Approximate Analysis of a Floor Assembly in a Multistory Building Frame

A computer algorithm, along with a workable program in the BASIC language, is presented by which each floor beam in a multistory building frame, together with the attached columns, may be analyzed as a subassembly. The objective is to obtain results close to those which would otherwise be obtained by a whole frame analysis. With the subassembly analysis method, more trials may be made in the preliminary design stage, although whole frame analysis still needs to be employed when deemed appropriate.
The subassembly method may be in first order, or in second order including both column instability and Pdelta effects, allowing the same options as in whole frame analysis. The far ends of the upper columns are assumed to be connected to plates fixed against rotation but free to have sidesway. The connections themselves, however, may be semirigid, rigid, or overrigid, quantitively described by a set of rotation coefficients that may be preset or automatically generated. The far ends of the lower columns are similarly connected, defined by another set of rotation coefficients; but the plates are restrained in both rotation and sidesway. The floor beams have unknown slopes at the columns, as well as an unknown sidesway.
Rotation coefficients for various patterns of gravity loads are suggested in the article, and they are automatically generated for combined gravity and lateral loads. They may be taken, too, from any trial or similar whole frame analysis.