Look at the school programs. It would be easier to possibly do a B.S. in Structural Engineering or possible Civil Engineering and then do a 3 yr. M.Arch with possibly a co-major in Structural engineering at a Master's level. Depends on the schools you attend and the offering.

If you find a qualified accredited school offering a B.S. in Structural engineering... do that and then M.Arch (3+ year professional program for those with a bachelor's degree not in Architecture)

I don't know about schools offering Masters in Structural engineering without requiring a B.S. in Civil Engineering. However, a B.S. in Engineering (structural) and going into an M.Arch.... sure.

Talk to the schools themselves about their programs and put the information together. One, you'll have the most current and up to date information about the programs by talking to the people running those programs directly....not someone who might ave been able to do it 10-15 years ago. It doesn't mean that can be done today. 

I believe it should be able to be done but if you do the leg work, you'll know.