K-FACTORS OF FRAMED COLUMNS RESTRAINED BY TAPERED GIRDERS IN UNITED-STATES CODES

The first part of this paper discusses the concept of the effective le ngth factor K used for the design of framed compression members in the current US National Codes. A stiffness modification factor based on t he current alignment charts put forward by the US National Codes, is t hen developed for those framed columns restrained by tapered rectangul ar girders with different far end conditions to enhance the versatilit y of the present charts in computing effective length factors. Finally , two numerical examples are provided to illustrate the proposed desig n procedure. It is concluded that the modified method is satisfactory for practical use.