Construction of bridge
3.1 Design rationale
Explain using diagrams, the
- General design
We kept to a very simple and light weight design. Instead of a standard K truss, we
used an X truss. Its connect to the base not only with glue like what most groups did,
but instead it interlocks with the gaps we purposely built into the base. This in a way
pushes the weight sides wards, distributing it.
- Members of the bridge
We used an approximately 100 ice creams sticks. We glued them with a gap
between each ice-cream stick. This is to allow the other members of the bridge to
interlock with each other. So not only does the glue hold them together but the
ice-cream sticks too.
- Base of the bridge
The base of the bridge is formed with 4 major sticks which used 12 sticks in total. Only half of each stick is glued to the next stick. This maximises the sticks, making it
lighter. Further more our sticks are sticked together vertically. This is because the
formula for pressure (P=F/A) is ver much dependent of the surface area. So we
thought if we reduced the surface area, the pressure applied will be lesser compared
if we place them horizontally.
- Anchors of the bridge
The anchors of the bridge are made of the 4 main sticks of the base. To fill up the
gaps between them, we cut sticks to fill it up. With the same principal in mind we
used to built the base, we placed the sticks vertically.
- Joints of bridge
The joints of the bridge are “wedge” by 2 ends of an ice cream stick so when it flexes
it wont “fly” out of place as there is an ice-cream stick preventing it to do so. So this
maximises the maximum strength of the ice-cream stick, eliminating the fear of the
joints snapping due to the glue.
3.2 Detailed dimensions
Mass of bridge
3.3 Construction of prototype
Photograph of prototype