Issue 51

F. Jafari et alii, Frattura ed Integrità Strutturale, 51 (2020) 136-150; DOI: 10.3221/IGF-ESIS.51.11 142 Figure 3 : ACI beta index for shear-torsion for different Monte Carlo cycles Figure 4 : ACI beta index for shear-torsion combination. ACI safety surface for bending-torsion In this section, the equations presented in section 2-3 are employed and the ACI safety index is calculated for bending and torsion states. Fig. 5 shows the beta index for bending and torsion state for three studied cross-sections. The standard surface of ACI for torsion is from 2.50 to 3.20 and the standard surface of ACI concrete for bending is between 2.50 - 4.15. The standard surface of ACI concrete for bending and torsion is between the values of bending and torsion and it is close to bending state, and the average value is 3.70 for bending-torsion. The maximum value of the safety index for the combination of torsion-bending occurs at t= 0.6.