+ Critical Load Christopher Lester Yvonne Pelham Moshe Kam D.G. Gorham TISP: Uruguay 9–10 May 2009 User Handout Day 2

+ Structural engineering and how to reinforce the design of a structure to hold more weight. Exercise 4: Critical Load

+ A high critical load is not the only parameter to consider Is the best bridge made by filling a canyon with concrete? It certainly would have a high critical load! Consider also the weight of the structure Lighter is better, given the same critical load These two parameters are combined in an “Efficiency Rating”: Efficiency 3

+ Groups of 2 Up to 12 cards + 1m tape Devise a plan to build a load bearing structure Should have a flat top Support load with base area of 10 x 10cm at least 8 cm above the table No altering of cards allowed – just tape! No wrap-ups of tape Tape is used to connect cards only Critical Load Your Turn 4

+ Critical Load Your efficiency rating: [Load at Failure] / [# of cards used] Predict what the rating of your design will be Build your design Test it! Discuss improvements, then repeat exercise for a second design Your Turn 5