Steel Tub Girder Load Rating [STG]

General

Girder: Girder for code check

Station: Station along the PGL

Load Rating 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.

Modular Ratio Comp. Method [EsbyEc/User Input]: The modular ratio can be computed either by dividing the modular ratio of steel by that of concrete or by using a user-defined input. This parameter allows users to specify the method for calculating the modular ratio.

Modular Ratio: If the Modular Ratio Comp. Method is defined with the option 'User Input,' a modular ratio can be defined manually. Otherwise, this parameter will be marked as not applicable (N/A).

Result Case To Find Points of Permanent Load Contraflexure: According to AASHTO 6.11.1.1, the effective span can be determined differently for simple spans and continuous spans. For continuous spans, the effective span length should be calculated based on the points of contraflexure of the major axis bending moment under permanent loads, or by considering both simple supports and points of contraflexure. Following this approach, it is necessary to specify the result extraction case that represents the permanent loads to identify the points of contraflexure and, subsequently, the effective spans. This parameter is used to define the result extraction case to be applied in calculations related to contraflexure.

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

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 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.

Distance from the Centerline 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.

Distance from the Centerline 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.

Cover Plates

Cover plates are additional plates that are attached to the flanges of girders to enhance the flexural capacity of the girder over a certain section of the beam. The load rating object provides users with the option to add side and cover plates to the top or bottom flange. Section modulus and stress values will be calculated based on these inputs under live loads. However, actual girder plate dimensions will be used for other permanent loads.

Top Flange Cover Plate Width:

Top Flange Cover Plate Thickness:

Bottom Flange Cover Plate Width:

Bottom Flange Cover Plate Thickness:

Top Flange Side Plate Height:

Top Flange Side Plate Thickness:

Bottom Flange Side Plate Height:

Bottom Flange Side Plate Thickness:

Section Losses

In case of corrosion in tub girder sections, section loss parameters can be used by the user to decrease the section dimensions or cover plate dimensions. If section dimension loss parameters are applied, stress caused by permanent loads and live loads will be calculated according to the section loss parameter. If only cover plate loss is taken into account, the live load stress computation will be the only one to utilize that parameter.

Top Flange Width (%) Loss:

Top Flange Thickness (%) Loss:

Bottom Flange Width (%) Loss:

Bottom Flange Thickness (%) Loss:

Web Thickness (%) Loss:

Top Cover Plate Width (%) Loss:

Top Cover Plate Thickness (%) Loss:

Bottom Cover Plate Width (%) Loss:

Bottom Cover Plate Thickness (%) Loss:

Web Cover Plate Thickness (%) Loss:

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.

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.

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 : This parameter is used to determine whether the effective deck width value is to be overridden.

Effective Deck Width : This parameter is used to specify the deck width value to be used.