Key points of construction technology control of super high-rise steel structure building(II)

4. Overview of the installation project when the steel structure is installed
The project in this paper is positioned as the east of the central area of a city, and the construction area is located in the downtown area, which has a relatively prosperous environment, dense traffic roads, and a large number of vehicles and pedestrians, and the construction space is small, and there is no place to place steel components, which requires the installation process to be transported with the lifting, reduce the secondary handling of components, and accelerate the installation speed.
The main marks on the main building steel structure are: underground 6 layers, depth -25m, above ground 54 layers, height 239.4m, length 63.5m, width 38.1m, core tube length 34.8m, the widest 19.5m. The steel reinforced concrete structure is mainly used in the outer frame, and the concrete structure is used in the core tube. The total amount of steel used in the main structure and podium structure is about 10000t.
5, in the process of steel column installation need to pay attention to the matters are: (1) the first section of steel column installation is very important, first use the leveling nut to level the column bottom plate. (2) After the installation of the first steel column, correct the plane position, verticality and elevation of the steel column in time. After the adjustment, firmly pad the bottom of the column with steel plate, install the pressure plate on the bottom plate, install the nut, and pull up no less than 3 wind ropes. (3) Install the second steel column, connect the first column with the connecting ear plate, adjust the perpendicularity, cable the wind rope, ensure the stability of the steel column, and then weld the butt weld. The third party inspection is commissioned, and after the weld inspection is qualified, the upper steel column is installed in the same way at a time until the installation of all steel columns is completed. (4) In the construction process, it is required to align the center line of the plane coordinates of the steel column body with the center line of the foundation plane coordinates, and its deviation must be controlled within a range of no more than 5mm. In order to ensure the plumb of the center line of the column length, the perpendicularity measured by the theodolite should be measured in the direction of 90° to ensure that all deviations are within the range required by the specification. (5) When measuring the distance between the center lines of each column, the deviation of its positioning center line should be controlled within a range of no more than 5mm. (6) The stable operating platform is mainly set up in the air joint of the steel column, when the upper and lower sections are opposite, the edge plate and the wing plate should have no dislocation phenomenon, and when the level is used to measure the elevation line of each platform on the same plane, the elevation of each layer should be taken as the benchmark, and the theodolite is mainly used for the measurement and alignment of verticality. (7) When the steel column butt weld, by two symmetrical welding, first bottom, please follow, and then symmetrical welding, notify the dynamic observation and measurement of the steel column perpendicality, when there is a deviation in the welding process to adjust in time to ensure that the steel column perpendicality deviation within the specification requirements. (8) If the wind is too large, the welding quality must be affected, and the welding platform and wind shed must be set up at the welding position to ensure the safety of workers and welding quality. 6. In the process of installation of steel beams and platforms need to pay attention to the following matters: (1) In order to speed up the construction progress, the steel beams are used in series lifting, hoisting and installing 3 layers of steel beams at a time to improve work efficiency. (2) In order to ensure the safety of high-altitude work, all the safety ropes are pulled on the installed steel column, the protective flat net is pulled below, and the facade is stretched and erected to ensure the safety of workers and improve the work efficiency of workers. (3) Check the verticality of the steel column after the steel beam installation is completed, and then install high-strength bolts. After the high-strength bolts are finally screwed, the steel beam is welded. The influence of dynamic tracking on the deformation of the steel column during the welding process is adjusted in time once the deviation exceeding the specification is found to ensure that the installation accuracy of the entire frame structure meets the corresponding specifications.
7. High-strength bolt installation, the connection between the steel beam, the connection between the steel beam and the steel column is designed to be high-strength bolt connection, the specific installation process has the following steps: (1) high-strength bolt approach inspection and storage. It is necessary to ensure the integrity of the factory quality guarantee when accepting the batch of supply from the manufacturer. In the process of transportation and storage, light loading and light unloading can prevent damage to threads. When storing high-strength bolt connection pairs, they should be placed indoors according to the batch number and specification indicated on the packing box, and the stacking should not be too high to prevent rust and dirt. Do not unpack the connection pair before installation and use. (2) The specifications and models of high-strength bolts must meet the relevant specifications, and high-strength bolts must be tested to determine the torque coefficient or recheck the bolt tension, and can be used after passing the random inspection. During the site installation process, the remaining high-strength bolts installed on the same day must be properly kept. During the installation process, the threads shall not be hurt or contaminated with oil, so as to prevent changes in the torsion coefficient from causing unqualified installation of high-strength bolts and failing to meet the design requirements, resulting in quality and safety accidents. (3) Problems to be paid attention to in the high-strength bolt fastening procedure and construction process: When installing high-strength bolts, the bolts should be freely inserted into the hole, not forced knocking, not gas cutting reaming. The direction of penetration must be the same, and the temporary installation bolts cannot be replaced by high-strength bolts. When installing high-strength bolts, they must be screwed in a certain sequence, tightened outward from the center of the bolt group, and completed on the same day. (4) When installing high-strength bolts, iron filings, floating rust and other dirt on the friction surface should be completely removed to ensure the contact area of the contact surface of the steel plate, meet the connection friction force, and ensure the safety and reliability of the structural connection.
Third, high-rise steel structure processing and installation experience
Through the construction of this project, we summarized a lot of experience in processing, installation and other aspects, prepared a special construction technology, the program first, in strict accordance with the construction plan and process operation, to ensure the quality of the project, for the future high-rise and super high-rise steel structure construction to lay a good foundation.
peroration
Because the height and span of the super high-rise building determine the development level of the construction industry in a country, in recent years, our country has gradually participated in the competition of the super high-rise building height. As far as the current situation is concerned, the application ratio of steel structure in super high-rise buildings is 70% to 80%, which is a relatively high proportion, and the development direction of China’s future construction industry is determined by the application of light steel structure, large-span space steel structure and high-rise heavy steel structure.