How to create LUSAS model automatically?
ICDAS CSB 2022.00R is including Concrete Bridges (COB). Refer ICDAS COB for how to create LUSAS model automatically. In Excel BRIDGE sheet set parameter Bridge (=2) for Cable-Stayed Bridge Revit and Lusas models, (12) LusasCSB.cmd only. What create in Lusas automatically ?
§ Geometric points, lines, surfaces with dimensions of the bridge as designed in Revit model from input.
§ Attributed meshes with names Top and Bot, Longi, Cross of the deck box are useful to make visible/invisible for control of the deck (3D shell QTS4). A surface element has dimension 1mx1m. § Parametric thicknesses of plates of the deck box given in input where the plates are created (top, bottom, longitudinal, cross)
§ Cable connected section point on the deck and the pylon in distance h5 automatically. (for Revit CabOffset is the cable end offset from bottom of deck, positive upwards)
§ Pylons and cables in 3D Thick nonlinear beam BTS3 elements
§ Groups of plate elements, pylon legs and cables on the left and right side of STLo overpass Stiffening ribs
The stiffening ribs are not modelled in the main model at Version 2022.02R. Instead the thicknesses of the top plates, bottom plates are calculated as equivalent tequi so the plates have the same bending stiffness as the original plates with stiffening ribs. The densities of these plates will be multiplied with an associated factor A/Aequi of the cross section area in order to keep the same weight as the original plates. The stress analysis by this assumption is therefore only valid for: SX-Top, SY-Top on the top plates (because the ribs at the bottom are missing) SX-Bot, SY-Bot at the bottom plates (because the ribs on top are missing)
Equivalent thickness and density
The top of deck is constructed with a top plate and stiffeners as shown in the cross section figure. The equivalent thickness tequi is calculated for a width B and assigned to the top plates of deck which is modelled as a rectangular 3D shell element QTS4. Structural lines input
The cross section of deck is constructed by the structural lines defining the top and bottom of deck. These lines are parallel to the STLo overpass. The cross section in figure below shows an example of 5 lines on the top left (L1-L5), 5 lines on the top right (R1-R5) and 9 lines at the bottom (B1-B9). Refer Geometry to input these lines.
Figure: Cross Section with 3D shell elements (Top) Thickness equivalent assigned to top and bottom plates of deck (Bottom) | 
