You say this building is rigid RELATIVE to the supporting soilstructure ( or substructure) . Take for example a moment-frame building with N = one storey you can approximate its frequency with 10*N = 10 Hz, now if the soil supporting it was stiffer ( higher frequency than 10 Hz) then the...
Along side with the connectivity of the column to the foundation, the overturning resistence of the footing plays a considerable rule in whether it is a pin end or a fixed end; suppose you welded the column to a built-in plate in the footing and the footing has no much of overturning resistence...
There is no such a thing called: Flexible or Rigid building !!! i never heard of such classification. and if it existed it should depend on some basic reference to compare with!.
They are probablistic and come from statistical studies, and usually taken as tolerances in any design. you can check for vertical tolerances in any building code.
One of my good colleagues used to consider the wall resisting a part of the Fixed end moment (Fem)from the beam(or slab) equal to:
Fem*{1-(Islab/Iwall)} ..and never allowed for Islab to be greater then Iwall.
This is a mere kind of interpolation between zero case (hinge) or full fixity case...
There can be a slight differnece between the cracked section and the uncracked section in regard to the value of E. As the value of E. is taken from some function of the uniaxial compression test of a concrete specimen. this can be the case for the cracked section, but not for the uncracked...
The relation between the load causing buckling is independent from the load causing collapse. As the first is defined at which total tangent stiffness matrix of the whole structure vanishes ( NON-linear analysis) while the former is defined at which the number of plastic hinges that develope in...
