1st Ld-Writethru: China Focus: Key component of world's longest cross-sea bridge installed

Chinese engineers installed a 6,000-tonne key part of the world's longest cross-sea bridge linking Hong Kong, Zhuhai and Macao.

The wedge, 12 meters long, and weighing more than 25 Airbus A380 jets, was lowered to connect the tubes which will form the tunnel section of the bridge, said Lin Ming, chief engineer of the island and tunnel section of the bridge.

The 55-kilometer bridge connects Zhuhai in Guangdong Province with Hong Kong and Macao. It includes a 22.9-km bridge and 6.7-km tunnel.

Before the wedge was installed on Tuesday, 33 immersed tubes, each 180 meters long and weighing 80,000 tonnes, had been installed.

"There is only one wedge for a tunnel, and we cannot afford to fail in its installation. It took two years to prepare for today," said Chen Yue, director of the chief engineer's office of the bridge's island and tunnel section. The installation procedure took more than 10 hours.

"The margin of error for the wedge is 1.5 centimeters. We have to measure precisely the influence of wind, current and buoyancy force," said Lin.

"It is like putting a needle through a hole in the sea -- a truly unprecedented event in the history of transportation," Lin said.

A gigantic crane, which was transformed from a tanker, was used to hoist the wedge, lowering it to the desired destination between the tubes.

The wedge will be welded and finished by June, Lin said.

By the end of the year, the bridge will be open to traffic, said Zhu Yongling, director of the bridge management bureau.

Construction began in December of 2009 at Zhuhai. The Y-shaped bridge connects Lantau Island in Hong Kong with Zhuhai and Macao.

Tan Guoshun, an expert in bridge construction who has participated in many big projects, told Xinhua that breakthroughs were made in construction management, technique, safety and environmental protection.

For instance, the bridge is designed to be used for 120 years. "Anticorrosion and quake-proof measures were improved so as to make the goal possible," he said.

The bridge was pieced together with different parts built in different locations like building blocks. "The progress of China's equipment manufacturing industry made this construction method possible," said Zhong Huihong, deputy chief engineer of the bridge management bureau.

Take the floating crane as an example. In the 1990s, China's floating cranes could only handle about one hundred tonnes. "Now their capacity has reached 10,000 tonnes," Zhong said.

"Some foreigners believe that completion of the bridge marks a leap forward of China's construction industry," said Su Quanke, chief engineer of the bridge management bureau.

The bridge will cut land travel time between Hong Kong and Zhuhai from three hours on the road to a 30-minute drive.

"As economic exchanges between Hong Kong, Macao and Zhuhai deepen, an urban agglomeration has formed. The bridge will further boost the interconnection," said Zheng Tianxiang, vice president of the Asia-Pacific Innovation Economic Research Institute.

Guo Wanda, executive vice president of the Shenzhen-based China Development Institute, believes that the bridge could also help boost the industrial gradient transfer of inland provinces like Guizhou, Yunnan, Hunan and Jiangxi.

"The area will become an important hub of the Belt and Road Initiative," he said. Endi