“World bridge construction: before the 1970s, Europe and America led; in the 1990s, Japan led; in the 21st century, China leads.”

　　Bridge-building “wonder”

　　On January 9, the “Daqiao Haiou” 3,600-ton crane vessel, independently developed, designed, and manufactured by China, was delivered for use in Qingdao. The vessel is currently China's largest and highest-lifting double-jib crane vessel, and will soon travel to Fujian to serve the Fuping Railway Pingtan Strait Road-Rail Bridge.

　　To meet the needs of full-span steel girder erection and offshore lifting of large components for the Pingtan Strait Road-Rail Bridge, in early 2015, China Railway Major Bridge Engineering Group invested 340 million yuan to design and build this 3,600-ton crane vessel.

　　The “Daqiao Haiou” crane vessel was invested in and designed by China Railway Major Bridge Engineering Group and manufactured by Qingdao Wuchuan Heavy Industry Co., Ltd. It is 118.9 meters long, 48 meters wide, with a draft of 4.8 meters, a lifting capacity of 3,600 tons, and a maximum main hook lifting height of 110 meters above the water surface. It is China's largest and highest-lifting double-jib crane vessel. Its crane adopts a luffing double-jib structure, which better meets the characteristics of bridge lifting construction, reduces the structure of bridge lifting spreaders, and thus increases the effective height of bridge lifting. The vessel is a non-self-propelled steel crane vessel with auxiliary navigation functions, mainly used for offshore lifting of bridge engineering components and equipment.
　　The full-span lifting and erection of the 80-meter and 88-meter steel truss girders of the Pingtan Strait Bridge requires a crane vessel with a lifting capacity of over 3,200 tons and a lifting height of 110 meters, with a service period of about 24 months. To meet the needs of full-span steel girder erection and offshore lifting of large components for the Pingtan Strait Road-Rail Bridge, in early 2015, China Railway Major Bridge Engineering Group invested 340 million yuan to design and build this 3,600-ton crane vessel. It will be an important equipment support for China Railway Major Bridge Engineering Group's “March to the Sea” strategy.

　　Liu Ziming, Chairman of China Railway Major Bridge Engineering Group and Project Manager of the Pingtan Strait Road-Rail Bridge, stated that during the construction of the Fuping Railway Pingtan Strait Road-Rail Bridge, a work vessel with strong wind and wave resistance was needed, one that could hold its position, and the ‘Daqiao Haiou’ meets such requirements. After delivery, the “Daqiao Haiou” will be immediately put into use in the construction of the Pingtan Strait Road-Rail Bridge, which is China's first truly road-rail sea-crossing bridge. With the commissioning of the “Daqiao Haiou”, bridge construction will adopt the full-span lifting and erection technology using crane vessels, which is another breakthrough in China's steel truss cable-stayed bridge main girder erection technology, marking that China's railway bridges are beginning to move from inland rivers to the ocean.

　　Pingtan Strait Road-Rail Bridge


　　Location: Pingtan —— Changle

　　Total length: 16.3 kilometers

　　Features:

　　It is China's first road-rail sea-crossing bridge, capable of running high-speed trains and automobiles;

　　It is a key control project of the newly built Fuzhou-Pingtan Railway and Changle-Pingtan Expressway;

　　It is an extension of the Hefei-Fuzhou Railway and an important part of the Beijing-Fuzhou corridor, a fast channel connecting the Changle sub-center city and the Pingtan Comprehensive Experimental Zone.

　　It is expected to open to traffic in 2019. By then, driving from Pingtan to Changle Airport will take only about 20 minutes, and train travel only about 10 minutes.

　　The world's most difficult sea-crossing bridge under construction

　　Construction conditions are harsh; Pingtan has strong winds above level 6 for an average of 309 days per year.

　　The construction team mobilized the only two high-power pile-driving vessels in the country and imported special pile-driving hammers from the Netherlands to cope with the severe weather.

　　The diameter of the main pier pile foundation of the strait road-rail bridge is the largest in the history of world bridge construction; the two innovations of a main pier diameter of 4.5 meters and an integral steel crossbeam length of 88 meters have both broken the records once set by China's Hangzhou Bay Bridge.

　　The seabed rock is exposed and as hard as iron, and the seabed is uneven. Due to complex geological conditions, the construction of 24 casings took two years, as shown in the figure below.

　　Wind resistance —— a challenge throughout

　　There are more than 200 days a year with strong winds above level 7, which is a huge challenge for the design, construction, and future operation of the bridge. Wind resistance is a constant issue faced by the Pingtan Strait Road-Rail Bridge.

　　The design load of the Pingtan Bridge must bear two railway lines and six expressway lanes, making it the heaviest load among sea-crossing road-rail bridges in the world. To ensure the safety of the bridge structure and vehicles on the deck under strong winds, multiple wind resistance studies and structural model wind tunnel tests were conducted, and the bridge structure ultimately adopted cable-stayed bridges with different spans and simply supported steel truss girder bridges.

　　The main towers of the cable-stayed bridge use reinforced concrete structures, with a maximum tower height of 200 meters. To ensure construction safety under level 7 wind conditions at the Pingtan Bridge, structures required for construction such as stiffening skeletons were strengthened in design. After the bridge is completed, wind barriers will be installed on both sides of the highway and railway decks to ensure that driving conditions on the bridge are no worse than those on land on both sides.