123456789_123456789_1123456789Cable-stayed Bridge Software 

Analysis Model
ICDAS YouTube Channel   ICDAS CSB 2017.00R

Geometry Model 

123456789_123456789_1 Page  1  2 
Cable-stayed Bridge
Model Examples

Model description


Geometry model

Analysis model

Landscape model

ICDAS Basis of Design

Workflow of Software

Additional features

Rendering & Animation 

Case Study and 






How to create LUSAS model automatically?

It happens when you import LusasCSB.cmd in Lusas (File > Import). The LusasCSB.cmd is created automatically

when you run ICDAS Add-Ins in Revit. The input files is located in C:\ICDAS\ICDAS BRIDGE when you installed

ICDAS CSB 2017.00R



What is created automatically in Lusas?

§         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)

§        Parametric lengths of element of the cable (3D Thick nonlinear beam)

§        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 2017.00R. 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).



FigureCross Section with 3D shell elements (Top)

 Thickness equivalent assigned to top and bottom plates of deck (Bottom)





Longitudinal plate and span input


A longitudinal plate is created by a top and a bottom

line of deck. The input to the right shows 4 longitudinal

plates on the left side of STLo nLoL=4, and four on the

right side nLoR=4.


Lines L1-B4, L2-B3... define the left longitudinal plates,

and R1-B6, R2-B7... define the right longitudinal plates.

The thickness of each plate is specified at row 4 and 7

for the Left and the Right side plates of STLo,

here 16mm.


The lengths of the spans are given in m in row 1.

The length of a section, e.g. Sect=7.5m is given in 

row 1 column (4). There are 7 elements (~7.5m)

automatically created along the section in STLo


cDia=200mm is the diameter of the cables visualized

in Revit, input at row 1 column (7).



Alternative Text 

Figure: Input of spans and 
longitudinal plates

Updated 17-06-2016

Page  1  2

123456789_123456789_1123456789ICDAS  •  Hans Erik Nielsens Vej 3  •  DK-3650 Ølstykke  •   E-mail: th@icdas.dk   •  Tel.: +45 29 90 92 96  •  CVR no.: 34436169