CompetitionYou are a group of engineers challenged to make a new bridge across the Thames to the houses of parliament.The government has very little money, so you have limited materials.The best bridge will win a contract to make their bridge.

Rules

Design and make a bridge to cross a 30cm gap across two stools, using 40 straws.

Sticky tape can not be wrapped around and around.

Test the maximum mass the bridge can take.

Criticise and Improve!Engineering project:

Research

When starting our engineering project, we need to consider three important things....

EconomicsGolden gate bridge

The project cost more than $35 million to build and took over four years.

Provided essential route to mainland San FranciscoMoney it will cost to build VsMoney it will generate when built

How can we keep costs low?Take less time

Have less staff

Use less materials

SafetyWhere is it being built?

Will people lose out if a new bridge is made?How safe is it to build for workers?How safe is it for the public to use?Ethics

Simple beam bridge - rigid horizontal structure that is resting on two piersThe weight is acting directly downward, through the centre of massScience - Forces and Physics!!

Compression is a force that acts to compress or shorten an object. Tension is a force that acts to expand or lengthen an object. If the compression is too large we get buckling.If the tension is too large we get snapping.Science Forces and Physics!!

How do engineers design bridges to make these forces smaller??

Truss - Creates both a very rigid structureIt transfers the load from a single point to a considerably wider area

Arch bridges Always under compression.

The force of compression is pushed outward along the curve of the arch to the piers.This greatly reduces the effects of tension on the underside of the arch.

The smaller the semicircle of the arch, the greater the tension relief effect.

Kintai Bridge

Iwakuni, JapanSydney Harbour Bridge

Australia

Criticise and Improve!

RulesDesign and make a bridge to cross a 30cm gap.Use as much of the materials provided as you like.

Test the maximum mass the bridge can take.

Divide this by the weight of the bridge to get the score for the bridgeBridge score =Max. MassBridge Mass