Girder Erection (Partial) [SIG]

If the construction of girders and cross frames needs to be divided into multiple stages, this component can be utilized. However, during the typical design process of steel I-girder bridges, a detailed analysis of the erection sequence for girders and cross frames is usually not necessary. Engineers who are responsible for girder erection typically conduct this detailed analysis after the design process.

General

Stage: Choose the stage in which you intend to construct the girders ,cross frames and lateral bracings.

Girders: Choose the girders for erection.

Girder Start Station: Entering the relevant stations, such as the splice point or girder start station, can be used to erect the girder in multiple steps.

Girder End Station: Entering the relevant stations, such as the splice point or girder end station, can be used to erect the girder in multiple steps.

Cross Frames: Choose the cross frames for erection.

The following objects are available for selection in the project:

• Cross-frame K Bot
• Cross-frame K Top
• Cross-frame X
• Cross-frame X (w/o Top Chord)
• End Cross-Frame
• Diaphragm
• Concrete Diaphragm
• Custom Bracing

Lateral Bracings: Choose the lateral bracings for erection.

The following objects are available for selection in the project:

• Lateral Bracing

Floor Beams: Select the floor beams to be erected during this construction stage. Floor beams connect girders and provide lateral stability.

Bolsters: Select the steel bolsters to be erected during this construction stage. Bolsters are the bearing pedestals that sit beneath the girders and carry load down to the bearings.

Splice Load [Ignore/Include]: If splice weight loads are to be included in the FEA, set the option to ‘Include’ for this parameter. If the option ‘Ignore’ is selected, the weight loads of the splices will be neglected.

Stiffener/Gusset Plate Load [Ignore/Include]: If the weight loads of the stiffeners or gusset plates are to be included in the FEA, select 'Include' for this parameter. If you need to neglect the weight loads of the stiffeners or gusset plates, select 'Ignore'.

Girder Self Weight Factor: The Girder Self-Weight Factor is a parameter used to adjust the contribution of a girder's own weight to the overall structural load calculations. This factor allows for the scaling or modification of the girder's self-weight in finite element analysis (FEA).

Cross Frame Fit

Fit Condition [No-Load Fit (NLF)/Steel Dead Load Fit (SDLF)/Total Dead Load Fit (TDLF)]: Same as on Girder/Cross Frame Erection (Complete): selects the fit condition for the cross-frames erected by this item and automatically imposes their lack-of-fit strains at this stage (locked-in forces reported under the EL — Locked-in Force Effects case). For SDLF the fit target is this item's stage geometry; for TDLF also select the Total Dead Load Stage. In multi-step erection sequences, set the fit inputs on each erection item that installs cross-frames.

Total Dead Load Stage: Shown for TDLF only — the final dead-load stage whose plumb-web geometry the cross-frames are fabricated to fit. For SDLF no additional input is needed: the fit target is this stage's geometry.