Fighting the Wind: teacher key

How Buildings Stand Up, grade 8 edition, written for 8th grade. Wind and gravity are the two big things tall buildings are designed around. Learn how tubes, cores, odd shapes and giant weights keep skyscrapers steady, and how engineers handled the ground under them.

Read the book. Print this page for the key.

Questions and answers

1. What did Fazlur Khan's tube design do?
   • Moved the structure to the outer wall and saved steel (answer)
   • Removed the elevators
   • Made towers shorter
2. What do outriggers connect?
   • Two towers
   • The central core and the outer columns (answer)
   • The roof and a church
3. Why is the Burj Khalifa Y-shaped?
   • To hold more elevators
   • To make it look like a flower
   • To reduce wind forces (answer)
4. Why did Citicorp Center need a damper?
   • Its light steel frame made it more likely to sway (answer)
   • It was built over a river
   • It was shorter than other towers
5. In an earthquake, what is a base isolator for?
   • Holding the building tight to the ground
   • Letting the building move less than the ground does (answer)
   • Lifting the building up

Words

• outriggers: core-to-wall arms
• damper: motion calmer
• isolator: shake blocker
• setbacks: stepped-in sections