Live loads in condition assessment of old bridges

Kamiński, T.; Bień, J.; Kużawa, Mieszko; Zwolski, J.

doi:10.1201/9781315207681-154

Cited by 1 publication

(2 citation statements)

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“…Linear variable differential transformers have proved to be successful in monitoring displacements in heritage structures. However, they provide only point-to-point displacement measurements for monitoring crack amplitudes and their variations in time [12,13]. Another contactless tool for measuring strain in masonry structures is represented by digital image correlation (DIC), or more broadly digital image processing [2,14].…”

Section: Introductionmentioning

confidence: 99%

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Smart bricks for strain sensing and crack detection in masonry structures

Downey

D’Alessandro

Laflamme

et al. 2017

Smart Mater. Struct.

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The paper proposes the novel concept of smart bricks as a durable sensing solution for structural health monitoring of masonry structures. The term smart bricks denotes piezoresistive clay bricks with suitable electronics capable of outputting measurable changes in their electrical properties under changes in their state of strain. This feature can be exploited to evaluate stress at critical locations inside a masonry wall and to detect changes in loading paths associated with structural damage, for instance following an earthquake.Results from an experimental campaign show that normal clay bricks, fabricated in the laboratory with embedded electrodes made of a special steel for resisting the high baking temperature, exhibit a quite linear and repeatable piezoresistive behavior. That is a change in electrical resistance proportional to a change in axial strain. In order to be able to exploit this feature for strain sensing, high-resolution electronics are used with a biphasic DC measurement approach to eliminate any resistance drift due to material polarization. Then, an enhanced nanocomposite smart brick is proposed, where titania is mixed with clay before baking, in order to enhance the brick's mechanical properties, improve its noise rejection, and increase its electrical conductivity. Titania was selected among other possible conductive nanofillers due to its resistance to high temperatures and its ability to improve the durability of construction materials while maintaining the aesthetic appearance of clay bricks. An application of smart bricks for crack detection in masonry walls is demonstrated by laboratory testing of a small-scale wall specimen under different loading conditions and controlled damage. Overall, it is demonstrated that a few strategically placed smart bricks enable monitoring of the state of strain within the wall and provide information that is capable of crack detection. Abstract. The paper proposes the novel concept of smart bricks as a durable sensing solution for structural health monitoring of masonry structures. The term smart bricks denotes piezoresistive clay bricks with suitable electronics capable of outputting measurable changes in their electrical properties under changes in their state of strain. This feature can be exploited to evaluate stress at critical locations inside a masonry wall and to detect changes in loading paths associated with structural damage, for instance following an earthquake.Results from an experimental campaign show that normal clay bricks, fabricated in the laboratory with embedded electrodes made of a special steel for resisting the high baking temperature, exhibit a quite linear and repeatable piezoresistive behavior. That is a change in electrical resistance proportional to a change in axial strain. In order to be able to exploit this feature for strain sensing, high-resolution electronics are used with a biphasic DC measurement approach to eliminate any resistance drift due to material polarization. Then, an enhanced nanocomposite smart br...

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Section: Introductionmentioning

confidence: 99%

“…This concept extends the potential of electrical resistance measurements within masonry elements. Currently, resistance tests are used to identify wetting and drying cycles along with structural inconsistencies in masonry structures [13,42].…”

Section: Introductionmentioning

confidence: 99%