Live Load
This section defines vehicular live loads, design lanes, and influence surfaces.
Overview
To affect live loads on your bridge, you must activate them according to your standard. Vehicle data definitions are provided before the design lane definitions. However, if you begin by defining a Design Lane, OpenBrIM will automatically assign the vehicle data.
Steps
Step 1: Import Design Lanes
Navigate to Live Load > Design Lane in the tree view.
Click the three-dot icon on Name and select Import Design Lane to import design lanes with parameters.
Step 2: Configure Design Lane Parameters
The incoming lane width [ft] and vehicle & lane edge [ft] data will remain constant for this project.
Step 3: Configure Vehicles
Navigate to the Vehicles tab.
The data in the Vehicles column is automatically set when we define the Design Lane. Enter the Vehicles Impact Factor values as required.
Step 4: Configure Additional Tabs (Optional)
Review and adjust the Lane Load, Vehicle Placement Settings, and Lane Placement Settings tabs if needed.
Step 5: Import Vehicles
Navigate to Loads > Live Load > Vehicle.
Click the three-dot icon on Name and select Import Vehicle. All vehicle data is automatically imported once the Design Lane has been imported.
Step 6: Define Influence Surfaces
Navigate to Loads > Live Load > Influence Surface.
Click the three-dot icon on Stage and select the appropriate stage. After the completion of pavement on a bridge, the forces exerted by vehicles include live load, load at braking, and centripetal force.
Set Roadway to R1 for each Influence Surface load.
Assign appropriate categories to each defined Influence Surface load.
Enter influence surface parameters:
Unit Load Spacing Long. [in]: 360
Unit Load Spacing Trans. [in]: 72
Step 7: Configure Centrifugal Parameters
Navigate to the Centrifugal tab and enter Highway Design Speed [ft/second]: 51.3.
Set Centrifugal Force Factor to Other Than Fatigue (1.33) for the ISCentr load.
Step 8: Define Live Load Cases
Navigate to Loads > Live Load > Live Load Case.
Define the Live Load Cases for which limit states will be used.
Assign Fatigue parameters as required.
Step 9: Assign Design Lanes to Live Load Cases
Navigate to the Design Lanes tab.
Click the three-dot icon on the Design Lane Option cell and assign design lanes to the Live Load Cases.
Verification
All live load components (design lanes, vehicles, influence surfaces, and live load cases) should be properly configured.
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