Seismic safety of reinforced concrete framed buildings designed according to Ec-2 and Ec-8

One of the main objectives of the design of earthquake resistant structures is to ensure that these do not collapse when subjected to the action of strong motions. Modern codes include prescriptions in order to guarantee that the behavior of the elements and the whole structure is ductile. It is especially important for the designer to know the extent of damage that the structure will suffer under a specific seismic action, described by the design spectrum. To achieve this damage there are several static and dynamic nonlinear procedures. This paper presents a procedure for nonlinear static analysis in which the maximum displacements are determined based on the condition of satisfying a minimum value of a finite element based damage index. This procedure is validated by applying incremental dynamic analysis, and is used in the assessment of the response of a set of regular reinforced concrete buildings designed according to the EC-2/EC-8 prescriptions for high seismic hazard level. The results of nonlinear analysis allows the formulation of a new seismic damage index and of damage thresholds associated with five Limit States, which are used to calculate fragility curves and damage probability matrices for the performance point of the studied buildings. The results show that the design of earthquake resistant buildings according to the prescriptions of EC-2/EC-8 not only ensures that the collapse is not reached, but also that the structural damage does not exceed the irreparable damage limit state.