The construction of the second phase of the Liuheng Expressway Bridge, one of the major transportation projects of Ningbo Zhoushan Port in Zhejiang province, started on Wednesday.

The construction is divided into two phases. The first phase — mainly roads and connecting lines in Ningbo — started last year.

The second phase is a large cross-sea project that spans 18.78 kilometers and will connect Liuheng with the Fodu Islands in Zhoushan and the Meishan Islands in Ningbo via connecting lines and several bridges, including two mega bridges – the Shuangyumen Bridge and Qinglongmen Bridge.

Construction of the second phase will involve a total of investment of 13.28 billion yuan ($1.81 billion) and take 57 months to complete. Upon completion, the line will notch two world records.

The Shuangyumen Bridge, with a main span of 1,768 meters, will set a new record on span length for a cross-sea bridge in China as well being the longest single-span steel box girder suspension bridge in the world.

With the span length of 756 meters, the Qinglongmen Bridge linking Fodu and the Meishan Islands is expected to be the largest steel box girder cable-stayed bridge with three towers in the world.

Yu Yin in Ningbo contributed to this story.