- Divide the cross-section to generate longitudinal members for the grillage model.
From the main menu, select [Structure] tab > [PSC Bridge] group > [PSC Box Bridge] > [Grillage Model]
Grillage Model Section dialog box
Select a cross-section to be divided into longitudinal members. The division locations of this section are applied to all the cross-sections along the bridge. The sections will only be shown which are defined in the Section Assignment in the Span tab.
Cautions when entering sectional dimensions
1. The applicable type of section is PSC-nCell, PSC-nCell2, and PSC-Value.
2. The number of cells shall be not less than two.
3. There must be a horizontal line at the top and bottom inside the cell.
Number of longitudinal members.
Automatically divide the cross-section for the grillage model according to two methods as follows.
The deck is cut into ’r;I-beams’ midway between webs.
The deck is cut into ’r;I-beams’ so that each web has identical proportions of top and bottom slab.
The section properties of the cross-section of the whole bridge before division.
The section properties of each longitudinal member after division.
Torsional stiffness per unit width of the longitudinal member and transverse member:
Moment of inertia per unit width of the transverse member:
The section properties of each longitudinal member with regard to the centroid of bridge cross-section before division.
After dividing cross-section into ’r;I-beams’ of the grillage model according to Division Option, change division locations by modifying the values of the table directly.