 | Save time using the standard joist girder connection calculation tool
In this article:
Canam Canada offers design engineers and steel manufacturers an interactive tool for the calculation of standard joist girder connections (Figure 1). This tool is used to design bearing brackets to support a joist girder when it cannot be seated on top of the column.
Figure 1: Canam joist girder
Bearing brackets
The joist girder is a supporting member that can be customized for various assemblies. However, the assembly proposed in this tool consists in seating the joist girder shoe on a bearing bracket in front of the column. This technique requires a W-shaped bearing bracket to be welded onto one of the column walls (Figure 2).
The tool was designed with a bearing bracket made from a W-shaped section since it is commonly found in a steel fabricator’s inventory.
This assembly is simpler than the other types that use end and knife plates and therefore is more economical in the manufacturing of the joist girder.
Figure 2: Example of a bearing bracket
Types of supporting columns
The tool supports W-shaped sections (flange assembly) and HSS sections (square or rectangular only) as stated in the AISC (American Institute of Steel Construction) and CISC (Canadian Institute of Steel Construction) documents.
It can also calculate using ASTM A500C HSS sections. The design of the Canam tool was based solely on the recommendations found in the CAN/CSA-S16-01 Canadian Standard.
A tool that is easy and quick to use
As with all of the other interactive tools currently available on the Canam web site, the tool presented in this article is easy to use. First, you must register for Canam's Engineering Tools, if you have not already done so, either by visiting the Online tools section on the Canam Canada web site or by clicking on the following icon:
Then,
| 1. | Click on Joist girders - Standard connections. |
| 2. | Determine the sections for the support bracket and the column. |
| 3. | Indicate the reaction at the joist girder support at this end. |
| 4. | Indicate the eccentricity of the reaction with relation to the column wall. |
| 5. | Indicate the minimum size of the fillet welds for the bracket web and flanges. |
| 6. | Indicate the type of electrode used. |
| 7. | Click on “Calculate”. |
Figure 3 gives an example of the data to be entered into the calculator.
Figure 3: Example of data entered by a user
Tool verifications
The following items can be verified by the tool:
| 1. | Bearing bracket: |
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- shear strength
- web crippling and slenderness ratio
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| 2. | Web and bracket flange welding |
| 3. | When the supporting column is a W-shaped section: |
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- web and flange strength of the column to assess if stiffeners are required
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| 4. | When the supporting column is an HSS section: |
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- Tube wall strength for wall rupture, punching shear and effective width. (These tests are carried out in accordance with the Design Guide for Hollow Structural Section Connections by J.A. Packer and J.E. Henderson.)
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Reporting results
Once the calculation is completed, the tool will automatically generate a complete report that can be printed or displayed on the screen (Figure 4).
The report includes:
- The physical properties of the sections used
- The reaction data and fillet welds entered by the user
- A table of results based on the CAN/CSA-S16-01 Standard.
- A schematic of the welds
 
Figure 4: Example of a results report
For a better view of this example, click here. 
These verifications are mainly designed to help the user select parameters if the assembly is inadequate. The user will thus find an appropriate solution based on the comments given in the results table generated by the tool. The tool can only modify the size of the fillet welds in accordance with the thickness of the plates to be welded.
Take note that the tool only verifies the assembly and the local strength of the column wall, not the column capacity. Moreover, the building designer must factor in the offset of the joist girder reaction on this type of assembly when dimensioning the column.
Click here to gain direct access to the standard joist girder connection calculation tool.
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