The weather in Cixi, Hangzhou

Opportunities and Challenges Brought by Hangzhou Bay Cross-sea Bridge

Hangzhou Bay Bridge is 36 kilometers long, including 35.7 kilometers. As a two-way six-lane expressway, the design speed is100 km/h. The total investment is about 654.38+007 billion yuan, and the design service life is more than 6543.8+000 years. The bridge has two navigation holes in the north and south. The North Navigation Span Bridge is a steel box girder cable-stayed bridge with twin towers and double cable planes with a main span of 448m, with a navigation standard of 35,000 tons. Nantong Aviation Bridge is a steel box girder cable-stayed bridge with single tower and single cable plane, with a navigation standard of 3,000 tons. The connecting line between the two sides of the bridge is 84.4 kilometers long, with an investment of 5.265438 billion yuan. Among them, the north connecting line is 2.9 1 km, and the investment is10.78 billion yuan; The south bank is 55.3 kilometers long with an investment of 3.43 billion yuan. The total investment of the bridge and the cross-strait connecting line is about 654.38+0.6 billion yuan. The construction period is about five years.

Hangzhou Bay Bridge is the longest sea-crossing bridge rebuilt in the world at present. Located in the Yangtze River Delta, the Bridge is the most dynamic and economically developed area in China. The project started construction in an all-round way at the end of 2003, and is expected to be completed by the end of 2008 and open to traffic in 2009.

The concept of landscape design was first introduced into the design of this bridge. With the help of the aesthetic concept of "Long Bridge Lying on the Wave" in Su Causeway of West Lake, the landscape designer determined the general layout principle of the bridge in combination with the hydrological environment characteristics of Hangzhou Bay and the psychological factors of drivers and passengers while driving. The plane of the whole bridge is S-shaped curve, and the overall linear shape is beautiful and lively. Viewed from the side, the navigation hole bridge of the North-South Passage is arched and has an undulating elevation shape.

The construction of the bridge is conducive to actively docking with Shanghai, expanding opening up, promoting cooperation and exchanges in the Yangtze River Delta, improving the opening up level of Zhejiang Province, especially Ningbo and Jiaxing, and enhancing its comprehensive strength and international competitiveness; It is conducive to improving the layout of the regional expressway network and national trunk lines in the Yangtze River Delta and alleviating the traffic pressure on the Shanghai-Hangzhou-Ningbo Expressway. It is conducive to changing the situation of Ningbo's transportation hub, thus becoming a transportation hub and implementing the regional development strategy around Hangzhou Bay; It is conducive to promoting the development of tourism in Jiangsu, Zhejiang and Shanghai.

Hangzhou Bay Bridge is a convenient passage for the national trunk line Shenhai to cross Hangzhou Bay, and it is a part of Hangzhou Bay Ring Road (G92) of the national expressway network. The bridge starts from Zhengjiadai, Haiyan, Jiaxing in the north, spans the wide sea area of Hangzhou Bay, and ends at Shuilu Bay, Cixi, Ningbo, with a total length of 35.5km. After the completion of the bridge, the land distance between Ningbo and Shanghai will be shortened by more than 120 km, thus greatly alleviating the pressure of the already crowded Shanghai-Hangzhou-Ningbo Expressway and forming a two-hour traffic circle between Jiangsu, Zhejiang and Shanghai with Shanghai as the center.

Engineering characteristics 1, engineering environment characteristics

The weather in Hangzhou Bay is complex and changeable, and typhoons, tornadoes, thunderstorms and sudden small-scale disastrous weather occur from time to time. The natural conditions of Hangzhou Bay have the following characteristics:

(1) The sea area is vast, with many typhoons, large tidal range and fast current, which has typical maritime climate characteristics and few effective working days;

(2) Deep soft soil and deep bearing stratum bring a series of problems to the design and construction of offshore foundation;

(3) The South Beach is long, and the construction conditions are complicated, so it is difficult to meet the requirements of the construction period by using conventional design schemes and construction methods;

(4) The environment is corrosive;

(5) Shallow gas is enriched in many places in the south beach, which endangers the construction safety.

2. Difficulties in engineering construction

(1) The project scale is large, and the offshore engineering quantity is large. The total length of the bridge project is 36 kilometers, and the offshore section is 32 kilometers. The whole bridge has a total of 2.45 million cubic meters of concrete, 820,000 tons of various steel products,+03,565,438 steel pipe piles, 3,550 bored piles, 0/272 caps/kloc and 65,438 piers, and the project scale is huge.

(2) The natural environment is harsh. The tidal range is large, the flow velocity is fast, the flow direction is chaotic, the waves are high, and the erosion is deep. In some areas, the soft soil layer is thick and the shallow gas is rich. Among them, the south bank 10 km beach area is dry and wet alternately, and most offshore projects are offshore operations, so the construction conditions are poor. Affected by hydrometeorology, there are few effective working days. According to on-site construction statistics, the annual effective days of offshore construction operations are less than 180 days, and the tidal flat area is about 250 days.

(3) It is very difficult to make the overall design scheme. The design requirements are new, in which the approach bridge in the underwater area (18.27km) and the approach bridge in the south bank beach area (10. 1km) are the key points of the whole project. The problem of structural corrosion protection is very prominent, and there is no standard to follow; In the process of bridge operation, the driving environment on the bridge deck is affected by unfavorable factors such as strong wind, dense fog, heavy rain and driver's visual fatigue. It is the key to ensure the driving safety on the bridge deck to adopt reasonable and effective design countermeasures. The design scheme involves the application of new materials, new processes and new technologies and the development of a number of large-scale special equipment.

In terms of construction technology, it faces many key construction challenges, such as overall prefabrication, transportation and erection of large-tonnage box girder in high pier area of offshore rapids, long-distance transportation and erection of large-tonnage box girder in wide beach area, design of super-long spiral steel pipe pile, anti-corrosion and pile sinking construction. In the aspect of measurement control, the deformation of structure measurement caused by the effect of super-long bridge length and earth surface is very prominent. Due to the limitation of marine environment, the traditional measurement methods can no longer meet the requirements of construction accuracy and progress. How to realize rapid and efficient survey construction with the help of GPS technology is the core technical problem that restricts the construction period of the whole bridge.

(4) The construction objectives are demanding, and the construction organization and operation management are difficult. This large-scale bridge project has attracted worldwide attention. At the beginning of the construction, Ningbo Municipal Party Committee and Municipal Government clearly put forward that the bridge project should be implemented according to the standard of "three first-class goals". Facing the complex construction environment and challenging projects, how to organize and manage the bridge project is a great challenge for the headquarters. Due to the large number of construction sites and long battle lines, there are synchronous and overlapping processes, which brings difficulties to organizing construction and controlling project quality, progress, safety and funds. How to take effective engineering control and operation management measures under meteorological and hydrological conditions such as typhoon, strong wind, spring tide, huge waves, rapids, heavy rain, fog and lightning is a new topic that needs to be faced in engineering management.

The highlight of the bridge is that it is 36 kilometers long, which makes it surpass the world-famous bridges, such as Chesapeake Bay Bridge and Bahrain Embankment Bridge, and become the longest cross-sea bridge built or under construction in the world.

According to preliminary verification, the bridge * * * needs 769,000 tons of steel, cement 1.29 1.000 tons, petroleum asphalt 1.65438 tons, wood 1.9 1.000 cubic meters and concrete. 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.

The 70m * 16m box girder of the approach bridge in the underwater area adopts the integrated scheme of full-hole system, transportation and erection, and the single girder weighs 2 180 tons, ranking first in China. The diameter of steel pipe piles driven into the approach bridge in the underwater area is 1.5- 1.6m, and the pile length is about 80m, totaling more than 4,000 steel pipe piles, which is the highest in the history of bridge construction in China.

The concept of landscape design was first introduced into the design of this bridge. With the help of the aesthetic concept of "Long Bridge Lying on the Wave" in Su Causeway of West Lake, the landscape designer determined the general layout principle of the bridge in combination with the hydrological environment characteristics of Hangzhou Bay and the psychological factors of drivers and passengers while driving. The plane of the whole bridge is S-shaped curve, and the overall linear shape is beautiful and lively. Viewed from the side, the navigation hole bridge of the North-South Waterway is arched and has an undulating elevation shape.

1.7km south of Nanhang Road, about 14km from the south bank, there is an offshore platform with an area of1.2000 square meters. During the construction period, the platform will serve as a living base for offshore operators and a platform for maritime rescue, survey, communication and maritime monitoring. After the completion of the bridge, this platform in the sea is a rescue platform for maritime traffic services and an excellent sightseeing platform for tourism and leisure.

Hangzhou Bay, located in the Yangtze River Delta, is the most dynamic and economically developed area in China. The construction of Hangzhou Bay Bridge has far-reaching strategic significance for the economic and social development of the whole region.

1. directly promotes the economic and social development of Ningbo and Jiaxing, and promotes the development of surrounding areas such as Hangzhou, Shaoxing, Taizhou, Zhoushan and Wenzhou, which has a positive impact on the overall development of the whole province and even the southern wing of the Yangtze River Delta. According to statistics, the GDP of Hangzhou, Ningbo, Wenzhou, Shaoxing and Taizhou accounts for more than 70% of the province. The project construction will make the development of these areas even more powerful, inject new vitality into the further development of regional economy and society, and play a greater role in improving the overall comprehensive strength of the province. The bridge project has not been fully started, and the "bridge economy" has been surging in Cixi City, Yuyao City and Haiyan County of Jiaxing on both sides of Hangzhou Bay. On the basis of scientific planning of the new area, the first phase of development presents a booming scene, and investors have settled here.

2. Actively connect with Shanghai to open wider to the outside world, promote cooperation and exchanges in the Yangtze River Delta region, and further enhance the comprehensive competitiveness and international competitiveness of our province. As the largest economic center city in China, Shanghai is an important platform for China's internationalization. In the new century and new stage, Ningbo should build a modern international port city and achieve great economic development and leap forward. It is necessary to integrate with Shanghai, integrate into the Yangtze River Delta and move towards internationalization. The construction of the bridge will greatly shorten the time and space distance between the southeast coast of Zhejiang and Shanghai, and make our province integrate into the international metropolis economic circle in a larger scope, at a higher level and with superior location advantages. This has a far-reaching positive effect on radiating the vast hinterland of our province, optimizing and upgrading the industrial structure, improving the investment and development environment, attracting foreign investment and improving comprehensive competitiveness. The construction of Hangzhou Bay Bridge will create more favorable conditions for optimizing the development environment and further attracting and utilizing foreign capital.

3. It is conducive to promoting the urbanization development strategy. The construction of the bridge will further strengthen the links between Jiaxing, Ningbo, Shaoxing and Taizhou, promote the formation of Hangzhou Bay urban continuous belt and coastal open plate in our province, and make this area an important part of the internationally competitive metropolitan group led by Shanghai. At the same time, the construction of the bridge will also have a far-reaching impact on the urbanization development of surrounding counties and cities. Cixi, Haiyan and other places aim at this once-in-a-lifetime strategic opportunity, have scientific planning ideas, attract population and industry gathering, and promote the rise of new districts and new cities.

4. As the first cross-sea bridge in China coastal corridor, it broke through the bottleneck of Hangzhou Bay, optimized the layout of national trunk road network, changed the situation of Ningbo's transportation hub, facilitated the implementation of the regional development strategic network around Hangzhou Bay, and greatly enhanced the competitiveness of Ningbo, an economic center city with great development potential. The construction of the bridge is also conducive to supporting the construction of Shanghai international shipping center, promoting the integrated development and utilization of Ningbo and Zhoushan deep-water port resources, promoting the development of tourism and national defense construction, and alleviating the traffic pressure of Hangzhou transit (Shanghai-Hangzhou-Ningbo Expressway).