Non-destructive testing (NDT) methods to determine the condition of existing concrete members, such as pre- or post-tensioned beams belonging to concrete bridge decks, are used in assessing the need for preventive maintenance, repair or replacement of the structure. In this work, a prestress force identification method for concrete beams using static deflections is presented. The procedure makes use of the Euler-Bernoulli beam model and it is able to estimate the prestress forces using one or a set of displacements measured along the beam span. The method also requires the knowledge of the flexural rigidity of the element under examination. The deflected shape of a post-tensioned concrete beam, subjected to a three point-bending test, was short-term monitored in several laboratory tests. The accuracy of the deflection measurements allowed to obtain good prestress force estimations. Finally, it was shown that “compression-softening” theory holds for post-tensioned concrete beams with prestress forces satisfying the decompression serviceability limit state. Results of this experimental work will be presented and discussed.

Deflection-based measuring method for the prestress force prediction in concrete members

BONOPERA, Marco;TULLINI, Nerio
2017

Abstract

Non-destructive testing (NDT) methods to determine the condition of existing concrete members, such as pre- or post-tensioned beams belonging to concrete bridge decks, are used in assessing the need for preventive maintenance, repair or replacement of the structure. In this work, a prestress force identification method for concrete beams using static deflections is presented. The procedure makes use of the Euler-Bernoulli beam model and it is able to estimate the prestress forces using one or a set of displacements measured along the beam span. The method also requires the knowledge of the flexural rigidity of the element under examination. The deflected shape of a post-tensioned concrete beam, subjected to a three point-bending test, was short-term monitored in several laboratory tests. The accuracy of the deflection measurements allowed to obtain good prestress force estimations. Finally, it was shown that “compression-softening” theory holds for post-tensioned concrete beams with prestress forces satisfying the decompression serviceability limit state. Results of this experimental work will be presented and discussed.
Concrete beam, Deflected shape, Inverse problem, Load identification, Static test
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2373967
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