Stability and Strength of Rigid and Semirigid Plane Frameworks

A computational technique for incorporating stability and strength into the analysis of plane frameworks is presented. The procedure for computing critical and/or collapse loads and for identifying the corresponding failure mode is outlined. The analysis is based on nonlinear kinematic relations and linearly elastic material behavior except at the plastic hinges-concentrated plasticity. The connections can be treated either as rigid or as flexible. The supports, in general, contain rotational restraints. The developed solution methodology is applicable to all multistory-multibay orthogonal frames. The examples analyzed in the paper include: (1) A single-story-two-bay frame with rigid joint connections; (2) a single-story-three-bay frame with flexible joint connections; (3) a two-story-single-bay frame with both rigid and flexible joint connections; and (4) a three-story-two-bay frame with rigid joint connections. In all cases the loading consists of a symmetric distribution of concentrated loads on the beams, applied at the midspan positions and at or near the beam-to-column joints. The effect of several geometric and structural parameters is assessed.