Bay_ENG
Structural
- Aug 12, 2020
- 4
Hey all,
I was hoping someone could help me understand how live load distribution (LLDF) factors are applied. The wording in the AASHTO specifications isn't clear and I haven't been able to find any helpful resources online.
My question is this: Since the LLDF is in terms of "Lanes", how is this applied to multiple lanes of loading? In the live load section of (AASHTO 3.6.1.1.2) it is stated that the extreme live load force effect shall be determined by each possible combination of number of loaded lanes.
My understanding of LLDFs thus far is that if you have a single lane bridge with single lane loading your resultant girder moment is equal to your LLDF multiplied by the total moment due to live load (Lane+truck). In the case of 2+ lane loading, is the resultant moment in the girder equal to your LLDF multiplied (total moment/lanes) or is it equal to LLDF multiplied by total moment due to multiple lanes of loading.
I was hoping someone could help me understand how live load distribution (LLDF) factors are applied. The wording in the AASHTO specifications isn't clear and I haven't been able to find any helpful resources online.
My question is this: Since the LLDF is in terms of "Lanes", how is this applied to multiple lanes of loading? In the live load section of (AASHTO 3.6.1.1.2) it is stated that the extreme live load force effect shall be determined by each possible combination of number of loaded lanes.
My understanding of LLDFs thus far is that if you have a single lane bridge with single lane loading your resultant girder moment is equal to your LLDF multiplied by the total moment due to live load (Lane+truck). In the case of 2+ lane loading, is the resultant moment in the girder equal to your LLDF multiplied (total moment/lanes) or is it equal to LLDF multiplied by total moment due to multiple lanes of loading.