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Probabilistic reliability analysis of a prestressed concrete bridge – part 1 – Semi‐probabilistic reassessment and probabilistic modeling of a single‐span 6‐webbed t‐beam bridge Maintaining the existing transportation infrastructure is a major challenge as the structures continue to age, the traffic loads increase and comprehensive replacement is impossible given limited budgets and resources. On existing structures present material characteristics, geometries or loads can be recorded on an object‐specific basis. In Germany the reassessment of existing bridges is carried out in accordance with the reassessment guidelines at the stages 1 and 2 using the semi‐probabilistic partial safety concept. Only in exceptional cases will a measurement‐based assessment or a scientific analysis acc. to levels 3 and 4 be carried out. However the inclusion of additional information from condition assessment offers many advantages for a realistic reassessment. In probabilistic calculation methods, such information can be taken directly into account. The aim of this two‐part article is to present the potentials and advantages of directly including the results of non‐destructive testing methods when assessing the condition of bridge structures. The concept is presented on a prestressed concrete bridge. The first part deals with the possibilities for transferring the input values of the usual semi‐probabilistic calculation into stochastic models. Starting from the semi‐probabilistic reassessment acc. to current regulations, the probabilistic modeling of all relevant basic variables for the ultimate limit states of bending, shear and torsion is carried out. [ABSTRACT FROM AUTHOR]

Translation abstract Probabilistic reliability analysis of a prestressed concrete bridge – Part 2 – Mechanical modelling and probabilistic reassessment of a single‐span 6‐webbed t–beam bridgeIn the second part of this article the limit state functions in the ultimate limit state for bending with axial force, shear with shear reinforcement and torsion are presented. The input variables of the mechanical resistance models are accompanied by numerous illustrations. The probabilistic verifications are carried out on the basis of the probabilistic models from the first part of this article and the mechanical models from this second part. In the subsequently compiled reliability analysis, reference is made to the semiprobabilistic calculation results. With the parameter studies it is shown which input variable measurable by non‐destructive testing methods have the greatest influence on the calculated reliability. On this basis finally it is shown what opportunities arise for a reassessment from conducting non‐destructive testing in the inspection. [ABSTRACT FROM AUTHOR]

How safe are our structures? – Conceptual paper of the DGGT Working Group 2.15 "Reliability‐Based Methods in Geotechnical Engineering" The future Eurocode 7 will explicitly allow the use of reliability‐based methods in geotechnical planning and design. In Germany, there is hardly any experience in the practical application of such methods so far and thus the reservations towards these methods are plenty. The new DGGT Working Group (WG) 2.15 "Reliability‐Based Methods in Geotechnical Engineering" has set itself the goal of providing a practical access to those methods by means of practice‐oriented instructions and recommendations as well as accompanying training and further education courses. The aim is to clarify the possibilities and limitations and, above all, to exploit their potential. This article presents the general principles as well as the future fields of work of the WG 2.15. Starting with the introduction of relevant technical terms, the implementation of reliability‐based methods within the current codes of practice and regulations is shown. Using the life cycle of a geotechnical structure, the uncertainties in geotechnical designs and assessments are described. Subsequently it is outlined, in which situations and to what extend reliability‐based methods can aid engineers, clients and inspectors in verification and decision‐making processes. In the future, WG 2.15 will develop recommendations on individual topics and publish them successively. [ABSTRACT FROM AUTHOR]