Project 2: Straw Bridge Situation: We should across the river safely. Design brief: To design and make a straw bridge model for practicing purpose Group : 3 or 4 members Duration: 3 cycles

Project 2: Straw Bridge Material provided: plastic straws – 40 (200mm long) Colourless Self Adhesive Tape Requirement : 1) You are free to design the structure. The product must be made of plastic straw and is fastened by colourless self-adhesive tape.

Project 2: Straw Bridge 2) The bridge model should be 100mm wide and over 500mm long. >500mm 100mm This is a sample only. Don’t copy!

Project 2: Straw Bridge 180mm 500mm Testing platform 175mm

Project 2: Straw Bridge Requirement : 3) Straws parallel overlapping design is not allowed.

Project 2: Straw Bridge Requirement : 4) Weights are placed one by one on the straw structure model until it breaks down so as to test the loading ratio. (Weight: 250ml juice pack, @275g) Juice Pack

Project 2: Straw Bridge Requirement : 5) Weights are placed one by one on the bridge until it breaks down so as to test the loading ratio. Maximum Loading Weight of the bridge model Loading Ratio =

Project 2: Straw Bridge Requirement : 6) The bridge should not consist any component touching the ground of the testing platform and nothing can be used to fix the model on the platform.

Project 2: Straw Bridge Testing procedures : Measure the weight of the bridge model by the electronic balance.

Project 2: Straw Bridge Testing procedures : 2) Place the bridge model on the testing platform which is designed for holding a bridge of over 500mm long. 500mm Testing platform

Project 2: Straw Bridge Testing Methods: 3) Place weights one by one on the central of the bridge model until it breaks down. Testing sample

Project 2: Straw Bridge Testing Methods: 3) Place weights one by one on the central of the bridge model until it breaks down. Testing sample

Project 2: Straw Bridge 4) Count the number of weights used. Testing procedures : 4) Count the number of weights used. 5) Calculate the loading ratio. Higher loading ratio is recorded, higher mark will be given. Maximum Loading Weight of the bridge model Loading Ratio =

Project 2: Straw Bridge http://pghbridges.com/basics.htm Information: Search the information about frame, structure and bridge via internet. Sample http://pghbridges.com/basics.htm

Project 2: Straw Bridge Design consideration: Solution Weight of the bridge model Stability Information Solution Bridge structure Special features of straws

Project 2: Straw Bridge Suggested Procedures Design Considerations Initial Ideas Final Idea Solution Make a bridge model (Cycle 2) Testing (Cycle 3) Evaluation (Cycle 3)

Project 2: Straw Bridge Assessment: Loading Ratio Size Marks < 5 Not fit 5 and <10  - - - 1 10 and <15 Fit in 2 15 and <25   - - - 3 25 and <35 4 35 and <45 5 45 and <55 6 55 and <65 7 65 8 Total 8 + 2

Project 2: Straw Bridge Assessment: e.g. The model’s size fits the testing platform Weight = 25g Loading = 4 x 275g = 1100g Loading ratio = 1100 / 25 = 44 35 and <45 5 Marks = 2 + 5 = 7

Project 2: Straw Bridge Information: Weights Bridge model Range = 500 mm

Project 2: Straw Bridge Information: Weights Bridge model Range = 500 mm

Project 2: Straw Bridge Information: Weights Bridge model Range = 500 mm

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge

Project 2: Straw Bridge