Question: Load bearing walls and poured-wall basement
How are load-bearing walls on the interior of a house supported in a basement built with poured concrete walls? Posts and steel beams? Is this the typical, most cost-effective way?
The background to this question is: I am designing our home, playing off a Don Gardner plan and my sister is advising me. She has taken residential construction classes and GC'ed her own home and two additions to that home, and a total remodel of the original part - so, in other words, she is extremely knowledgeable! But she doesn't have experience with building on a poured wall foundation, only on a crawlspace.
In designing the finished, walk-out basement on our plan, she advises me that the walls in the basement HAVE to be in line with the load-bearing walls on the main floor to carry the load. I completely understand the concept and am not doubting that. But I thought that in a finished basement, the load is still carried by steel posts and beams, not by the studs in the walls. I thought that in finishing the basement's interior, the posts are either incorporated into the walls or are finished out as decorative columns.
Am I on the right track? My sister insists that the steel beams and posts is costly and will be one more thing driving up our already over-budget plan. In our current home which was completed when we bought it, the builder used engineered wood I-beams (forgotten the trade name for these) which I am guessing take the place of steel beams and posts. My sister insists that this method will be even more expensive.
(I've included a photo "borrowed" from the May post by ImaCurvyGrrl. I hope she doesn't mind!)
This is what I think of as the "typical" construction method for finished basements.