The influence of composite girders on the modified buckling factor for columns was investigated in both braced and unbraced frames. girders' end conditions were represented as rigid hinged . Furthermore, based proposed stiffness parameter, derived formulation follows same assumptions standard effective length (K-factor). Moreover, suggested equations frames obtained using slope-deflection metho...

The present study evaluates how the soft first story irregularity condition should be defined: (a) as a significant reduction of the lateral shear stiffness of all resisting frames within a given story, as established in the seismic provisions of Mexican building codes or, (b) as a substantial reduction of the lateral shear stiffness of one or more resisting frames within a given story, as prop...