Bridges: Venoge

Case study: SOFO System

Steel-concrete composite structure
Concrete monitoring during setting
Slab monitoring during load testing

Project Description

Summary: Concrete monitoring during setting, crack detection, slab monitoring during load testing

Clients: Vaud Canton

Place: Vaud Canton (Switzerland)

Period: 1995 - 1997

Installation: ICOM/IMAC-EPFL

Structure's short description: The Venoge highway bridge is a four spans bridge consisting in two parallel steel girders supporting a concrete deck. To widen the structure, two identical bridges were built on each side creating a third traffic lane and a new emergency lane in each direction.

Aim of monitoring: Monitoring of the shrinkage effects, especially during the first hours after concreting, verification of the bridge deformations under known static loads.

Number of sensor: 20

Main Results: Thanks to the measurements obtained with the SOFO system, it was possible to observe the apparition of transversal cracks a few days after concreting. This effect was predicted by a theoretical model and is the consequence of the partially hindered thermal shrinkage. Being the SOFO system unaffected by the temperature effects, it was possible to measure the apparition of the cracks and the associated redistribution of the deformations in a quantitative way. Measurements were also performed during the charging tests, where heavy trucks were placed at specific locations on the bridge and the associated deformations were observed and compared to the ones predicted by finite elements programs and security standards.

Recorded deformations during 2 months after concrete pouring

Measuring SOFO sensors

Concrete pouring on SOFO sensors

Bibliography:

SOFO?: Surveillance d'ouvrages par senseurs ?fibres optiques, D. Inaudi, S. Vurpillot, Ing?ieur et Architecte Suisse, Vol 121, No 26, p 522-529, 1995

SOFO?: Monitoraggio di opere del genio civile tramite sensori a fibre ottiche, G. Ballerini, D. Inaudi, S. Vurpillot, ARCHI, architettura e ingegneria, ed. Casagrande, Nr. 1, p 74 -80, 1998

Bridge monitoring by interferometric deformation sensors , D. Inaudi, S. Vurpillot, N. Casanova, Conference on Laser Optoelectronics and Microphotonics: Fiber Optic Sensors, Beijing, invited paper, SPIE, Vol 2895, p 34-45, 1996

Bridge monitoring by fiber optic deformation sensors: design, emplacement and results , S. Vurpillot, D. Inaudi, J.-M. Ducret, SPIE, Smart Structures and materials, San Diego, USA, Vol 2719, p 141 - 149, 1996

Fiber optic deformation sensors for bridges monitoring , D. Inaudi, N. Casanova, S. Vurpillot, Int. Conf. on New Technologies in Structural Engineering, Lisboa, Portugal, p 975-982, 1997