Hello Avadesh,

As you have determined, the straight Response Spectrum option is generic and not directly connected in any way to a country specific region or Code. So the calculation of the tensile and compressive allowables falls back on the base design Code.

I would suggest that you work with your regional representative and have a Change Request (CR) filed for this option. This would be categorized as a new feature and would be in the 2019 version at the earliest.