Optimising the seismic performance of steel and steel-concrete structures by standardising material quality control (OPUS) : final report

Despite modern seismic standards, like Eurocode 8, admit ductile design of steel and composite structures, current European production standards do not provide adequate limitations on steel mechanical properties limiting free application of such approach. Additional safety factors and design checks, aiming to guarantee optimal plastic hinges' location, must be foreseen, reducing practical applicability and possible advantages of seismic ductile design. The proposal investigated the influence of material scattering on structural performance of a set of case studies designed according to Eurocodes. These structures were probabilistically analysed and used as applicative case studies in order to quantify: the benefit of introducing upper limits on yielding stress -Re,H (fy) - at the production plant; the effective contribution of γOVfactor in the capacity design formula; the effectiveness of EN1998-1-1 seismic design procedure; the assessment of the harmonisation level between production and structural standard. These analyses were performed adopting a Monte Carlo simulation technique based on the following parts: materials' properties probabilistic model able to represent actual scattering of European steel production; executive protocol for a profitable application of incremental dynamic analysis technique on case studies; probabilistic procedure for analysing all results obtained from IDA simulations. More than 106 of non-linear dynamic analyses were carried out during the project. Moreover, the proposal defined preliminary guidelines for the planning of a future harmonisation between structural standards and production standards able to maintain actual high safety levels of steel and steel-concrete structures against seismic actions.