Bielec,
There's no frame in the fuselage. It's a semi-monocoque, fail-safe structure -- however there are some reinforcing elements (stringers and stations), it's the skin what bears significant part of the loads. (see
Fuselage - Wikipedia, the free encyclopedia, nice picture of the 747 fuselage structure:
http://upload.wikimedia.org/wikipedi...selage-747.jpg). Fail-safe means that the structure is somewhat redundant and can retain required properties (stiffness etc.) even in case of partial failure, like in case of the Aloha B737 mentioned by Amelin.
However in crashes like that in Smolensk such a structure behaves like an egg's shell (in fact an egg's shell is exactly a monocoque structure).
Regards,
Mike