June 19, 2014
How to Use Moving Loads
RISA-3D and RISA-2D will allow you to add a moving load pattern to your model and include it in your envelope solution.
1. Adding a New Moving Load Pattern
To learn about adding new moving load patterns to your Moving Load Patterns library, please see the How Can I Add a New Pattern to the Moving Load Database blog.
2. Defining the Moving Load Path
Once you have added your moving load pattern, you can apply it to your model in the Moving Loads spreadsheet (Spreadsheet > Loads > Moving Loads).
In this spreadsheet, you will define the following:
- Tag: Label of the moving load (this cannot be changed).
- Pattern: Select the moving load pattern from the dropdown menu. This menu reads in all the patterns that are listed in your moving load library (Advanced > Moving Loads).
- Increment: Specify the distance at which the load will be stepped through the path.
- Both Ways: If you want the load pattern to reverse once it has reached the final node along the path, check this box.
- Node Entries: These define the path of the moving load.
Note: You may skip intermediate points along a straight line when specifying the path.
3. Adding the Moving Load to your Load Combination
Once you have defined your moving load, you can include it in your load combinations through the Load Combinations spreadsheet (Home tab > Load Combinations).
- Simply click within one of the BLC cells and click on the red arrow to open the Set BLC Entry dialog.
- Click in the radio button next to Moving Load and select the appropriate moving load from the dropdown menu.
- Click OK and when you go back to your Load Combinations spreadsheet you will see that the BLC entry is set to the Moving Load Tag (M1, M2, etc.).
- Enter a Load Factor and then you are able to run the solution.
Note: When a moving load is included in the solution, it will automatically run as an Envelope solution. This is because a moving load solution includes so much information; the output has been simplified down to just the max and min values.
4. Graphically Verifying your Moving Load
Before solving you can graphically verify the moving load using the 'Animate Moving Loads' option in the View toolbar.
- Click on the 'Moving Loads' button in the Animate section of the View toolbar.
- The animation settings dialog will open and either the moving load or load combination with the factored moving load can be viewed as an animation.
- Click Animate to open the moving load animation
This will open a new 3D view with the moving load now animated and the animation controls.