Hollow Section VS I Beam - News - lefin steel

Hollow Section VS I beam

View Details

Hollow section and I beam are two commonly used types of structural steel sections in construction. Each has its own unique characteristics and advantages that make them suitable for different applications.

LEFIN STEEL produces the Hollow Section and I beam with the following items:

Hollow sections: also known as rectangular or square tubes, are a popular choice for building lightweight structures such as fences, handrails, and scaffolding.

 1. Types: Hollow Section including Circular Hollow Section(CHS), Rectangular Hollow Section(RHS) and Square Hollow Section(SHS)

 2. Standards: EN, EN, ASTM A500, ASTM A501, JIS G

 3. Advantages: Hollow sections are easy to fabricate and install, making them a cost-effective alternative to other structural steel sections.

 4. Application: Hollow Section are used in the construction of high-rise buildings and bridges as they offer high strength-to-weight ratio and excellent torsional resistance.

I beams: also known as H beams

 1. Types:  Wide flange beams,  S-beams,  Junior beams, W-beams

 2. Standards: EN, ASTM A36、ASTM A572、ASTM A992

 3. Application: are widely used in heavy construction projects such as bridges, industrial buildings, and skyscrapers.

 4. Advantages: They are known for their high load-bearing capacity and durability, making them ideal for structures that require long spans and heavy loads.

When comparing hollow sections and I beams, both have their own unique advantages and disadvantages. However, it's important to note that neither is inherently better or worse than the other. The choice between the two will largely depend on the specific needs of the project.

In summary, whether you choose a hollow section or an I beam, both offer significant benefits and can play an important role in the successful completion of a construction project. It's essential to consult with a structural engineer or architect to determine which steel section is best suited for your specific needs and requirements.

Link to Huizhe

How often do we pay attention to the geometric shape of steel sections used in construction, and realize the importance of the shape? All the steel design and construction codes worldwide identify a few common shapes to be used as a steel member. These sections are noted by their cross-section shape profile. Below mentioned are a few commonly used sections.

Why do we need different section types?

After going through the above list, one might wonder, why do we need to mold the steel sections into different shapes, instead use solid shapes (rectangular, square, circular or other polygons)? In order to know the reason, we need to understand a little about the load applications, structural phenomena subjected on member, parameters that control the structural capacity of a member.

Most common load applications that are encountered in the construction includes one or combination of below:

• Point Loads
• Uniformly distributed loads
• Moment/direct bending
• Rotation

Depending on type and manner of the load application/s, a member is subjected to one or combination of structural phenomena such as:

• Compression
• Tension
• Shear
• Flexure
• Torsion

In order to assess a member against the above-mentioned phenomena, there are few parameters (including but not limited to) that indicate the resistance offered such as:

• Cross section area
• Total Depth
• Thickness of Web, Flange/s, and Legs
• Moment of Inertia and/or Section modulus
• Torsional Constant

Check out SkyCiv's free moment of inertia calculator

Circling back to molding a solid section into different steel profiles; Based on multiple load combinations load applied, structural phenomena subjected and resistance parameter required, solid sections are molded and configured to various shape profiles. The molding of a solid section into shape profiles help to achieve high material to capacity ratio. Thus, conserving steel consumption (volume and weight).

Here we go through each section type briefly. We analyze each section type based on structural design criteria, usability and shape profile benefits.

I Shape / W Shape / H Shape

The shape profile of this section looks similar to alphabet “I” or “H”. W shape is the common notation used in AISC Steel Construction manual for this type of section. This section is used for all the types of load combinations, except pure rotation. This section is highly efficient to resist (in order) flexure, and compression. Most common usages of this section are beams/girder, columns in Buildings and Bridges.

Benefits

• High conservation of steel compared to solid rectangular or square section.
• Universal member - can be used for most structural member applications.
• Wide range of defined section availability in steel design manuals, allows for optimum structural design.
• Provides good compatibility for connections to other primary or secondary members.

Disadvantages

• Cannot be loaded in the X-X direction, as the section offer very little structural capacity compared to Y-Y direction.
• Offers less torsional resistance, since it is an open section.

figure: Typical usage of I shape section as Beams and Columns

C Shape / Channels

The shape profile of this section looks similar to alphabet “C”; hence we call them C shape. Channel is the common notation used in AISC Steel Construction manual for this type of section This section is mostly used for uniformly distributed load applications with small moment/bending. This section is highly efficient to be used as a secondary structural member where the loading is transferred onto other primary structural members. Most common usages of C Shape/Channels as secondary structural member are transverse joists supporting floor, purlins for roof trusses, studs in the wall framing, supporting members for ceiling assemblies, etc. Related: Try our purlin span calculator for C Sections.

Benefits

• Ideal substitute for I-shape when flexure is not a critical factor, conserving almost half the steel.
• Provides high structural capacity when used a multiple member system. Ex. Floor Joist system, Purlins in roof truss, etc.
• Can be placed back to back to create a virtual I-shape section.
• Provides good compatibility for connecting to other steel members and concrete/brick surfaces.

Disadvantages

• Highly unstable when loaded without bracing top flange, due to unsymmetrical geometry in Y-Y axis.
• Not suitable for heavy load applications.

figure: Typical usage of Light gauge steel C Shape section as studs for wall and roof joists

L Shape / Angle

The shape profile of this section looks similar to alphabet “L”; hence we call them L Shape. This section is also called as “Angle” as noted in AISC Steel Construction Manual and also due to its feasibility to accommodate angular connections. This section is highly used for point load applications to resist shear, tension and compression. This section is a perfect fit to be used as a connection member, primary component of a built-up member etc. Most common usages of this section are connection between I-shapes and/or other shapes, bracing in truss members, Chords, Battens and/or Laces of built-up member, Diaphragm members in bridge girder system, Web stiffening elements for I-shape sections, etc.

Benefits

• Provides high structural capacity in connections to resist the bolt/weld shear.
• Highly preferred to be used as a bracing member for trusses, as they offer good combination of axial-flexural capacity (Tension/Compression).
• Can be placed back to back to create a virtual T-shape section.

Disadvantages

• Unsymmetrical geometry in both X-X and Y-Y directions.
• Very low material/structural capacity ratio offered, compared to other shape sections

figure: Typical usage of I shape as main girders, and Angles as diaphragms in Bridge Girder System

T Shape / Structural Tees

The shape profile of this section looks similar to alphabet “T”; hence we call them T shape. Structural Tee is a common notation used in AISC Steel Construction Manual for this type of section. This section is usually split from standard I-shapes by removing the bottom flange. This section can be used for all load applications similar to I-shape section. This shape offers significant flexural capacity on the flange side compared to non-flange side. Most common usages of this section are connection member between I-shapes or other shapes, secondary beam members (lintels), Chord member in trusses and primary member of built-up member, End Diaphragm members in bridge girder system etc.

Benefits

• Ideal substitute for I-shape sections where one side flexure is not significant or to reduce the overall depth of member.
• Offers high axial - flexural capacity compared to L shape, due to web depth and symmetry.

Disadvantages

• Cannot be loaded in the X-X direction, as the section offer very little structural capacity compared to Y-Y direction.
• Very limited applications due to unsymmetrical geometry about X-X axis.

figure: Typical T shape structural member

Square, Rectangular, and Round Hollow Structural Section (HSS)

The Hollow Structural section (HSS) is obtained by steel tubing in the shapes of Square, Rectangular and Round/Circular. This section is a closed class, compared to other sections discussed above. This section is highly applicable for point loads and rotation. This section provides high structural capacity against compression and torsion. Most common usages of this section are structural column, shafts, etc.

Benefits

• Provides high torsional resistance compared to I, C, L, and T shapes.
• Provides high structural capacity in both directions (X-X and Y-Y) compared to I, C, L, and T shapes.
• Can be used as a jacket for concrete column for increased axial capacity.
• Relatively beneficial weight:capacity ratio (in axial)

Disadvantages

• Not commonly used as flexural member due to more steel usage compared to an equivalent I-shape section.
• Connections such as bolting is hard to install, since the section is closed.

figure: Typical usage of HSS shape as Column, I shape as primary beams and C shape as secondary beams

Conclusion

Other shape sections that are also used as steel member are Pipe section, Plate section, and Bar sections. Based on above discussion we can now understand the differences between different shape sections, their relative benefits, their structural strengths etc. An optimum structural design includes all the above individual shape sections to be correctly chosen, designed to support and transmit loads properly throughout the structure.

If you are looking for more details, kindly visit hollow rectangular tube(ko,ha,lo).