Title: Vertical Deflection of a Pre-Stressed Concrete Bridge Obtained Using Deformation Sensors and Inclinometer Measurements

Author(s): Samuel Vurpillot, Gaston Krueger, David Benouaich, Denis Clement, and Daniele Inaudi

Publication: Structural Journal

Volume: 95

Issue: 5

Appears on pages(s): 518-526

Keywords: bridge monitoring; deformation; fiber optic sensor; long-term monitoring; smart structures; structural analysis;

DOI: 10.14359/566

Date: 9/1/1998

Abstract:
The serviceability of a bridge is generally analyzed by a comparison between the vertical deflections expected by the engineer and those measured during a load test or in the long term. The existing methods do not allow the determination of the vertical displacements from the measurements carried out by a network of deformation sensors placed inside the bridge. The mathematical model presented here allows the determination of the displacement field from internal horizontal deformation measurements and helps in the design of the required sensor network. This model was tested on an experimental model and on the Lutrive Highway Bridge (Switzerland) by comparing the changes in vertical displacements under daily temperature variations obtained with the proposed method, with those measured directly using an absolute hydrostatic leveling system. Fiber optic deformation sensors and electrical inclinometers were used to carry out the measurements. With this deformation monitoring system, featuring a precision of 10 Fm on 1 m long deformation sensors, it is possible to retrieve the vertical displacement field of a beam with a global error less than 8 percent.