NINGBO: The two halves of the Hangzhou Bay Bridge, the world's longest cross-sea span, are to be linked today after more than three years of construction.

The occasion represents a major milestone in the history of Chinese bridge-building, an official said.

The 36-km trans-oceanic bridge, which links Ningbo's Cixi County in the south to Jiaxing in the north, has six lanes and a designed lifespan of 100 years. It is located in East China's Zhejiang Province.

The S-shaped, stayed-cable bridge is scheduled to have surface pavement by the end of November and to open to traffic before the Beijing Olympics Games, which start next August, said Jin Jianming, deputy director of the Hangzhou Bay Bridge's construction office.

"It is a significant milestone in the history of cross-sea bridge-building in China," Jin said, adding that the project led to more than 250 innovations and engineering breakthroughs.

The span is the largest single bridge project undertaken in China. The 11.8 billion yuan ($1.55 billion) bridge, which will shorten the road journey between Ningbo, a major port city, and Shanghai by 120 km, is expected to give a huge boost to regional economic integration and spur development.

"The bridge will facilitate regional economic integration between Zhejiang and Shanghai, the most prosperous regions in the country, and in the Yangtze River Delta as a whole," said Chen Jianjun, a research fellow with the Regional Economy and Urban Economy Research Center at the Hangzhou-based Zhejiang University.

Work started on the bridge in November 2003. It can accommodate a top driving speed of 100 kph.