Engineering Mechanics Institute (EMI)

Speaker: Ahsan Kareem, Robert M. Moran Professor, NatHaz Modeling Laboratory, University of Notre Dame, Notre Dame, IN

1 PDH will be awarded to eligible attendees for each lecture (Minimum Zoom time of 55 minutes is required)  

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Abstract: The seminar will focus on addressing the three elements of tall buildings' life cycle from design, and construction to performance evaluation. It summarizes the history of wind effects on tall buildings from the design of the World Trade Center Towers to the present-day skyscrapers and beyond. From earlier studies at the National Physical Laboratory in the UK involving the World Trade Center Towers, it was realized that it was essential to model the inflow that was reflective of the atmospheric boundary layer rather than a uniform flow in an aeronautical tunnel. At that juncture, the dynamic response was evaluated using base-pivoted aeroelastic models while a search for a more expeditious means of assessing wind loads was in progress, which led to the development of various force balances. In this context, a general overview of the basic techniques for the quantification of wind loads and their dynamic effects using analytical, experimental, computational fluid dynamics (CFD) and model-based and data-driven simulation schemes, database-enabled platforms, code and standards-based procedures and lessons from full-scale monitoring will be presented in a historical perspective. The issue of human sensitivity to motion will be described from its early day experiments by Fazlur Rahman Khan to current motion simulators. This will be followed by a synopsis of the emerging frontiers in CFD from isolated buildings to cityscapes, mesoscale to micro-scale, shape and topological optimization, the vulnerability of glass cladding in extreme winds, the role of organic damping and damping devices for the mitigation of building motion.

Speaker: Armen Der Kiureghian, Taisei Professor of Civil Engineering Emeritus, University of California, Berkeley, President Emeritus, American University of Armenia (affiliate of University of California)

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Abstract: A variety of methods for assessment of structural reliability and for reliability-based optimal design have been developed in the past fifty years. Among methods in current use are first- and second-order reliability methods (FORM and SORM), various efficient simulation methods, and surrogate-modeling methods. After a short review of these methods, this lecture will focus on the existing challenges in applying these methods to complex real-world problems characterized by nonlinearity, stochastic dynamics, multi-phase interactions, and having high computational demand. The lecture will hopefully provide motivation to young researchers to pursue research and development in addressing some of these challenges.