AASHTO Truck Loading 2

[BR0]

The AASHTO Bridge truck loading has a "Design Truck" and "Design Tandem" loading. The design tandem loading is defined as a pair of 25.0 kip axles spaced 4 ft apart. These loads are applied with the lane loading.
When applying these tandem loads the diagrams I've seen appear to show the loads acting independently of the remaining portions of the truck axle loads. I've attached a loading diagram from a Structure Magazine article.

https://www.structuremag.org/?p=15753

My question is if this interpretation is correct: When you apply the load case with the two 25 kip loads combined with the lane load you don't include any other truck point loads to the span?

Thanks in advance

 

[STrctPono]

Your interpretation is correct. Within that span and within that lane, there are no other truck axles to consider... only the lane load. The 3rd diagram you posted represents the truck train that is only to be used for considering interior pier reactions and between points of contraflexure for negative moment effects.

Trucks adjacent to that one (different lane) but within the same span are accounted for with the MPF and the LLDF.

 

[BR0]

STrctPono, I appreciate the response.