Desarrollo de una guía de inspección técnica basada en el análisis de patologías estructurales de 18 puentes metálicos modulares semipermanentes (PMMS) del Ejército Nacional – vigencia 2025.

Abstract

This study develops a standardized technical inspection guide for the National Army’s Semi-Permanent Modular Steel Bridges (PMMS), addressing the lack of specific protocols and the reliance solely on visual inspections—a limitation highlighted by the fact that "100% of evaluations were restricted to superficial visual assessments." A mixed-methods approach was employed, integrating a quantitative analysis of 18 inspection reports from 2025, a literature review focused on structural pathologies and Non-Destructive Testing (NDT), and experimental validation involving ultrasonic testing, liquid penetrant testing, and spark testing on a Bailey-type PMMS with 19 years of service. Statistical analysis revealed significant recurrence of pathologies undetectable by visual means: 72% showed corrosion at bottom nodes, 65% had loose bolts, 60% exhibited signs of fatigue cracking, and 50% showed internal corrosion. In the case study, ultrasonic testing revealed thickness losses of up to 33%, while liquid penetrant testing detected linear discontinuities ranging from 6 to 25 mm, confirming active corrosion-fatigue mechanisms. These findings demonstrate that visual inspection underestimates cross-sectional loss and micro-crack propagation, thereby compromising the volumetric integrity of the steel. The correlation between observed pathologies and documented deterioration mechanisms confirms the necessity of integrating NDT into PMMS evaluations. Ultrasonic testing is critical for HSLA steels—such as ASTM A572 Gr. 50—due to its ability to detect laminations and internal section loss; liquid penetrant testing identifies open cracks in high-stress concentration zones; and spark testing facilitates verification of steel composition regarding potential alterations caused by aging or heat treatment. An inspection guide based on quantitative criteria and damage thresholds is proposed to support the institutional transition toward a predictive maintenance model. The systematic integration of NDT will enable improved structural reliability, the prioritization of interventions, and the optimization of the lifecycle management of PMMS.