A COMPUTATIONAL FRAMEWORK FOR HFRP-BASED REHABILITATION OF REINFORCED CONCRETE CHEMICAL CONTAINMENT POOLS

Abstract

Reinforced concrete chemical containment pools are exposed to hydrostatic pressure, chemical attack, and moisture penetration, which can compromise their structural integrity and liquid-retaining performance. This study presents a preliminary computational framework for evaluating the effect of hybrid fiberreinforced polymer (HFRP) rehabilitation on such structures, demonstrated through finite element modal analysis. Two three-dimensional SAP2000 models with identical geometry, material properties, and support conditions were compared: an existing reinforced concrete pool and the same pool retrofitted with a 5 mm thick HFRP layer applied to the inner and outer wall faces and the bottom slab. The modal analysis showed that HFRP rehabilitation increased all of the first five natural frequencies by approximately 25%. Because the composite layer adds little mass, this increase is attributed mainly to the additional stiffness it provides. The results indicate that modal frequencies can serve as a practical indicator of the stiffness change produced by rehabilitation. However, the present analysis is limited to the free vibration of an undamaged, empty pool. Hydrostatic and fluid–structure loading, stress and displacement response, local stress concentrations, concrete–composite interface behavior, and chemical durability were not evaluated, and the numerical results have not been experimentally validated. The framework is therefore intended as a basis for the preliminary comparison of HFRP rehabilitation alternatives and for subsequent static, dynamic, and durability studies.