# Steel Tub Girder Code Check (AASHTO) \[STG]

## Steel I Girder Code Check (AASHTO) \[SIG]

## General

**Girder:** Girder for code check

**Station:** Station along the PGL

**Code Check Template:** The code check template is utilized to extract global parameters, results from finite element analysis, and limit states employed in the design process.

**Panel Type \[InteriorPanel/EndPanel]:** The terms "end panel" and "interior panel" are used to describe the sections of a steel girder plate that are positioned at the ends and interior sections of the girder, respectively, as depicted in the accompanying figure. The interior panels comprise the remaining segments of the girder that lie between the end panels. \[Interior Panel=1/End Panel=2]

![](https://openbrim.atlassian.net/wiki/download/attachments/2126676003/image-20230307-193138.png?api=v2)

**Res. Case To Find Points of Permanent Load Contraflexure:** The analysis result case used to locate points of permanent-load contraflexure along the girder. These points separate positive- from negative-flexure regions and govern the deck-rebar participation used in the composite section properties.

**Straight/Curved \[Straight Bridge/Curved Bridge]:** This parameter defines the bridge type.

**Variable Depth Start or End Location \[Yes/No]:** Set to *Yes* only at stations where web depth variation occurs, as specified in AASHTO 6.10.1.4. When set to *Yes*, the checks for equations (D6.5.2-1), (D6.5.2-2), and (D6.5.2-3) in D6.5.2 – Web Local Yielding will be performed. \[YES=1/NO=0]

If this input enabled, and a web stiffener is present at the code check station, the D6.5.2 – Web Local Yielding check shall not be performed.

**PDF Name (Export):** This parameter allows the name of the code check document to be modified when saving it as a PDF. When renaming the file, special attention must be given to the text characters on the [linked](https://docs.openbrim.org/faq/general/faq-illegal-chars) page, as certain characters may interfere with parametric equations and lead to unexpected results.

### Deck Reinforcement

**Input Data Preference \[Override Deck Rebar/Use Deck Rebar]:** For deck rebar to be used in girder code checks, users are provided with two options. The code checks can either be conducted using the modeled deck rebar or with new rebar definitions.

If the input data preference is defined with the option 'Override Deck Rebar,' the parameters listed below can be used to define the rebars for code checks. Otherwise, if the input data preference is defined with the option 'Use Deck Rebar,' the parameters below will not be applicable.

**Lumped Top Reinforcement Area within the Effective Width:** This parameter can be used to specify the lumped reinforcement area within the effective width when overriding deck rebar.

**Dist. from the CL of Top Bars to the Top of the Deck:** This parameter can be used to define the distance from the centerline of the top reinforcement bars to the top of the deck.

**Lumped Bottom Reinforcement Area within the Effective Width:** This parameter can be used to specify the lumped reinforcement area within the effective width for the bottom deck rebar.

**Dist. from the CL of Bottom Bars to the Bottom of the Deck:** This parameter can be used to define the distance from the centerline of the bottom reinforcement bars to the bottom of the deck.

**Deck Rebar Material**: This parameter can be used to specify the material used for the deck rebars.

**Concrete Creep Adjustment Factor**: This parameter can be used to define the adjustment factor for concrete creep in calculations.

### Appendix B6

This Article shall apply for the calculation of redistribution moments from the interior-pier sections of continuous span I-section flexural members at the service and/or strength limit states. These provisions shall apply only for I-section members that satisfy the requirements of Article B6.2.These optional provisions provide a simple rational approach for calculating the moment redistribution from interior-pier sections due to the effects of yielding. This approach utilizes elastic moment envelopes and does not require the direct use of any inelastic analysis methods. The restrictions of Article B6.2 ensure significant ductility and robustness at the interior-pier sections.

**Mrd at Supports List (Strength) :** In the second run, the user needs to enter the Mrd values of each pier reported in the summary as an input to the code check for any span region adjacent to pier locations. This will help determine if the distributed moment can cause any problems at those locations. If the user wishes to utilize Appendix B6, they must define a separate template for each girder to correctly input the Mrd values at pier locations.

**Mrd at Supports List (Service):** In the second run, the user needs to enter the Mrd values of each pier reported in the summary as an input to the code check for any span region adjacent to pier locations. This will help determine if the distributed moment can cause any problems at those locations. If the user wishes to utilize Appendix B6, they must define a separate template for each girder to correctly input the Mrd values at pier locations.

{% hint style="info" %}
Note that a moment value must be entered at all bearing points, even if it is zero. However, no moment should be assigned to support lines that are additionally placed solely for geometric adequacy. ![image-20250515-064738.png](https://openbrim.atlassian.net/wiki/download/attachments/2126676003/image-20250515-064738.png?api=v2)
{% endhint %}

**Adj. to Interior-Pier Section Stations (Str):** The user can specify the range for moment redistribution with station values along the PGL for each pier. To help users understand the behavior, the following logic can be applied: the demand will be redistributed, increasing the demand at the adjacent stations while decreasing the demand at the pier. The expected outcome is that the maximum demand value at the pier will decrease, and the maximum demand value at the adjacent stations will increase. However, the above logic is simply explained to demonstrate the behavior. For a more detailed explanation, users need to refer to the AASHTO code and OpenBrIM detailed report.

**Adj. to Interior-Pier Section Stations (Srv):** The user can specify the range for moment redistribution with station values along the PGL for each pier. To help users understand the behavior, the following logic can be applied: the demand will be redistributed, increasing the demand at the adjacent stations while decreasing the demand at the pier. The expected outcome is that the maximum demand value at the pier will decrease, and the maximum demand value at the adjacent stations will increase. However, the above logic is simply explained to demonstrate the behavior. For a more detailed explanation, users need to refer to the AASHTO code and OpenBrIM detailed report.

### Overrides

**Override Effective Deck Width\[Yes/No]:** The Override Effective Deck Width parameter provides the option to manually specify the effective deck width instead of relying on the automatically calculated value. When set to "YES," it allows engineers to enter a user-defined deck width that may better represent the actual structural condition, such as when the composite action is partial or the geometry is irregular. When left as "NO," the system computes the value automatically. \[YES=1/NO=0]

**Effective Deck Width:** The Effective Deck Width parameter defines the deck width used in composite section calculations when the override option is enabled.\
**Computed Effective Deck Width (readonly):** Parameter displays the effective deck width automatically determined by the software based on geometric inputs. This value represents the width of the deck slab acting compositely with the girder.\
**Override Span Length:** Parameter enables manual input of the span length for code check computations. By default, the span length is determined automatically from the geometric model using insertion points and support lines, but when this override is activated, the user can define an alternative length. \[YES=1/NO=0]

**Span Length:** Parameter allows the user to enter the desired span length in feet when the override option is active.

**Computed Span Length (readonly):** Parameter displays the system-calculated span length derived from the model geometry using insertion points and support lines. This field is read-only and provides a transparent reference for verifying the geometric span assumed in the design check.

**Override Transverse Stiffener Spacing \[Yes/No]:** Enables manual input of transverse stiffener spacing for code check computations. When set to YES, users can define custom spacing, otherwise the system computes it automatically based on the girder geometry.

**Transverse Stiffener Spacing:** The user-specified transverse stiffener spacing applied when the override option is active. Enter a length value.

**Computed Transverse Stiffener Spacing (readonly):** Displays the system-calculated transverse stiffener spacing derived from the girder geometry and the transverse stiffener objects attached to the girder. (Read-only)

**Override Maximum Unbraced Length \[Yes/No]:** Enables manual input of the maximum unbraced length used in the lateral-torsional buckling checks. When set to YES, users can specify a custom value, otherwise the system computes it automatically from the bracing configuration.

**Maximum Unbraced Length:** The user-specified maximum unbraced length applied when the override option is active.

**Computed Maximum Unbraced Length (readonly):** Displays the system-calculated maximum unbraced length of the compression flange derived from the cross-frame and bracing configuration along the girder. (Read-only)

**Girder Start Station (readonly):** Displays the start station of the girder along the PGL. This value is automatically determined from the girder geometry. (Read-only)

**Girder End Station (readonly):** Displays the end station of the girder along the PGL. This value is automatically determined from the girder geometry. (Read-only)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.openbrim.org/templates/steel-tub-girder-bridge-workflow/superstructures-code-check-stg/steel-tub-girder-code-check-aashto-stg.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.