報告書番号

N04003

タイトル（和文）

動的上下動が鉄筋コンクリート製地中構造物の耐震性能に与える影響評価 -－水平成層地盤中に埋設された場合の応答特性－-

タイトル（英文）

Effects of Vertical Ground Motion on Seismic Performance Verification System of RC Underground Structures-Discussion on Response of RC Structures Embedded in Horizontally Layered Ground-

概要 （図表や脚注は「報告書全文」に掲載しております）

本研究では,原子力発電所屋外重要土木構造物の耐震性能照査時における上下地震動の取り扱いについて検討した．ここでは，地盤－構造物連成系モデルによる非線形地震応答解析を実施し，水平成層地盤中に埋設された鉄筋コンクリート製地中構造物に対する動的上下動の影響について，次のような知見を得た． 地中構造物全体のせん断変形に起因する応答値（層間変形角，部材断面力（曲げモーメント，せん断力），曲率）は水平動のみの場合のそれとほぼ一致した．一方，その鉛直成分は上下動によって生じ，構造物の鉛直方向部材の軸力の変動をもたらすが，その変動の範囲が非常に小さいため，軸力に依存した構造物の限界値（限界層間変形角，せん断耐力）に対する影響はほとんどない． また，水平動・上下動の最大加速度の発生時刻差が，地中構造物の応答やその限界値に及ぼす影響は，無視できる程度に小さい．

概要 （英文）

The objective of this study is how to estimate vertical ground motion on the seismic performance verification method for crucial civil engineering structures in nuclear power plants. This paper presents the numerical study about the effects of vertical ground motion on underground RC structures. Several soil-structure interaction models embedded in horizontally layered ground were prepared, and the nonlinear earthquake response of the models were discussed under observed earthquake ground motion.Based on the numerical results, the findings are summarized as follows : Horizontal component of earthquake load is hardly affected by vertical ground motion, then the deformation angle, section force(bending moment and shear force) and curvature in RC member cause by global shear deformation on structure almost coincide with them developed by horizontal ground motion. On the other hand, the vertical ground motion brings a slight increase of axial force on upward columns, however that has little effect on limit deformation angle and shear strength of RC member which are affected by axial force fluctuation. And response and limit state values on structure are almost stable regardless of time instant difference of the peak acceleration between horizontal and vertical ground motions.

報告者

キーワード