1. Structural Engineering
SciTech 11

2. What is a structure?
______________ – something that is ___________________
Joining parts to meet a certain _______ or perform a _______________

3. Types of Structures
Natural Structures

4. Types of Structures Human Structures

5. Design Design depends on ______ -dam must be ___________
-tower to transmit tv and phone signals must be __________
-houses built for ___________ and _____________
-factories and offices for ______________

6. Who Designs Structures?
Civil Engineers – ______________________ _____________________________________
-most work on roads, water systems, sewers, and public structures
Structural Engineers – civil engineers that focus on _____________________
Architect – ______________________ and oversees construction

8. Who Designs Structures?
Questions they might ask:
-how many __________ or ____________ on bridge per day
-how might skyscraper be affected by ____________________
-how to protect a structure in ____________________

9. Forces on Structures
Force – __________________________ ______________ to an object
External force – come from __________, act _____________ the structure
Internal force – force that ____________ _____________, act _________ structure

10. Types of Forces 4 types: compression, tension, torsion, shear
1. _____________ – shortens or crushes
2. __________ – stretches or pulls apart
3. ____________ – twists
4. ___________ – pushes parts in opposite directions

12. 2.3 Internal Forces Within Structures
Compression, Tension, and Shear
Compression forces crush a material by squeezing it together. Compressive strength measures the largest compression force the material can withstand before it loses its shape or fails.
Tension forces stretch a material by pulling its ends apart Tensile strength measures the largest tension force the material can withstand before failing.
Shear forces bend or tear a material by pressing different parts in opposite directions at the same time. Shear strength measures the largest shear force the material can withstand before it rips apart.
Torsion forces twist a material by turning the ends in opposite directions. Torsion strength measures the largest torsion force the material can withstand and still spring back into its original shape.

13. Types of Forces
Load – _________________ acting on an object, eg: ___________, pressure from wind/water
Static Load – _____________________, eg: bricks in a building, twigs in nest
Dynamic Load – __________________, eg: car crossing bridge, oil in pipeline

14. Structural Materials Wood
-one of the ______________ used for structures
-still the ________________ materials for _________ production
-comes in many varieties
-for construction, strong wood used = ________ __________
-________ of wood helps determine _________ (size, shape, direction of fibres)

15. Structural Materials Disadvantages of wood:
-_______________________ with changes in ________________
-damaged by _______________________
-breaks down if not maintained

16. Engineered Wood
-_______________ wood strands, fibres, veneers with _____________
-can __________________________
-formed into panels, laminated beams, I-joists
-structural panels (___________) most common
-made by gluing together ____________
-odd number of layers, _________________
-less likely to ________________________ (_______________________)

17. Structural Materials ________
-laminated, used for ________ construction in homes
-light, available up to 60 ft, don’t ______ or _________
-eliminate ________________ because don’t shrink

18. Structural Materials _____________________
-glue together ______________ of wood
-consistently ____________, can be made very long

19. Steel Steel is an ________ (metal made of _____________________)
made from ________ and _________
may have _____________ and ________ to _____________
made into _________________ (I-beams, pipes, wires) and joined many ways (rivet, bolt, weld)
used as _______ or ________ to strengthen _____________

20. Concrete made by mixing ____________________ ________________________
hardens into strong material
examples?
very _________ in _______________
poured into forms to make almost ______ ______________

21. Concrete _______________
-may be reinforced with steel bars to make ____________________
_____________ concrete contains ______ that are under __________ all the time
produce beams, floors or bridges with a _____________ than reinforced concrete
wires produce a ___________________ that offsets ___________ stresses

22. Structural Members Structural Members:
-building materials joined to make a __________________
Common shapes include:

23. Bridges Before a bridge is built: -_______ samples
-_______ speed and direction
-_________ levels and speed of water
-models tested in lab or on computer
-community hearings
-planning takes several _________ and _____________ of dollars!

24. Bridge Types

25. Skyscrapers
History:
-___________________ in ancient Egypt, which was 146 metres (480 ft) tall and was built in the 26th century BC
-Ancient __________ housing structures reached 10 stories
-Medieval times: many towers built for ______________
-_______________________ built in 1178

26. Skyscrapers
-first “skyscraper” was Home Insurance Building in _____________, 1885
-____ stories
-load-bearing ____________ instead of load-bearing walls
-practical with the invention of the ______________ (no more stairs!)

27. Skyscrapers
-Current record = ______ __________, 1,670 ft tall
-has huge ______________ near top to counteract ______________

28. Skyscrapers -high quality ________________ bear immense weight
-beams _________, _________, or _________ together
-most weight is transferred to _________ _____________, the spreads out at base and substructure
-_______________ is a major concern

29. Wind Resistance -many tall buildings __________________ in strong wind
-structure is _____________ constructed to _______ movement
-_____________ monitor sway and move huge _________________ to compensate

30. Earthquake Resistance
-ban construction along ______________
-many buildings built on layers of _______ ___________ or a ____________ surface