Inspección no destructiva de estructuras mediante georradar: análisis de daños por corrosión y por otras patologías
- Autores: Viviana Alejandra Sossa Arancibia
- Directores de la Tesis: María Vega Pérez Gracia (dir. tes.), Jose Ramón González Drigo (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2021
- Idioma: español
- Materias:
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- Resumen
This thesis aims to studythe capacities and limitations of Ground Penetrating Radar (GPR) to support inspection, assessment, maintenance and rehabilitation tasks, helping to earlydetection and evaluation ofpathologies in unreinforced masonryconstructions, as well as in reinforcing concrete structures.
One ofthe most common pathologies in existing reinforced concrete structures is corrosion damage. In fact, this is a pathologythat, in more advanced stages, may comprom ise the integrity of sorne structural elements, or e\en of the whole structural system. Corros ion dam age reduces the effecti\e cross section of steel reinforcing bars , dim inishing the bond between reinforcement and concrete, and affecting, dueto physical and chemical processes, the concrete that inwl\es the corroded steel reinforcing bars. In reinforced concrete structures, the corrosion ofsteel reinforcing bars is, in general, hidden. Accordingly , remotely or at distance assessment techniques are desirable , which aims to assess the integrity of steel elements, generally inaccessible through direct contact.
The implementation of non-destructi\e tests (NDT) is a com mon practice when analysing pathologies in historical buildings, where inter'A:lntions should be as minimal invasi\e as possible . Sorne ofthe mostcommon methods to assess corrosion, such as the potential of corrosion, the petrographic analysis and the resistivimeter, present sorne disadvantages in comparison to the GPR. In fact, the uses of such methods require a considerable time, they are slightty invasi\e, and its application is localized, which means thattheir application only co\ers a reduced area of analysi s.
In orderto assess the GPR capacity for detecting corros ion dam age, different laboratory tests were respecti\ely de\eloped, being the obtained results extremely satisfactory. Accordingly, it is possible to identify the following achie\ements: (i) a fast data acquisition planning methodologywas well established; (ii) the key elements and parameters for corrosion detection, within a qualitati\e analysis, were respecti\elyidentified; (iii) the contoureffects, related to a change on geometry, were identified and duly controlled; and (iv) a numerical approximation method, based on energy attenuation of GPR, for assessing the presence and degree ofcorrosion in damaged samples, was proposed with success. Obtained results are themsel\es a strong contribution of de\eloped research studies for the state of art.
Four in-field tests, implemented on existing structures were respecti\ely developed, aim ing to apply and validate the methodologies, results and conclusions, obtained from laboratory tests. Toree case studies are related to historical constructions, belonging to the cultural heritage of the city of Barcelona, in Spain. The obtained results from GPR, combined, in sorne cases, with boreholes and seism ic tomography, allowed to identify pathologies dueto hum idity, corrosion and differential setttements. A fourth case study, de\eloped on a contemporary structure, in reinforcing concrete, and only using GPR, allowed to identifyand localize pathologies dueto corrosion damage.
The laboratorytests and the case studies, using GPR, combined or not with other techniques, showed a strong capacityto detect and assess early stage pathologies, especially dueto corrosion damage, through fast, non-invasi\e and non destructi\e prospections.
This strategy has econom ical and social advan tages . lndeed, a fast detection of pathologies , allow the rehabilitation of existing structures with a minimum amount of budget, when comparing with the needed resources to face damage in a more se\ere stage. The assessment ofpathologies in earlystages with GPR, especiallywhen combined with other techniques, allow then to ensure more resilient structures, by increasing their reliability, safety, and availability, and by decreasing their operational costs.
