報告書番号

381021

タイトル（和文）

三軸圧縮応力下におけるコンクリートの強度特性

タイトル（英文）

ULTIMATE STRENGTH PROPERTY OF CONCRETE UNDERTRIAXIAL COMPRESSIVE STRESSES

概要 （図表や脚注は「報告書全文」に掲載しております）

原子力発電所に建設されるプレストレストコンクリート製格納容器（ＰＣＣＶ）は，内圧，温度荷重，地震荷重に対して十分な安全性が要求される大規模なコンクリート構造物である。導入されるプレストレスが大きく，部材寸法も大きいので，ＰＣＣＶは一般的に多軸応力状態にある。このため，設計の合理化を計り，また経済性とともに安全性をより一層高めるためには，この多軸応力状態を考慮して許容応力度を定め，また応力－ひずみ構成式を作成し，これを用いて応力解析を行なうことが肝要である。本報告は，上記の問題点の究明を計ることを目的として，３軸圧縮応力下におけるコンクリートの終局強度特性を明らかにし，さらに終局強度基準を八面体応力の関数で表示した。

概要 （英文）

THE PURPOSE OF THIS PAPER WAS TO STUDY THE ULTIMATE STRENGTH PROPERTIES OF CONCRETE UNDER SHORT-TERM TRIAXIAL COMPRESSIVE STRESSES,AS AN AID TO DESIGNING AND ANALYZING THE CONCRETE STRUCTURES SUBJECTED TO MULTIAXIAL STRESSES SUCH AS PRESTRESSED OR REINFORCED CONCRETE VESSEL STRUCTURES. A SUMMARY OF THE RESULTS IS SHOWN BELOW. (1)THE SURFACE FRICTION BETWEEN SPECIMEN AND LOADING PLATEN IS CONSIDERABLY INFLUENCED UPON THE ULTIMATE STRENGTH OF CONCRETE UNDER TRIAXIAL COMPRESSION.SO AS TO REDUCE THE SURFACE FRICTION TO A MINIMUM,THE PADS OF TEFLON SHEETS COATED WITH SILICONE GREESE WERE USED.THE COEFFICIENT OF FRICTION OF THE PADS WAS MEASURED TO BE 1.4% ON THE AVERAGE. (2)IT BECAME CLEAR AFTER EXAMINING THE EXPERIMENTAL RESULTS THAT THE ULTIMATE STRENGTH OF CONCRETE SUBJECTED TO TRIAXIAL COMPRESSION EXTREMELY INCREASED AS COMPARED TO UNIAXIAL COMPRESSIVE STRENGTH AND THAT THE INCREASE OF STRENGTH WAS MAINLY DEPENDENT ON THE COMBINATION OF PRINCIPAL STRESSES,NAMELY NOT ONLY MINIMUM PRINCIPAL STRESS BUT ALSO INTERMEDIATE PRINCIPAL STRESS,BEING HARDLY AFFECTED BY MIX PROPOTIONS. (3)THE MATHEMATICALDESCRIPTION OF THE ULTIMATE STRENGTH FOR TRIAXIAL COMPRESSION COULD BEDERIVED SEMI-EMPIRICALLY FROM THE THEORY AND THE EXPERIMENTAL RESULTS.AT FIRST,THE ULTIMATE STRENGTH ENVELOPES IN A RENDULIC STRESS PLANE WERE APPROXIMATED BY THE PARABOLIC EQUATIONS USING OCTAHEDRAL STRESSES. THE ULTIMATE STRENGTH ENVELOPES IN A DEVIATORIC PLANE MAY BE GIVEN BY THE EXPRESSION USING A ELLIPTIC SEGMENT. (4)THESE EXPRESSIONS HAVE BEEN FOUND TO PROVIDE A CLOSE FIT FOR EXPERIMENTAL RESULTS OF CONCRETE UNDER TRIAXIAL COMPRESSION.

報告者

キーワード