NOVEL DESIGN ALGORITHMS FOR K-FACTOR CALCULATION AND BEAM-COLUMN SELECTION

Existing methods for calculating the LRFD design nomograph for an effe ctive length K factor utilize iterative algorithms such as the method of bisection. This paper presents a novel algorithm that computes the K factor with no iterations. This algorithm computes an approximate K factor, which is often within 2% of the true nomograph value of K. The initial section selection method offered in the LRFD Manual is primar ily a hand-calculation technique relying on the engineer's intuition f or selection trial sections. A computer-based algorithm is developed h erein for the initial beam-column section selection using the LRFD str ength criteria (the beam-column interaction equation). An example prob lem presents typical preliminary member sizes for girders and beam-col umns using these techniques. The computer program DFRAME, which uses t hese methods, is briefly described and is implemented in C++, an objec t-oriented language, using Digital Equipment and Sun workstations.