多層K型筋かい付鋼骨組の塑性設計試案

抄録

Many previous studies on simple K-braced frames suggest that the most efficient means to improve the overall toughness of K-braced multi-story steel frames are (1) to avoid the formation of collapse mechanisms on those beams supported by K-braces and (2) to prevent the early growth of yieldings on columns. In this paper, an efficient method of preliminary plastic design of multi-story K-braced steel frames is developed taking into account these two design requirements. A basic design factor ftj, the shear force ratio of bracings, is defined for the j-th story as the ratio of the story-shear-force to be assigned to the bracings to the prescribed design shear force of the story. Procedures of computing the vertical distributions of 0j are demon- strated. All the necessary informations for the preliminary plastic design can be easily derived from these fa values. A design example of ten-story three-bay K-braced frames shows that the method is very simple and effective to nrovide reasonable member sections?