Abstract
A feature extraction methodology based on lamb waves is developed for the non-invasive detection and prediction of the gap in concrete–metal composite structures, such as concrete-filled steel tubes. A popular feature extraction method, partial least squares regression, is utilised to predict the gaps. The data is collected using the piezoelectric transducers attached to the external surface of the metal of the composite structure. A piezoelectric actuator generates a sine burst signal, which propagates along the metal and is received by a piezoelectric sensor. The partial least squares regression is performed on the raw sensor signal to extract features and to determine the relationship between the signal and the gap size, which is then used to predict the gaps. The applicability of the developed system is tested on two concrete-metal composite specimens. The first specimen consisted of an aluminium plate and the second specimen consisted of a steel plate. This technique is able to detect and predict gaps as low as 0.1 mm. The results demonstrate the applicability of this technique for the gap and debonding detection in concrete-filled steel tubes, which are critical in determining the degree of composite action between concrete and metal.
Highlights
Concrete-metal composite structures, such as concrete-filled steel tubes (CFSTs), constitute critical components of civil infrastructure such as columns, piles, bridge piers, railway decks and roofs [1].These composites have many advantages compared to columns exclusively made of steel or reinforced concrete [2,3]
This study aims to apply the partial least square regression (PLSR) technique on the lamb wave received by a piezoelectric transducer in a pitch-catch configuration, in order to predict the gap in concrete-metal composite structures like CFSTs
A PLSR-based method for the prediction of the gap in concrete-metal composite structures was proposed for the first time in this paper
Summary
Concrete-metal composite structures, such as concrete-filled steel tubes (CFSTs), constitute critical components of civil infrastructure such as columns, piles, bridge piers, railway decks and roofs [1].These composites have many advantages compared to columns exclusively made of steel or reinforced concrete [2,3]. Concrete-metal composite structures, such as concrete-filled steel tubes (CFSTs), constitute critical components of civil infrastructure such as columns, piles, bridge piers, railway decks and roofs [1]. The steel member of the composite structure provides high tensile strength and ductility, while the concrete member provides high compressive strength and stiffness Due to this reason, CFSTs are abundantly used in building and bridge construction [4]. The interaction between the steel surface and concrete delays the local buckling of steel tube and the confinement from the metal increases the strength of concrete This interaction reduces the drying shrinkage and deterioration of concrete [5,6]. Factors such as shrinkage of concrete, temperature variations and poor construction quality lead to debonding and gap formation between metal and concrete surface [7]
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