As the result of the Dynamic analysis is unsigned, you may want to create two load combination (Static+Dynamic) and (Static - Dynamic) . However, you may also use the signed response spectrum results. There has been a parameter in Response Spectrum load cases called DOMINANT. DOMINANT command is used for dominant mode method.
Please see the following link that discusses on using the signed response spectrum result in a column design.
communities.bentley.com/.../255558
Please see the following link that discusses on using the signed response spectrum result in a column design.
communities.bentley.com/.../255558