Custom Diaphragm [PIG]

Bracing

Girders: Choose the two girders that are connected by the custom diaphragm.

Skew Angle : A positive skew value rotates the custom diaphragm in a clockwise direction, while a negative skew value rotates it in a counterclockwise direction. It is important to remember that the custom diaphragms are positioned at the specified station along a line perpendicular to the PGL, which is then rotated according to the entered skew value. The skew angle can only be specified if the station of the diaphragm is defined with a value. Otherwise, if the station of the diaphragm is defined using the provided options (Start/End), this parameter will not be applicable (N/A).

Open

Station [Start/End]: Define the station either using the options Start/End or by entering the station along the PGL. When dealing with curved girder bridges, collecting distance along the girder length can lead to different inputs for the right and left girder that are connected by diaphragm, causing ambiguity. Therefore, collecting the station along the PGL is a more reliable solution to avoid such issues. Furthermore, since diaphragms are typically continuous in the transverse direction, entering the same station for all diaphragms ensures that their locations are consistent between each girder.

The same principle can be applied for skewed diaphragms. If the user enters the same station and skew values for the diaphragms between Girder 1-2, Girder 2-3, and Girder 3-4, it ensures continuity between the diaphragms. It should also be noted that the diaphragms are positioned along a line perpendicular to the PGL, which is rotated according to the entered skew value.

Inaccurate finite element models and disconnected nodes/elements in the diaphragm can occur if the entered station values are not >= the girder start station or <= the girder end station. This can cause stability issues in the finite element model. To ensure correct station input, users should select the start/end options from the station input. This approach is especially recommended for diaphragms located at the beginning or end of girders.

Open

Section: Assign a section for the diaphragm.

Offset from Center of Web :The parameter represents the offset amount from the center of the girder web to the diaphragm.

Offset from Top of Girder: The parameter represents the offset amount taken from the top flange boundary of the girder for the diaphragm object.

Type [Truss/Beam] : The finite element representation is in the form of a truss or beam. The finite element representation is in the form of a truss or beam. Trusses can be used in cases where axial forces (tension and compression) are needed for calculations, while beams can be chosen for cases where bending, shear, and axial forces must be taken into account.

Orientation Angle: This parameter can be used to specify the orientation angle of the diaphragm.

FEA

Axial Rigidity Coefficient: This parameter can be used to define the axial rigidity of the element, which is directly related to its stiffness. Thus, it plays a crucial role in the analysis and design of structural components.

Geometry

Chord-Vertical Distance of WP from the Top of the Girder: The location of the FE line in the vertical direction relative to the top of the girder can be adjusted using this parameter. The definitions for this tab will affect both the 3D and FE models.

Chord-Horizontal Distance of WP from the Center of the Web:The horizontal distance of the WP from the center of the web can be adjusted using this parameter. This definition will affect both the 3D and FE models.