Construction of the Shenzhen-Zhongshan Bridge, another mega bridge and tunnel project along with Hong Kong-Zhuhai-Macao Bridge in the Guangdong-Hong Kong-Macao Greater Bay Area, entered a new stage when construction of an immersed tube tunnel began in July.

With a length of 6.8 kilometers and a width of 46 meters, the two-way eight-lane tunnel will be the largest and widest in the world upon completion. More than 320,000 metric tons of steel will be required for its construction.

Song Shenyou, chief engineer of the Shenzhen-Zhongshan Bridge, said the construction of the structure is a highly complicated procedure. In some aspects it is even greater than the Hong Kong-Zhuhai-Macao Bridge because a number of factors need to be taken into consideration, such as height limits, flood control and environmental protection measures.

At 24 km in length, the Shenzhen-Zhongshan Bridge links eastern and western cities in the Pearl River Delta. The two areas have shown unbalanced development in recent decades as a result of underdeveloped transportation networks, with the western area lagging behind in terms of economic growth.

The bridge is expected to improve the situation. Experts say it will become an important channel connecting the east and west of the region and promote integration of cities in the Greater Bay Area.

In particular, cross-boundary cooperation between the mainland and the two special administrative regions of Hong Kong and Macao will be strengthened.

During recent visits of the chief executives of the two regions to Zhongshan, both expressed the hope that Hong Kong and Macao’s research resources could be incubated in Guangdong province.

Liang Haiming, chief economist at the China Silk Road iValley Research Institute, said better transportation links will improve contacts between mainland cities in the Pearl River Delta region and Hong Kong and Macao.

Song said: “Because of the bridge’s strategic significance, cities and areas involved in the project have attached great importance to it. In terms of determining the routes and engineering proposals for the bridge at the preliminary stage of project demonstration, we needed to submit (plans) to the higher level of government for decision-making.”

The plan to build a roadway across the Pearl River dates back to 2002, when the Guangdong government started research into building a cross-river channel between Shenzhen and Zhuhai, which are both in Guangdong.

In 2008, the government carried out a feasibility study on the construction of the Shenzhen-Zhongshan Bridge. Seven years later, in December 2015, the National Development and Reform Commission, the country’s top economic planner, officially approved construction of the structure.

With total investment of 44.69 billion yuan ($6.69 billion), the bridge is expected to come into operation in 2024.