Fatigue Tests Of Cracked Reinforced Concrete Slabs For Estimating The Service Life Of Composite Bridge Decks

Abstract

ABSTRACT A large-scale experimental program was co-sponsored by the main French owners of composite bridges in order to estimate the fatigue service life of cracked decks, as it occurs due to restrained shrinkage of concrete. The fatigue tests were carried out at the Structures Laboratory of LCPC on six transversally cracked reinforced concrete slabs largely equipped with gauges and sensors. 1.4 to 12 million cycles were applied. This loading program represents more than 100 years of heavy motorway traffic. The onset of fatigue failure of lower transverse reinforcing bars appears to be the fatigue limit-state of such structures. It leads to safety factors from 1.3 to 1.8 on the mechanical point of view for existing structures under 100 years of heavy traffic. Moreover, shear transfer remains ensured along through-going cracks even under high load variations, and there is no interaction between the static punching shear failure mode and the transverse cracks. The modified stress distribution (significant d...