Steel I Girder Code Check T [SIG]

General

Load Combination Table: The load combination table is used to map the analysis result cases and their corresponding factors to the template, along with the limit states. It serves as the basis for all finite element analysis results used in the code check equations.
Check For[StrengthServiceFatigue/Construtibility]: The code check component only allows for either a constructibility or a strength-service-fatigue limit state check in a single run. Therefore, if the user intends to perform a constructibility check, the finite element results that need to be mapped will likely differ significantly from those required for a strength-service-fatigue limit state check.
Include Haunch For Section Properties[Yes/No]: According to DOT requirements, haunch area may or may not be included in the sectional property computations. When haunch is included, it increases the inertia and section modulus and decreases the stress values, making the calculation less conservative. When the option "Include Haunch for Section Properties" is set to "No", the dimensions of the haunch are still used to determine the locations of the deck and girder sections. As a result, entering a larger haunch depth can lead to a higher section modulus, even though the option to include the haunch is set to "No".
Mlat Comp Method[FEA/AASHTO_Eqn_C4_6_1_2_4b_1/EnvelopeofFEAandAASHTOeqn]: If the user selects the FEA option, the lateral bending moments are calculated using finite element analysis. The OpenBrIM model divides the steel I-girder into three finite elements, using a beam for the top and bottom flanges and a shell for the web. This approach provides the user with a more accurate way to calculate realistic lateral bending values. However, if the user prefers to use the AASHTO equation, which converts the major axis bending moment to lateral bending, it may result in a more conservative approach. OpenBrIM provides an additional option for the user called "Envelope of FEA and AASHTO equation" which selects the larger value between the FEA and AASHTO equation results.

Select State Provisions: In cases where additional code checks are needed based on state provisions, this parameter can be used to specify the required state provision.

Type of Construction [ShoredConstruction/UnshoredConstruction]: For steel I-girder bridges, unshored construction is commonly employed. In this method, any permanent load applied before the concrete deck has hardened or become composite is assumed to be borne entirely by the steel section, while any permanent load and live load applied after this stage are assumed to be supported by the composite section. In the case of shored construction, all permanent load is assumed to be applied after the concrete deck has hardened or become composite, and this information should be clearly stated in the contract documents.

Fatigue Parameters

ADTT: The annual daily truck traffic is a parameter used in fatigue checks.
Number of lanes available to truck: Number of lanes available to truck is a parameter used in fatigue checks.

Ductility Parameter

Including the haunch in determining Dt [YES/NO]: This parameter can be used to specify whether the haunch will be included in ductility checks within the code checks. Since including the haunch is optional, the total depth is calculated based on the actual haunch depth if this parameter is set to 'Yes', or calculated conservatively if set to 'No'.

The ductility-related code check can be performed either by making a conservative calculation or by directly using the modeled haunch depth. The screenshot below provides an example of excluding the haunch in determining Dt, with the parameter set to 'No'

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Appendix A6

These provisions shall apply only to sections in straight bridges whose supports are normal or skewed not more than 20 degrees from normal.

Use Appendix A6 Provisions[Yes/No]:The optional provisions of Appendix A6 account for the ability of compact and noncompact web I-sections to develop flexural resistances significantly greater than My. The potential benefits of the Appendix A6 provisions tend to be small for I-sections with webs that approach the noncompact web slenderness limit of AASHTO Eq. A6.1-1. If the user selects "Yes" for Appendix A6 provisions, the code check component will internally verify for additional requirements and will not use it if all conditions are not met.

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.

Use Appendix B6 Provisions[Yes/No]: If the user selects "Yes" for Appendix B6 provisions, the code check component will internally verify for additional requirements and will not use it if all conditions are not met. If all conditions are met for the support stations, the code check will report the amount of major axis bending moment to be redistributed (Delta Mrd) from piers to span regions for strength and service limit states. This information can be used to determine if using Appendix B6 satisfies the AASHTO requirements for the support locations in their first run.

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.

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(Ser): 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.

Deflection

As specified in AASHTO 2.5.2.6.2, "The live load portion of Load Combination Service I of Table 3.4.1-1 should be used." Additionally, you can directly set a deflection case.

Support Lines Used For Span Length Comp.[All / Selection]: In some projects, the support line object can be used as an extra bearing point. In this case, the span length calculation may not be done correctly. In such situations, it is important to manually select the supportlines that separate the spans.

Selected Support Lines: Manual support line selection for span length calculation.

Criteria for Deflection L/: The value to be used in the deflection limit calculation as specified in AASHTO 2.5.2.6.2.

Deflection Result Case from[Service I-LL Case/User Input]: Selection of the deflection case source.

Deflection Result Case: Set Manual deflection case instead of Service 1 LL case.