Multi Step Bridge Live Load Pattern Generation Form

Use the Multi Step Bridge Live Load Pattern Generation form to refine the lane loading for a moving load analysis.

Vehicle drop-down list. Choose the type of vehicle for which the load is being defined from this list of previously defined vehicle(s).

Note: Vehicles that are defined using a uniform load will not be included in the program generated multi-step load case. Click this note on the form to view a list of vehicles defined using uniform loads.

Lane drop-down list. Choose the lane to which the vehicle load is being applied.
Start Dist. Enter a value for the starting distance for the specified vehicle, measuring from the start of the lane as specified when the lane was defined.
Start Time. Enter a value for the starting time for the specified vehicle. While the units of distance can be change, time is always in seconds.
Direction drop-down list. Choose to have the vehicle move Forward or Backward, relative to the start of the lane as specified when the lane was defined.
Speed edit box. Specify the speed of the specified vehicle.
- Add button. With selections made and values entered in the above drop-down list and edit boxes, click the Add button to add the vehicle to the definition.
- Modify button. Highlight a previously defined vehicle definition by clicking on it. Modify the selection or values in the appropriate drop-down list or edit box, and then click the Modify button to change the selected vehicle definition.
- Delete button. Highlight a previously defined vehicle definition by clicking on it. Then click the Delete button to delete the vehicle definition.

Load Discretization Information. Use the options in this area of the form to specify how the load is discretized.
- Duration of Loading is edit box. Specify the total duration of the multi step moving load pattern in seconds.
- Discretize Load every edit box. Specify the frequency in seconds between each step in the multi step moving load pattern.
Units drop-down list. Use the units displayed or select new units from this drop-down list for use with this form.

Access the Multi Step Live Load Pattern Generation form as follows:

Define a bridge layout line, a lane(s) and a vehicle(s).
Click the Loads > Load Patterns command to display the Define Load Patterns form.
Define a moving load by selecting BRIDGE LIVE in the Type drop-down box.
Click the Add New Load Pattern button.
Highlight the newly defined load and click the Modify Bridge Live Load button to display the Multi Step Bridge Live Load Pattern Generation form.