Assessment of existing civil engineering structures

The upcoming CEN Technical Specification (TS) on assessment of existing structures is to be related to the probabilistic concepts and fundamental requirements of the EN Eurocodes. The document should concern all types structures made of concrete, steel and other materials, exposed to all kinds of actions. The final draft of the Technical specification was already submitted to the technical committee CEN TC250. It contains requirements, general framework of operational assessment, data updating, structural analysis (linear, nonlinear, dynamic), verifications (partial factors, probabilistic methods, risk assessment), past performance, interventions, annexes (flowchart, time-dependent reliability, assessment of heritage structures). The submitted contribution provides background information on the principles included in TS. Particular attention is paid to specifying appropriate target reliability levels and application of these values in engineering practice through adjustment of partial factors. It is shown that the operational assessment of existing concrete structures provides prediction of the remaining working life of a structure using a convenient reference period (commonly 50 years) taking into account durability aspects and mutual dependence of the failures in subsequent basic time periods (usually considered as one year).