Why Do Suspension Bridges Use Cables?

What Crafty Clover says in this video

Intro

Hey there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do suspension bridges use cables?

The Big Idea

Giant cables hang from tall towers, and hold the road like a hammock. The cables take the stretch, so the road doesn't sag into the water. That's why suspension bridges use cables!

Raise Towers, Spin Cables

Step one: raise the towers, and spin the cables. Two tall towers are built on firm banks, or in the water. Machines walk back and forth laying wires, until the main cables are thick.

Hang the Hangers

Step two: hang the hangers. Vertical ropes, called hangers, drop from the main cables to the road deck. Steel wire is very strong when it's pulled, and many thin wires twisted together can hold thousands of cars.

Lift the Deck, Cars Roll

Step three: lift the deck, and the cars roll. Road sections are lifted and clipped to the hangers. Traffic weight pulls the cables tight, and the towers push back down.

A Closer Look

Let's take a closer look at a suspension bridge! The towers hold up the main cable. The main cable carries the pull. Hangers connect the cable to the deck. And the anchorages, huge concrete blocks, hold the cable ends.

Quick Facts

Quick facts! Each Golden Gate Bridge cable holds 27,572 wires! Each main cable can be as thick as a tree trunk. Wind can twist a thin deck, so modern decks are shaped like airplane wings. Elevators, cranes, and zip lines use the same pull-don't-snap idea.

Think Like a Scientist

Now, think like a scientist! Hang a string between two chairs. Clip paper clips along the string. Does the string sag more as you add clips? That's what the towers and anchors fight!

Outro

Strong cables and tall towers hold up a road in the sky. What a bridge! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!