鋼アーチ橋に設置した座屈拘束ブレースの応答値 Demand of Seismic Brace Dampers Installed in Steel Arch Bridges

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Abstract

本研究は土木鋼構造物の耐震性向上策として適用が有望視されている座屈拘束ブレース (BRB) を上路式鋼アーチ橋に設置した場合のBRBに対する応答値 (<I>Demand</I>) の大きさについて検討したものである. 入力地震動は, レベル2地震動 (I, II種地盤用でタイプ1, 2地震動) の12波を用いた. 応答値の指標としては, 応答塑性率および累積応答塑性率の2つの量を取り上げた. 数値解析の結果, 上部構造 (アーチリブ, 補剛桁, 床版) に健全度2以上 (ひずみ応答が降伏ひずみの2倍以内) を確保する場合, SS400を用いたBRBの応答塑性率および累積応答塑性率の最大値は, それぞれ概略18, 140程度であった.

Use of brace dampers is an effective way to improve seismic performance of steel arch bridges against major earthquakes. In the design of seismic brace dampers, determination of capacity such as ultimate strain is an important consideration. For this purpose, it is necessary to investigate demand of the seismic brace dampers adopted in steel arch bridges. In this study, time-history analyses of steel arch bridges with brace dampers are performed using 12 earthquake motions, and demand variation of 162 brace dampers is investigated. Moreover, the effect of material grade is also studied. As a result, demand of the seismic brace dampers is clarified and the corresponding required ductility (capacity) is then proposed.

Journal

  • Proceedings of the JSCE Earthquake Engineering Symposium

    Proceedings of the JSCE Earthquake Engineering Symposium 28(0), 136-136, 2005

    Japan Society of Civil Engineers

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