Advise on accommodating a staircase in existing structural plan

I  have been following your articles and this forums for the information all about construction. This website is  of a great help for all of those having questions about construction.   I wanted your advise and below is my question.

I am constructing a house which has just completed Column footings and casting columns until ground level height . We are in process of filling up earthwork and planning for plinth beams as next item.  We initially  planned for Stilt (Parking)+ 4 floors(Independent  Floor). Now we are thinking of having a duplex model for first and second floor with an additional internal staircase connecting first and second floor and need your advise on that.

I have attached floor plan, Column Footing drawing and schedule for your reference.

Is it possible for us to include staircase without much changes to the existing structural plan.  

FYI- Column sizes are 9" X 15".

I have marked the location of staircase in the floor plan with  blue color.

Before discussing this with our Engineer, I would like to have your expertise advise. 

Thanks for your time in advance. Awaiting your valuable response.

Your Sincerely,

Naveen