Set five world records! See the super "wisdom" behind the Shenzhen-Zhongshan Bridge

Editor's Note

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The Shenzhen-Zhongshan Channel, a cross-sea channel connecting Bao'an, Shenzhen and Ma'an Island, Zhongshan, is about 24 kilometers long. With its unique "East Tunnel and West Bridge" design, it is like a dragon going out to sea, lying across the Lingdingyang, becoming another important milestone in the integrated development of the Guangdong-Hong Kong-Macao Greater Bay Area. After seven years of careful construction, the Shenzhen-Zhongshan Channel not only laid the world's first two-way eight-lane steel shell concrete immersed tube tunnel, but also built the country's first underwater interchange for expressways, as well as the world's largest span fully offshore steel box girder suspension bridge - the Shenzhen-Zhongshan Bridge.

Night view of the Shenzhen-Zhongshan Bridge. Photo courtesy of the Shenzhen-Zhongshan Channel Management Center

Looking down from the air, the Shenzhen-Zhongshan Bridge is like a long rainbow lying on the waves. Located at the mouth of the Pearl River, facing the harsh environment of high temperature, high humidity, high salt, and frequent strong typhoons, the Shenzhen-Zhongshan Bridge has set five world records. How to build a bridge on the vast Lingdingyang? What hard-core technologies are behind the super project? Recently, the reporter interviewed the builders of the Shenzhen-Zhongshan Bridge and truly felt the important transformation of our country from "Infrastructure China" to "Intelligent China".

A bridge masterpiece that set five world records

At the beginning of construction, the design of the Shenzhen-Zhongshan Channel was considered from many aspects. Taking into account the complexity of the waterway, aviation height restrictions, navigation clearance and geological conditions, the "East Tunnel and West Bridge" plan was finally determined. This plan not only meets the construction conditions, but also achieves the coordinated development of multiple industries, and the safety risks are controllable.

Zhang Changliang, deputy director of the Shenzhen-Zhongshan Link Management Center, said: "The Shenzhen-Zhongshan Link is a national key project. Its design and construction need to be considered comprehensively from the perspective of national development and the overall development of the Pearl River Delta. The challenges we face include the cost, construction period, risks and technical conditions of the project, all of which require us to make the most reasonable choice."

The Shenzhen-Zhongshan Bridge, as an important part of the Shenzhen-Zhongshan Channel, has become the world's largest span fully offshore steel box girder suspension bridge with its 1,666-meter main span. The main tower is 270 meters high and the navigation clearance is 76.5 meters. It has set five world records, including the largest span of an offshore offshore suspension bridge, the highest navigation clearance, the highest main cable wire strength, the largest anchorage volume in the sea, and the highest flutter test wind speed. In April 2024, the Shenzhen-Zhongshan Bridge won the "George Richardson Award" in the bridge industry.

An architectural model of stability and safety

Behind all the achievements of the Shenzhen-Zhongshan Bridge from its initial design stage to its completion and opening to traffic is the engineers' unremitting pursuit of bridge stability and safety.

When a strong typhoon hits, vortices will form near the bridge deck, forming periodic upward and downward suction and pull waves. When the frequency of the wave coincides with the frequency of the bridge itself, resonance will occur, and the bridge will swing like a swing. The innovation team has conducted parallel research for more than three years and developed a new type of combined pneumatic control technology, which has increased the critical flutter wind speed of large-span steel box girder suspension bridges from the world-recognized 70 meters/second to more than 80 meters/second, breaking the authoritative judgment of foreign countries in one fell swoop.

"The design and construction requirements of the Shenzhen-Zhongshan Bridge are extremely high, and the biggest challenge we face is typhoons," said Chen Huanyong, deputy director of the General Engineering Office of the Shenzhen-Zhongshan Link Management Center. "We need to prevent the bridge from fluttering and becoming unstable, so we continuously conduct aerodynamic tests, and eventually the critical wind speed of the test flutter reaches 88 meters per second, ensuring that the bridge can withstand typhoons above level 17."

The Shenzhen-Zhongshan Bridge has two huge anchors, each of which has a concrete volume of about 344,000 cubic meters and weighs about 1 million tons, making it the largest anchor in the sea. The function of the anchor is to withstand tension and stabilize the bridge. The main cables of the Shenzhen-Zhongshan Bridge are tied to these two "weights". The total weight of the bridge plus the vehicles on the bridge deck exceeds 100,000 tons, relying on these two "fixed stars".

Chen Huanyong introduced: "A suspension bridge is a bridge whose main beam and slings are suspended on the main cable, so the main cable is the lifeline of the entire bridge. The anchor of the Shenzhen-Zhongshan Bridge is located about 50 meters below the sea surface, and then the friction between the 1 million tons of anchor and the bedrock is used to balance the tension, thereby anchoring the entire bridge."

An engineering marvel of wisdom and innovation

The completion of the Shenzhen-Zhongshan Link has not only shortened the driving time from Shenzhen to Zhongshan from 2 hours to 30 minutes, but has also greatly promoted the integration of culture and tourism in the Guangdong-Hong Kong-Macao Greater Bay Area and enhanced regional economic and cultural exchanges. In the first month of the opening of the Shenzhen-Zhongshan Link, the traffic volume exceeded 3 million trips, accounting for about a quarter of the total traffic volume across the Pearl River Estuary, and has become an important link that closely connects the people of the Bay Area.

"Our management and control platform has basically completed the development of the situational awareness, warning and prediction module functions, and is currently tuning and continuously optimizing the simulation algorithm to improve the traffic efficiency and intelligent management and control capabilities of the entire road network." said Xu Xianwei, deputy director of the Shenzhen-Zhongshan Link Road Network Dispatching Center.

The Shenzhen-Zhongshan Link, a world-class engineering miracle, not only promotes the rapid development of the Greater Bay Area with its innovative technology and outstanding conception, but also helps China's economy to break through the waves. Its story will inspire the construction workers of major engineering projects to continue to move forward on the road of science and technology and wisdom.

Audit:

Chen Yueshen, Deputy Chief Engineer of Central Channel Management Center

Chen Huanyong, Deputy Director of the Chief Engineer's Office of Shenzhen-Zhongshan Link Management Center