Ahsan Kareem

Robert M. Moran Professor,
NatHaz Modeling Laboratory,
University of Notre Dame,
Notre Dame, IN

Swaying Skyscrapers: Unveiling the Dance Between Wind and Tall Buildings Through the Ages
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Wednesday, March 6, 2024 - 4:30 pm EST

Ahsan Kareem is the Robert M. Moran Professor of Engineering and the Director of the NatHaz Modeling Laboratory at the University of Notre Dame. His research uses computer models, laboratory, and full-scale experiments to study the dynamic effects of environmental loads under winds, waves, and earthquakes to understand, predict, and mitigate the impact of natural hazards on the constructed environment. Dr. Kareem received his Ph.D. from Colorado State University, M.Sc. from the University of Hawaii/MIT, and B.Sc. (valedictorian) from the West Pakistan University of Engineering and Technology. He is a Distinguished Member of ASCE and a Member of the US National Academy of Engineering and also a foreign member of the Engineering Academies of India, China & Japan. (wikipedia.org/wiki/Ahsan_Kareem)

Swaying Skyscrapers: Unveiling the Dance Between Wind and Tall Buildings Through the Ages. 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.