Pathological evaluation of the Concordia bridge (Bolivia) by means of non-destructive tests; Technical infeasibility and recommendation of demolition

Abstract

The prolonged stoppage of road infrastructure works in Latin America generates conditions of accelerated deterioration that compromise structural safety and the technical feasibility of its reactivation. The objective of this study was to evaluate the pathological condition of the Concordia Bridge (Quillacollo, Bolivia), a work paralyzed since 2018, to determine the feasibility of its rehabilitation or demolition. A mixed methodology (qualitative-quantitative) of descriptive-diagnostic level was used, applying non-destructive testing (NDT) based on international standards: sclerometry (ASTM C805-18), pachometry, fisurometry (ACI 224R-01) and laser leveling (ISO 17123-3), complemented with visual inspection, geometric verification and structural modeling in CSI Bridge v.24.0 under AASHTO LRFD 2020. The results showed widespread carbonation throughout the superstructure, reinforcement coatings up to 10 mm below the normative minimum, cracks (0.05-0.60 mm) and cracks of up to 3 mm in head beams, as well as differential settlements of 31 mm between piers with rotation of 18 mm in the left head. Although sclerometry indicated high surface resistances (328-570 kg/cm²), these are higher due to carbonation and do not reflect internal integrity. The geometric discrepancies between the design and the execution generated rigidity losses of 20-30% in beams. It is concluded that the superstructure of the Concordia Bridge presents an irreversible deterioration that makes it technically unfeasible for any rehabilitation intervention, so its total demolition and reconstruction is recommended. This case shows the need to implement mandatory periodic inspection protocols for paralyzed works in Latin American contexts.