Issue 51

F. Jafari et alii, Frattura ed Integrità Strutturale, 51 (2020) 136-150; DOI: 10.3221/IGF-ESIS.51.11 140 & * * 0 * * r r s s V B w w V M C V M C ACIG b d I b d I                  (12) The safety surface of bending-torsion-shear The following limit sate function , & ( ) V B T ACIG is considered to obtain the safety surface of the ACI standard for three states of shear, bending, and torsion.         , & 2 2 * * 2 * * 2 * * 0 * * 1.7 * * * * 1.7 r w s w r r s s V B T w w w w T b d T b d M c V M c V ACIG I b d I b d b d b d                          (13) In Eqn. 13, three states of shear, bending and torsion effect appear simultaneously and by considering this limit state function, the safety surface is predicted. Sections and dimensions In order to calculate the beta index of T, L, and the rectangular cross-section beams, specified geometrical futures are assumed as shown in Fig. 1 and Tab. 2. The distributed load (25kN/m) is exerted on the beam length. Cross-sections of the mentioned beams are selected in such a way that the area of the T-shape section is twice that of L-shape section and the rectangular section area was  * w b d . Figure 1 : Schematic figure of the L, T, and Rectangular sections w b (mm) D q (kN/m) f (MPa) c  e b (mm) y f (MPa ) 450 25 21 850 420 f b (mm) d(mm) L(mm)   * ; 1 / L D M ratio M ratio t t    200 400 2000 0.4-1.0 Table 2 : The nominal parameters of this study