Hirofumi Kaneko

RESIDUAL SEISMIC PERFORMANCE OF WOODEN HOUSES WITH PLYWOOD LOAD-BEARING WALL AFTER EARTHQUAKE: －Research on seismic behavior of wooden houses Part VI－@@@－木造住宅の地震時挙動に関する研究 その６－

* 信州大学大学院 修士課程 * 京都大学生存圏研究所 教授/建築研究所 客員研究員・博士(工学) * 独立行政法人建築研究所構造研究グループ 研究員・博士(工学) * 筑波大学大学院システム情報工学研究科博士課程 修士(工学) * 筑波大学システム情報系 教授・工博 * 信州大学工学部 助教・博士(工学) * 信州大学工学部 教授・工博 Grad. Stud., Graduate School of Engineering, Shinshu Univ. Prof., RISH, Kyoto Univ./ Visiting Researcher, BRI, Dr.Eng. Research Engineer, Dept. of Structual Eng., BRI, Dr.Eng. Grad. Stud., Graduate Sch. of Systems and Information, Univ. of Tsukuba, Mr.Eng. Prof., Faculty of Engineering, Information and Systems, Univ. of Tsukuba, Dr.Eng. Assist. Prof., Faculty of Engineering, Shinshu Univ., Dr.Eng. Prof., Faculty of Engineering, Shinshu Univ., Dr.Eng. 日本建築学会構造系論文集 第81巻 第728号,1683-1690, 2016年10月 J. Struct. Constr. Eng., AIJ, Vol. 81 No. 728, 1683-1690, Oct., 2016 DOI http://doi.org/10.3130/aijs.81.1683 【カテゴリーIII】

STUDS EFFECT ON BEHAVIOR OF LATERAL BUCKLING OF COMPOSITE STEEL BEAM

The lateral bracing effect of studs on lateral buckling of composite beams within frames under seismic loading was examined experimentally and analytically. Regardless of the bracing condition on the top flange, the beam slenderness ratio and web thickness ratio that were taken as parameters, all tested beams did not experience buckling until at least a drift ratio of 2.0%, confirming that the lateral bracing of the studs was very effective. Also the influence of the total number of studs on the buckling was investigated by an elasto-plastic analysis. Changing the total number of studs did affect neither the magnitude of the total lateral force of studs that failed by buckling nor the distribution length ratio.

Structural Materials. Influence of Welding Heat on Low Yield Strength Steel.

The yield stress of the low yield strength steel (LY100) that is used well as a hysteresis dumper is reduced by coarsing grain in the heat treatment process of steel plate production. Therefore, the yield stress rises, when the steel plates are built up by welding to a member. The test specimen that welded 2 sheets of steel plates by butt welding was prepared, in order to investigate the influence of the welding heat input and the cause on the mechanical properties of the steel plate. Gathering the test pieces according to the distance from the weld line, the tension test, chemical composition analysis, optical microscope and micro Vickers hardness test were performed. Also, the change of the yield stress by means of heat treatment become hot after welding was examined. As a result, it is guessed the cause that the heat input record and the cooling under residual stress refine the grain size at the temperature rise part of vicinity of the weld line. And, the grain is coarsened once again by heat treatment for one hour at 850°C after the welding assembly. Therefore it is possible that the yield stress that have rised at the time of the welding assembly is made lower equal to that of the base material.