> For the complete documentation index, see [llms.txt](https://docs.openbrim.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.openbrim.org/examples/steel-bridge-examples/example-steel-i-girder-bridge-ex1-sig/loading-ex1-sig/loads-ex1-sig/inf-surf-based-llbrce-ex1-sig/influence-surface-ex1-sig.md).
# Influence Surface
{% hint style="info" %}
**Navigation:** Loading > Loads > Inf Surf Based Llbrce > Influence Surface
For detailed parameter explanations, see the [Influence Surface Reference](https://docs.openbrim.org/templates/steel-i-girder-bridge-workflow/loading-sig/loads-sig/inf-surf-based-llbrce-sig/influence-surface-highway-sig).
{% endhint %}
**Step 1:** Click **three-dots icon** on Stage cell and select a **Construction Stage** as **LLStage.**
**Step 2:** As a result of these operations, an issue will appear on the OpenBrIM screen. This does not necessarily mean that any operation was done incorrectly. The issue will be resolved when the roadway is define in the next step.
Quick Tip: Learn how to read issues
When encountering the warning as seen in OpenBrIM app, there is a "issue" , it is advised to review the parameters you have provided. This warning suggests that there might be a missing or incorrect parameter in your input. Check inputs to ensure they are accurate and complete.
When a warning is clicked, the reason can be displayed. The warning is expressed in the format of Component Group Name (can be viewed in the treeview) > User Defined Component Name (can be viewed in the spreadsheet name column) > Parameter Name (can be viewed in the spreadsheet column header).
After clicking on 'Superstructure > Connections > Bolted Field Splice' in the tree view, navigate to the Bolt category. Set the Bolt Property input. The issue will be resolved after these steps.
The screenshot demonstrates one example of two Bolted Field Splice components named BFS1 and BFS2 by the user, with parameter names **Flange Bolt Property** and **Web Bolt Property**.
**Step 3:** Click the **three-dots icon** on the **Roadway** cell, and then set **R1**.
**Step 4:** Keep the **Live Load Category, Unit Load Spacing Long.** and **Unit Load Spacing Trans.** and **Direction** as default.
**Step 5:** Keep th**e parameters of the remaining tabs** set to their **default values**.
**Step 6:** Set name as **ISGravity**.
| **Influence Surface** | |
| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
| General
\
ISGravity LLStage R1 Gravity 360.0000 72.0000 Along PGL\
ISBraking BRStage R1 Braking 360.0000 72.0000 Along PGL\
ISCentr CentStage R1 Centrifugal 360.0000 72.0000 Along PGL\
| Centrifugal
\
ISGravity N/A N/A\
ISBraking N/A N/A\
ISCentr 51.3000 Other than Fatigue(1.33)\
|
| **Influence Surface** | |
| ------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------ |
| Braking
\
ISGravity N/A\
ISBraking Bidirectional\
ISCentr N/A\
| Settings
\
ISGravity 0.0001\
ISBraking 0.0001\
ISCentr 0.0001\
|
{% hint style="success" %}
The completed influence surfaces are illustrated below. Please verify that you have the same model on your end by examining each view provided here. For more information on how to perform visual checks, refer to the quick tips.
{% endhint %}
{% hint style="success" %}
To view the entire procedure explained on this page, please watch the recorded Video below.
{% endhint %}
{% embed url="" %}
Influence Surface
{% endembed %}
---
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