I have a circular section with D=1000 mm The nonlinear temperature is shown in the pic
I assume that the nonlinear temperature on the section will be like the red portion in the pic
I can calculate the equivalent axial force and moment based on the equation in Sofiload manual:
Axial force N=2061.7kN, moment=557.8kNxm
While Sofistik give me,
Axial force N=793.3kN, moment=313.2kNxm.