FORCE MEASUREMENT IN STAY CABLESAND STRUTS: A NECESSITY FOR BRIDGEMANAGEMENT

Abstract

Knowledge of forces in stay cables, struts or post-tensioningcables is very important all along the bridge life.During the bridge erection, this information will allow to controlthe uniform stress repartition in the deck structure. Further morefor stay bridges, the exact forces has to be known to adjust thelongitudinal profile. During bridge life, these forces must also be control to verifygood structural behaviour.Determining the forces by measuring own frequencies is a rapidand accurate (2 to 5%) method.This paper explains the measurement method and afterwards, itpresents some measurements cases performed by the Directionde l’Expertise des Ouvrages. Different kinds of campaigns aredescribed: measurements during bridge erection (Millauviaduct) and forces control during load test or bridge life.