Friction due to thermal effect (Eurocode)

[Moksh]

I have a unrestrained steel beam sitting on another structure. Movement due to thermal effects leads to friction between the two surfaces. I am not sure whether I should consider this friction as:
1. Variable action as it is caused by thermal effects
2. Or permanent action as in this case it is equal to coefficient of friction x self weight of beam only.

EN 1991-5 states that thermal actions are to be considered as variable actions. However, friction is an indirect action caused by thermal movement and EN 1990 states that indirect actions may be either permanent or variable.

Any views? Thanks in advance.

 

[ishvaaag]

Since really you are looking at an effect of a thermal load, and considering that rheological loads, temperature one of them, have always been considered with separate set(s) of coefficients, I think considering it as part of the permanent actions would be contrary to the customary intent in the combinations, and quite likely to that of Eurocode.