Semi-quantitative classification of consequences of failure for seismic risk management of existing buildings

This paper presents a uniform and consistent semi-quantitative classification of consequences of failure of buildings as part of a multi-level seismic risk management framework for existing buildings to help building owners make risk-informed decisions for the seismic evaluation and retrofit of existing buildings to minimise the life safety risk. The management framework consists of three levels of risk assessment, namely: (i) Level 1: Preliminary seismic screening; (ii) Level 2: Semi-quantitative seismic risk screening; and (iii) Level 3: Quantitative seismic evaluation. The proposed classification consists in general of three classes, namely: (i) Consequence Class - Low (CC-L), (ii) Consequence Class - Medium (CC-M); and (iii) Consequence Class - High (CC-H). These consequence classes are based on semi-quantitative criteria, including building occupancy, number of people at risk, building area, number of storeys, and mobility and ability to escape. The proposed classification can be used to refine the building importance classification in many codes, standards and guides to yield more uniform classification of consequences of failure that can be integrated with the seismic risk management framework to determine more uniform risks of failure. An example illustrating the application of the proposed classification is provided for the case of office buildings.