Application of digital image correlation in reinforced concrete elements testing

W artykule przedstawiono możliwości wykorzystania cyfrowej korelacji obrazu (Digital Image Correlation), a dokładniej systemu ARAMIS SRX w badaniach elementów żelbetowych. Przykładowe pomiary wykonano dla belki żelbetowej poddanej obciążeniu do zniszczenia. Obejmują one przemieszczenia, odkształcenia oraz zarysowanie na wybranych obszarach. Opisano również zastosowaną wersję systemu ARAMIS, zmiany i nowe funkcje wprowadzone względem starszych wersji.The article presents using of Digital Image Correlation, and more specifically the ARAMIS SRX system, in the research of reinforced concrete elements. Exemplary measurements were made for a reinforced concrete beam subjected to a load to failure. New and old version of the ARAMIS system was described, as well as its changes and new functions introduced in relation to older versions

Analiza wpływu rozmieszczenia prętów zbrojeniowych na deformacje i obraz zarysowania belki żelbetowej

The article presents the analysis of the influence of the rebars distribution, in reinforced concrete beam section, on the perpendicular (to the side surface) deformation of the tested element. The beams were tested under the load of two forces. Displacements and crack formation in middle part of reinforced concrete beams were measured by using 3D optical scanner. Test results confirm the large influence of the asymmetry of the reinforcing bars distribution, within beams cross-sections, on their deformation and crack formation during loading. It is shown that the displacements perpendicular to the side surface are consequent upon irregularities in the distribution of the main reinforcement due to errors in the stage of beams manufacturing in the precast factory.W artykule przedstawiono analizę wpływu niesymetrycznego rozmieszczenia prętów zbrojeniowych w przekroju belki żelbetowej na deformacje w kierunku prostopadłym do powierzchni bocznej badanych elementów, którą przeprowadzono na podstawie wyników badań uzyskanych ze skanera optycznego 3D oraz inwentaryzacji zbrojenia. Uzyskane wyniki przemieszczeń i zarysowania środkowego odcinka belek żelbetowych, obciążanych do zniszczenia dwoma siłami skupionymi, potwierdzają duży wpływ niesymetrycznego rozmieszczenia prętów zbrojeniowych w przekroju belek na ich deformację i zarysowanie podczas obciążania. W pracy przedstawiono, iż przemieszczenia prostopadłe do powierzchni bocznej są wynikiem nieprawidłowości w rozmieszczeniu zbrojenia głównego, spowodowanego błędami na etapie wykonywania belek w zakładzie prefabrykacji

Non-Destructive Testing Methods for In Situ Crack Measurements and Morphology Analysis with a Focus on a Novel Approach to the Use of the Acoustic Emission Method

This article presents a concise review of modern non-destructive testing (NDT) methods that allow the detection, tracking, and measurement of cracks in reinforced concrete structures. Over the past decades, the range of solutions available on the market has increased. This provides excellent opportunities when choosing and designing systems for diagnosing and continuously monitoring structures. Cracking affects the mechanical properties, durability, and serviceability of a structure or its elements. Therefore, there is a need to develop methods that would allow the determination of the moment of a destructive process’s formation, i.e., a crack’s appearance. At the same time, it is crucial to be able to track the development of cracks for the entire structure, not just selected locations. This work also presents the concept of combining selected NDT methods and creating a system for the continuous monitoring of structural integrity and predicting changes in the durability of existing and future buildings

Application of Digital Image Correlation to Evaluate Strain, Stiffness and Ductility of Full-Scale LVL Beams Strengthened by CFRP

Due to limitations of traditional measuring methods, a necessity of verification of applicability of optical measuring systems in different fields of science is required. The paper presents the application of a non-contact, non-destructive ARAMIS optical system in the analysis of static work of unstrengthened and strengthened laminated veneer lumber beams (LVL) with composite materials, subjected to a four-point bending test. The beams were strengthened with Carbon Fiber Reinforced Polymer (CFRP) sheets and laminates. The sheets were bonded to the external surfaces in three configurations differing in the number of layers applied and the degree of coverage of the side surface. The CFRP laminates were glued into predrilled grooves and applied to the underside of the beams. An adhesive based on epoxy resin was used. The scope of the work includes analysis of the strain distribution, stiffness and ductility. The analysis was performed on the basis of measurements made with an optical measurement system. The strain analysis indicated a change of the distribution of the strain in the compressive zone from linear for the unstrengthened to bilinear for the strengthened beams. The stiffness increase was equal from 14% up to 45% for the application of the CFRP laminates in the grooves and CFRP sheets bonded externally, respectively. Similar improvement was obtained for the ductility

Diagnostics of Concrete and Steel in Elements of an Historic Reinforced Concrete Structure

Existing buildings, especially historical buildings, require periodic or situational diagnostic tests. If a building is in use, advanced non-destructive or semi-destructive methods should be used. In the diagnosis of reinforced concrete structures, tests allowing to assess the condition of the reinforcement and concrete cover are particularly important. The article presents non-destructive and semi-destructive research methods that are used for such tests, as well as the results of tests performed for selected elements of a historic water tower structure. The assessment of the corrosion risk of the reinforcement was carried out with the use of a semi-destructive galvanostatic pulse method. The protective properties of the concrete cover were checked by the carbonation test and the phase analysis of the concrete. X-ray diffractometry and thermal analysis methods were used for this. In order to determine the position of the reinforcement and to estimate the concrete cover thickness distribution, a ferromagnetic detection system was used. The comprehensive application of several test methods allowed mutual verification of the results and the drawing of reliable conclusions. The results indicated a very poor state of the reinforcement, loss in the depth of cover and sulphate corrosion

Diagnostics of Concrete and Steel in Elements of an Historic Reinforced Concrete Structure

Existing buildings, especially historical buildings, require periodic or situational diagnostic tests. If a building is in use, advanced non-destructive or semi-destructive methods should be used. In the diagnosis of reinforced concrete structures, tests allowing to assess the condition of the reinforcement and concrete cover are particularly important. The article presents non-destructive and semi-destructive research methods that are used for such tests, as well as the results of tests performed for selected elements of a historic water tower structure. The assessment of the corrosion risk of the reinforcement was carried out with the use of a semi-destructive galvanostatic pulse method. The protective properties of the concrete cover were checked by the carbonation test and the phase analysis of the concrete. X-ray diffractometry and thermal analysis methods were used for this. In order to determine the position of the reinforcement and to estimate the concrete cover thickness distribution, a ferromagnetic detection system was used. The comprehensive application of several test methods allowed mutual verification of the results and the drawing of reliable conclusions. The results indicated a very poor state of the reinforcement, loss in the depth of cover and sulphate corrosion

Condition assessment of selected reinforced concrete structural elements of the bus station in Kielce

The paper presents the results of the research aimed at assessing the condition of reinforcement and concrete cover in selected elements of the structure of the most recognizable structure in Kielce, i.e. PKS station, located at Czarnowska Street. Currently, demolition works are underway resulting from the planned modernization. The assessment of the corrosion risk of the reinforcement in the construction elements was carried out with the use of a semi-non-destructive electrochemical method. The use of this method made it possible to determine the probability of reinforcement corrosion in the selected areas and to estimate its rate. The protective properties of concrete cover were checked by the carbonation test (test using a 1% phenolphthalein solution) and phase composition analysis (X-ray diffraction analysis). In order to determine the position of the reinforcing bars and to estimate the concrete cover thickness distribution in the areas corresponding to the aforementioned measurements, ferromagnetic detection system was used