Influence of concrete strength fractile estimation on the safety level of existing structures assessed using the Adjusted Partial Factor Method

In case of existing concrete structures, the estimation of the characteristic strength values from limited data is a difficult, but important task. There are currently different assessment methods available, among which the classical coverage method, a Bayesian procedure with vague prior distributions (as mentioned in EN 1990) and the method described in EN 13791. With respect to the assessment of existing structures, the authors have developed and investigated an Adjusted Partial Factor Method, which is compatible with current Eurocodes, but additionally enables to incorporate alternative target reliability levels and reference periods and also additional information based on

e.g. on-site inspection data and data from testing. In this contribution the influence of the different fractile estimation methods on the safety level of concrete structures is investigated, considering the Adjusted Partial Factor Method. The performance of the different estimation methods are evaluated and compared using Monte Carlo simulations and FORM analyses.