Description: Themes: Earthquake loads as an element to consider in the lateral design of tall buildings; Techniques employed to mitigate effects of earthquakes; Ethical question of addressing a significant design flaw in an occupied building; Ethical question of designing structures that are publically funded.
Learning Objectives: Students should be able to: EARTHQUAKES: Describe impact major earthquakes have had on people and buildings; Describe the relationship between ground motion and building stiffnes; What do tuned mass dampers do?; Relate the time period of an earthquake's vibrations to the height of buildings most affected by it; Explain why the buildings most affected in the Mexico City Earthquake were of intermediate height (five to fifteen stories); Describe three possible structural systems used by buildings to increase resistance to earthquakes and wind, and explain how they work (see also lectures on Khan); ETHICS: Discuss the dilemma of the Citicorp Tower (how should an engineer 'handle' a major design flaw when it is discovered?); Through Calatrava, discuss the ethics of economy and elegance; Describe how an added constraint in the layout of the Citicorp Tower led to a design flaw; Discuss the dilemma of the Citicorp Tower (how should an engineer 'handle' a major design flaw when it is discovered?); Discuss the tradeoffs between the elegance of Calatrava's works and their efficiency and economy; Use Calatrava's works as a case study to discuss the ethical consequences of Calatrava's design choices
Keywords: Earthquake, lateral load, natural period, resonance, stiffness, mass, tuned mass damper, Citicorp, quartering winds, column arrangement, chevron bracing, weld, bolt, ethics, economy, cost, public money