#firstquestion Hello Sir, Do we have to consider EQx+-0.3Eqy or Eqy+- 0.3Eqx for the column in inclined grid ?

Hey Happy to help you. Civilera forum is to discuss questions and learn from it.

Registered students for paid memberships do have another forum where they can learn from daily discussion on topics that I announce.

IS 1893 2016 and most seismic codes suggest you to take 30% of seismic forces from the other direction of the columns are not orthogonal. Here in this case where you have shown the structural scheme/structural column layout, this is not applicable. You have the grid alone drawn inclined.

Here is a video below which will clarify your doubts. However please read the entire answer below aswell for full understanding and for some more general structural doubts posted by students.

Students have doubts on many points like this. Some are listed below.

1) If the entire building plan is inclined,should one consider this clause

Ans : No. You can tilt the plan and make it horizontal. Architect might have shown the plan inclined and a reference road straigt. Does not matter. You can tilt it to make it straight in plan and model for analysis

2) What if the building has a V shape in plan and one leg or both legsa are inclined in plan?

Ans : Option 1 and the best - Provide a separation joint in the building and make 2 legs separate and analyse separately as normal 2 buildings

Option 2 : If the joints cannot be provided due to any reason, make 1 leg orthogonal and then do the analysis. Create normal combinations and the special combinations with 30% extra in the other direction. For straight portion, use normal combinations and for non orthogonal portion use the special combinations for design.

3) Why are we considering this. Or why is ETABS and STAAD considering only seismic in orthoganal direction only, ground can move in any angle in plan?

Well, the maximum forces occur in members when it is orthogonal to loads. Hence you are good to consider this way.

I had done a webinar some time back on this topic and see it in the video. Hope it helps.

More of civilera blogs, you can read here and see the structural design videos.