Everyday Science: Bridge Quiz

1 min
Image: fotog, Getty Images

Chances are, if you've done even the slightest bit of traveling, you've crossed your fair share of bridges. These feats of engineering can span anything from a trickling stream to a raging river. Can you cross the bridge quiz without falling?
The distance between two bridge supports is called the:
arch
span
fathom

Bridges are differentiated by the distance they can cross, also known as their span.

Which of the following is not one of the two major forces bridges deal with?
momentum
compression
tension

Compression is a force that acts to compress or shorten the object it's acting on; tension is a force that acts to expand or lengthen the object it's acting on. These are the two main forces that bridges must contend with.

What determines the distance a beam bridge can span?
the material of the beam
the size of the beam
the density of the beam

The size of the beam (in particular its height), controls the distance that the beam can span.

What can be added to make beams taller?
concrete
trusses
suspensions

Supporting lattice work, or a truss, adds rigidity to the existing beam, greatly increasing its ability to dissipate the compression and tension.

What gives an arch bridge its strength?
its shape
its size
its material

Due to their curved shape, arch bridges don't need any additional supports or cables; they're naturally strong bridge structures.

Which part of a suspension bridge receives the most compression?
the cables
the deck
the towers

A suspension bridge's cables transfer the bulk of the compression to the towers, which dissipate the compression directly into the earth where they're buried.

Tension acts primarily on which part of a suspension bridge?
the anchorages
the cables
the towers

The supporting cables running between the bridge's two anchorages receive most of the tension. They're literally stretched from the weight of the bridge and its traffic.

What purpose do bridge dampeners serve?
to reduce noise
to mitigate vibrations
to counteract tension

Dampeners help to mitigate the resonance, or vibrating, effect in bridges. They interrupt any resonant waves that form and prevent them from growing.

What force is responsible for most bridge failures?
torsion
compression
weather

While the danger of other forces has been largely eliminated through better design, weather forces are much harder to combat.