This paper outlines the extension of an electrical resistance tomography (ERT)–based sensing skin technology for detecting cracking patterns in full-scale reinforced concrete structural elements. The sensing skin consists of a thin layer of conductive film that is applied to the surface of a structure. Cracking results in a local reduction of electrical conductivity of the sensing skin, enabling detection of cracking with ERT. As the size of the sensing skin increases, however, the resolution of sensing skin for detecting small cracks diminishes. In the present paper, we overcome this limitation of sensing skin with the use of internal electrodes. We applied a sensing skin equipped with four internal electrodes to a reinforced concrete beam with overall dimensions of 4.5 m × 1.0 m × 0.3 m, where the 4.0 m × 1.0 m surface of the beam was equipped with the sensing skin. Cracking was induced in the beam using four-point bending. The large-area sensing skin successfully detected cracking at different stages of loading. The results also indicate that in the absence of internal electrodes, detecting the cracking pattern in the large sensing skin was not feasible.
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