Contribution of the soil-structure interaction to the seismic behaviour of the Mosque-Cathedral of Córdoba

This paper deals with the contribution of the soil-structure interaction (SSI) effects to the seismic analysis of cultural heritage buildings. This issue is addressed by considering, as a case study, the Mosque-Cathedral of Córdoba (Spain). This study is focussed on the Abd al-Rahman I sector, which is the most ancient part, that dates from the 8 th century. The building is a UNESCO World Heritage Site and it is located in a moderate seismic hazard zone. It is built on soft alluvial strata, which amplifies the SSI. Since invasive tests are not allowed in heritage buildings, in this work a non-destructive test campaign has been performed for the characterisation of the structure and the soil. Ambient vibration tests have been used to calibrate a refined 3D macro-mechanical-based finite element model. The soil parameters have been obtained through an in situ geotechnical campaign, that has included geophysical tests. The SSI has been accounted for by following the direct method. Nonlinear static and dynamic time-history analyses have been carried out to assess the seismic behaviour. The results showed that the performance of the building, if the SSI is accounted for, is reduced by up to 20% and 13% in the direction of the arcades and in the perpendicular direction, respectively. Also, if the SSI is taken into account, the damage increased. This study showed that considering the SSI is important to properly assess the seismic behaviour of masonry buildings on soft strata. Finally, it should be highlighted that special attention should be paid to the SSI, which is normally omitted in this type of studies, to obtain a reliable dynamic identification of the built heritage. • First study of the SSI effects on the seismic analysis of the Mosque-Cathedral of Córdoba. • Non-destructive tests and 2D-MASW used for structural and soil characterisation. • Complex 3D finite element model considering the SSI, using the OpenSees framework. • SSI increases damage and worsens performance by up to 20% compared to the fixed condition. • Emphasis on the need to consider the SSI in the seismic assessment of heritage buildings.