Rectangular [CBG]
Footing
Substructure: Choose the substructure element associated with the footing, such as columns. The center of the selected element will be utilized for positioning the footing.
Footing Width: The width of the footing refers to the measurement in the transverse direction along the PGL.
Footing Length: The parameter specifies the footing length in the longitudinal direction.
Thickness: The thickness of the footing is also employed to define the shell element thicknesses in the analytical model.
Longitudinal Offset: Employed to determine the position of the footing. Longitudinal offset along the Projected Grade Line (PGL), where 0 refers to the center point of the substructure above.
Transverse Offset: This parameter can be used to specify the location of the footing's center, where a value of 0 places it at the center of the chosen substructure. A positive value will offset the footing to the right, and a negative value will offset it to the left when looking up-station along the PGL.
Material: Material of the footing.
Rotation: This parameter is utilized to rotate the rectangular footing, with 0 indicating that it is perpendicular to the PGL.
FEM
Generate FEM ? [Yes/No]: Setting the "Generate FEM" parameter to "No" can disable the analytical representation of the footing.
Rigid Section: A rigid section is employed to establish rigid line elements that connect the footing to pier columns or piles. Column connections are established using five rigid elements to distribute pier forces to the footing from five distinct locations (center, top right, top left, bottom left, and bottom right) rather than a single point, which would result in unrealistic high stress concentrations. When the user assigns different sections, the locations of the rigid lines and the footing mesh adapt accordingly.
FEM Type[Shell/Stiffness Matrix]: This parameter is used to determine the FEM type preference. Stiffness Matrix: If you have one stiffness matrix representing the footing and piles for multiple columns, the 6×6 stiffness matrix option can be selected. As shown in the screenshot below, this object will create rigid elements and place a single 6×6 stiffness matrix at the centroid of those rigid elements. If a different 6×6 stiffness matrix is defined for each column, the pier object can be used to define those matrices.
Mesh Size: The maximum length of the shell elements representing the footing.
Min Number of Strips in Longitudinal Direction: The longitudinal direction corresponds to the direction that is along the length of the footing. The number of strips is employed to extract major axis bending moment results from shell elements using the fecomposite approach for design purposes. Essentially, it consolidates the forces of shell elements at their centers of gravity. If 1 is selected, the design will utilize the combined forces of all shell elements.
Min Number of Strips in Transverse Direction: The longitudinal direction corresponds to the direction that is along the width of the footing. The number of strips is employed to extract major axis bending moment results from shell elements using the fecomposite approach for design purposes. Essentially, it consolidates the forces of shell elements at their centers of gravity. If 1 is selected, the design will utilize the combined forces of all shell elements.
As per AASHTO C5.12.8.4, the moment of the forces acting on one side of the vertical plane passing through the entire section should be used; therefore, using one strip is suggested
6x6 Stiffness Matrix: If the Stiffness Matrix option is chosen, the 6x6 stiffness matrix can be specified. This matrix defines the resistance in three translational and three rotational degrees of freedom.
The expected 6×6 matrix terms are shown below.
Additional Result Extraction Point in Longitudinal Direction: Enter the distance from the back end of the footing to view results at that specific location. This does not alter the FEA model or introduce new nodes; the software simply interpolates between existing end forces. These station settings only affect how composite FEA results are displayed in the spreadsheet or FEA view, and do not impact standard analysis results like member end forces, displacements, or reactions.
Additional Result Extraction Point in Transverse Direction: Enter the distance from the right end of the footing to view results at that specific location. This does not alter the FEA model or introduce new nodes; the software simply interpolates between existing end forces. These station settings only affect how composite FEA results are displayed in the spreadsheet or FEA view, and do not impact standard analysis results like member end forces, displacements, or reactions.
Quantities
Bottom Surface Area: The surface area of the section assigned to the bottom of the rectangular footing is calculated and displayed to the user in this column.
Top Surface Area: The surface area of the section assigned to the top of the rectangular footing is calculated and displayed to the user in this column.
Total Pile Surface Area: The total pile surface area of the rectangular footing is presented to the user in this column.
Net Bottom Surface Area(excluding piles): The net bottom surface area of the rectangular footing, excluding piles, is presented to the user in this column.
Side Surface Area: The side surface area of the rectangular footing is presented to the user in this column.
Top Surface Perimeter: The top surface perimeter of the rectangular footing is presented to the user in this column.
Volume: The volume of the rectangular footing, based on the definitions provided by the user, is calculated and displayed to the user in this column.
Weight: Based on the defined geometry and material properties of the element, the weight of the modeled element is calculated and presented to the user in this column.
Height: The height of the rectangular footing is presented to the user in this column.
Top Surface Width: The top surface width of the rectangular footing is presented to the user in this column.
Top Surface Height: The top surface height of the rectangular footing is presented to the user in this column.
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