Seismic vulnerability assessment of reinforced concrete buildings. Analysis of primary schools’ buildings of the southwestern Iberian Peninsula
Among existing natural disasters, earthquakes have historically caused the most outstanding damage and human losses. The destructive impact of an earthquake depends on its magnitude, and the vulnerability and the resilience of the population. Therefore, in order to minimise its consequences, prevent...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universidad de Sevilla (US) |
| Repositorio: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/130485 |
| Acceso en línea: | https://hdl.handle.net/11441/130485 |
| Access Level: | acceso abierto |
| Palabra clave: | Seismic vulnerability assessment RC buildings Seismic retrofitting Ductility Nonlinear static analysis rehabilitación sísmica edificios de hormigón armado ductilidad análisis estáticos no lineales |
| Sumario: | Among existing natural disasters, earthquakes have historically caused the most outstanding damage and human losses. The destructive impact of an earthquake depends on its magnitude, and the vulnerability and the resilience of the population. Therefore, in order to minimise its consequences, prevention and resilience should be improved. In fact, the minimisation of the geological and geotechnical risks associated with natural disasters has become one of the main challenges of European and national policies, especially after the damage caused by recent earthquakes in Europe. Rigorous seismic vulnerability analyses to enhance the behaviour of buildings can help to reduce the seismic damage, the human losses and the economic impact due to future seismic events This thesis addresses this challenge by establishing two main objectives: i) to assess the seismic vulnerability of RC buildings focusing on primary school buildings located in the southwestern Iberian Peninsula, particularly the Algarve-Huelva region; and ii) to develop specific seismic retrofitting methods for the schools to improve their seismic behaviour and to reduce their expected seismic damage. It has focused on the study of RC primary school buildings in southwestern Spain due to their vulnerability: i) a major part of them was constructed with RC structures prior to restrictive seismic codes (i.e., aseismic design, low-quality structural materials, reinforcement ratios, among others); ii) the considerable seismic hazard of the area, characterised by far away earthquakes of a long-return period and large-very large magnitude; iii) the low/adult child ratio and the post-traumatic stress and depressive disorders that children can suffer from after surviving an earthquake. To do so, first, the seismic hazard of the Algarve-Huelva area has been analysed. This study has revealed considerable differences in the seismic codes of Spain and Portugal, particularly in the definition of the response spectra. Then, the characterisation of the primary school buildings located in Huelva has been carried out, which has not been performed to date. Later, the seismic performance of the buildings has been assessed by means of the performance-based method. The capacity of the structures has been obtained through nonlinear static analyses. The seismic safety has been analysed by means of two procedures: i) obtaining the local damage following the European seismic code procedure; and ii) defining the global damage by means of fragility curves. According to the results, a major part of them were built with an RC system and do not comply with the seismic safety requirements, being seismically vulnerable. In order to enhance the seismic performance of the buildings, several seismic retrofitting strategies have been assessed. They have been selected according to the analysis of the state of the art. An index-based method has been proposed to select the most suitable solution according to efficiency, the construction cost and the architectural impact. The results showed that the steel X-bracings and the single braces retrofitting strategies were the most profitable. In addition, due to the lack of guidance in the seismic codes, a procedure to assess the ductility of existing Spanish buildings has been presented. The analyses concluded that the deep-beams models outperformed the rest. Furthermore, it was found out that enhancing the ductility leads to higher damage reduction, resulting in configurations that are more beneficial. Therefore, the enhancement of the ductile behaviour of RC framed buildings considering retrofitting techniques has been assessed. Different non-invasive solutions have been considered in order not to disrupt the normal use of the buildings. They have been compared in terms of a benefit-cost ratio. Finally, the effects of soil-structure interaction haven analysed. It has been concluded that they can worsen the seismic performance of buildings. They should be included in future seismic vulnerability analyses. |
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