How to factor a combination correctly?
In terms of factoring a structural combination 1.2G + 1.5E but assuming that the seismic was occurring with the pipe at T1. If take the Gr and E1 components from a GRT1E1 combination and factor them separately appears that unwanted friction force are being included.
Based on the example above, the forces and moments of single load case 'components' during load sequencing is a delta force between the previous load case applied and the current load case being applied. If looking to apply an earthquake without a thermal case (cold), set the default state to GR, not OP1. This should provide GE1.
For load sequencing, GE1 should be the load being factored by 1.5, as this is the load the structure experiences during the earthquake. Gravity should be the load that is factored by 1.2
Note: AutoPIPE 10.00.xx.xx and higher has fixed the following issue: TFS-D169522: Frictional Seismic Loads on Supports Wrong
"Non-Code Comb." tab