PSI - Issue 84

Mirza Adeel Zeb et al. / Procedia Structural Integrity 84 (2026) 256–263

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4.3. Time-series kinematics of critical structures A detailed kinematic analysis of displacement time series was performed to move beyond conventional static and velocity-based assessments, enabling the quantification of cumulative deformation affecting critical infrastructure. This approach facilitates the understanding of long-term geotechnical trends, the identification of acceleration phases, and the estimation of total differential settlement. These parameters are essential for structural integrity assessments and predictive maintenance planning as reported in Qin and Perissin, (2015). The active subsidence wasidentifiedalong 16 bridges and viaducts. Among these,six representative structures (B34, B77, B53, B119, B186, and B234) were selected for detailed time-series kinematic analysis. This method represents the deformation severity trend over five years and allows for a focused and interpretable analysis. Figure 4 presents cumulative displacement, exhibiting a consistent downward trend over the five-year observation period. Bridge B34(Fig. 4a)shows the most severe and persistent subsidence, withthehighest displacement of approximately -47 mm from 2019 to 2023, corresponding to an average rate of -7.5 mm per year.

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Fig. 4. Cumulative vertical displacement time series graph (2019-2024) for six selected bridges.

For the bridges under consideration, previous assessment activities incorporated extensive on-site inspections to evaluate structural condition and to identify the most recurrent defects, including cracking, fissuring, and foundation related settlement, as documented by Zizi et al. (2023). Detailed in situ surveys revealed advanced deterioration, characterized by significant cracking, material loss, and deformation patterns consistent with differential settlement. Within these, the Agnena bridge B34 (Fig. 5a) exhibited pronounced structural damage, including extensive cracking, and was subjected to specific studies aimed to adopt provisional mitigation measures, as reported by Zizi et al. (2022). These critical conditions were confirmed by the present study, which revealed the severity of the deformation processes identified through time-series analysis, highlighting the practical relevance and engineering significance of the proposed monitoring approach. Moreover, bridges B53, B77 and B119 (Fig. 4c, 4b, 4d) experience moderate but continuous subsidence, accumulating approximately -30 mm, equivalent to about -6 mm/year. The linear nature of these trends suggests a constant driving mechanism, most likely related to long-term consolidation of compressible subsurface deposits. Notably, bridges B53 and B119 (Fig. 5b) are located in close proximity, near the coastal area, and exhibit comparable ground displacement trends, indicating similar critical conditions. Both structures were therefore subjected to detailed investigations, which ultimately led to the decision to proceed with their demolition and reconstruction. This spatial