Failure of Steel Structures: Causes & Prevention

June 24, 2022 12:00 am Published by Leave your thoughts

Structural engineers design buildings and additional structures to resist a wide range of forces. The types of forces include the mass of the structured content that consists of the structure itself, transient forces from the occupancy of the structure, and environmental forces such as snow, wind, rain, and earthquakes. In the case of steel, there are various causes for structural failure as well as tips for prevention that you can implement.

Failure Causes & Prevention

When it comes to structural steel design, one limitation of steel is its susceptibility to corrosion when exposed to the high temperatures that normally occur in fires. Steel structures are also susceptible to fatigue if they are loaded cyclically and are vulnerable to buckling if they are under high compression.

Shear Failure

Shear failures normally occur in connections between members. Designing these connections is a challenging task. Connections normally contain high shearing forces that an engineer must keep in mind when creating the connection. If the structural engineer underestimates the design force the connection is able to withstand, a failure can occur. For prevention, common connections in steel structures can be created with welds, bolts, or both.

Flexural Failures

Flexural failures occur in flexural members such as girders. In some cases, they even occur in compression members such as columns. These types of failures typically occur when flexural loadings cause the element to buckle. Since steel is strong, steel members are created to be efficient and slim. This means that they are at a high risk of buckling. However, stocky members that are heavier are less prone to buckling.

Flexural loadings cause compression and tension forces in members.

Compression Failures

Compression failures normally occur in compression members, including braces and columns, when the compressive axial force that is applied to them is forced to become overstressed or buckle.

Both brace and column members are susceptible to high compressive stresses that may experience buckling. When creating a column, consider its slenderness ratio, which is a ratio of cross-sectional geometry to the length of the member. This is because a member with a high slenderness ratio is more prone to buckling than one with a lower ratio. Additionally, members that have a low slenderness ratio may still fail to work when the compressive stresses exceed the strength of the material of the member.

Tensile Failures

This type of failure normally occurs in hangers or brace members. When the steel member is stretched to a degree that is greater than the material strength of the member, a failure can occur. However, this type of failure happens in different stages: yielding, necking, and failure.

Steel is very reliable and strong, especially in the structural construction of buildings. However, the effectiveness of steel is only reliable if it has been designed properly to withstand imposing forces. When it has been designed poorly, it can cause any of the above-mentioned failures of steel structures.

 

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