Auswirkungen von Verkehrserschütterungen auf jungen Beton: Teil 1

Abstract

Effects of traffic-induced vibrations on young concrete: part 1. In the COUNT (Concreting under traffic) research project, the effects of traffic vibrations on young concrete are extensively examined. This research question has recently become more relevant since traffic closures often have to be imposed when bridges are renovated or widened, as there is a concern that the vibrations caused by traffic will damage the young (hardening) concrete. COUNT aims to determine critical vibration values and underlying damage mechanisms based on three test series. Both harmonic and real bridge vibrations due to train, truck and car traffic are adopted, and the effects on the material concrete itself are investigated, as well as on the bond behaviour between concrete and reinforcement, and the contact between existing and new concrete parts. This first part of the article reports on the results of test series 1 and 2, in which small samples were systematically excited by artificial vibrations during hardening. It was found that conventional traffic vibrations do not affect the strength of concrete per se, but that the bond between the concrete and the reinforcement can be weakened if the vibrations are too great. In addition, it was found that (differential) displacements is a more suitable measure for damage assessment than the vibration velocity.