Hello,
I have a bridge model that is consistently telling me there are fatigue stress issues with my plate girder section.
I have exported the live load range that the model has created for a given girder and while comparing it to the section modulus at the locations reported to have issues I am coming up with a stress that is significantly less that what is reported.
When I use just the bottom fiber Sx for the areas, I compute the stress for point 42.18 as follows:
When I add in the load factor of 1.75 x 2 ksi I get the stress to be 3.52 ksi at point 42.18 for example. The fatigue report is telling me this stress is being computed for the 12 ksi allowed is 1.75 x 6.089 = 10.66 ksi. This leads to the the report of 88% of capacity being returned.
I am not sure how to reconcile these stresses, the model I have is a bridge that is skewed in excess of 20 degrees, so perhaps there is a deflection base later flange stress being considered, but the reports for this in the analysis do not return a lateral bending moment in the flange. If anyone can provide some direction it would be greatly appreciated, thank you in advance.
I got all the files and i was able to download successfuly. I shall test the file and will get back to you at the earliest.
Was this issue ever solved/explained? I believe I am having the same issue. I have V19 of LBS.