RELIABILITY ANALYSIS OF REINFORCED CONCRETE MEMBERS UNDER THE COMBINED ACTION OF SHEAR AND TORSION

Torsion-shear strength reliabilities of the code formula (GB50010-2002) and the formula proposed by Huang Liang are analyzed. The results show that for the second-level security structure, the shear reliability index and the torsional reliability index of the Code formula are 3.23 and 3.25 when a brittle shear-type failure occurs, and 4.02 and 2.88 when a ductile torsion-type failure occurs, which cannot meet the demand of 3.7 and 3.2 in GB 50068-2001. As for the formula by Huang Liang, the reliability indexes are near 3.6 no matter what kind of failure occurs, which is close to the demand of the code, but still not safe when a brittle shear-type failure occurs. The reliability indexes of the Code formula change remarkably with the variation of torsion-shear ratio, and there is a clear difference between the shear and torsional reliability indexes. Whereas, the formula proposed by Huang Liang overcomes this defect. A modified formula is provided and its reliability is analyzed. The results show that the reliability indexes of the modified formula are near 3.75, which can satisfy the demand of GB 50068-2001.