2013 ?!? Hold the phone... are some structural engineers driving cars younger than their EIT's? I must be doing it wrong; my 2005 Matrix still parks outdoors.
In broad strokes:
1) At the bottom, I found the "doing" of structural engineering to be an odd mix of exhilaration and tedium. With the introduction of software, it's a blend of god-like behavioral exploration and the playing of a super boring version of Minecraft. Many find the pace a bit grueling. It can be a field replete with intellectually stimulating, arcane, "beyond college" challenges but that generally requires a lot of pro-bono, after hours effort.
2) In the middle it's a game of project management and not much different from project management in any number of other fields. Stick to the budget, stick to the schedule, keep quality high enough that you don't kill anybody, keep your boss happy enough that you keep moving forward in your career, keep your minions happy enough that they keep your projects moving forward
and keep moving forward in their careers. You'll spend a lot of time coordinating your efforts with interesting folks from the other engineering disciplines that are involved in your projects.
3) At the top, it's a game of sales, business administration, and very high level project management not much different from top tier positions in other fields. Be a consistent, profit Rockstar. Make sure that your local reputation is such that your firm has to be concerned that your high value clients would leave with you if you left. Help the mid-level project managers be successful and lead good lives rather than crumble under the intense pressure from both above and below in the org chart.
At all levels, it will be satisfying and pay dividends to make contributions to the field outside of your project work by way of mentoring, committee work, adding to the body of knowledge, etc. Structural engineering is interesting work and, at worst, a decent living. The "doing" of structural engineering pays little. Successful project management pays reasonably well, as in any field. Successful sales pays
very well, as in any field.