# Live Load

This section defines vehicular live loads, design lanes, and influence surfaces.

{% hint style="info" %}
**Navigation:** Loading > Loads > Live Load
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## 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.

![Design Lane navigation](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-143549.png?api=v2)

Click the **three-dot icon** on **Name** and select **Import Design Lane** to import design lanes with parameters.

![Import design lanes](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-144542.png?api=v2)

![Imported lanes](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-151419.png?api=v2)

### 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.

![Vehicles tab](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-152700.png?api=v2)

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.

![Lane Load](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-154208.png?api=v2)

![Vehicle Placement](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-154223.png?api=v2)

![Lane Placement](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-154245.png?api=v2)

### Step 5: Import Vehicles

Navigate to **Loads > Live Load > Vehicle**.

![Vehicle navigation](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-134614.png?api=v2)

Click the **three-dot icon** on **Name** and select **Import Vehicle**. All vehicle data is automatically imported once the Design Lane has been imported.

![Import vehicles](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-134720.png?api=v2)

![Imported vehicles](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-154939.png?api=v2)

### Step 6: Define Influence Surfaces

Navigate to **Loads > Live Load > Influence Surface**.

![Influence Surface navigation](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-160456.png?api=v2)

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.

![Stage assignment](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-162102.png?api=v2)

![Influence surfaces](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-162855.png?api=v2)

Set **Roadway** to **R1** for each Influence Surface load.

![Roadway assignment](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-163000.png?api=v2)

Assign appropriate categories to each defined Influence Surface load.

![Categories](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-163838.png?api=v2)

Enter influence surface parameters:

* Unit Load Spacing Long. \[in]: **360**
* Unit Load Spacing Trans. \[in]: **72**

![Parameters](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-164446.png?api=v2)

### Step 7: Configure Centrifugal Parameters

Navigate to the **Centrifugal** tab and enter Highway Design Speed \[ft/second]: **51.3**.

![Centrifugal tab](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-165450.png?api=v2)

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**.

![Live Load Case navigation](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-171242.png?api=v2)

Define the Live Load Cases for which limit states will be used.

![Live Load Cases](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230223-171359.png?api=v2)

Assign Fatigue parameters as required.

![Fatigue assignment](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230224-090317.png?api=v2)

### Step 9: Assign Design Lanes to Live Load Cases

Navigate to the **Design Lanes** tab.

![Design Lanes tab](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230224-091901.png?api=v2)

![Design Lane options](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230224-091937.png?api=v2)

![Design Lane assignments](https://openbrim.atlassian.net/wiki/download/attachments/2169831428/image-20230224-092115.png?api=v2)

Click the **three-dot icon** on the **Design Lane Option** cell and assign design lanes to the Live Load Cases.

## Verification

{% hint style="success" %}
All live load components (design lanes, vehicles, influence surfaces, and live load cases) should be properly configured.
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