連成座屈を考慮したH形断面梁部材構成板要素の幅厚比制限値評価法

摘要

板要素の幅厚比制限に関する日木建築学会の鋼構造設計規準で は、各板要素単独の座屈のみを考慮し、連成座屈効果が考慮されて ない。例えば、H形断面梁のフランジに関しては、純圧縮を受ける 3辺単純支持1辺自由の境界条件における十分長い平板の座屈耐力 から、ウェブに関しては、純せん断を受ける周辺単純支持の境界条 件における十分長い平板の座屈耐力から、それぞれ幅厚比の制限値 を定めている。%Width-thickness ratio limitation of thin plate is defined in current standard by considering boundary condition and stress situation under either pure compression or pure shear. On one hand, considering the effect of bending force, the larger width-thickness ratio of thin plate is able to be used in many cases of H-shaped beams when overall buckling does not happen. On the other hand, overestimation may be caused in cases of light-gauge thin plates formed H-shaped beams with long span which are easily affected by overall buckling. This paper is to study the proper evaluation of limitation about width-thickness ratio of H-shaped beam members under bending and shear based on the coupled buckling analysis in previous studies by energy method, and an easy evaluation method is proposed.