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123456789_123456789_1123456789Cable-stayed Bridge Software 

Model Examples
ICDAS YouTube Channel   ICDAS CSB 2018.01R

Road Bridge Model Examples
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Cable-stayed Bridge
Model Examples



Model description



Input



Geometry model



Analysis model



Landscape model

 

 

 

ICDAS Basis of Design



Workflow of Software



Additional features



Rendering & Animation 



Case Study and 
Research
 



Subsciption











































 

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Design in immersive visualization

 


New Lusas 16 and Revit LIVE has raised design of bridges in a new level of graphical visualization. Revit LIVE allows the users to enter Virtual Reality just by one click ‘VR’, and one click ‘Go Live’ from Revit to Revit LIVE. In Virtual Reality (HTC headset required) the users will experience immersive visualization of the bridge in ratio 1:1 and 360°, on top of deck or inside the deck box.

 

In addition, ICDAS has successfully developed addin to automate both of Lusas and Revit models from Excel parametric input. In short time, the users can create and upload the model on cloud service (Revit LIVE) and share the model with others anywhere in the world by sending a link in an email. It is practical even in the same country for all partners in a project. 

 


Figure: Danube 2018 Idea Model. Lusas (left) and Revit model in Revit Live (right). 

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Lusas V16.0-1c1 new 3D perspective view and Revit Live 2.0 require both graphics memory for testing on 300m length cable-stayed bridge above. ICDAS has run them both (and Revit) and found out that the monitor is updated significant faster if one of the modes is shut down. Lenovo laptop i7-3720QM CPU 2.6GHz 32GB RAM and graphic adapter NAVIDIA Quadro K2000M 2GB RAM has been used. Refer VDC hardware and wearable devices for further information. However, Lusas and Revit work smoot concurrently during automation test in wireframe visual style and realistic visual style in Revit without attention.


 

Revit LIVE 2.0

 

Revit LIVE is not needed in ICDAS CSB but it is recommended to subscript it in Autodesk AEC CollectionRevit LIVE graphical visualization and Virtual Reality is the future and already applied in many companies today. When you orbit and fly in Revit LIVE scene the first time there are some notices below:

 

- The Revit model Danube2018.rvt tested here is only 6.724MB. The ‘Go Live’ button create a so-called live-scene file

  Danube2018.lvsc of 436MB, a folder Danube2018* of 486MB and a folder Danube2018*_data of 3.19GB. The two big

  folders include maybe i.a. Virtual Reality technology. Once upload on the cloud, you can save the live scene *.lvsc and

  associated folders anywhere in an external hard drive. The scene is on the cloud where you can open it anywhere from

  any PC/Laptop with Revit LIVE and internet connection, and without the need of Revit model.


- You cannot move the model physically (as in Lusas or Revit) but fly around it. It is especially unusually to focus on the

  bridge with big length-to-width ratio compared to a square building.

 

- Language codes for Revit LIVE is maybe in internet programing, unlike normal language for working on local PC/Laptop.

  You can enter your scene anywhere from any PC/Laptop by sign-in in your cloud service account.  


The images with cloud background are from Revit LIVE.


Design with ICDAS automation is best to work with both of Lusas and Revit concurrently. ICDAS CSB has coded Lusas model first then use to Revit. Some dimensions need to measure and some additional help-lines sketch in Revit to find a common input for both of models. Lusas FEM analysis is useful to design as well, e.g. at pylon-deck clash. Below are some images for working with ICDAS CSB.


 

Revit model

 

The pylon, cable arrangement and deck can be easily modifying by parametric input for a new look. For symmetric bridge the design time is reducing to a haft since a mirror copy take no time in Revit. The figure below has only taken time to enter parameters in Excel input, run addin in Revit and upload the model on Revit Live. The detailed work for pylon-deck clash is implementing manually and easily. 

 

 

Figure: Revit model uploaded on Revit LIVE cloud service. 

 

 

ICDAS CBS automates the outer contour of streamlined deck where the internal thicknesses will be designed manually with ICDAS Revit Manual. For double symmetric bridge deck, the user only need to create thicknesses on the left haft of the deck cross section, then copy mirror to the right haft, as shown below. 

 

 

  

 


Figure: Streamlined steel deck with stiffening ribs unloaded from family files.

 


ICDAS provides library of stiffening ribs for different sizes and shapes for rectilinear alignment streamlined steel deck. Further, the users can apply the step-by-step ICDAS Manual to model new ribs and add to the library (Revit family files).

 

ICDAS CSB is including concrete bridges (COB) for approach bridges and the cable-stayed deck can be in concrete as well, e.g. in combination of concrete-steel-concrete for side, main and side span. The cable-stayed concrete box deck need some input manipulation outlined in Cable stayed bridge User's Manual.


 

 

Lusas model

 

Easy to identify each group of elements in the bridge

 

 

Together with automatic creation of the FEM model, ICDAS automates also groups for pylons, cables and plates for each group of the streamlined deck box in Lusas Groups and Attributes tab as shown below.


 

 

Figure: Check thicknesses of plates creating streamlined deck girder. 



The users can e.g. check thickness 16mm for every 2nd cross plates at the cables, by right-click on the attributed names and ‘Select Assignments’ shown above, for the left and the right cross plates.

 

 

Pylon-deck clash

 


Figure: Split deck surfaces and delete at pylon.



The figure above has set visible only 4 sections of the deck at the pylon leg where the right haft top of deck plates is set invisible.  By default, ICDAS automate all nose plates along the deck. The users can easily delete them at the pylon, manually. It can be done by Lusas splitting surface in parametric distance (into two surfaces in this case). Set 4/7 for section on the side span, and 3/7 on the main span as all longitudinal surfaces has X-axes in the bridge STL direction. There are 7 elements mesh in these surfaces and factor 3/7 successfully fit the needed space. Otherwise, set parameter between 0 and 100% length of the section. Once splitting, just delete the nose surfaces at the pylon.

 

The case of vertical pylon, more space is needed at the deck in cross direction. Therefore, the designed line L3 (and R3) are to create surfaces to be delete at the pylons. In this case they are 1100mm from line L2 (and R2). Thus, the emergency lane 3000m reduces to 1900mm at the pylons. All distances input for line L1, L2…, R1, R2… are specify in Excel input file.  

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Figure
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Undeformed cables geometry in Lusas perspective view.
 

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Geometric Nonlinear Analysis & Virtual Reality

 

Because of large cable sag in cable-stayed bridges, the cable force is not varying linear with traffic loads on deck, even from the deadload condition. Therefore, nonlinear analysis is employed to computer the cable sag based on an initial input of cable tension. The initial cable force can be calculated as its vertical component assumed to be equal to the weight of the deck section (kN). With this linear assumption we will get zero vertical displacement of the deck at the cable point. By say ‘linear’ we assume the cable is perfectly rectilinear with 0 cable sag, which is not in reality. Therefore, the nonlinear analysis - once convergence – we get the cables force closed to the initial tension, and a cable sag corresponded to the assumed initial tension. Note that, as many nodes (=elements+1) defined along the cable line, as long time to take for the nonlinear analysis (6 equations to solve for displacements at each node).

 

Figure to the left show the undeformed geometry of the cables line (rectilinear line from the deck to pylon point automated from LusasCSB.cmd). Once perform a nonlinear analysis, the new perspective view of Lusas will show a realistic cable sag e.g. at dead load condition. Create these deformed cables FEM nodes in Revit, upload on Revit LIVE and go to Virtual Reality with HTC headset, we will experience the cable sag as standing on the real bridge. Thus, Revit and Lusas combined from the start, and from results of the FEM analysis to reflect the bridge before it is built as well.

 

Refer case study for further details about nonlinear analysis. Refer Lusas cable tuning analysis for linear structures for calculation of the cable initial tension. The tuning is useful in case of asymmetric side span – main span having different section length of the deck. The obtained cables force will then be use as input for the nonlinear analysis, if the cables sag is not neglected. 


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 Updated 01-02-2018 




123456789_123456789_1123456789ICDAS  •  Hans Erik Nielsens Vej 3  •  DK-3650 Ølstykke  •   E-mail: th@icdas.dk   •  Tel.: +45 20 20 33 78  •  CVR no.: 34436169 
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