Analysis of key construction points of steel column and frame beam of high-rise steel structure
1、 Analysis on key points of steel column construction of high-rise steel structure
Steel column is a vertical component that determines the floor height and the total height of the building, and its fabrication and processing needs to meet the corresponding specifications and standards. At the same time, the shrinkage deformation of the weld and the compression deformation caused by the vertical load need to be considered in the process of turning and blanking. Therefore, the turning and blanking length of the steel column is not equal to the design length, even if it is only a few millimeters, it can not be ignored. Moreover, when the sections of the upper and lower steel columns are completely equal, they are not allowed to be interchanged. It is required that each steel column shall be numbered differently and installed in place correctly. The welding of stiffener plate in rectangular or square steel column shall adopt nozzle electroslag welding according to the requirements of current specifications, and other forms such as opening on box plate and slot plug welding are not allowed.
2、 Analysis on key construction points of high-rise steel structure frame beam
In order to ensure that the joint area at the connection between the frame beam and the steel column has good ductility, connection reliability and floor height accuracy, during factory manufacturing, a cantilever beam (short corbel) is set at the position where the frame beam is located. The connection between the upper and lower flanges of the cantilever beam and the steel column adopts cut penetration weld, and the web adopts fillet weld. The frame beam is connected with the cantilever beam (short corbel) of the steel column, the upper and lower flanges are connected by the full penetration weld of the lining plate (also the arc striking plate), and the web is connected by high-strength bolts. Since the allowable deviation of reinforced concrete construction is far greater than the accuracy requirements of steel structure, when the frame beam is connected with reinforced concrete shear wall or reinforced concrete cylinder wall, the connecting plate of web can be opened with elliptical holes, which shall meet the requirements of hole edge distance. The blanking length of frame beam is also not equal to the design length, and the welding shrinkage deformation shall be considered. The welding shrinkage deformation can be calculated by empirical formula, and then checked according to the actual processing, so as to determine the exact length of the turning and blanking. High strength bolt connection or welding connection can be adopted for the connection of the upper and lower flanges of the frame beam. At present, most of them adopt full penetration welding connection with lining plate. During construction, the lower flange shall be welded first, and then the upper flange shall be welded. One end shall be spot welded for positioning, and then the other end shall be welded. The web is connected with high-strength bolts. It is necessary to fully understand whether friction type or pressure bearing type high-strength bolts are used in the design. The friction coefficient of friction type high-strength bolt should be selected reasonably. When using high-strength bolt group connection, the accuracy of hole position is very important. At present, template drilling and multi axis NC drilling are generally used for hole making. The former has low precision and the latter has high precision, so the latter should be given priority. When the formwork is used to make holes, the accuracy of the formwork shall be ensured to ensure the accuracy requirements of the assembly holes of high-strength bolts and site installation holes. In case of local deviation of hole position, reaming with reamer is only allowed. It is strictly prohibited to use gas cutting for hole expansion. If gas cutting is used for hole expansion, it shall be handled as a major quality accident.
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