Structures review.

1. Structures Review

2. What is a structure?
● Set of parts of an object that resist the effects of forces
acting on it
● Help keep the objects shape

3. What is a force?
● The powers that act on structures

4. Functions of structures
1) Keep the object’s shape and support its weight
2) Resist external forces
3) Support weights
4) Protect objects

5. What is a load?
● The external forces that act on structures

6. What is a stress?
● The internal tension that objects experience when one or
more forces act on that object
● Stresses are the responses to forces

7. Name four of the six types of stress
Stress Definition Example
Traction Forces stretch the object
away from its center
Compression Forces compress or squash
the object toward its center
Bending Forces bend or misshape
object
Torsion The forces twist the object
Shear The forces cut the object
Buckling Compression forces acting
on an object that also leads
to a bending force on the
center of an object

8. 2 - Conditions of
Structures

9. Resistance
● Ability of a structure to hold its own weight and the
weight of other loads without breaking

10. Rigidity
● A structure’s ability to hold loads without changing shape

11. Stability
● Structure’s ability to stay in its original position without
falling over despite a load

12. Centre of Gravity
● The point where all the forces acting on the object
intersect
● Where all the object’s mass is concentrated

13. 3 - Structural Elements

14. Bases, Anchors and Foundations
● Elements that support the weight of the rest of the
structure

15. Columns
● Vertical posts that other structural elements rest on
● They resist compression

16. Beams and Bars
● Prisms or cylinders that are longer than they are wide,
supported at one or two points
● They experience bending in the middle and shearing at
the ends

17. Frames
● A set of elements that create the horizontal structure
and divide up the floors of a building
● They transmit loads through joists, beams and columns

18. Trusses and Struts
● A set of rigid bars that join at the end to form a triangle
● Resist traction and compression
● Very light and rigid

19. Braces and Guy Lines
● Cables that hold other structural elements to increase
the object’s stability and resistance
● Resist traction

20. Arches
● Elements made of two columns and a curved part that
supports the structure’s weight

21. Profiles
● Beams, barts, columns and other structural elements
have differently shaped cross sections
● They are usually long pieces of metal
● Can be used horizontally or vertically
● Loads are transmitted through them

22. 4 - Types of Structures

23. Massive Structures
● Made of large blocks of stone or concrete
● Materials are stacked without spaces

24. Framed Structures
● Made of a combination of vertical and horizontal
elements fixed together to form a frame
● Structural elements may be beams, columns, bars and
profiles

25. Triangulated Structures
● Made of crossing bars, arranged in triangles
● Can be wood or metal

26. Hanging/Suspended Structures
● Made of cables, braces or guy lines that support the rest
of the structure
● Cables experience high traction stress

27. Shell/Laminated Structures
● Made of flat surfaces in the form of sheets or shells that
cover other elements
● They give shape and protect

28. Pneumatic Structures
● Made of a composite material membrane that resists the
traction stress of compressed air inside it

29. Vaulted Structures
● A set of arches that support high tension stress
● Vaults and domes

30. Geodesic Structures
● Made of a combination of triangulated and vaulted
structures, creating a geodesic dome