Sohaib Ahmad - Research Student
email : Sohaib.Ahmad@sheffield.ac.uk
SEISMIC VULNERABILITY ASSESSMENT OF REINFORCED CONCRETE STRUCTURES
The seismic risk assessment process consists of hazard assessment and vulnerability analysis. The research will focus on the seismic vulnerability assessment, and aims to assess the probability of occurrence of damage to buildings of a specific stock during an earthquake event. From post-earthquake survey reports from many developing countries, it is evident that many of the existing reinforced concrete (RC) building structures did not perform well during earthquakes because they were designed for gravity loads and lacked the necessary ductility to sustain the high deformation demand on structural members. For example in Pakistan, most of the RC structures are still being designed for gravity loads and are vulnerable to big seismic events.
In October, 2005 an earthquake of magnitude 7.6 on the Richter scale struck Pakistan´s northern part having its epicenter in Kashmir. This caused severe damage in that region and left approximately 80,000 people dead, more than 100,000 wounded and 3.3 million displaced. It is estimated that damages incurred were well over US$ 5 billion which gave a big blow to the economy. Besides the destruction of the vast majority of the brick and rubble masonry construction, the earthquake also damaged many RC structures due to their poor design, detailing and construction. This calls for an urgent assessment of the vulnerability of the existing building stock to mitigate the losses and develop retrofitting techniques and disaster management for future earthquake events.
The current project aims to develop a seismic vulnerability model using empirical and analytical techniques, for low to medium height reinforced concrete building structures (engineered and non-engineered) typical of urban areas of developing countries like Pakistan.
The emphasis will be on simulating the effect of brittle failures in beam-column joints of different categories of RC buildings. The effect of shear failure mode due to various reasons like material degradation, detailing deficiencies and infill walls will be incorporated in existing vulnerability models.
Retrofitting and mitigation strategies will be proposed for different levels of damages based on a new vulnerability model.