It is too conservative and unnecessary to use a 1.2 load factor for the TU load case for design/analysis of substructures. The 1.2 load factor is only needed when calculating thermal movement for joints, expansion devices, and bearings as stated in AASHTO LRFD 10th Edition page 3-13. Using a max TU load factor of 1.2 along with a min TU load factor of 0.5 also unnecessarily doubles the load combinations which increases the time needed to run the design and analysis.
| Civil Product Used | OpenBridge Designer |
I agree that the max load factor 1.2 should not be used for force effects when evaluating the strength/service limit states. However, using load factor 0.5 could lead to an unexpected less conservative design if the partial cracked moment of inertial is considered. So, I suggest using the default max load factor 1.0 and min load factor 0.5 for the strength limit states. Please let me know if this works for you.