Coupling behavior of Local-Lateral buckling on Steel members

Research Project

Project/Area Number	63460171
Research Category	Grant-in-Aid for General Scientific Research (B)
Allocation Type	Single-year Grants
Research Field	Building structures/materials
Research Institution	Tokyo University
Principal Investigator	KATO Ben Tokyo Univ., Fac.of Engineering, Professor, 工学部, 教授 (60010576)
Co-Investigator(Kenkyū-buntansha)	MUKAI Akiyoshi Tokyo Univ., Fac.of Engineering, Research Assistant, 工学部, 助手 (90166223)
Project Period (FY)	1988 – 1989
Project Status	Completed (Fiscal Year 1989)
Budget Amount *help	¥4,300,000 (Direct Cost: ¥4,300,000) Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1988: ¥2,800,000 (Direct Cost: ¥2,800,000)
Keywords	Steel member / Lateral buckling / Local buckling / H-shaped steel beam / Laterally bracing / 横補剛 / 連成挙動
Research Abstract	Lateral buckling and local buckling govern load carrying capacity and deformability of steel beams. When these buckings occur in the plastic range, it is difficult to make clear specifications by the theory. In bucking behavior of beams in steel structures, the effect restrained by adjoining members is not definite completely. This paper reports on strong axis bending tests of H-shaped steel beams braced laterally, and connected with reinforced concrete slab. Braces restrain lateral displacements of the both franges, and slabs lateral displacements and torsion of the tension frange. These tested beams were made of H-150x50x3x6 (or H-150x50x3x5) of SS41 steel, and subjected to one-end moment. In Braced beams, variables were the posutuin and number of bracing members, and the span. In beams with slab it was the span only. The slenderness ratio about the weak axis of H-shaped beams were 270,360 or 450. The effect restrained by a slab was vary large. The load capacity of beams amounted to the full-plastic moment, even when the weak axis slenderness ratio was 450. In the beam that the slenderness ratio was 270, the local buckling behavior appeared at the same time as the lateral buckling. Except it, tested beam-strength depended on the appearance and progress of lateral buckling only. When bracing spaces were shortened, reaction forces in bracing members at post-buckling became large. Its maximum magnitudes were 2% of half a yield axisual force.