As everyone knows, the structural safety of steel-framed factory buildings primarily focuses on three key points: the stability of the upper structure.

Component strength and foundation stability.

Upper Structure Stability

Firstly, conduct a detailed survey of the overall layout and overview of the factory building structure based on the drawings, and verify whether the structural form used in the building conforms to the design drawings and specifications.

National standards and regulations, clarity of load transfer routes, rationality of structural layout, completeness of the support system, and whether the slenderness ratio of the support system meets the specifications.

Requirements, as all these involve structural stability issues. With years of construction experience at Dadi Yunlong Steel Structure, structural stability has always been a key factor in steel structures.

Major issue: Once a steel structure instability incident occurs, it not only results in significant economic losses but also easily causes severe personnel casualties.

So we must understand the basic concepts of structural stability; only then can we better discover and identify in the safety assessment of steel structure factory buildings.

Addressing issues of steel structure instability.

Stability of steel structures can be categorized into two types: the overall stability of the structure and the local stability of its components.

The overall structural stability primarily relies on the support system within the vertical structure, such as the inter-column supports of steel columns and the upper and lower supports of steel trusses.

Lower chord horizontal supports and vertical supports, etc. Can the support system reliably transfer the structural vertical horizontal loads?

(Lateral loads such as wind, seismic, and crane loads in the factory building). Laterally, the stiffness of the structure itself (frame or portal frame) ensures it.

Primarily, consider the structure's ability to reliably transfer lateral horizontal loads.

The stability of the component itself is mainly ensured by the inherent stiffness of its constituent parts, and it is necessary to guarantee both the component itself and its constituent parts (bars or plates).

Under load, there is no buckling and loss of stability (this condition mainly occurs in compressed or bending components). Therefore, the component itself

Stable factors primarily include the calculated length of components and their cross-sectional characteristics, encompassing both in-plane and out-of-plane directions. Of course, material properties should also be included.

The magnitude of strength and stress. It primarily identifies the unstable equilibrium state between external loads and the internal resistance of the structure, i.e., the state where deformation begins to increase sharply.

Therefore, it is a deformation issue. For example, in an axially compressed column, due to instability, lateral deflection causes a significant increase in bending moment within the column.

Therefore, the column's failure load can be significantly lower than its axial compression strength. Clearly, the axial compression strength is not the primary cause of column failure.

Structural stability inspection focus:

High-strength bolt connection quality of steel structure factory building components, using total station to check the bolt external thread leakage in the component connection sections.

The welding connection quality of steel structure factory building components is determined by the ultrasonic testing method to ascertain whether the weld quality grade meets the standard requirements.

Deflection deformation of steel structure factory components is determined by using a level instrument or stringing method to ascertain the deformation amount.

Component Strength

After addressing the stability issues of the structure, the next is the strength of the components. We must adopt different modern testing technologies based on various structural forms.

Obtain necessary structural functional parameter indicators, such as using core drilling method, rebound method, and rebound method combined with core strength correction when the rack column is made of reinforced concrete column.

Methods for testing concrete compressive strength; weld strength is inspected using ultrasonic testing for internal weld defects; steel plate strength is measured by the Leeb hardness test for steel grades.

The issue of strength essentially refers to whether the large stresses caused by loads on the structure or individual components exceed the ultimate strength of the construction materials in a state of stable equilibrium.

Therefore, this is a stress issue. The value of ultimate strength depends on the material's characteristics; for brittle materials like concrete, it can take its high strength.

The yield point of steel is commonly taken. A low component strength can lead to insufficient structural load-bearing capacity, significantly affecting the normal use function and seismic resistance of the structure.