Questions about Traffic Load Optimization in Transverse Direction

In the CSiBridge (a Sap2000 equvalence for Bridge Engineering) and Midas Civil, the traffic load can be optimized in the trasverse direction as follows:

  1. In each single lane, if width of the traffic load is less than width of the lane, the traffic load can move in the transverse direction of the lane to get the most unfavorableload effect.
  2. If the total width of multiple lanes is less than the total roadway width, the softwares will optimze the lanes in the transverse direction to get the most unfavorableload effect. This is so called “Floating lanes” in the CSiBridge

In Midas Civil, it’s called Traffic Load Optimization

Moving Load Optimization
Moving load optimization allows you to find the number of loaded lanes and the exact position of vehicles in the transverse direction as well as longitudinal direction, which will give the most critical responses.

How to optimize traffic load in the transverse direction in Sofistik Teddy?

I may find something that can do “Traffic Load Optimization in Transverse Direction”
But I have some questions:

  1. In Ella -> LSEL -> DY, it means Influence width of the lane.
    The default value is 99m, which is much larger than the width of a single lane, is it means if DY is larger than the width of a single lane, the traffic load point will cover full width of a single lane?
    If DY is less than the width of a single lane, e.g. DY=2m, the width of a single lane is 3m, then 2/3 of the width of a single lane will be covered with traffic load?
  2. What’s the physical meaning of Ella -> LSEL ->B, YMAX and YMIN?


(1) The transverse shift can be applied with the commands ‘TRAIN YEX’ or ‘POSL YEX’. More detailed information about the commands can be found within the ELLA manual (chapter 3.17 and 3.22).

(2) SOFiSTiK is able to calculate the lane width automatically for standard lane widths according to the selected design code. The corresponding TEDDY command is ‘LANE’. If you are working with the eurocode, ELLA is calculating the lane width according to the table 4.1 (DIN EN 1991-2:2010).
In order to understand the features you can check out the SSD task ‘Traffic Loader’. This task shows you the possible lane arrangement gravically.

Further explanations are mentioned within our online bridge design training videos.

Best regards
Frederik Höller
Your SOFiSTiK Support Team

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I think YMAX and YMIN are suitable when you model your deck with quad elements and you use INT>2. If the deck is made with beam elements POSL YEX works very good.

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