P6/7 Brunel Project – Suspension Bridges

This week for our Isambard Kingdom Brunel Project we looked at suspension bridges and how the Clifton Suspension Bridge was designed. We compared this to the Forth Road Bridge and noticed similarities. We conducted an investigation into how the forces are distributed on these types of bridges and what makes them so strong.

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Clifton Suspension Bridge

First each group made 2 cylinders out of card. Our cylinders could be bent and squished sideways but we found that when compressed at either end they were reasonably strong structures. We then taped a piece of string at either end to each cylinder. These bridges were incredibly weak and we couldn’t even get them to hold the cardboard sleeves we made to hold the weights in. UNSUCCESSFUL!!!

We then took a longer piece of string which went over the tops of the cylinders and stuck it to the table either side like you see in the photos below.  Some of these structures went from not even being able to hold the weight of a small piece of card to holding over 1KG! SUCCESSFUL!!!

This is because the force of the weights pulling down is transferred to the cylinder towers which we found at the beginning to be strong when compressed from the ends. Its in this way that suspension bridges can cover large distances yet still stay strong! Clever!

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