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With the inspection of the last tie rod arch boom completed
The Yangtze River Delta Railway is currently the world's first long bridge
The first time on the Dankunte Bridge of the Beijing-Shanghai high-speed railway
The inspection of the arch bridge of the high-speed rail tie rod is completed
What is a tie rod arch bridge?
Tie rod arch bridge is a beam arch combination architecture, novel structure, complex force, is a special structure bridge, and in the high-speed rail special structure bridge accounted for a relatively large proportion, according to the regulations, the operation of the special structure, technical complex bridge, should be verified once every 10 years.
The Beijing-Shanghai high-speed railway has been in operation for more than 10 years, and the Industrial and Electrical Testing Institute of China Railway Shanghai Bureau Group Co., Ltd. conducted a comprehensive test of the tie rod arch bridge of the Beijing-Shanghai high-speed rail Dankunte Bridge across the Xicheng Canal in the shanghai high-speed rail infrastructure section.
The bridge is a girder arch combined Nelson system tie rod arch bridge. The bridge of this system is to combine the two basic structural forms of arch and beam, jointly bear the load, give full play to the structural properties and combination of beam bending and arch compression, and the horizontal thrust of the arch end is borne by the tie rod, so that the arch end support does not produce horizontal thrust.
How to detect?
Since October 18, the Industrial and Electrical Inspection Institute of China Railway Shanghai Bureau Group Co., Ltd. has used 7 night skylight points to arrange sensors and detect the structure above the bridge deck, and to collect data and detect the structure below the bridge deck during the daytime operation time, including bridge status inspection, dynamic load test, pulsation test, bearing capacity assessment, etc., to judge the operational performance, durability and bearing capacity of the bridge.
The total length of the Dan Quinte Bridge is 164.851 kilometers, which is the world's first long bridge Yin Chao photographed
In the process of testing, according to the stress characteristics of the structure, the inspectors used the unmanned aerial vehicle mounted with a high-magnification zoom camera, the magnetostrictive waveguide for nondestructive detection of the corrosion of the steel wire inside the boom, the crawling robot for the external damage detection of the boom pe sheath, and other new technologies, focusing on the three-dimensional scanning of the linear shape of the bridge arch and beam, and conducted all-round detection of the key stress components and hidden parts of the structure, such as the grouting tightness of the prestressed aperture channel, the interior of the tie rod and the boom and the rust of the anchor head. At the same time, the structure is tested on dynamic performance indicators such as amplitude, acceleration, dynamic deflection, dynamic stress and support seat shift.
This is the first comprehensive inspection of high-speed rail bridges that have been in operation for more than 10 years by China Railway Shanghai Bureau Group Co., Ltd., and it is also the first time in the whole road, and this test will accumulate valuable experience for the future detection of the same type of bridges on the whole high-speed railway.
The world's longest bridge, the Dan Quinte Bridge, cost about $8.5 billion
The Dankunte Bridge is part of the Beijing-Shanghai high-speed railway in Jiangsu Province, from Danyang to Kunshan, crossing Changzhou, Wuxi, Suzhou, Yangcheng Lake on the way, in these cities throughout the land. The total length is 164.851km, which is equivalent to half of the distance from Nanjing to Shanghai. Because it is located in a developed area, the road network is longitudinal and horizontal, consisting of 4,000 porous 900 tons of box girders, more than 180 roads at all levels such as cross-highways, cross-railways, cross-waterways, etc., with a total weight of 4 million tons, which is 8 times that of the Burj Khalifa in Dubai.
The Dan Quint Bridge spans the entire land of southern Jiangsu with the proud posture of a modern high-speed iron bridge.
Usually, the cost of laying a railway directly on the ground is much lower than that of building an viaduct, but because the soft soil and silt soil in southern Jiangsu are widely spread and the soil bearing capacity is very poor, the construction of the railway directly on it is prone to uneven settlement, making the train bumpy, and these tiny bumps are fatal to the high-speed high-speed rail, so the Dan quint bridge was built here.
Southern Jiangsu is located in the alluvial plain of the Yangtze River Delta, characterized by a wide range of low-lying soft soil and a dense network of canals and lakes. At the same time, due to the developed economy of this region, land resources are relatively scarce. The use of viaducts to build bridges can reduce settlement, save land, and avoid collisions with pedestrians and vehicles crossing the railway.
Of course, this ultra-long railway special bridge cannot be a single-span structure, but a composite bridge formed mainly by more than 4,000 standardized concrete box girders, with a small number of long spans that must be built across roads and water networks.
In order not to cause too much burden on the water body, the Dankunte Bridge passes through Yangcheng Lake, which is rich in hairy crabs, and adopts the method of damming cofferdams to transport the sewage to the shore for centralized treatment after "three-level settlement".
This method is to circle a circle with steel pipe piles around the bridge line to ensure that the lake water inside and outside the cofferdam is isolated from each other, and then the lake water in the cofferdam is drained and the construction is carried out on the bottom of the cofferdam. In this way, water operations are changed to land operations, and leakage of oil, mud and concrete can be limited to land and cleaned up before the cofferdam is removed, without entering the lake and causing pollution.
The main difficulty of the ultra-long bridge is that it needs to face a variety of environments in a long area. Some of these soil layers are hard, some are soft, and they also have to pass through some lakes, and the amount of settlement of these soil layers is different, and the uneven settlement is bound to affect the overall flatness of the bridge, so it is very important to strictly control the deformation of the piers.
The foundation of the pier adopts the mode of composite pier and friction pile, that is, it can rely on the friction of the soil to the deep pile to bear the load, and can also rely on the pile to disperse the pressure.
The first pile was poured on April 7, 2008, the bridge was erected on May 24, 2009, the track laying work was completed on November 6, 2010, and it was put into use with the Beijing-Shanghai high-speed railway on June 30, 2011. The construction of the Dan Quinte Bridge employed about 10,000 people and lasted for four years at a cost of about US$8.5 billion (about 54 billion yuan).
Since ancient times, the southern Jiangsu region, which is the hometown of fish and rice, is an active economic growth point, and the Dankunte Bridge connects Changzhou, Wuxi, Suzhou, Kunshan and other cities together, accelerating the exchange between cities and promoting the economic development of the Yangtze River Delta region with the advantages of transportation.