1. Initial deformation analysis of steel
In the steel structure engineering, steel is the basic and key material. These steels are usually supplied to the market by steel manufacturers in the form of hot-rolled sheets and hot-rolled sections. The thickness range of hot rolled steel plates is wide, ranging from 4.5 mm to 60 mm, while the thickness of thin steel plates is between 0.35 mm and 4.0 mm. The types of hot-rolled steel include Angle steel, channel steel, I-steel, H-steel, steel pipe, C-steel, Z-steel, etc., of which the thickness of cold-formed thin-wall steel is generally between 2 mm and 6 mm.
Due to the physical factors in the rolling process and the influence of human operation, the steel often has some initial deformation when leaving the factory. In particular, cold-formed thin-wall steel is more prone to this problem. Therefore, before the production of steel structure members, it is necessary to strictly inspect the material and correct the existing deformation to ensure that the degree of deformation does not exceed the allowable range of steel regulations.
2. Deformation problem in processing and production
In the process of steel structure processing, deformation is a common problem, mainly divided into the following categories:
(1) Deformation caused by cold processing: for example, when cutting steel plates, bending and twisting deformation may occur, especially on narrow plates and thick plates; Bending deformation may also occur after planing, especially on narrow plates and thin plates.
(2) Deformation in the production and assembly process: due to unreasonable processing process design, uneven assembly site, incorrect assembly method or improper support, it may cause different types of deformation such as bending, distortion and distortion.
(3) Deformation caused by welding: local heating and subsequent uneven cooling in the welding process will lead to residual stress in the weldment, but also accompanied by deformation, which is often referred to as welding residual deformation. This kind of deformation usually includes longitudinal and transverse contraction deformation, bending deformation, Angle deformation, wave deformation and twisting deformation. The main causes of welding deformation include unreasonable welding process, improper selection of welding parameters and inappropriate welding times. In order to ensure the quality of the structure, welding deformation should be controlled within the allowable error range of manufacturing.
3. Deformation during transportation and installation
During the transportation and installation of the steel structure, if appropriate measures are not taken, it may also lead to the deformation of the structural members. For example, careless operation during transportation, unreasonable arrangement of installation process, improper selection of lifting point location, insufficient temporary support or uneven stacking site may lead to obvious structural deformation. Especially if the installation is forced, the deformation problem will be more serious.
4. Deformation during use
In the process of use, the steel structure may also be deformed for a variety of reasons. For example, overloading, collision, high temperature and other factors may affect the structure, resulting in different degrees of deformation. Therefore, the rational use and maintenance of steel structures, avoiding overload and improper operation, is essential to maintain the integrity and stability of the structure.
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