PSI - Issue 84

994 Gian Felice Giaccu et al. / Procedia Structural Integrity 84 (2026) 991–998 0.6, 0.8, 1.0 and 1.2. In Fig. 3a, the stress ratio  is plotted across the transverse coordinate χ . As expected, the peak stress ratio is observed in the section nearest the location of axial load N c application (  = 0.2). For values   1.2, the distribution of Σ along χ tends toward constancy, consistent with stress diffusion patterns documented by Byers (1999). Fig. 3b presents the integral stress ratio  , which quantifies the axial force N c in non-dimensional terms, resulting from an applied compressive force N at a given longitudinal location  and transverse position χ . The parameter η is particularly sensitive to the stiffness of the shear connectors, modeled here through flexible and rigid connection approaches. In the flexible connection model, connector stiffness reflects the actual geometric configuration, as discretized in the finite element formulation (Silva Nicoletti et al. 2021). This modeling approach captures the interface slip that occurs due to reduced connector stiffness, in contrast to the idealized rigid connection scenario. The results in Fig. 3b show that a stress diffusion angle of 30° provides a reliable basis for defining the effective slab width for axial stress evaluation. This projection angle aligns with international standards, including AASHTO (1994) for segmental box girders and DIN 1075:1981, which suggests an angle of 26°. The plot for the flexible connection case reveals a markedly nonlinear relationship between  and χ when  = 0.2 and  = 0.06.

(a) (b) Fig. 3. T1 Case. Linear parametric study for the considered beam with  = 0.06, (a) stress ratio  and (b) integral ration  as a function of the relative position χ for different cross-section positions , for flexible and rigid connections. This nonlinear trend becomes progressively more linear in slab regions farther from the load application and with lower eccentricities. Under these conditions, axial stresses reach their maximum values near the supports, particularly in areas with a reduced effective slab width. As anticipated, the flexible connection model consistently produces lower