Explore!

So how does a change in geometry influence forces in the cables and the towers?

In the diagram below, try changing the tower height by dragging the nodes at the tops of the towers.

·        What happens to the reaction forces in the towers? In the anchors?

·        Compare the vertical force at the top of the tower to the vertical force computed in ‘Reactions’.

·        Note the change in cable force as the towers move up and down.

·        If the towers were taller, would you have to increase or decrease the cable diameter?

Next, try changing the sag in the cable by dragging the node at midspan of the bridge.

·        What happens to the forces in the cables?  In the towers?

·        Compare the vertical force at the top of the tower to the vertical force computed in ‘Reactions’.

·        Note the change in cable force as the towers move up and down.

·        If the sag is decreased (i.e. the height of the cable at midspan is close to the tower height), what happens to the forces in the cable?  What happens to the reactions in the towers?

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