Lane definition in grillage model 

Question:

How to assign traffic lanes in grillage models?

Example: 
I am currently carrying out a assessment of a bridge using HA, HB and SV loads. 

I am getting very high load effects, both bending and shear under live loads only i.e. HA,HB and SV. 

For self weight and other static loads the load effects are ok.

I have looked in to various things and I am unable to find the cause.

I have attached the Midas model for you to investigate.

see example of very high bending load effect under HA.


Answer:

Step 1:  Create a structure group containing transverse cross-beam members, as shown below. The bridge is a grillage model, so the transverse cross-beams group should be used for live load lane definition.



Step 2: Activate the crossbeam group in each live load lane definition as shown below. 



Note: High loads will be experienced if the vehicular distribution of lane elements is selected in grillage bridges.

Referring to the example:  After changing the vehicular distribution in traffic lanes to crossbeams from lane element, live load result for MVall: HA for bending moment values reduces drastically.




Creation date: 6/4/2021 3:57 PM      Updated: 5/21/2023 2:06 PM
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