Bridge pier scour measurement by means of Bragg grating arrays

¹ Politecnico di Milano, D.I.I.A.R. – Piazza Leonardo da Vinci 32, 20133 Milan ( Italy )
² Politecnico di Milano, Department of Mechanics – Via La Masa 1, 20156 Milan ( Italy )
³ Politecnico di Milano, Department of Energy – Via Lambruschini 4, 20156 Milan ( Italy )

^a e-mail: stefano.manzoni@polimi.it

Abstract

This paper deals with a new method to measure scour level at bridge piers. The proposed technique is based on an array of Bragg grating temperature sensors, heated by an electrical circuit. The Bragg gratings in water sense a lower temperature than those buried in the river bed, because of the different heat scattering principles in the two situations. Furthermore the response of each sensor is slower if it is buried in the bed, with respect to the case it is in water. The paper presents laboratory tests, showing the method effectiveness and reliability, and it explains the advantages with respect to other more traditional methodologies to measure scour level.