STIFFNESS-BASED OPTIMAL-DESIGN OF TALL STEEL FRAMEWORKS SUBJECT TO LATERAL LOADING

This study presents an effective stiffness-based optimal design techni que for planar tall steel building frameworks subject to lateral loadi ng. An initial design under strength constraints is first performed, a nd then the lateral load resistant system is designed to control any l ateral drift of the structure that yet exceeds the drift criteria. The rigid diaphragm effect of the floor slab is accounted for so as to re duce the degrees of freedom to three at each floor level. Design optim ization based on a mathematical programming technique involves minimiz ing the lateral stiffness of the lateral load resistant system for the structure while satisfying specified drift constraints. Three steel f rameworks with diagonal bracing systems are presented to illustrate th e features of the design optimization method.