Durability of concrete bridges with respect to fatigue under increasing traffic loads

摘要

Increasing traffic loads lead to higher fatigue stresses of bridge structures. The effects on the stresses of the main load-bearing structure depend on the load models representing weight and the ratio of the load model length to the bearing distance of the superstructure. Within a research project described in Griinberg et al. (2006) several different bridge constructions were analysed with respect to their fatigue strength. Hence, the stresses in the concrete and steel components are examined on extensive numerical models in the longitudinal and the transversal direction. First of all the fatigue investigations of these existing bridges are performed by specified load combinations according to the german standard for actions on bridges DIN FB102 (2003). The future development of heavy traffic loads is included by using specified load models. During investigation several load models representing expected vehicles of heavy duty traffic are calculated and compared with the fatigue load model FLM3 described in the german standard for the actions on bridges DIN FB101 (2003). The different effects of the analysed load models are shown by a predefined coefficient of utilisation and a specific degradation factor considering a linear damage accumulation.