PSI - Issue 64

Antonino Maria Marra et al. / Procedia Structural Integrity 64 (2024) 2117–2124 Marra et al./ Structural Integrity Procedia 00 (2019) 000 – 000 3 The term in square brackets represents the expression adopted to obtain the likelihood function, ( ̅| ), separating measurement errors from modeling uncertainties. It is derived by the integral of the measurement error ( ̅| , ) and modeling uncertainty ( | ) distributions (Simoen et al., 2013; Bartoli et al., 2017). The last term of Eq. (1) refers to the preliminary information on the elastic stiffness of the horizontal springs of the supports in the longitudinal direction, denoted by 0 ( ) , which is called prior distribution. Finally, the coefficient is the normalization constant of the Bayes theorem, which can be computed through ∫ ( ̅| ) ⋅ ( ) ⋅ . More details on the procedure are reported in Marra et al. (2024). 3. Case study: Indiano Viaduct Ambient vibration tests were carried out on an approaching span of the Indiano Viaduct, a 4 km-long viaduct located in Florence including a cable-stayed bridge. Two multiple-span entrance and exit ramps were selected for a structural dynamic identification campaign. The two ramps exhibit an open section deck, with two I-shaped steel girders connected by a concrete slab at the top and by a steel truss on the lower side (Fig. 1a). The girders are 1.5 m high and located at a distance of 4 m from each other, while the concrete slab is 8.2 m wide, equal to the total width of the deck, and about 25 cm thick. The span selected for the full-scale measurements has a radius of curvature of 29.22 m and a length of 21 m, referred to the longitudinal axis of the curved deck. The main dimensions of the investigated span are reported in the plan view in Fig. 1b. The single-span I-girders are restrained to concrete piles at the ends. 2119

Fig. 1. (a) Span tested; (b) plan view of the deck. Dimensions are in meters.