How was the Hangzhou Bay Bridge built?

Hangzhou Bay Bridge is designed as a two-way six-lane expressway with a design speed of 100km/h, a design service life of 100 years and a total investment of about11800 million yuan. The bridge has two navigation channels, namely, the North Channel Bridge is a rhombic steel box girder cable-stayed bridge with twin towers and double cable planes with a main span of 448 m, and the navigation standard is 35,000 tons; Nanhang Road Bridge is a type A steel box girder cable-stayed bridge with single tower and double cable planes, with a main span of 3 18m and a navigation standard of 3,000 tons. Except for the South and North Waterway Bridges, the other approach bridges all adopt prestressed concrete continuous box girder structures ranging from 30 to 80 meters. The bridge * * needs 767,000 tons of steel, cement 129 1000 tons, petroleum asphalt165,438 tons, wood 19 1000 cubic meters, 2.4 million cubic meters of concrete and more than 7,000 piles of various types. The 50-meter * 16-meter box girder in Nantan adopts the technology of whole-hole prefabrication and large-scale flat car transportation, which sets a new record for transporting heavy beams at home and abroad. 1. Overall Design of Hangzhou Bay Cross-sea Bridge The Hangzhou Bay Cross-sea Bridge is 36 kilometers long and its construction conditions are very bad. In order to ensure the safety and quality of offshore construction, design and construction must be considered comprehensively. After many investigations and expert consultations at home and abroad, the general principles of construction decision-making design were formulated, and the offshore construction was changed to onshore construction as far as possible, and the design and construction principles of factory, large-scale and mechanization were adopted. 2. Complete sets of technologies for design, manufacture, anticorrosion and construction of large-diameter and super-long steel pipe piles.