engineering - 20210531

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How many methods are there for lifting columns? What is the effect of mast cranes and crawler cranes on the lifting of columns? Answer: Rotation method and sliding method. When using the rotation method to lift a column, the layout of the column’s plane should be such that the binding point, the center of the column foot, and the center of the foundation cup lie on the same arc; on this arc with a radius equal to the lifting radius R, the column foot should be positioned near the foundation. In this way, the lifting radius remains unchanged during lifting, with the boom rising and the hook rotating simultaneously. Before the column is erected, its base remains stationary, while the top of the column gradually rises as the crane rotates and the hook ascends, thereby verticalizing the column at its base position. Then, lift the column about 20–30 centimeters off the ground, rotate the boom to raise the column above the cup’s opening, and insert it into that opening. Using the rotation method, the column experiences minimal vibration and high productivity. Note: When lifting a column using the rotation method, the boom elevation angle remains unchanged, and the position of the crane does not change. Only the boom is rotated while the hook is raised; the position of the column base remains fixed during this rotation process. Features: The columns experience less vibration and offer high production efficiency, but they require high mobility from the crane, and their arrangement takes up a large amount of space. This method is often used when crawler cranes are employed. When lifting columns using the sliding method, the planar arrangement of the columns should be such that the binding point and the center of the foundation cup lie on the same arc; on the arc with a radius of R (the lifting radius), the binding point should be located closer to the foundation cup. In this way, when lifting the column, the boom remains stationary while the hook rises, causing the top of the column to move upward; the base of the column slides along the ground toward the foundation until the column is vertical. Then, the boom rotates, lifting the column above the socket of the column foundation, and it is inserted into the socket. With this lifting method, the column experiences vibrations as its base slides; therefore, protective measures must be taken for the column base prior to lifting. This method is suitable for use when the flag rotation method cannot be applied. Features of the sliding method for lifting columns: During the sliding process, the column is subjected to vibrations, but it requires less mobility from the crane (the crane only raises its hook, without rotating the boom). This method is often used when lifting columns using a single-leg pole or a human-assisted pole. We welcome active participation in discussions; the system offers generous rewards for answering questions from VIP members! ! !