11800 million yuan investment, more than 2.4 million cubic meters of concrete, more than 600,000 tons of various steels, and more than 8,000 steel pipe piles and bored piles are combined to build the longest sea-crossing bridge in the world, with a service life of at least 100 years.
Wang, head of the design project of Hangzhou Bay Bridge and deputy chief engineer of China Communications Highway Planning and Design Institute, said that the concept of landscape design was emphasized in the design of Hangzhou Bay Bridge. With the help of the aesthetic concept of the West Lake Su Causeway and the characteristics of the hydrological environment in Hangzhou Bay, the overall design of the bridge is in the shape of "S", just like Changhong lying on the waves. The Hangzhou Bay Bridge, which attracts worldwide attention and spans the central part of Hangzhou Bay and connects Ningbo, an open port city, with Jiaxing, a commercial city, will shorten the land distance between Ningbo and Shanghai by more than120km. Wang said: "Building Hangzhou Bay Bridge is the dream of several generations of Ningbo people. From their enthusiasm and concern for bridge construction, we can deeply understand their strong desire for bridge construction. "
The Hangzhou Bay Bridge, which runs through the whole line, is full of tourists. There are not only tour groups composed of people over half a year old, but also international friends from Wan Li. According to the person in the Qiaotou parking lot, during the "May 1" and "Eleventh" periods, the cost paid by tourists to the parking lot in one day was as high as 40,000 to 50,000 yuan, which shows that the bridge has infinite charm. At that time, Mr. Yang, an American Chinese in his 80s, heard that the Hangzhou Bay Bridge would be built, and personally wrote a long letter to Zhu Ji, then Premier of the State Council. He felt that the domestic design unit was unable to complete the construction of this world-class bridge and recommended himself as the chief designer of Hangzhou Bay Bridge. A copy of this letter is still in Wang's hand. Now, the successful completion of the Hangzhou Bay Bridge has solved the old expert's doubts. In February 2005, Wang attended the meeting of the International Bridge Association in New Delhi, India, and gave a keynote speech on the design of Hangzhou Bay Bridge to representatives from more than 70 countries. He recalled: "After listening to my introduction, many people asked me about the situation and exchanged information, showing great concern for China's bridge construction achievements." The tidal bore in Qianjiang River is still at 200 1, so the State Council has doubts when approving the Hangzhou Bay Bridge project. Premier Zhu Rongji raised three questions: whether the construction of the bridge will affect the tidal bore of Qiantang River, how much it will affect the long-term development of Hangzhou Bay Port, especially Zhapu Port, and whether the bridge construction technology in such a harsh and complicated sea area of Hangzhou Bay is mature. In response to these three questions, Wang made three reports to the National Development and Reform Commission and answered them one by one. The tidal bore in Qiantang River is one of the wonders of nature, and it must not be destroyed just because of building a bridge. To this end, they have done a lot of experiments on the influence of tidal bore. The results show that the highest tidal head during tidal bore can reach 2.5 meters high, and the influence after bridge construction is less than 2 centimeters, which can be ignored and basically invisible to the naked eye. The north bank of Hangzhou Bay Bridge is a deep trough area, and the south bank is a 10 km long tidal flat area. Zhapu Port is located on the north bank. After the completion of the bridge, due to the acceleration of water flow, Shenzhen and Hong Kong have not been silted up, but have played a dredging role. The bridge is located at the bell mouth, and Zhapu Port is just downstream of the bridge. Ocean current will only increase the maintenance of deep grooves and will not adversely affect the port. There is indeed siltation on the south bank beach, but Wang said that as long as the reclamation is not continued, the beach area can basically remain stable. When introducing the natural environment of Hangzhou Bay, Wang said, "This is one of the most unsuitable places for building bridges I know". In the design process, they fully grasped the five difficult problems of local meteorology, hydrology, geological topography, marine environment and construction organization design, and then solved them one by one, perfectly integrating into the design, construction and operation management of the control bridge. Wang bluntly said, "Before doing the design task of Hangzhou Bay Bridge, I just finished the feasibility study of Stonecutters Bridge and Lingdingyang Bridge on Hong Kong Route 9. The construction scale of these two bridges is also very large, especially the sea conditions in Lingdingyang are very complicated. In terms of bridge design, we have a certain foundation and grasp. " After passing through Shuilu Bay, Cixi City, Ningbo City, a pink ribbon will float into your eyes, which is the southernmost tip of the bridge crash barrier. In order to prevent drivers from fatigue during driving, the 36-kilometer-long guardrail of Hangzhou Bay Bridge is divided into 7 sections and 5-kilometer-long sections, and painted with five colors of red, orange, yellow, green, blue and purple from south to north, just like a rainbow. The difficulty lies in invisibility. Since1March, 999, Wang has walked 100 kilometers along the country road by the river to determine the position of the bridge. According to the specific situation of the site, he summarized five design difficulties. Meteorological conditions-located in the area affected by typhoon. The trumpet-shaped and very empty Hangzhou Bay area is often hit by typhoons. Although there is no record of typhoon landing once in 50 years, its indirect influence is still a great test for the wind stability of bridge structures. Not only that, Hangzhou Bay is also a disaster-prone area such as fog, tornado and thunderstorm. Through a large number of calculations, the safety of structure, construction and bridge deck driving is improved. Try to use structures with good wind resistance, such as the box girder of the approach bridge and the main girder of the waterway bridge, to disperse the wind. The twin-tower double-cable plane five-span continuous rhombic steel box girder cable-stayed bridge of North Channel Bridge and the single-tower double-cable plane three-span continuous A-shaped steel box girder cable-stayed bridge of South Channel Bridge all choose relatively stable triangular structures. The basic wind resistance of the bridge is improved through the mutual restraint of the spatial triangle among the stay cables, the box girder and the bridge tower. Windshields were built on both sides of the higher part of the bridge. 1.5m crash barrier is used in general places, which is the highest in China; The wind barrier of the navigation hole bridge section is 3 meters high, and the highest is 4.8 meters near the cable tower. Even if there is strong wind around 1 1 at sea, the bridge can still run. Hydrological conditions-the maximum semidiurnal tide drops nearly 8 meters. The bridge site is located in the sea area of Hangzhou Bay and the mouth of Qiantang River. The maximum velocity of the bridge site is 5m/s, the semidiurnal tide drops nearly 8m, and the wave height is nearly 7m. Especially when waves and tides are coupled, the bridge is under great stress. Therefore, the scale of bridge foundation is completely controlled by wave force, which has never been encountered in other bridge designs. In addition, for half a year, the wind force in Hangzhou Bay was above 8, and the current was fast and the tidal range was large, which brought considerable difficulties to the construction. Wang said that complex hydrological conditions mainly affect the construction of the bridge. In order to solve this problem, they adopted the scheme of prefabricating and installing all components as much as possible, which reduced the risk of offshore operation. Hangzhou Bay Bridge can be roughly divided into three parts: the part around the shore and beach is called the beach area, then it is called the beach area in the water, and the middle of the bridge is the deep water area. According to the characteristics of different regions, different schemes were adopted in the construction. Precast cast-in-place construction is adopted in the beach area, which has low cost and convenient construction management. The mudflat area is the most troublesome, "like water but not water, like shore but not shore", and the muddy geology makes it impossible for vehicles and boats to enter, so the method of "transporting and erecting beams" is adopted, that is, after precast concrete beams on the shore, they are transported from the shore to the sea through the built bridges, prefabricated box beams weighing 1.430 tons and 50 meters long are simply erected 10 km. Faced with many problems in water construction, they changed the habit of "design determines construction" and replaced it with the design concept of "construction determines design". Before making the design, they did a lot of research in the whole country, and then chose the engineering scheme suitable for the bridge according to the actual situation. In order to ensure the minimum risk, the fastest construction speed and the best quality of bridge construction, all-round and full consideration has been made, so that such a huge project can be completed within 4 years. Geological landform-the soft soil layer is thick, and there is shallow methane in the south bank beach area. The thickness of Quaternary overburden at the bridge site of Hangzhou Bay Cross-sea Bridge is 130m ~ 220m, and the bridge foundation cannot penetrate the overburden to reach the bedrock, and the muddy soil layer is 40 ~ 50m thick. In addition, there is shallow methane in the range of Nan 'an Beach 10km, and the geological conditions are very poor. The project team has taken a number of reliable measures: in the deep water area, the bridge foundation adopts driven steel pipe pile foundation, which avoids the influence of bad geology on the construction; In the tidal flat area, the method of "controlling deflation" is adopted in the position of bored piles, that is, drilling a small conduit to slowly deflate, and then constructing bored piles to cross the gas-bearing layer and enter deeper soil layers to meet the needs of bearing capacity. Marine environment-seawater is seriously corroded. A new steel casing was corroded after being placed on the platform in the sea for two months. As the first super-large bridge with systematic structural durability design in China, they have solved this problem well through passive corrosion protection and active corrosion protection. According to the vertically divided atmospheric zone, splash zone, underwater zone and silt zone, different structural durability schemes are designed. For example, the splash zone is the most important for durability. They used epoxy-coated steel bars, at the same time, thickened the protective layer of concrete, and carried out anti-corrosion coating on the surface of concrete for isolation. These measures are passive anti-corrosion. For important components, such as the bridge tower, it is necessary to electrically connect the whole steel bar, and then adopt the current cathodic protection method of titanium mesh to realize the active protection of the bridge tower. Construction organization design-Hangzhou Bay Bridge is huge in scale, and it is difficult to design the construction organization and manage the later operation. In order to improve work efficiency and ensure quality, they adopted the scheme of dividing into blocks according to the same major. For example, the prefabrication of 540 70-meter box beams is completed by one unit, giving full play to the advantages of equipment and resources of the construction unit. Considering the operation and management after the completion of the bridge, there are 9 connected U-turn areas on the bridge. In the event of a traffic accident, the U-turn area can be opened and the 33-meter-wide bridge can maintain normal driving. At the beginning of bridge design, the later maintenance was considered. The beam end of each beam is provided with an inspection channel, and the electric inspection vehicle is installed below the steel box beam.
Hope to adopt.