The objective of this project is to systematically integrate the seismic hazard resulting from aftershocks in modern earthquake engineering design codes based on the emerging concept of performance-based earthquake engineering, thereby reducing the potential for loss of life and damage. Major earthquakes are often followed by multiple aftershocks. These aftershocks can occur very soon or significantly later than the occurrence of the main shock. Aftershocks have the potential to cause severe damage to buildings and threaten life safety even when only minor damage occurs in the main shock. Aftershocks may have different energy content and can occur at a different location on the fault, that is, closer to a population center. To achieve the objective a series of analytical/numerical studies utilizing a portfolio of realistic building models will be conducted. The models will be calibrated using the data available in the repository of the Network of Earthquake Engineering Simulation hub (NEEShub) site. These models will be used to develop system fragilities, which provide the probability of different damage states, for structures with varying levels of damage. The fragilities will be combined with aftershock hazard models to quantify their effect on the building performance. As a final outcome, the project will provide a methodology to future researchers and practitioners to integrate the system fragilities and the effect of aftershocks in current state-of-the-art performance-based design approaches.
In order to include the effect of aftershocks on a broader scale, the approach developed in this project will be integrated into next generation seismic design methodologies, which are being formulated in the ATC-58 Project of the Applied Technology Council for performance-based design of new buildings and evaluation of existing buildings. This project will generate useful data that can be used by practitioners and code development bodies to incorporate the effect of aftershock in building design for enhanced life safety and performance. This data will be made available to other researchers through the NEEShub repository. The project will also provide advanced training to graduate students in earthquake engineering and performance-based earthquake engineering.
