PT 1.2 3 Designs and Decision making matrix

Before we went to designing our bridges...

We started researching about the designs that will help us to build a successful bridge. So first we researched about the anchors of the bridge. So in our research, we knew that there were different types of anchors for the bridges. And it has come to our sense that building a triangle anchor is the best.
      

Since our bridge is 60 cm long, it is 23 inches. So according to the picture above if the bridge is 23 inches, it is recommended that we Howe (K) anchor. Then we researched on the different bridges that can carry a lot of weight. So we found this picture.



All the above bridges are made from triangles. So we decided that we should choose to work on a bridge which uses less ice cream sticks because if we use a lot of ice cream sticks, the bridge may be very heavy and thus affecting our efficiency score. So we decided to work on (d). But before we worked on it, we wanted it to withstand high amount of weights. So we carried on researching. Then we found this. 

 

From this picture, as you can see, there is a basement support for the bridge. This will allow the bridge to hold as much weight as possible. They are also made from triangles. So we deicided to combine our ideas together, to create different bridge designs and to see which one withstands the most amount of weight.

Criteria 

So some of the criteria that we chose were Weight, Size, Durability, Feasibility and Availability of materials. So the reasons that we chose these conditions are because they are the most important. Firstly, the weight of the bridge is very important. If the weight of the bridge is high, we might lose points in the efficiency.


Example: If the weight of the bridge is 250 grams and the maximum load the bridge can carry is 40 kg, the efficiency score will be 160. But if the weight of the bridge is 150 grams and it can carry 40 kg, the efficiency score will be 266. So the weight determines the grade that we get


The size of the bridge is important because we are required to build the bridge within a given dimension so if we were to go over the limit of the dimensions, we will be marked down. Next is the durability.  We have to make the bridge as strong as possible so it can support the maximum amount of weight. What is the point of building a bridge that doesn't support any weight.

Feasibility is very important because we are given only ice cream sticks. Ice cream sticks are not bendable so we shouldn't make a bridge which has a lot of curves. A simple design will do the work but it must be feasible. The availability of materials is extremely important. Because we are given only 500 grams of ice cream sticks, that's around 300 ice cream sticks. So if we were to build a bridge which requires a lot of ice cream sticks we might not finish the bridge and it might break easily. So these are the reasons why we chose those two criteria.

Our designs of the bridges 


Design 1 






Design 2

Design 3 

Design 4 


The designs chosen were design 1, 2 and 3


Evaluation and Decision Matrix 


Evaluation matrix


So according to the decision matrix design 2 won. And so we decided to work on the bridge using Design 2


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