1. Features of Structures

2. Features of Structures
Before building a structure architects and ________________ need to figure out every detail of the ________________ in advance. There are four especially important _______________ to consider: ________________, ________________, ________________, and ________________.
engineers
design
features
function
shape
materials
joints

3. Function __________________:
Before building a structure, we need to think about what the thing is supposed to do. Most structures have ______________ functions. For example…
__________________:
_______________________________________________________________________________________________________________________________________________________________________________________________________________________
several
A bridge
- its job is to support vehicles and people
- but the steel and concrete used to make the bridge can weigh much more than the vehicles and people that cross
 so a very important function of any structure is to support its own weight

4. Function (cont) functions water perspiration cloth
Designers have a hard time creating structures that perform all of their ________________ equally well. For instance, plastic-covered running shoes keep the _______________ out when you run through a puddle. But they also keep _________________ in, so your feet could get hot and sweaty. Designers try to compromise. Most running shoes have rubber and plastic soles and ________________ uppers.
functions
water
perspiration
cloth

5. Shape rectangular squish load forces joints collapse weaknesses
Square and __________________ frames are easy to build and designers like to use them. However they also ______________ when a ______________ presses on them. Enormous ________________ develop at the ______________ and the frame is likely to ________________. Designers have come up with ways to overcome these __________________.
rectangular
squish
load
forces
joints
collapse
weaknesses

6. Problem 1 Braces ties gussets triangles
Rectangular frames can easily be pushed and pulled out of shape. Solution: _________, _____, and ________ turn rectangular corners into rigid ________________, able to resist large forces.
Braces
ties
gussets
triangles
Braces
Gussets
Ties

7. Problem 2 braces arches double cantilever ground
Frames made of vertical columns and horizontal beams are weak in the middle. Pressing down on the middle causes the beams to push the columns out and the frame to collapse.
Solution:
Use ___________, __________, or a ____________ ________________to spread forces evenly through the whole structure and down to the ______________.
braces
arches
double
cantilever
ground
Brace
Arch
Double Cantilever

8. Problem 3 cylindrical less thinner load
Solid, four-sided beams use a lot of building materials and are very heavy.
Solution:
Use __________________ columns, which are harder to build but use ____________ material. Or make the beam or column ________________ in places that carry less ____________.
cylindrical
less
thinner
load
I-Beam
T-Beam
Box Beam

9. Cardboard (corrugated)
Problem 4
Plywood, cardboard and other building materials are made in flat rectangular sheets. When a load presses on the middle or the sides are compressed together, the sheet bends out of shape.
Solution:
Make the material out of ______________ (laminations) that are ____________ or pressed together. Arrange the layers so that they ________________ each other.
layers
glued
strengthen
Cardboard (corrugated)
Plywood

10. Materials structure combined Reinforced composite tension compress
The properties of the materials must match the purpose of the ______________. Different materials can be _____________ to give the exact properties you need. ________________ concrete is called a ________________ material. Steel rods and cables can support very strong ______________ forces but they bend and twist if you ______________ them. Concrete resists large ________________ forces, but breaks if it is ______________ or ________________. If they are combined they create a much stronger material.
structure
combined
Reinforced
composite
tension
compress
compression
pulled
twisted

11. Joints
How a structure is ________________ together is an important ______________ because structures are often ______________ where their parts are joined together.
fastened
decision
weakest

12. Joints (cont)
Mobile Joints: ________________________________________ Examples: ________________________________________ Rigid Joints:
Joints that allow movement
door hinges, elbows, pins in a bike chain
Fasten parts firmly together
nails, screws, bolts, tape, glue, zippers

13. Joints (cont) All joints can fit into five groups:
Fasteners (nails, staples, bolts, screws)
Ties (thread, string, rope)
Adhesives (glues, sticky substances)
Melted joints (pieces of plastic or metal melted together)
Interlocking joints (carefully shaped parts that hold themselves together, ex) Lego)