The Influence of Span Length on the Selection of WF Size

In steel structure construction, particularly in warehouses, factories, and large-span structures without central columns, the selection of Wide Flange (WF) sizes cannot be done haphazardly. One of the most crucial factors is the structure's span length.

The longer the planned span, the greater the strength requirements the WF profile must meet. The following is a technical explanation of the effect of span length on WF size selection.

1. Span Length Determines the Magnitude of Bending Force
In steel beam structures, the bending force increases with span length. This means that the WF must be able to withstand:

• Dead load (self-weight of the structure)
• Live load (activities, equipment, vehicles)
• Additional loads such as wind and earthquakes

Small WFs with long spans will experience excessive deflection and risk compromising the structure's performance.

2. Relationship between Span and WF Height and Weight
The longer the span, the more commonly selected WF size will have:

• Larger profile height
• Wider flange width
• Higher weight (kg/m)

This aims to increase the WF's moment of inertia and flexural capacity to maintain stability over long spans.

3. Deflection Control
In addition to strength, WF size selection also aims to control deflection. In long-span buildings, excessive deflection can cause:

• Visual discomfort
• Impairment of building function
• Damage to non-structural elements

Properly sized WFs help keep deflection within safe limits according to technical standards.

4. Risks of Inappropriate Wedge Size for Span Length
Incorrectly selecting a WF size can cause several serious problems, including:

• Excessive deflection
• Cracks in supporting elements
• Reduced structural life
• Risk of structural failure

Using a WF that is too small for a long span often seems "adequate" initially, but is problematic in the long term.

5. Structural Efficiency and Cost
Selecting a WF size that matches the span length does not always mean choosing the largest WF. Engineers typically seek a balance between strength and cost efficiency, taking into account:

• Span length
• Type and magnitude of loads
• Structural system used

The correct WF size can actually save overall construction costs, not the other way around.

6. The Importance of Following Structural Calculations

WF size cannot be determined solely based on field experience or previous projects. Each project has:

• Different span lengths
• Different loads
• Different building functions

Therefore, WF selection must always refer to structural calculations and working drawings.

Conclusion
Span length has a significant impact on:

The size of the WF used

Structural strength and stability

Deflection control and building lifespan

The longer the span, the larger and stronger the WF required. Accurate selection of WF size is key to the safety and efficiency of steel structures.

Quality WF Steel Solutions for Various Building Spans
PT Intisumber Bajasakti provides quality WF steel, meeting SNI standards, in a variety of sizes to support short-span to long-span structures.

📞 Phone: 021-66675999
🌐 Web: intisumberbajasakti.com
✉️ Email: info@intisumberbajasakti.com

Contact our team now for a consultation on selecting the right WF size for your project needs.

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