Shemp,
I agree with Polecat that ASCE would be the most appropriate organization for membership to cover structures and all of civil engineering. ASCE has the Structural Engineering Institute (SEI), to which you can be a member for free if you are an ASCE member (with the publication Structures). In my experience, ASCE also has the more active local groups where technical meetings and conferences along with networking can be advantages.
If publications are your main incentive, some may be obtained without membership (for example, Modern Steel magazine from AISC). Many other publications are only discounted by memberships.
To summarize:
1) The organization that you will be most active in will provide the best membership rewards, so choose what you want to do.
2) The organization that can best help you career-wise will be the one most closely linked to your business class and technical skills. ~dison