How to prevent local buckling and distortion buckling of steel column beams in light steel workshops under long-term loads?

Publish Time: 2025-11-20

Light steel structure steel column beams are widely used in industrial plants, logistics warehouses, and prefabricated workshops due to their advantages such as light weight, fast construction, and recyclability. Steel columns and beams, as the main load-bearing components, are usually made of cold-formed thin-walled steel. However, because these components have thin walls and a large width-to-thickness ratio, they are prone to local buckling under long-term static loads, wind loads, or snow loads—that is, the plate sections buckle due to compression instability before reaching the material's yield strength. This failure mode not only weakens the load-bearing capacity of the components but may also lead to degradation of the overall structural stiffness.

1. Reasonably control the width-to-thickness ratio of the plates: Improve stability from the source

The most fundamental measure to prevent local buckling is to strictly control the width-to-thickness ratio of the compressed plates during the design phase. There are clear width-to-thickness ratio limits for flanges and webs under different stress states. For example, the width-to-thickness ratio of the compression flange should generally not exceed a certain limit to ensure stability during the elastic or elastoplastic stages. By selecting steel plates of appropriate thickness or optimizing the cross-sectional shape, the buckling resistance of the plate can be significantly improved without significantly increasing the amount of steel used.

2. Installing Effective Stiffening Ribs: Enhancing Plate Constraint Stiffness

When the width-to-thickness ratio cannot be significantly reduced, stiffening measures are commonly used in engineering to improve local stability. Common practices include: installing transverse or longitudinal stiffening ribs on both sides of the web to divide the large compression area into several smaller plates, thereby reducing the effective width-to-thickness ratio of individual plates; adding rolled edges to the free ends of C-shaped or Z-shaped flanges to form edge constraints, significantly improving the flange bending stiffness. Although these stiffening structures are small, they can effectively change the buckling mode of the plate, transforming the originally prone overall buckling into local deformation of higher-order, higher-critical-stress, thus delaying the occurrence of instability.

3. Optimize Cross-Sectional Form and Material Matching

Modern light steel structure design tends to adopt efficient cross-sectional forms, such as box beams composed of double C-shaped steel sections or closed sections with internal diaphragms. Closed sections have greater torsional stiffness and a more uniform stress distribution, resulting in stronger mutual restraint between the web and flanges, and a significantly higher local buckling critical load compared to open sections. Furthermore, while using high-strength steel does not directly improve the width-to-thickness ratio, it can indirectly reduce the width of the plates by decreasing the required cross-sectional dimensions, thereby indirectly improving stability. It should be noted that high-strength steel has slightly lower ductility; its impact on overall performance should be comprehensively evaluated during the design process.

4. Consider Long-Term Load Effects and Initial Defect Influence

Light steel structures often have a service life of 20–50 years. Long-term loads may induce material creep or residual stress redistribution, thereby reducing buckling capacity. Simultaneously, unavoidable initial geometric defects during manufacturing can significantly reduce the actual buckling load. Therefore, reduction factors should be introduced in the design calculations, or nonlinear finite element analysis should be used to consider defect sensitivity and ensure safety margins. For critical workshops, residual stress can be partially eliminated and the long-term stability of components improved through factory pre-stressing or vibration aging treatment.

5. Collaborative Guarantee in Construction and Maintenance

Besides design, construction quality is equally crucial. During installation, avoid rough handling that could cause localized dents in components; ensure clear force transmission paths at connection points to prevent eccentric compression from exacerbating stress concentration in the plates. After commissioning, regularly inspect the column and beam surfaces for abnormal bulging, corrosion, or loose connections, and promptly maintain the anti-corrosion coating to prevent buckling induced by corrosion-induced thinning of the plates.

Preventing localized buckling of steel column beams in light steel workshops under long-term loads is a systematic project encompassing material selection, cross-sectional design, structural details, manufacturing processes, and operation and maintenance management. Only under the guidance of the integrated concept of "precise calculation, precise structure, and meticulous workmanship" can the high efficiency advantages of light steel structures be fully utilized, solidifying the safety foundation of industrial buildings.