A column is a structural element that transfers the weight of the structure above to other structural elements below. A steel column is usually design under compression and bending. From design perspective, such type of structural element is usually called a beam column. In most cases, the design of steel columns is governed by buckling, therefore slenderness of cross section plays important role in design. In this article we will explore most common types of steel sections used as column.
Hollow steel sections for steel column
They are great choice in case when the column is subjected to compression and bi axial bending. In US, they are termed as HSS (Hollow Steel Section) while in the Europe they are termed as SHS (Square Hollows Section) or RHS (Rectangular Hollow Section). They have also more aesthetic appeal than the I shapes. Because of its rectangular design, this type of hollow section steel is simple to cut and connect to other flat surfaces. They also need little edge preparation for welding or joining.
Here are some of the pros and cons of using hollow steel section as a column.
Benefits
- Torsional resistance is higher than that of the I, C, L, and T shapes.
- In comparison to the I, C, L, and T forms, it has a higher structural capacity in both directions (X-X and Y-Y).
- Can be used as a jacket for concrete columns to boost their axial capacity.
- Relatively beneficial weight-to-capacity ratio (axial).
Disadvantages
- Due to the higher steel use compared to a comparable I-shape section, this is not a frequent flexural member. So if you have higher bending moments being transferred to steel columns like in case of moment resisting frames (MRF), I shape can be a better alternative.
- Connections such as bolting are difficult to install since the part is closed.
I shape steel sections for steel column
This section shape is also one of the popular choice for a steel column. It offers much better flexure resistance. In Europe these sections are called IPE or HE section while in US, they are termed as W or HP sections. For steel columns usually wider flange I shapes are adopted due to being better in compression. So, HE and HP shapes are the common choices. I shapes are also great for bolted connections as they offer more flexible access during the fabrication process. Here are some pros and cons for I shapes for steel columns
Benefits
- Steel conservation is higher than for solid rectangular or square sections.
- A wide range of specified sections are available in steel design guides, allowing for optimal structural design.
- Provides good compatibility with other major or secondary members.
Disadvantages
- Cannot be loaded in the X-X direction because the section has relatively low structural capacity compared to the Y-Y direction.
- It provides less torsional resistance since it is an open section.
Hollow Circular sections for steel column
Circular section offer the same advantages of box or rectangular hollow section. The offer more aesthetic appeal and great choice from architectural recipes. In US, they are called pipe sections while in the Europe they are termed as CHS (Circular Hollow sections). Here are some pros and cons of using circular section as steel column.
Advantages
- Great choice from architectural point of view.
- By symmetric in both axis.
Disadvantages
- Connections such as bolting are difficult to install since the part is closed.
- Can only be used with welded connections
