Lane definition in grillage model
Question:
Answer:
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.
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FA8 Group [bents 58-14 58-15 58-16] - full slab width model one span.mcb 311 KB |
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