For starters, because the economic steel structure column hoisting force and application force is different, therefore the operation of the hoisting check calculation is very much necessary. As you may know, when the lifting force of steel structure frame is different from that of application, the choice of lifting point should accord with the criterion of minimum moment of hoisting, so as not to destroy the lifting moment. If, in this case, according to the criterion of minimum lifting moment, it is confirmed that the relative value of the positive moment in the span is the same as the negative moment at the suspension point when the distance between the lifting point and the top of the cylinder is 3.5 m. When the distance between the original lifting point and the top of the column is 2m, the maximum moment section is 4.8 m from the foot of the column. Thus it can be seen that the central positive moment of the original lifting point span is 1.88 times larger than that of the lifting point span which is confirmed by the criterion of minimum hoisting moment. A large crack appeared in the column at 4.8 m from the foot of the column, and the cause of fracture occurred, which also confirmed the maximum lifting moment at the section of the steel structure frame. So When the lifting force of steel structure frame is different from the applied force, the choice of the lifting point should accord with the request of applying the force as far as possible, for example, the two lifting points of the simply supported beam should be close to the two ends of the beam, and the two hanging points of the cantilever beam should be at the two supports of the beam. If the steel structure frame is not satisfied with the bending strength and crack resistance after hoisting and checking, the first thinking is to consider the inverted lifting. In this case, the bending strength and crack resistance can be satisfied when the overturning suspension is used, and if the inverted lifting is still not satisfactory, the lifting points may be increased, and the small half hoisting can be changed to two points to reduce the lifting bending moment, or to take temporary measures to add the length of the crane is also recommended.
All in all, in order to facilitate the position, in order to ensure that the steel structure frame is hoisted and secured, the key line of the hoisting hook should be directed at the center of gravity of the component when the member is bound. The steel structure frame degree should distinguish between two hoisting ropes when hoisting the steel structure at two points. And the components of the equal section should be separated from each other. The internal and external symmetry of the two suspension points and the difference in the length of the two ropes are also requested.