FAQ Grade 8 Project - Bridgebuilding Survivor

All information and frquently asked questions for this term 2 project will be posted here

1) When is the date of the competition?
We would probably have the event early in the 3rd term to allow boarders and busy parents to do some work with their children but the final date will be given to you in writing when it is finalised.

2) Can I use winning designs from previous years?
Yes

3) Can I use outside help such as advice from a actual civil engineer with the design of my bridge?
Yes

4) May any other person except me and my parent build the bridge?
No

5) I do not like the material handed to me, may I ask a carpenter to cut my own material form A grade pine? (twenty five sticks of 4mm x 4mm x 600mm)
Yes

6) Does the project count for marks?
Yes

7) I cannot get my Westpoint bridge designer to work on my computer. Is it absolutely neccesary to do the design for the shape of my bridge on Westpoint?
No

8) Will I loose marks if I do not use Westpoint Bridge Designer?
No

9) Approximately how many hours do I have to set aside for the making of my bridge?
About 40 hours of work in sessions of 3-5 hours at a time.

10) What safety gear will I use when I test my bridge?
Safety Glasses, some form of protection to prevent the glue from damaging furniture and clothing. The glue cannot be removed once it has touched another surface.

11) Do I keep my trophy/medal if I win?
Yes, you keep it permanently.

12) Can I use extra wood or glue on my bridge?
No

13) Can I use another type of glue or wood?
No

14) Can I build more than one bridge?
Yes, but I only provide material for one, if you want more material you would need to pay for it.

15) Where do I buy the Pritley Pratley Quickset Clear - Epoxy Resin?
Any hardware shop at about R30

16) Where can you buy extra wood?
The wood for the competition is very hard to get hold of. You will have to find a friendly carpenter to cut the wood for you from A Grade SA Pine, or so called clear Pine.

17) May I use a partner from school?
No

18) May I ask other teachers and specialists such as architects and civil engineers for help?
Yes

19) What happens if my PC at home does not have Westpoint bridge designer or I have no internet?
The computers in the Media / Library resource centre have been loaded with Westpoint. You can work at break or after school.

20) Will there be a lecture to explain some basics to our parents?
Yes

21) When and where will the parent lecture take place?
Monday evening the 15th of June, in the school hall from 17h00 - 18h00 and both parent and student may attend. Attendance is not compulsory but strongly advised.


22) How do I calculate what length of wood to use for 1 truss?
a) You are provided with 15000 mm of wood which comes in lengths of 600mm at a time.
b) You have to leave wood for diagonal cross bracing, supports, cross bracing between the 2 trusses.
c) Because there are 2 trusses, in most cases, you would need about 6000mm - 7000mm for each truss.
d) Therefore you will probably use about 10 sticks for each truss.
e) You count the actual length of wood you will use for your truss by measuring it off your first 1:1 design template.

23) Where can I see examples of good /winning bridges?
Photos will be posted to the Blogsite gallery.

24) How will my bridge be tested to make sure I have used the legal amount of wood and glue?
The bridge will be weighed on the day of the competition.

25) Whats the distance from desk to desk that my bridge has to cover?
The "gap" is 650mm the actual required length is 750mm.

26) How many sticks do we get?
You get twenty five (25) sticks that are 600mm long.

27) Will I be given the epoxy glue or will I have to buy it myself?
No, you must buy the epoxy glue yourself.

28) Can I check to see if the loading harness fits my bridge before the competition?
Yes

29) What tools will I need to make the bridge?
All the tools you need are listed in the project overview
a) Plastic clothing pegs to hold the glued wood in place while drying.
b) Lions matches to mix and apply small dabs of glue to the wood.
c) Cutting pliers to easily snip the wood.
d) A 4 typing paper to mix the epoxy resin glue on.
e) Tape measure and calculator
f) Surgical gloves to avoid the oil from your hands soaking into the wood. (optional)

30) Does the loading harness have to fit into my bridge in a specific place?
Yes, the loading harness must fit through the side of your bridge in the middle of your bridge.
NB! It must also be more or less on the level plane which runs at desk level.

31) Can I ask Mr. Buys to buy the glue for me and give him the cash?
Yes, but only if you have tried to buy it yourself first.

32) How many other schools compete in the regional final?
About 25 other schools which include entries from grade 11 and matric pupils from St Stithians College, KES, Roedean School, St John's College, St David's Marist Inanda.

33) What happens if one of my sticks break?
You use the stick for the shorter parts / members of the truss.

34) How will the final weight that the bridge can hold be recorded?
The weight that the bridge held before it broke will be the weight that will be taken as the final weight.

35) Will the weight of the loading harness be added to the final weight?
Yes, but Mr. Buys will add it after the competition to avoid counting the weight from the loading harness twice. Thus you will record and hand in ONLY the weight that was loaded ONTO the harness.

36) What happens if my bridge accidentally breaks on the day of testing before it has been tested?
Mr. Buys will award an approximate weight that he thinks the bridge would have held.

37) What happens if my bridge broke and I do not agree with the weight that Mr. Buys estimates my bridge would have held?
You will be given 2 days to fix your bridge and it will be tested in the normal way. You have to make sure that Mr. buys tests your bridge as after 2 days all results will stand as they are with no exeptions.

38) Can I take pictures of the sample bridge?
Yes

39) Can I take the sample bridge home?
No

40) If I have fixed my broken bridge and my weight tests out lower than Mr. Buys's estimation, can I get the weight of the estimation?
Yes, because the wood would have been fatigued by the break and will not perform in the original intended manner.

41) May I take part in the competition at school even if I am not in grade 8?
Yes, you will just be required to pay for a bundle of wood and we would need to order an extra medal for you if you place in the top finishers. You may then also go on to take part in the prestige group which represents the school at the University of Witwatersrands Civil Engineering competition the following term.

42) What happens if my bridge is not built to specifications?
a) If your bridge has too much material or incorrect dimensions you will suffer a 25% - 75% deduction on the weight it can hold as shortening the bridge or using extra wood or glue exponentially increases its loading capacity.
b) Your 50% for building the bridge will be deducted by 5% for every specification it cannot hold.

43) What happens if the loading harness does not fit my bridge on the day of testing?
You will be asked to remove parts of your bridge to enable the harness to fit. If the harness then cannot fit Mr. Buys will make an estimation of what your bridge would probably have held subject to the same rules as if your bridge accidentally broke on testing day.

44) What happens if I am sick on the testing day?
You have the option of sending someone to test the bridge for you or you can test it at school when you are better. If you are in the medal group we will order an extra medal for you.

45) Do I test the bridge alone?
No, you test it with your parent.

46) Will the testing happen on the school stage?
No, because of the spring effect of the stage boards sending a so called L-shock wave / pulse through someones feet when they walk on the stage which travels into your bridge though the tables legs. The wave/pulse bounces the bridge up and down which has the same effect of a person jumping up and down on a plank of wood that is leaning against a rock at an angle.

47) What is the best way to put the weights onto the harness?
a) Do not let the harness swing at all.
b) Do not "slam" or drop the weight onto the harness, not even for 1mm.
c) Use bigger weights in the beginning and smaller weights towards the end.
d) Make sure the stem of the weight harness sits in the middle of the peg at the bottom of the loading harness.
e) Make sure that your bridge sits evenly on each side of the desk.
f) make sure that the harness is positioned in the middle of your bridge both in lateral and longitidue positioning.

48) Will we work in pairs like previous years, and if not, why?
No, the objective of the project is different and the learning experience is set out is in the letter to the parents.

49) Do we get the wood through the school?
Yes

50) Where do we build the bridge?
We start at school with demonstartions but the bridge is largely built at home.

51) How much do we pay for the wood, and how is the payment made?
An amount of about R35 will be added to your school fee account for the wood.

52) If I break a stick in half does it count as one or two sticks?
You may cut up the 25 sticks of 600mm long as many times as you want.

53) When I test my bridge, and one stick breaks, do I have to stop testing or can I carry on if I want to?
You do not have to stop if your bridge is still holding the weights in the air. Your final weight will be taken as the weight that was held by your bridge before it breaks.

54) Where will my bridge be tested?
On the floor area of the school hall.

55) Why are we doing this project?
To learn about structures, material properties of epoxy resin and wood and to work with your parent in a testing/difficult situation that requires you and your parent to cooperate.

56) What if I never plan on becoming an engineer?
You will still be able to use the theory in much more ways than what an engineer would use the theory for and the theory is prescribed in your Technology syllabus.

57) How do I get marked for my bridge?
You get 50% for just building the bridge and then you add 1% for every 1kg. your bridge holds.

There are however some deductions if your bridge is not built correctly:
a) 5% deducted from your original 50% for every specification not met.
b) 25% -75% deducted from the weight your bridge holds if the bridge was not built to specifications.

58) What happens if my bridge holds 60kg and is built to specifications without any deductions?
50% plus 60% will equal 110% but you can only get a maximum of 100% for the project. Your reward for achieving a higher weight will be awarded a higher placing in the top 20 medals.

59) Can I keep my bridge if it survives?
Yes

60) How much will this project count for my term mark?
50% for term 2 and 50% for term 3

61) Do I have to pay for the wood if I am a bursary student?
No, the school pays for bursary students. You will however have to tell Mr. Buys that if you are.

62) Can I spraypaint or decorate my bridge?
No, the paint and decorations adds extra strength and also throws off the weight calibration.

63) How much must the bridge weigh?
That information is not revealed.

64) Do I need to steam the wood to bend the members?
Yes, but be carefull as pre-bending a member pre-stresses your bridge member as well. If you are not exactly sure of what you are doing you can end up making the bridge much weaker rather than stronger.

65) Do I loose any marks if my bridge breaks?
No, the idea is to test it to just before it breaks or untill it breaks. The focus is on building a design that is strong and the bridge would need to fail for you to know its strength.

66) Whats the highest one of these bridges have held?
In 2009 Mr. Buys's top students at his previous school attained 156kg, 143kg and 137kg. Enough to place first, second and third at the Wits Civil Engineering Competition.

67) What are the common mistakes that students make with regards to specifications?
They use too much wood and glue, make their fillets too big and build their bridge too short.

68) If the sticks are shorter than the length that the bridge should be, how do I get the bridge to be longer?
You may join the sticks with inserts which are 50mm apart.

69) Does my bridge have to look like my template?
Yes

70) What is the most important part of the bridge?
The top compression member which is allways a strengthened/double member

71) May I use a Butt joint to join members together?
Yes, but I would reccommend that you use a Lap joint or Splice joint before you use a Butt joint as they are much stronger.

72) How do I find out about joints?
Internet research.

73) Is there any other way to make sure that a joint is strong?
Yes, by overlapping the joint with other sticks or inserting small pieces of wood to act as gusset plates.

74) Approximately how much glue do I use for 1 single joint of wood?
The size of two match stick heads.

75) Must there be a clear space "inside" the length of my bridge as if a car would drive through the bridge?
No, you must use the space in the middle.

a) It is vital that you put in diagonal cross bracing to prevent the bridge from becoming a parralelogram. Remember that these structures are actually called "Pin jointed truss structures" and that the word bridge is not an accurate description of what you are building.
b) The bridge is also not tested / loaded with a dynamic force. (A force that moves from the one end of the bridge to the other end)
c) The way that the bridge is tested is with a static force through the use of a loading harness.

76) What do I do if my dad is unable to help me?
You may ask any other member of your family. It would however be unfortunate as working with your dad is part of the goal of the competition. Please inform your dad that Mr. Buys would very much like him to be involved and that he should read the letter to the parent and pupil on the website.

77) Can I use cellotape or duct tape on my bridge?
Only during construction to keep members/pieces in place. When you test the bridge the bridge may ONLY consist of the allocated wood and glue.

78) The gap is only 650mm why do I have to build my bridge 750mm long?
Valid question with a simple answer, because its the rule of the competition. You bridge is in effect stronger if you build it to 700mm and nothing stops you from building the bridge to 700mm and cosmetically extending the length of the bridge to 750mm on each side with a single 25mm member to come in under the competition specificastions.

In life there is often a compromise between what is the optimum and what is the specification requirement. In this case the optimum is not to build the bridge to the specified length as the longer your bridge is the more your top compression members undergo a bending force. The purpose of the competition, however is for the bridge to carry the most load whilst still being built to specification. The trick is thus to comply with both requirements with the focus on the strength of the bridge.

79) If I have a double member can I fit another member into or running through the required clear space of the 50mm between the spacers?
Yes