# The Beam Bridge

## Beam Bridge - a simple sketch

simple sketch of a beam bridge

A Beam Bridge is the simplest design for crossing a distance.

It consists of a horizontal beam supported at each end by piers. The weight of the beam pushes straight down on the piers. The farther apart its piers, the weaker the beam becomes. This is why beam bridges rarely span more than 250 feet.

## Modern Beam Bridges

Qiantang River Bridge
Feiyun River Bridge, Zhejiang Province

## Load and Thrust

Load is a consequence of gravity and always acts vertically.

The ground exerts an equal and opposite force upwards on the weight. This force is called thrust.

a weight on a beam

When a weight is placed on a beam it exerts a load. However, the weight is not directly in contact with the ground.

Hence the load reaches the ground by passing along the beam and the down the piers as shown in the diagram opposite.

Advantages of a Beam Bridge:

1. easy to construct
2. relatively cheap

1. cannot span great distances

If the deck is supported by a number of beams instead of just one then it would be easier to erect and easier to fix.

beam with a load

As a bridge is loaded, the beam bends in a downward direction - sag. When the beam bends, new forces are imposed along the length of the beam:

The top of the beam is compressed (shortened)

The bottom of the beam is tensioned (pulled apart).

As you can see from the diagram, the lines mark equal distance on the beam and the angle of these lines converge at a point above the beam.

## Testing to destruction

General rule: material breaks far more readily when it is under tension the when it is compressed.

Elastic Substances: materials that deform under a load and then returns to its original shape when the load is removed. Steel is slightly elastic

Advantages of Elastic Substances:

1. when exposed to a massive load they will deform before collapsing entirely
2. they give warning (visual inspections can determine if buckling has occurred)

## The Bridge Challenge

Waren E 7 years ago from HAS LEFT THE BUILDING............

Hi nice hub on architecture ,have you started using CAD programs yet? If so which one ,"auto cad" perhaps!

lydia_rae 7 years ago Author

no I haven't I have no idea how to get it but I deffinately need to start. thnx for the comments :)

destiny 6 years ago

you are a bitch

hannna montana 6 years ago

oh my cosh wt kind of things that we can tell something else hahahahahahahahaha.

hi 6 years ago

hi hi hi hi hi hi

Die all 6 years ago

Hi all Beam Bridge

lol 5 years ago

this really helped!

jaskson seyfarth 5 years ago

dfhdufgydkgydruigydrk

oroog 5 years ago

hjhdg

jaskon 5 years ago

hi people i dont now

spencer 5 years ago

hey yall

jack 5 years ago

hi jackson

jaskson 5 years ago

kylee awsome

texas freak 5 years ago

heyyy honey

Ian Graffunder 5 years ago

Spencer. Email me. MY email adress is iangraffunder@gmail.com

Lukas 5 years ago

holaaa )) hello, i wanna be your friend http://www.facebook.com/profile.php?id=10000106726...

^^

Texas 5 years ago

klyees awsome

Spem43 5 years ago

Bradon and Kylee kissed on the lips

Spem34 5 years ago

never mind they didn't

sant 5 years ago

Hi peoples

Spem34 5 years ago

I like Some one in this room

texas freak 5 years ago

who?

spem34 5 years ago

I sort of like u

Ian Graffunder 5 years ago

OOOO Spem34. :)

spem34 5 years ago

yeah ian

spem34 5 years ago

klyee is going to get killed to night

Ian Graffunder 5 years ago

How is Kylee going to get killed? And why?

jas55 5 years ago

yoyoyoyoyoyoyoyo

jas55 5 years ago

stupid

olololol 5 years ago

cooooooooooooool

yourmom 5 years ago

im a monkey

spem34 5 years ago

who are u?

Spem34 5 years ago

i wanna be friends with klyee

Ian Graffunder 5 years ago

Why? U just hit her with a rubber band!

spem34 5 years ago

REALLY!!!!!!!!!!!!!!!!!!!!

Ian Graffunder 5 years ago

YES!!!!!!!!!!!!!!!

spem34 5 years ago

I still like her ian

I11 5 years ago

ok. akward

Tegan Swope 5 years ago

I am in a club called 'Bridges'at school.

yfxcy 5 years ago

tuirfdc

spem34 5 years ago

im board

none 5 years ago

you stink

nabaa 5 years ago

nabaa rocks

SuperCrackbaby 5 years ago

For SPARTA

big daddt 4 years ago

wow you kids on here are kinda sad...

mrproffeserdude 4 years ago

nice piece, might i say, and you kids are soo annoying get a life for crying out loud.

higilmk; 4 years ago

idgi

me 4 years ago

llllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll

the dons 4 years ago

really people? you dont have a life

BOB 4 years ago

who wants to fight???

BOB 4 years ago

who wants to fight???

weggy woggy weg weg 4 years ago

i want a fight

fighter 4 years ago

i also want a fight

Ouuo 4 years ago

So much spam here... Thanks tho!

GERSATA 4 years ago

STUPS

gtg 4 years ago

nnnnnnnnanananannn

someone 4 years ago

hi hi hi hi

yoyoyoyoy 4 years ago

we in the hood tonight we be getting candy all ova my bod

TY :3 4 years ago

THANK U IT REALLY HELPED WITH MY PROJECT

Kylee 4 years ago

I was killed last night and now i am coming to haunt who ever commented on this. Did you know it takes approximentally 24 minutes for blood to dry? Well, just as i had to find this out, so you all will too!

megs xx 4 years ago

THIS REALY HELPED ME

Jess 4 years ago

Amazing ! Helped SOOOO much with my work!

the dons 3 years ago

me and my primary friend commented on this along time ago, he moved somewhere else :D

Irfaan

Bob 3 years ago

:P

jenny 2 years ago

sup dawg

abdu m 2 years ago

it is so short