Probabilistische Berechnungsverfahren als zusätzlicher Baustein der ganzheitlichen Bewertung von Brücken im Bestand

Probabilistic analysis methods as an additional component for the integrated assessment of existing bridges

With the implementation of the guideline for the assessment of existing bridges (Nachrechnungsrichtlinie) a tool is given to designers and engineers, which offers the possibility of a realistic assessment of existing bridges by special arrangements and requirements. The analysis can be done in 4 steps. In step 3 and particularly in step 4 it is allowed to use scientific, e. g. probabilistic methods, for the assessment. The research in the field of probabilistic analysis was strongly promoted in recent decades. The tools for modelling and computing are now available which allows the use of probabilistic methods in the engineering practice. The paper shows a possible procedure for the probabilistic assessment of existing structures. The sensitivity analysis is here of special importance. This analysis shows the impact of each influencing parameter of loads and resistance on the reliability of the bridge. In addition to the presentation of the approach the paper gives details for the stochastic modelling of loads, resistance and model uncertainties. Two examples, a prestressed concrete girder bridge and a reinforced concrete arch bridge, show the advantages of the presented approach.