**STEM: BUILDING BRIDGES**

Vocabulary continued...

Radius

: The radius of a circle or a sphere is the length of a line segment from the center to the perimeter.

Radii

: A straight line extending from the center of a circle or sphere to the circumference or surface.

Ravine

: A deep, narrow gorge with steep sides.

Scaled Prototype

: A prototype that is smaller than the real object but is exact in another form of measurement. ( Ex.: 1 mile= 1 foot)

Sketches

: A rapidly executed freehand drawing that is usually not intended as a finished work.

Suspension Bridge

: a type of bridge in which the deck is hung below suspension cables on vertical suspenders.

Triangle

: a closed plane figure having three sides and three angles.

Truss

: A structure that "consists of two-force members only."

Research

•Arch bridge

•Wheelchair average width= 24 to 27 inch.

•Materials= concrete and rebar

•12 feet by 5 feet bridge

72 cubic feet = reinforced concrete

•Total cost of reinforced concrete for the whole 12 x 5 bridge= $5795.28

•Cost of concrete per cubic foot= $80

•Cost of rebar per foot= $1.40

REQUIREMENTS

Budget:

$7,500

Details:

• The ravine is 12' wide at the narrowest spot.

• Bridge must be wide enough for two adults to easily past each other.

• Be able to fit a standard adult wheelchair and be ADA compliant.

• The bridge is made for dog park.

• Has to be either an arch, suspension, or a truss bridge and it can't be a beam bridge.

Prototype

: the original or model on which something is based or formed.

**By: Frances, Will, and Ryland**

Question

1. How did you use what you have learned about geometry in this project?

We knew about the different shapes including triangles and semicircles. We had to calculate formulas to figure out things like the area and perimeter of the semicircle of the arch. Knowing that we can use radius and circumference to figure out measurements of a semicircle makes it easier.

2. What other mathematical ideas and figures were useful during this project?

3. Where else could your designs be used?

Simple math skills were helpful in this project, because we had to calculate costs and materials.

American Disabilities ACT

: a civil rights law that prohibits discrimination against individuals with disabilities in all areas of public life.

Angle

: the space within two lines or three or more planes diverging from a common point, or within two planes diverging from a common line.

Arc

: any unbroken part of the circumference of a circle or other curved line.

Arch Bridge

: a bridge with abutments at each end shaped as a curved arch.

Beam Bridge

: the simplest structural forms for bridge spans supported by an abutment or pier at each end.

Budget

:an estimate, often itemized, of expected income and expense for a given period in the future.

Load

: the weight supported by a structure or part.

Our design can be used in any area that needs a small, low-maintenance bridge, such as rivers, canyons or ditches.

Arch Bridges

Beam Bridges

Suspension

Bridges

Truss Bridges

Analysis

Our project met most of the constraints, such as the budget and the correct bridge types, but we didn't use the best material, considering that the other group used steel, but our group has a low-maintenance, cost-effective bridge. Our prototype is strong and holds up against many bridge bending forces, such as compression and tension.

Thank you for watching our presention!