Steel structure factory buildings are a type of specific functional building that requires large spaces and spans, as well as various corresponding equipment. Generally, steel structures are used for the upper part. Below, let's take a look at several issues that need special attention when designing steel structure factories.

1. The length of a single roof panel is not suitable for being too long. There are generally two types of roof water seepage: ① When using roof nail plates, there may be water seepage at the nail hole positions; ② Water seepage at the horizontal overlap of roof panels, mainly due to the long panels and rainwater overflowing the wave peaks, resulting in large-scale water seepage at the overlap. Therefore, the length of a single slope should be reasonably selected based on the characteristics of the panel material and local rainfall.

2. How to choose the corresponding section (net section, effective net section, effective section, gross section) reasonably when checking the steel structure components of the steel structure factory building? ① Coarse section: does not deduct the cross-sectional area of the hole, and does not consider the weakening of the section by the hole. When checking the overall stability of the component, the gross cross-sectional area can be used for calculation; ② Net cross-section: Subtracting the cross-sectional area of the holes, considering the weakening of the cross-section by the holes, mainly used for strength verification; ③ Effective cross-section: Consider the strength after buckling but do not deduct the effective area of the cross-section of the hole. Generally speaking, for cold-formed steel with relatively large width and thickness, the effective area is selected to consider the local buckling strength issue; Considering that the plate is too thin, local buckling may occur under compression, making it impossible to use the entire cross-section for load-bearing. Therefore, for this thin-walled component, it is considered that a part of the cross-section (effective cross-section) is under normal stress, while the other parts are not considered for their effect Effective net cross-section: Consider the post buckling strength and deduct the effective area of the cross-section after deducting the holes. The compressive strength of components should consider both the weakening of cross-sectional strength by holes and the local post buckling strength. Generally, the effective net section is selected for calculation. When the component is under tension, local buckling does not need to be considered, so the net section is still selected.

3. Instability and solution of bent I-beams: When the applied load is not very large, the beam usually bends within its maximum stiffness plane; When the applied load reaches a certain value, the beam will simultaneously undergo significant lateral bending and torsional deformation, and eventually quickly lose its ability to continue bearing. At this point, the overall instability of the beam is inevitably caused by lateral bending and twisting.

There are three solutions: ① Increase the lateral support points of the beam (such as setting corner braces as lateral support points for roof beams). ② Change the cross-section of the beam, increase the lateral moment of inertia of the beam, or increase the width of the compressed flange (such as the upper flange of a crane beam) Changing the constraint of the beam end support on the section, if the support can provide rotational constraint, the overall stability of the beam will be greatly improved.

4. The connection between the secondary beam and the main beam is generally designed as hinged: if the secondary beam is rigidly connected to the main beam and there is the same load on both sides of the same section of the main beam, the impact on the main beam is not significant. If there is only a secondary beam with a rigid connection on one side, for the main beam, it is necessary to calculate the torsional resistance when subjected to out of plane torsion. The overall instability of the beam is manifested as lateral bending and twisting, so it should be avoided as much as possible from being twisted outside the plane of the beam. In addition, if rigid joints are used between the secondary beam and the main beam, the on-site welding workload will be greatly increased.