Comparative study on the seismic performance assessment of existing buildings with and without retrofit strategie

• Autor(a) principal: Rakesh, Dumaru
• Data de Publicação: 2018
• Outros Autores: Rodrigues, Hugo, Varum, Humberto
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.8/4165
• topic: Non-engineered and pre-engineered buildings; Retroft techniques; Irregularity of infll panels; IDA curves; Fragility curves

A large number of inflled RC frame buildings have undergone moderate to extensive structural damages and even collapsed after the 2015 Gorkha earthquake. The repair and maintenance works are still being carried out in the existing RC buildings, many of them without any consultation with design engineers. Such practices are likely to create a beneft of doubt on the efciency of the retroftting works and repair/maintenance works. Therefore, the present study aims to evaluate the seismic performance of the existing non- and pre-engineered buildings, and later employed retroft measures that are commonly practised in the region. The analytical results revealed that the selected buildings were seismically defcient and are most likely to undergo extensive damage to collapse states, at 0.3 g PGA. It was found that the retroft measure signifcantly enhances the stifness, maximum strength and ductility in the existing buildings. The pushover curves indicated that the steel bracing highly increased the stifness, strength and ductility capacity in all case study buildings. The steel-braced building was recorded to have increased the maximum base shear capacity by almost ten times for the soft-storey MRT1 building. Similarly, the retroft measures also eliminated the potential single storey drift concentration recorded in the original building, such that a uniform inter-storey drift profle can be attained throughout. The conditional probability of collapse for the case study buildings, at 0.3 g PGA, ranges from 13.5 to 42% and could be minimized below 4% in the worst case scenario for the shear wall. All the numerical results demonstrated that steel bracing was much more efective in enhancing the seismic performance of the existing buildings.