Steel Tub Girder Code Check [STG]

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".

Include Top Lateral Bracing for Section Properties? [Yes/No]: According to DOT requirements, the top lateral bracing area may or may not be included in the sectional property computations. When included, it increases the inertia and section modulus while decreasing the stress values, making the calculation less conservative.
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.

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).

Fatique Parameters

ADTT: The annual daily truck traffic is a parameter used in fatigue checks.
Number of Lanes Available to Trucks: 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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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.