History of suspension bridges 3
Some well-known cable bridges: 4
History of arch bridges 5
History of beam bridges 6
Girder bridges 6
Trench Bridge 6
Bridge Collapse 7
Oldest bridge 7
History of suspension bridges
A suspension bridge is a bridge which has (not necessarily) two high pillars between which a thick cable is spun. By symmetry, the vertical pillars divide the weight equally and doing so on both sides of the pillars making it in perfect balance. This allows those pillars to perform as a lightweight concrete structure. In between is a main suspension cable or chain, it looks like a parabola shaped figure.
The main suspension cable hanging on spaced vertical cables - 'hangers' called – suspend the bridge deck. Unlike most other types of bridges, this deck is very light and bend slap out. This bridge is one of the cheapest affordable. Disadvantages of this are its sensitivity to vibration and aerodynamic effects (which is why the bridge is sometimes closed during storms) and the sensitivity to concentrated loads such as a train.
In the main suspension cable very large tensile forces act. Combining this with the large working arm at the beginning and end of the bridge explains how the forces (and moments) of the very long bridge decks can respond. At the beginning and end of the bridge the cable is anchored in the foundation. The cables are attached as nearly horizontal, so the biggest forces on the foundation are not vertically, but horizontally oriented. That is why in the Benelux, and by extension in Europe, almost no suspension bridges are build; the soil is usually too weak for these large horizontal forces to cope with.
This type of bridge is mostly chosen to cross very large distances. The longest bridges in the world with spans of several kilometres are suspension bridges, the Akashi-Kaikyo Bridge in Japan is nearly 2000m. The principle of the bridge is somewhat...