Why is half the bridge gone ?
|Original Picture Source : Wikimedia|
It should look like this.
|Source : Wikimedia|
All metals used today to build structures , especially steel and Aluminum are strong but not as strong as they should be.
In theory steel should be 10 to 30 times stronger than it is. So far, with the industrial methods used to produce steel, it is impossible to make it that strong.
The metal material is generally formed of a main metal atom (Fe for steel) arranged in cubic form and attached together in what is called a crystal. Steel has a body centered crystal form (BCC), as shown in the picture below ,which means an atom in the center and four atoms on the corners of the cubic shape. These cubes grouped together make the large solid object.
It is also exactly like the Atomium structure in Belgium, it is meant to represent a single steel crystal.
|Source : http://architecturelinked.com/profiles/blogs/the-atomium|
What makes steel weaker ?
The reason is simple… imperfections.
Imperfections are other atoms that should not be in the mix, atoms that are in the wrong place, not belonging to the crystal or snuggling additionally in a crystal where it should not be. The picture below shows some examples, and the video after it has a nice young lady explaining how steel deforms easier with the existence of imperfections.
|Source : http://www.corrosionclinic.com/corrosion_online_lectures/ME303L02.HTM|
Watch this video till the third minute, the remaining 1 minute could be too technical.
The strength of steel is slowly improving, with the development of manufacturing technology and processes used after casting, like quenching and annealing, which are two methods the control the cooling speed of the metal so that the imperfections could decrease or increase and other properties of the metal change too. (Without diving into details here, if interested to know more simply google the words).
So why is half the bridge gone ?
Because it is redesigned and manufactured from Perfect Steel.
So if steel was produced perfect. How would the Tour Eiffel look like ?
How would Sydney Harbor Bridge look like ?
What other structures do you think could change drastically ?
|Source : Wikimedia|
|Original Picture Soure: Wikimedia|
|Original Picture Source: Wikipedia|