Analysis and summary on how to improve the installation precision of steel structure subject

In the construction industry, with the increasing popularity of the use of steel structure main body, the production, transportation and installation process technology of steel structure main body has received more and more attention, and has also been rapidly developed and continuous improvement. To further improve the production and installation accuracy of the main steel structure and reduce the cost is a topic in front of the main steel structure industry. Regulations and industry standards already have a lot to say about this, requiring every step from parts to completion.

The precision of the steel structure main production size is the basic and prerequisite for ensuring the accuracy of the overall structure size and the smooth installation of the steel structure main body, therefore, It is necessary to accurately grasp such as the straightness and distortion of the steel column, the distance between the connecting hole of the column and the beam and the column bottom plate, the processing accuracy of the connecting hole itself, the straightness of the roof beam and the processing accuracy of the connecting plate of the column and the beam, the position size of the tie rod or the supporting connecting plate on the beam and the column itself, and the position size of the purlin support plate.

At present, the main column of the main body of the steel structure is made of purchased H steel processing or plate assembly. If it is made of ready-made H beam steel, the production precision of the column is easy to control; If it is assembled from a sheet, pay attention to shaping the steel column after assembly and welding to ensure the straightness of the steel column and prevent distortion. Most of the roof beams are herringbone structures, often assembled by 2 or 4 trusses. The roof beam is generally assembled by the manufacturer with the plate, and the web of the beam is often irregular quadriateral, the manufacturer with strong technical ability can accurately grasp the lofting and unloading of the web, while the manufacturer with weak technical ability has deviation in the lofting size of the web. Because the shape size of the roof beam is related to the tightness of the connection between the beam and the column, the size of the web directly affects the shape size of the beam, so it is particularly important. In the design of the main body of the general steel structure, there are often certain arch requirements for the roof beam, whose purpose is to offset the downward deflection of the beam body due to its own and roof load after the overall installation, so that it just reaches the installation size. The height of the arch is determined by the design. In order to ensure the camber degree, the shape and size of the roof beam must be adjusted to a certain extent, from this point of view, the production difficulty of the beam is much greater than the production difficulty of the column.

The outline size of the beam and the connecting plate of the beam end are the key inspection items, the purpose of which is to ensure the overall effect after installation and ensure the tightness between the beam and the column. We have found that there is a wedge gap between the beam and the column after installation, and the large hexagonal head bolt has lost the most important role proposed by the original design, and only bears the supporting role, and there is no friction between the beam and the column. Later, the shear key was added on each column close to the lower side of the beam connecting plate to improve the supporting ability of the roof system, and the practice proved that the effect was very good.

In actual construction, due to a variety of factors between the beam and the column often can not be closely combined, some seem to be combined, but in fact can not meet the requirements, resulting in the relative weakening of the friction between the joint surface. In view of this, when designing the main body of the steel structure, the shear key is added on the cylinder plate close to the lower edge of the beam connecting plate to ensure the column’s supporting ability to the roof. The shear bond is small, but it does a lot.

In order to avoid and reduce the deformation of columns, beams, tie rods and other connectors in the transportation process, the transportation company should be required to increase the support point in the full length range of bundling members, as far as possible between the wood pad, the external bundling should be firm, in order to minimize the deformation of the components due to vibration or heavy pressure during the transportation process; In the loading and unloading to use two points, such as the member is too long, can use the pole and increase the lifting point; When the components are stacked at the installation site, the number of stacked layers should be reduced as far as possible, generally not more than 3 layers, and the supporting points should be appropriately increased to prevent the compression and deformation of the components. Do not relax the control of transportation, lifting, stacking and other links, otherwise, even if the main components of the steel structure are more accurate, there will be problems due to transportation and other links, leading to big troubles on the main installation of the steel structure.