Setting up step-by-step moving load analysis involves the following steps:

Define Vehicle (via "Define > Bridge Loads > Vehicles")
Define Lane (via "Define > Bridge Loads > Lanes")
Use "Define > Load Pattern" menu command to define Load pattern of type BRIDGE LIVE. Click "Modify Bridge Live Button" to define the parameters for this live load pattern, such as lanes, vehicles, vehicle speed, movement direction, etc.

This will automatically create a Multi-step static load case that you can review using "Define > Load Cases" menu command.
You can also evaluate dynamic response by changing the load case type from "Multi-step Static" to "Time History" and setting analysis type to nonlinear, direct-integration. Set the damping and other parameters as necessary.

Step-by-step moving load analysis first steps

See Also