 | New optimization tools for joists and steel deck under snow pile-up
In this article:
Canam Canada offers several interactive calculation tools. Two new tools to optimize joist and steel deck designs under snow pile-up were recently added to the nine other tools already available online.
11 interactive engineering tools developed by Canam Canada
Joists
- Economical depth selection
- Moment of inertia
Joist girders
- Economical depth selection
- Standard connections
Steel deck
Roof:
- Maximum loads
- Maximum spans
Floor:
- Maximum load
- Maximum unshored spans
Snow pile-up
- Snow pile-up perpendicular to joists (constant deck thickness)
- Snow pile-up perpendicular to joists (constant joist loading) - NEW
- Snow pile-up parallel to joists (deck optimization) - NEW
 Access the tools
Snow pile-up
Snow accumulates on roofs irregularly around obstacles such as mechanical units and on lower areas of adjoining buildings. Building design engineers must indicate the following on their plans:
- Maximum snow load
- Length of the snow accumulation
- Location of the accumulation
This data is used when designing the steel roof joists and deck. The 2005 NBC (National Building Code of Canada, 2005) expresses snow pile-up as follows:
 | xd
S
Smax | Length of the accumulation
Live load due to snow
Maximum snow load |
| Figure 1: Drawing of snow pile-up | | |
Snow pile-up perpendicular to joists
Snow pile-up can either be parallel or perpendicular to the joists. Two tools can be used to optimize joist and deck designs under snow pile-up perpendicular to the joists:
- Constant deck thickness
- Constant joist loading
1) Constant deck thickness
This tool has actually been available on our website since April 2007. It calculates the spacing required between the joists under the entire length of the accumulation, while taking into account the capacity of the deck type selected by the user. As a result, deck sheet thickness remains constant under the entire length of the snow pile-up.
This solution reduces the risk of error during erection by eliminating the use of deck sheets with different marks. The joists, on the other hand, do not necessarily need to have the same mark numbers.
Figure 2: Schematic of snow pile-up perpendicular to joists (constant deck thickness)
Examples of 1) the type of data to enter in the calculation tool and 2) a results report
Figure 3: Example of the type of data entered by a user
Figure 4: Example of a results report
Access the tools
2) Constant joist loading
This new tool calculates the spacing required between the joists under snow pile-up to give the same linear design load as on the adjacent joists that are not under the accumulation. This will make it possible to design joists with the same mark numbers, under snow pile-up or not.
In any given project, using joists with the same mark, or at least reducing the number of different marks, generally means cost savings for the customer and decreases the risk of error for the erector.
The tool also determines the nominal thickness(es) of the deck sheets required under the entire length of the snow accumulation, depending on the type of span:
The deck is selected according to the total load factored and the service load (unfactored snow load) for a specific deflection, which are both calculated for each predetermined joist spacing.
When the load capacity of the thickest deck profile is exceeded, the maximum joist spacing for that profile is displayed.
Figure 5: Schematic of snow pile-up perpendicular to joists (constant joist loading)
Examples of 1) the type of data to enter in the calculation tool and 2) a results report
Figure 6: Example of the type of data entered by a user
Figure 7: Example of a results report
Access the tools
Snow pile-up parallel to joists (deck optimization)
The new tool determines the nominal thickness(es) of the deck sheets required under the entire length of the snow accumulation, depending on the type of span:
The deck is selected according to the total load factored and the service load (unfactored snow load) for a specific deflection, which are both calculated at the beginning of each deck sheet.
When the load capacity of the thickest deck profile is exceeded, the maximum span for that profile is displayed.
Figure 8: Schematic of snow pile-up parallel to joists
Examples of 1) the type of data to enter in the calculation tool and 2) a results report
Figure 9: Example of the type of data entered by a user
Figure 10: Example of a results report
Access the tools
Our quick and easy tools
As with all the other interactive tools currently available on our website, the new tools presented in this article are quick and easy to use. First, register for the engineering tools by clicking on the following logo:
Then follow these steps:
1. Click on “Snow pile-up”
2. Select the tool you wish to use
3. Determine the parameters of the deck profile
4. Enter the uniform loads (dead load and snow load)
5. Enter the maximum snow pile-up and its length
6. Enter the deck span
7. Click on “Calculate”
Results report
Once the calculation is completed, each tool will automatically generate a complete report that can either be viewed on screen or printed.
The report includes:
- The parameters of the deck profile
- The loads and the length of snow pile-up entered by the user
- A drawing showing the dimensions of the profile selected by the user
- A table of the results
Information
For more information, contact our experts:
Our projects
Consult the list of projects completed by Canam Canada.
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