Flared Girder Geometry Appendix
Precast/Prestressed Girder allows the user to accurately model realistic geometric conditions and handle analysis of more advanced cases wherein girders may not be parallel to one another, and have been laid out as flared (splayed) girders, and also cases where start and end skews may cause individual girder lengths be different. Currently, while the vast majority of prestressed slab on girder type bridges would still fall outside the realm of flared girders, recent trends (bridge rehabilitation, widening, restrictive urban site/geometric constraints, precast girders on curved alignments) are beginning to indicate the demand for more complex geometric layout and analysis.
General Operation
When the option to use Flared Girder Geometry is selected on the Project tab in Precast/Prestressed Girder, the Geometry tab is transformed to present a more advanced user interface allowing the user to enter information for alignment, bridge layout and cross section. Two dimensional drawings of elevation, section and plan allow the user to verify the information modeled in the dialogs. This option is limited to I-Girders, Spread Box Beams and Open Box Beams (i.e. U-Beams). Switching between Flared Girder and Non-Flared Girder options is allowed for these beam types, but information may be lost when switching from Flared Girder Geometry to . The individual dialog input and definitions are explained in the following sections.
