PSI - Issue 78

Andrea Gennaro et al. / Procedia Structural Integrity 78 (2026) 663–670

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Fig. 1. Case study – PRC half-joint bridge.

Fig. 2. (a) longitudinal view; (b) transverse view.

2.2. Material test A campaign of investigations was designed for the characterization of the materials. The compressive strength of the concrete was estimated through fourteen-cylinder concrete compressive tests and 14 SonReb tests on piers, abutments, beams and on the slab. In detail, the average compressive strength ˆ was calculated as the mean value of the compressive strengths obtained from both SonReb tests and cylinder tests. The material tests results are resumed in Table 1.

Table 1. Compressive strength results.

Piers

Abutments Beams Slab

N° SonReb tests

8 9

-

6

-

N° cylinder compressive tests

3

-

2

Average compressive strength f c [MPa]

47.30 52.43

31.10 67.40

2.3. Ambient Vibration Test An AVT was carried out to extract the modal response of the bridge. The test employed 8 uniaxial accelerometers and was performed in two distinct setups, designated as Setup 1 and Setup 2, as illustrated in Fig. 3, in the central part of the bridge. Four recordings were made with Setup 1 and two with Setup 2. The test was conducted considering white noise and vehicle traffic moving in both directions. Ambient vibrations were recorded at a sampling frequency of 100 Hz. Time series acquired under service conditions were processed using output-only technique. The experimental parameters were extracted using MACEC 3.3 toolbox (Reynders et al. 2014) using p-LSCF (Peeters and Van Der Auweraer 2005) method combining the results of the two setups. 2.4. Initial Finite Element Model The initial 3D FE model was developed in Midas Civil software (MIDAS IT 2022) . All bridge components were modelled using linear beam-type elements with two nodes and six degrees of freedom per node, except for the slab, which was modelled as linear shell-type elements. Full continuity between longitudinal and transversal beams is assumed in the model. The boundary conditions consist of pinned constraints at the abutments and pier foundations.