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長周期地震動に対する鋼構造柱梁接合部の耐震性能

安田 聡*1・成原 弘之*1・関 清豪*2・長谷川 隆*3

超高層建築物や免震建築物などの固有周期の長い建築物における耐震設計に対しては,通常の地震に加え,遠方で発生する大地震に対しても長周期地震動による影響の評価と対策が必要になっている。本研究では,鉄骨造の超高層建築物を対象として,長周期地震動を想定した多数回の繰返し変形を受ける柱梁接合部梁端溶接部の限界性能を把握することを目的に実大規模の試験体を用いた構造実験を実施した。実験の結果,超高層建築物で多用される現場溶接形式と工場溶接形式の2種の梁端接合形式について変位振幅と疲労寿命の関係で表される疲労曲線を得た。また,変動変位振幅履歴下の疲労寿命予測に用いられる線形累積被害則(Miner則)の妥当性を検証した。

キーワード:  長周期地震動,超高層建築物,梁端溶接部,多数回繰返し,構造実験

*1 技術センター 建築技術研究所 建築構工法研究室
*2 設計本部 構造Ⅲ群統括
*3 (独)建築研究所

Seismic Performance of Welded Beam-to-column Connections against Long-period Earthquake Ground Motions

Satoshi YASUDA*1, Hiroyuki NARIHARA*1, Kiyohide SEKI*2 and Takashi HASEGAWA*3

The influence of long-period ground motions on the seismic designs of super-high-rise buildings and base-isolated buildings must be measured and evaluated. This paper summarizes the results of multi-cycle loading tests on full-scale welded beam-to-column connections. These tests were done as part of a study on the seismic performance of super-high-rise buildings subjected to long-period earthquake ground motions. Based on the test results, new fatigue curves are proposed for accurately calculating beam-to-column connections welded in the field, as is generally done for super-high-rise buildings, as well as shop-welded beam-to-column connections. The results validate the use of Miner's law for predicting the fatigue life of steel members under varying displacement amplitudes.

Keywords:  long-period earthquake ground motions, super-high-rise building, welded beam-to-column connection, multi-cycle loading, structural test

*1 Building System and Material Research Section, Building Engineering Research Institute, Technology Center
*2 Managing Group Leader, Structural Engineering Ⅲ, Design Division
*3 Building Research Institute