8D Magic Chongqing: Our reputation as the “City of Bridges” is well deserved!

Chongqing, as one of the top ten popular tourist cities in China in 2024, 8D Magic, Cyberpunk, Mountain City, Foggy City... These familiar nicknames are just one side of it. Chongqing also has a world-renowned business card - the City of Bridges.

Image source: Pixabay

Chongqing has always been a city famous for its bridges due to its unique topography. It is not uncommon for a bridge to become a popular check-in spot. The Baijusi Bridge in Chongqing, which has recently become popular on the Internet, has attracted many netizens with its unique "interstellar" flavor captured by photographers. The Baijusi Bridge is just one of the many famous bridges in the "Bridge City".

01 Natural genes build the “City of Bridges”

Chongqing's title of "Bridge City" is not just a reputation passed down among the people, but an officially certified statement.

Image source: Fingertip Photography

As early as 2005, the Mao Yisheng Bridge Committee, a professional organization in my country's bridge construction, selected China's bridge capital at its annual meeting. At that time, Chongqing stood out from many candidate cities and was recognized as the only "Bridge Capital" in China. You should know that Mr. Mao Yisheng is a famous bridge design expert in my country and the father of modern bridges. The "Bridge Capital" selected by the organization named by him is of great value.

Why was Chongqing selected as China's "Bridge Capital"? The Mao Yisheng Bridge Committee also gave a convincing selection criteria: Chongqing is one of the best in China and abroad in terms of the number of bridges, construction scale, technical level, and bridge diversity.

One of the important indicators is the number of bridges, which is closely related to Chongqing's geographical "genes".

As we all know, Chongqing is both a mountain city and a river city. Just around the main city of Chongqing, there is a topographic pattern of "four mountains (Jinyun Mountain, Zhongliang Mountain, Tongluo Mountain, Mingyue Mountain) sandwiched between two rivers (Yangtze River and Jialing River)". The entire Greater Chongqing area is mountainous, accounting for about 75.33%, and has a dense network of water systems, with more than 5,300 rivers of all sizes, of which 274 rivers have a basin area of ​​more than 100 square kilometers, and 42 rivers have a basin area of ​​more than 1,000 square kilometers.

Chongqing is a mountainous city with numerous rivers and dense water networks. In such a geographical environment, to ensure smooth land transportation, "building roads through mountains and bridges over rivers" is naturally the best choice for Chongqing people. Therefore, there are more than 4,500 bridges of various types in Chongqing, which far exceeds the number and density of other cities in China.

As of 2023, there are as many as 37 cross-river bridges, and with the cross-river bridges under construction, the total number exceeds 50. It is these bridges that connect the mountains and waters of Chongqing, creating Chongqing's unique "bridge city" style.

02 Various bridges, everything you need

As the "bridge capital", Chongqing's excellence lies not only in the number of bridges, but also in the diversity of bridges. Bridges can be divided into five basic systems according to their structural system and force characteristics: beam bridges, arch bridges, rigid frame bridges, suspension bridges, and cable-stayed bridges. Each type of bridge can be found in Chongqing.

Beam bridge - Shibanpo Yangtze River Bridge

The beam bridge is a very traditional bridge structure. When the ancients first built the bridge, they placed a piece of wood on several load-bearing objects (piers) across the river. This was the prototype of the beam bridge.

After thousands of years of evolution, the technical standards of beam bridges have changed greatly compared to their "ancestors", but they still maintain the overall structural form of "piers plus bridge deck, piers bearing force". This structural form is relatively simple and convenient to construct.

The Shibanpo Yangtze River Bridge, which is tacitly called the Chongqing Yangtze River Bridge by the "old Chongqing" people, is a beam bridge. This important cross-river bridge connecting Chongqing Yuzhong District and Nan'an District was opened to traffic in 1980. It is also the first super-large urban highway bridge in the middle reaches of the Yangtze River.

Arch Bridge - Chaotianmen Yangtze River Bridge

Arch bridge is another type of bridge structure with a long history and widespread use. As the name implies, its biggest feature is the "arch" on the bridge, which gives the entire bridge structure a curved arc. Don't underestimate these arches, they can disperse the vertical load on the bridge deck through the arch structure, thereby reducing the vertical force on the bridge deck and improving the compressive strength of the bridge.

Traditional arch bridges are designed with the bridge deck directly in an arch shape. However, with the advancement of engineering technology, the "arch" of an arch bridge can be an arch-shaped auxiliary load-bearing structure attached to the bridge deck.

Chongqing also has many arch bridges, among which the most famous one is the Chaotianmen Yangtze River Bridge, which spans the Yuzhong Peninsula and connects Wulidian in Jiangbei and Danzishi in the south. This arch bridge was officially opened to traffic in 2009. Its main span is 552 meters and its total length is 1,741 meters. When it was built, it was the arch bridge with the largest span in the world at that time, so it is also known as the "world's first arch bridge."

Lijia Jialing River Bridge

A rigid frame bridge is a composite bridge structure that combines a beam bridge and an arch bridge. Its biggest feature is that there is an arched beam or plate load-bearing structure above the bridge deck, which gives it the characteristics of an arch bridge. At the same time, it has several piers underneath that bear the load.

Due to the combination of the load-bearing structure of the bridge arch and the bridge pier, the rigid frame bridge often has greater compressive strength, and therefore this structure is often used in cross-line bridges (bridges that cross traffic routes such as highways, railways or urban roads).

One of the more well-known rigid-frame bridges in Chongqing is the Lijia Jialing River Bridge. This bridge, which was officially opened in 2021, is 785 meters long, has a maximum span of 245 meters, is designed with 8 lanes in both directions, and is 18 meters wide. It is the first top-supported large-span beam-arch combined prestressed system rigid-frame bridge in the country.

Suspension Bridge - Egongyan Rail Bridge

A suspension bridge is also called a suspension bridge. The Luding Bridge in the elementary school textbook "Flying over Luding Bridge" is a classic traditional suspension bridge. From the Luding Bridge, we can see that the main structural feature of a suspension bridge is to suspend and pull a number of gravity-bearing cables through the cable towers set on both sides, and then lay the bridge deck on the cables.

Modern suspension bridges have added more auxiliary load-bearing structures on the basis of traditional suspension bridges. Instead of laying the bridge deck directly on the cables, many hangers hanging from the cables are used to connect the bridges. At the same time, the cables are often made of materials such as steel cables with higher tensile strength. These design improvements have greatly improved the load strength of modern suspension bridges, and many large-span bridges today use suspension bridge structures.

The more famous suspension bridges in Chongqing include the Egongyan Rail Bridge, which is a dedicated bridge for rail transit vehicles and was opened to traffic at the end of 2019. The Egongyan Rail Bridge is about 1,650 meters long, with a main span of 600 meters, the longest span of any self-anchored suspension bridge in the world.

Cable-stayed bridge - Qiansimen Jialing River Bridge

Although cables are also used for stress, the stress structure of the cable-stayed bridge is completely different from that of the suspension bridge. Compared with the suspension bridge, the cable-stayed bridge has an additional structure called a bridge tower. The bridge tower functions similarly to the piers of a beam bridge, but it does not "hold" the bridge from below to bear stress. Instead, many cables extend from the top of the bridge tower to "hold" the entire bridge. The bridge deck, bridge tower and the inclined cables form a triangular stress system, thus ensuring the stability of the cable-stayed bridge.

Image source: Pixabay

The Qiansimen Jialing River Bridge, which is adjacent to the Chongqing Science and Technology Museum, is one of the more famous cable-stayed bridges in Chongqing. This cable-stayed bridge, which opened to traffic in 2015, connects Yuzhong and Jiangbei. It is 1,647 meters long and has a main span of 720 meters. It can be used as both a highway and a rail transit bridge. It is the world's largest span single-tower single-cable cable-stayed bridge and won the title of Chongqing's first "Top Ten Most Beautiful Bridges" in 2015.

In addition to the official title, the Qiansimen Jialing River Bridge is the best place to view the night view of Hongyadong. During the peak hours of holidays, the bridge is closed to please fans, so it has also received praise from netizens as "the largest pedestrian bridge in the world". Next time you visit the Science and Technology Museum, you may want to look out from a distance and appreciate the beauty of this bridge as a "mountain, water, city and bridge".

Source: Chongqing Science and Technology Museum

Author: Yang Zhen, popular science writer

Review experts: Huang He, Li Chunli, Xu Xiaoping

Statement: Except for original content and special notes, some pictures are from the Internet. They are not for commercial purposes and are only used as popular science materials. The copyright belongs to the original authors. If there is any infringement, please contact us to delete them.