Suspension Bridge

- Undoubtedly invented in China

- 2 more primitive forms of suspension bridge, the catenary bridge and a simple rope bridge, also originated in China

- Rope bridge is the simplest form

- Rope was shot over a gorge using an arrow. The crossbow allowed for more power, heavier cables, and longer distances.

- Rope was threaded through a piece of bamboo which made it easier to cross. This type of bridge is still in use at the Tibetan-Chinese border

- Bridges of cables and ropes evolved into multiple cable bridges sometimes with as many as three cables (two for walking while holding the third above the head for balance)

- Also a woven walkway (matting) was incorporated between the two ropes or cables

- Another variation was to have a series of hanging straps by which the user pulls themselves forward.

- All of these types of bridges were used in the high mountains between China and Tibet

- A lot of the bridges had a path that was only 16 or 17 inches wide

- Cable bridges were most efficient when they were made of bamboo

- Hemp rope can stand a stress of 8000 pounds per square inch. Bamboo can stand a stress of 26000 pounds per square inch

- Ordinary steel cables can stand a stress of up to 56000 pounds while modern steel alloys such as the ones used on the Golden Gate Bridge can stand a stress of up to 256000 pounds per square inch.

- The most famous suspension bridge in China is a catenary bridge called the An-Lan Bridge.

- Total Length is 1050 feet consisting of eight successive spans, and there is not a single piece of metal in the structure. Believed to have been built in the third century B.C. by Li Ping

- Iron Chain suspension techniques were pivotal in helping the Chinese invent “true” suspension bridges such as the bridge at Lu-ting in Sikang

- Its chains are embedded 40 feet into the stone pillars on both sides. Total length of 361 feet.

- Built in 1705, but it is presumed that it replaced an earlier version at the same site

- Suspension bridges are more likely to be found in the south-west of China in more remote locations.

- Arch bridges are found mostly in the North.

Arch Bridges

- Li Chun discovered that a bridge could be built on a segmental arch

- Segmental arch is seen as a gigantic circle embedded into the ground of which only the tip shows

- Bridges built this way take less material and are stronger than ones built as semi-circular arches.

- The Great Stone Bridge is still intact today (built in 610)

- It is seen as one of the great achievements of early Chinese engineering

- The holes in these bridges were able to accomplish several things: flood waters could rush through them which made it unlikely for the bridge to be swept away, the total weight of the bridge would be lessened diminishing the chance to buckle by the ends sinking down into the river banks, and it saved a lot of material

- The Great Stone Bridge spans 123 feet.

- The largest surviving Roman bridge spans 117 feet, but the average Roman whole arch bridge was between 60 and 80 feet.

- The Chinese were 500 to 600 years ahead of Europe in this type of bridge building.

- The greatest segmental arch bridge is the Marco Polo Bridge west of Peking spanning 700 feet.

- It is named so because Marco Polo described it at great length.