-Ice Cream sticks
-White multipurpose glue
-Weights (2.5kg, 5kg, 10kg)
-Strong nylon strings
- Use a bridge simulation software (West point bridge design 2014: 2nd edition) to virtually build the bridge design.
- Plan out the designs in the bridge simulation software (West point bridge design 2014: 2nd edition).
- Choose the 3 best designs from the bridge simulation software (West point bridge design 2014: 2nd edition) and plan out the physical design for the bridge.
Building the bridge
- Buy the necessary materials needed to build the bridge.
- Refer to the plan of the bridges for building the 3 bridges.
- Build 3 identical bases of length 69cm and width 11.5cm.
Placing ice cream sticks onto the structure of the bases
Design of final base
- For bridge 1, it acts as a constant, therefore there will be neither deck nor truss on it.
Sticking the sides of bridge 1
Glueing of bridge 1
Top view of completed bridge 1
Side view of completed bridge 1
Other side view of completed bridge 1
3/4 view of completed bridge 1
- For Bridge 2, build a through truss.
- For bridge 3, build a deck truss.
- To make a through truss for bridge 2, 48 pairs of ice cream sticks in the shape of an X are to be made.
The X-shape ice cream sticks
- Stick 2 pairs of 6 individual Xs together to form the truss of the bridge.
The design of the truss
- Stick the truss design to the side of the base of bridge 2
Sticking the design to the sides of the bridge
- Leave the truss to dry for 24 hours.
- After the truss is dried, stick ice cream sticks on top of the bridge to make the top of the bridge. Wait for it to dry. When it is dry, bridge 2 is completed.
The drying process for the top of the bridge (bridge is laying by the side for this photograph)
Top view of completed bridge 2
Side view of completed bridge 2
Other side view of completed bridge 2
3/4 view of completed bridge 2
- For bridge 3, stick 4 ice cream sticks that are made up of ice cream sticks which are glued together to form 17.25cm and a cross made up of ice cream sticks which are glued together to form 17.25cm sticks onto the side for the base to form one side of bridge 3.
Planning of the sides for the 3rd bridge
The side of the third bridge (note that protruding edges at the top of the sides were not sawed off yet)
- Saw off the protruding edges at the top of the sides.
- Repeat step 15 and 16 for the other side of bridge 3.
- Stick the sides of bridge 3 to the base of bridge 3.
The sticking process of the side of bridge 3 to the base of bridge 3
- Leave the sides to dry for 24 hours.
- When the sides have dried, stick ice cream sticks at the bottom of the bridge to create the bottom of the bridge. Wait for the bottom to dry. After the bottom of bridge 3 has dried, bridge 3 is done.
Top of completed bridge 3
Side of completed bridge 3
Other side of completed bridge 3
3/4 view of completed bridge 3
- Leave all the bridges for 48 hours before testing them.
Testing the bridge
- After 48 hours, measure the weight of bridge 1 using a weighing machine.
Weight of bridge 1
- After measuring the weight of bridge 1, place bridge 1 onto a bridge testing machine.
Bridge 1 on the bridge testing machines
The support beams for the bridge testing machine
- Place a 2.5 kg weight on the bridge every 10 seconds if the bridge shows no sign of cracking, breaking or collapsing and record the entire process on video.
- Continue step 24 until the bridge cracks, breaks or collapses.
Broken bridge 1
- Record the weight that the bridge broke under and calculate the efficiency (the mass that the bridge is able to hold divided by the mass of the bridge) of bridge 1.
- Repeat steps 22-26 with the other 2 bridges designs.
Testing of bridge 3
- Compare the datas recorded for the 3 different designs (Weight of the bridge, weight the bridge can hold, efficiently of the bridge).
- Collect the data and represent them in a table.
- Plot a table of values of mass of bridge, the maximum mass of bridge, and the efficiency if the bridge.
- Efficiency is defined as the mass that the bridge is able to hold divided by the mass of the bridge.
- The bridge with the highest efficiency can then be found.
Risk and Safety
The coping saw can cut our hand which might cause cuts which might lead to bleeding.
Ensure that you hair is neatly tied up and that you are not wearing any accessories or jewellery. Before we start using the coping saw, we should check for any defects like uneven set teeth. A line should be marked on the wood to ensure that there is a guide when sawing. When you make the first cut, use your thumb or the knuckle of your thumb on the hand holding the wood as a guide to ensure you cut along the cutline. Make sure no one is near you when sawing. If there are any accidents, seek immediate medical attention and report to a teacher.
White multipurpose glue
The glue can accidentally enter our eyes, irritating it.
Make sure there isn't old glue clogging the nozzle. If you find any type of damage to the glue gun or to the cord, do not use it! Place the glue gun on a secure surface such as a table. Place a sheet of paper underneath it to protect the table surface. Place a piece of aluminum foil under the nozzle of the glue gun to catch the overflow of glue that will run out of the nozzle. Be sure to keep your glue gun away from open flames. Use them with extreme caution and wear cloth gloves while operating it. If there are any accidents, seek immediate medical attention and report to a teacher.
The weights and metal tin can crush and injure our hands or feet if handled without proper care and may cause internal injuries. Handle the weights with care by holding them with both hands. Do not swing or throw the weights around. If any of the weights are dropped onto the hands or feet, consult a teacher immediately to seek for medical attention.