Consistency of analysis methods considered in EC8-3 for the seismic assessment of RC existing buildings

This paper offers a parametric study on reinforced concrete frames representative of structural types widely present in the European building stock. It focuses on buildings which have been designed only for vertical loads. These are detailed by adopting the simulated design procedure proposed in Masi (Bull Earthq Eng 1(3): 371-395, 2003) and introduced in the European code for the seismic assessment and retrofitting of existing buildings EC8- 3 (CEN in Eurocode 8: design of structures for earthquake resistance-part 3: assessment and retrofitting of buildings, prEN 1998-3, Brussels, 2005). Some structural types have been selected by varying the numbers of storeys (2, 4 and 8 storeys) and the infill configuration (bare, infilled and pilotis frames). The seismic analyses have been carried out applying linear and non-linear static analysis methods in accordance to EC8-3. Different performances were computed by adopting different seismic intensities (4 cases: very low to high seismic zone), behaviour factors (4 cases, only for linear analysis), knowledge levels (3 cases), and concrete strength values (3 cases: 10, 18 and 28 MPa). The performances were compared to investigate the consistency of the analysis methods under study that is to verify whether they provided results which were mutually consistent in terms of outcomes regarding safety verifications taking into account differences in complexity and accuracy. The role of some structural parameters is emphasized and future developments of the study aimed at upgrading the current version of the European code are outlined.