Girder [SIG]
Girder Layout: The girder layout is utilized to determine the position of the girder in both the longitudinal and transverse directions. Girder The user is not required to input the vertical elevation of the plate girders. The vertical positions of the plate girders will be generated automatically based on the alignment, deck thickness, and haunch thickness.
If the top flange width, bottom flange width, top flange thickness, and bottom flange thickness are changing at the same stations, the user can select all columns and view all parameters in one spreadsheet by clicking "Edit (Spreadsheet)."
Top Flange Width [in] / Top Flange Thickness [in] / Web Depth projected to CL of box [in] / Web Thickness [in] / Bottom Flange Width [in] / Bottom Flange Thickness [in]:
Users have the option to specify changes in the plate girder section dimensions either along the PGL or along the length of the girder. To access the editor, click on the three dots and choose "Edit (Spreadsheet)." If the user enters the length along the girder, the end station will be calculated automatically. Conversely, if the user enters the end station, the length data will be calculated automatically.
Girder webs can have nonprismatic variations, which are supported. To access the variation features, the user can click on the three dots and select "Variation" to open the pop-up window. From there, the user can define variations using linear, parabolic, circular, polynomial, or custom functions.
The finite element mesh takes into account the locations of section changes and various other mesh quality parameters such as aspect ratio, mesh element size, orthogonality, and skewness.
Haunch Thickness [in]: The haunch thickness is defined as the measurement between the bottom of the deck and the bottom of the top flange. Like plate girder dimensions, nonprismatic variations and various haunch values can be added by selecting "Edit (Spreadsheet)" from the three dots menu. Additionally, nonprismatic variations can be entered using the "Variation" pop-up window.
Additional Haunch Width [in]: The additional haunch width is measured from both the right and left extensions of the top flange. During deck construction, the automatic haunch load computation is impacted by both the haunch thickness and additional haunch width.
Top Flange Material - Web Material - Bottom Flange Material: Hybrid girders are supported, allowing the assignment of different materials to the top flange, bottom flange, and web. Furthermore, it is possible to use varying steel materials between different stations through station-dependent material definitions.
FEA Settings
Mesh Size (Longitudinal) : The maximum distance between nodes in the longitudinal direction is specified using the longitudinal mesh size. In most cases, a smaller mesh size can be generated based on the bracing locations, deck pouring or deconstruction definitions, or section change locations.
Mesh Size (Vertical): It has been introduced to divide the tub girder web in the vertical direction but is disabled in our standard workflows to reduce live load analysis result extraction time. It can be activated upon request by enterprise customers for specific projects.
Merge Tol: The "Merge tol"distance parameter is utilized to prevent the creation of small elements. If the generated mesh results in two small elements, it can increase the aspect ratio and potentially lead to incorrect finite element analysis results. Using the default value is a good choice unless you receive other recommendations from the OpenBrIM support team.
# of Result Extraction St.: The result extraction station settings are solely for viewing FEA composite results in either the spreadsheet or FEA view, and do not impact standard finite element analysis results like member end forces, node displacement, and node reactions. For girder code checks, exact code check stations will be utilized for FEA composite results.
Rigid Section: Rigid beams are employed to link the bottom nodes of tub girders with bearing locations/supports as seen in the screenshot below. Please refer to the following documentation to understand how to define rigid sections.
Add Comment