PSI - Issue 84

Angelo Masi et al. / Procedia Structural Integrity 84 (2026) 321–328

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required to ensure safe load transmission and structural continuity as well as the possibility of rotation about at least one axis. An appropriate combination of restraints is essential to avoid parasitic stresses and to guarantee an isostatic structural behaviour. Based on material and functional characteristics, the bearing typologies most commonly encountered in existing Italian bridges (Fig. 1) include steel bearings (pins and rollers), elastomeric pads (plain or laminated), pot bearings, and bearings equipped with steel–PTFE sliding surfaces. Although several design variants exist, these categories represent the most widespread solutions within the national bridge stock and constitute the reference classification adopted in this study (Masi et al., 2025).

Fig. 1 General classification of bridge bearings

Representative examples of these devices, documented during field inspections, include elastomeric pads with early surface degradation, pot bearings in good condition, severely corroded steel rollers installed in Gerber half-joints (Santarsiero & Picciano 2023), and more recent steel–PTFE bearings allowing multidirectional sliding.

Fig. 2. LG2020 Level 1 bearing inspection form Within the framework of the Italian Guidelines for risk classification and management of bridges (LG2020), the condition of bearing devices is assessed through Level 1 visual inspection forms (Fig. 2). These forms allow inspectors to record predefined defect types, severity levels, and parameters describing defect extent and intensity. Defects are grouped into general bearing defects, elastomeric-specific defects, metallic or pendulum-related defects, and generic deterioration phenomena, enabling a standardized data collection across different bridge owners and inspection teams. To support the large-scale application of LG2020 and to overcome the fragmentation of inspection data, a dedicated database of bridge bearings was developed within Work Package 4 of a research programme coordinated by the