From three-step single-plank bridge to suspension bridge, stone slab bridge, arch bridge, cable-stayed bridge, steel bridge and concrete bridge, from single-function pedestrian bridge to highway bridge, railway bridge, multi-functional multi-storey bridge, composite overpass and viaduct, bridges have greatly opened up people's activity space and are a symbol of the scientific and technological level of an era. Zhao Zhouqiao, Hebei Province, built in 6 16, has become a representative masterpiece in the architectural history of stone arch bridge with its scientific and ingenious conception. Anping Bridge in Jinjiang, Fujian Province, built in 1 15 1, is the earliest existing ancient stone bridge with the largest stone slab weighing 25 tons. It was once called "no bridge in the world is as long as this one". Wanzhou Yangtze River Bridge, with a main span of 420 meters, is the largest concrete bridge in the world. The second long dike bridge in Lake Pontcharta, Louisiana, USA is nearly 40 kilometers, which is the longest bridge in the world. The Tower Bridge in London on the Thames is one of the world's scenic spots. When the big ship passes by, the lower floor can be hoisted to both sides.
Shanxi Fenhe Bridge, built in 206 AD, is the earliest iron suspension bridge in the world.
Suspension bridge, also known as suspension bridge, is a bridge with cables or chain cables bearing tension as the main load-bearing components. A suspension bridge consists of suspension cables, pylons, anchorages, suspenders and deck system (Figure 6 is a schematic diagram of the suspension bridge). The main load-bearing component of suspension bridge is suspension cable, which mainly bears tensile force and is generally made of steel (steel wire, steel strand, steel cable, etc.) with high tensile strength. ). Because the suspension bridge can make full use of the strength of materials, and has the characteristics of material saving and light weight, the span of the suspension bridge is the largest among all kinds of bridges, and the span can reach more than 1000 meters. The Humbil Suspension Bridge in England was built at 198 1 with a span of 14 10 meter, which is the largest bridge in the world at present. The main disadvantage of suspension bridge is its low stiffness, and it is easy to produce large deflection and vibration under load, so corresponding measures should be taken.
According to the stiffness of bridge deck system, suspension bridges can be divided into flexible suspension bridges and rigid suspension bridges. Generally, the deck system of a flexible suspension bridge is not provided with stiffening beams, so the stiffness is small. Under the vehicle load, the bridge deck will be S-shaped with the change of the shape of the suspension cable, which is not conducive to driving. But its structure is simple, and it is generally used as a temporary bridge. The deck of rigid suspension bridge is strengthened by stiffening beam, which has great stiffness. Stiffened beams can bear vertical loads together with the whole bridge structure. In addition to the above forms, in order to enhance the stiffness of suspension bridges, double-chain suspension bridges and suspension bridges with inclined suspenders can also be used, but their structures are more complicated.
A bridge whose deck is supported by suspended cables (usually called large cables) is called a suspension bridge. Suspension bridge means "suspended bridge" in English, so it is also translated as "suspension bridge". In most cases, the suspension system of "suspension bridge" is composed of "cable", so it is translated as "suspension bridge". However, in some cases, "cable" is also composed of rigid rods or key rods, so it cannot be translated into "suspension bridge". Contrary to the arch rib, the suspension cable section only bears tension. Simple suspension bridges used only by people and animals often lay the deck directly on suspension cables. Suspension bridges with modern means of transportation are not. In order to keep the bridge deck straight, the bridge deck is suspended from suspension cables with slings. Unlike arch bridges, arch ribs as load-bearing structures are rigid, while suspension cables as load-bearing structures are flexible. In order to avoid the deformation of bridge deck and suspension cables when vehicles pass, modern suspension bridges are generally equipped with rigid beams (also known as stiffening beams). The bridge deck is laid on a rigid beam, and the rigid beam is suspended on a suspension cable. The suspension cables of modern suspension bridges are generally supported on two towers. Saddle-shaped brackets are arranged at the top of the tower to support suspension cables. The end of the suspension cable under great tension is fixed in the foundation through anchorage, and part of it is fixed at the end of the rigid beam, which is called self-anchored suspension bridge.
I haven't read Fenhe's article. The following is for your reference:
The earliest cable-stayed bridge in China-Jihongqiao
Author: Source:
Release date: 2004-01100: 46:12
On both sides of the Lancang River, the mountains are high and the valleys are deep, the cliffs and reefs are densely covered, and there are many dangerous beaches. The water quantity changes with the seasons, which brings inconvenience to shipping. "Crossing the river like every other day, crossing the river like crossing a danger". For thousands of years, in order to conquer this natural disaster, people of all ethnic groups living on both sides of the strait have opened countless ferries and built many bridges, the oldest of which is Jinlan Gudu.
The Lancang River, where Bonan Mountain and Luomin Mountain are far away, is Jinlan Gudu, which is the only way to take Yongchang Road. There are two piers near the ferry, and Jihongqiao, the oldest cable-stayed bridge in China, is built. Legend has it that in the past, business travelers and people waiting to cross the bridge lined up for five or six miles every morning before the gate of the bridge pavilion was opened.
Lan Jindu built a bamboo cable suspension bridge in Nanzhao. In the Yuan Dynasty, it was changed into a wooden bridge, and in the Ming Chenghua period (A.D. 1465- 1487), the iron cable suspension bridge was rebuilt and named "Jihongqiao". On March 28th, 12th year of Chongzhen in Ming Dynasty, Xu Xiake crossed the Hongqiao Bridge, and the east of Tiesuo Bridge was "Hejiang, with Gong Shi as the gate, leaning on the East Cliff, and building Wuhou Temple and Tax Bureau". On the west side of the bridge, Guan Gong did the same thing. He leaned against the cliff on the west side and built a tower to commemorate the people who built the bridge. "This bridge is" the throat of the west, and it will not be changed for thousands of years "(Volume 8 of Xu Xiake's Travel Notes in Yunnan). Today's Tiesuo Bridge was built in the 20th year of Qing Emperor Kangxi (A.D. 168 1). Kangxi wrote the title "The Other Side of Hong Fei" for this bridge, so the "Imperial Book Building" was built on the east bank. After the iron cable is often corroded, there will often be military disasters and repeated repairs.
Yongping in Baoshan City, Yandong in Pingpo Township, and Jihongqiao flying on the Lancang River. Before the completion of the Yunnan-Myanmar Highway, Jihongqiao was always a transportation hub in western Yunnan, and remained basically unchanged during the Republic of China. North-South related buildings, with gates at both ends and tax cards; There is a bunker at the bridge head on the west bank, and there is danger near the river. If there is one person to keep it, ten thousand people can't force it. Ji Hongqiao is115m long, 3.8m wide and 56.2m clear. Jihongqiao consists of 18 thick chain, 16 load-bearing bottom chain arranged in the form of 2, 4, 4, 4 and 2, and two other handrails. There is an iron splint at the bottom, which is about 6 meters apart. Lock the bottom rope of 16, spread a cross board, tie it to the chain with lead wire, and then fix it with battens and nails.
Semi-circular piers are built on both sides of the bridge, and both ends of the chain are riveted on the abutments on both sides of the bridge. The west coast is a cliff, the east coast is a dangerous peak, and below it is a raging river, which is very dangerous. There are pavilions at both ends of the bridge. There is an ancient iron pile at the foot of the cliff, with a mushroom-shaped top, about 80 cm above the ground and a circumference of 72 cm. Legend has it that it is a ship pillar in the Ming Dynasty.
There is an east-west road to Hongqiao. The east road runs from Dali to Yongping Yang Shan, and then spirals down Bonanshan until it reaches the river; The west road runs from Baoshan to the bridge via Shuizhai. Compared with the two, the East Road is relatively flat and there are many historical sites, so the taste of the "ancient road" is relatively strong.
Standing at the bridge head of the thorn bridge, the upstream 100 meters of the Lancang River is covered with silver flowers and snow waves, but the water is slowly approaching. At that time, Xu Xiake used the words "dead and forgotten, deep and silent, unfathomable" to describe the status quo here. Because ancient roads, precipices and bridges are closely related to the development of western Yunnan and have scientific value in history, culture and bridge construction, the government has allocated funds to repair them and listed them as provincial cultural relics protection units. Although she has bent down, grandma's wrinkled face blooms a chrysanthemum-like smile; Although her eyes are cloudy, the beautiful memories of her youth are still filled with her whole thin body.