The night scene of Humen II Bridge taken by the drone. Zaxi/photographed
The 200-meter cable tower towers into the clouds. The span of thousands of meters is unparalleled in the world.
Visit the latest masterpiece of the "infrastructure maniac": Humen II Bridge
[Global Times Special Correspondent to Guangzhou Li Sikun] On the eve of Hong Kong's return in 1997, Humen Bridge was completed and opened to traffic. More than 20 years have passed, 10 kilometers upstream of Humen Bridge, Humen Second Bridge is like another giant dragon crossing both sides of the Pearl River. Compared with the "big brother", what are the characteristics of Humen Second Bridge in design and construction? As a "infrastructure madman", what "black technologies" have China added to this bridge? The day before Humen II Bridge was officially opened to traffic, a Global Times reporter came to the bridge site to experience the technological charm of the bridge on the spot.
8 Liaoning ships and 600 Boeing 737 weights
html On the morning of April 1, a Global Times reporter boarded the Nansha Bridge section of Humen Second Bridge. The weather was not good that morning. The chilly spring breeze was mixed with raindrops, and a thin layer of fog was filled with the sky. The reporter came to the main span of the Nansha Bridge, and the tall west cable tower on the bridge instantly occupied the reporter's sight. At the top of the cable tower, several large red characters "Nansha Bridge" are hidden in the fog. Against the backdrop of fog, the 190-meter-high cable tower towered into the clouds. Looking around, the east tower on the other side of the bridge was already blurred in the fog, which made the already very far distance between the cable towers on both sides of the bridge even more insignificant. Yang Min, the project leader of the Humen Second Bridge and deputy general manager of the Fifth Company of China Communications Second Communications Bureau, told the Global Times reporter that the main bridge of the Humen Second Bridge across the Pearl River Estuary is composed of the Nansha Bridge and the Nizhou Waterway Bridge, with the main spans of 1,200 meters and 1,688 meters respectively. "One project consists of two over kilometer suspension bridges, which is the first in the world," he said.and 1688 meters of span are unparalleled in the world among the currently built steel box girder suspension bridge. In addition to having the longest span, Yang Min told reporters that the second bridge of Humen is also arrogant in its width. "The width of the bridge deck of a normal bridge is about 33 meters to 35 meters," said Yang Min. "The width of our two suspension bridges reaches 49.7 meters. The bridge has eight lanes in both directions. It is by far the widest steel box girder suspension bridge structure in the world."
"After the Humen Second Bridge is opened to traffic, it can share at least 30% of the traffic volume of Humen Bridge and 317% of the traffic volume of Huangpu Bridge," said Yang Min. "It will also connect the highway networks of Beijing-Zhu, Pingnan, Yanjiang, Dongshen, Guangzhou-Shenzhen, and Congguan on the east and west sides of the Pearl River, giving the Guangdong-Hong Kong-Macao Greater Bay Area wings to take off."
such a huge bridge body is naturally small in weight. The information provided by China Communications Construction Second Public Administration made a vivid description of this: the main bridge of the Nansha Bridge alone is composed of 94 steel box girders, with a weight of 25,400 tons, which is equivalent to more than 600 Boeing 737 aircraft combined.
, and to support the main bridge with a weight of 600 Boeing 737, strict requirements are put forward for the anchor that "holds" the main cable of the bridge. Yang Min told reporters that the concrete poured by a single anchor on the Nansha Bridge reached 189,000 cubic meters, weighing about 472,500 tons, equivalent to the weight of eight Liaoning ships. The two pairs of anchors on both sides of the east and west cable towers of the Nansha Bridge are like players squatting at the end when tug of war. They use their own "weight" to firmly "hold" the main cable of the suspension bridge and bear the weight of the entire bridge main body and the vehicles on the bridge.
2mm diameter nylon rope was pulled out of a bridge
Who would have thought that this towering and heavy super behemoth, often with several Liaoning ships or hundreds of Boeing 737s, was "pulled" from a nylon rope that was only 2mm.
Zhu Xiaojin, technical director of the Humen Second Bridge project of China Communications Second Communications Bureau, told the Global Times reporter that the first time connecting the two sides of the bridge was a nylon material pilot cable with a diameter of only 2 mm. It was different from the previous practice of using ships to traction on the river surface, or using airships, helicopters or even rockets to traction in the air, the traction of the Humen Second Bridge pilot cable used the "new weapon" of the drone.
Zhu Xiaojin said that although the Dasha Waterway, the waterway in which Humen II is located, is only 1,200 meters wide, has 5 routes and is busy with shipping.Using water traction is equivalent to "cutting the river across the river and stopping all the ships on the river", which will bring significant social and economic losses.
and it is not feasible to use airships, helicopters and even rockets to traction. Zhu Xiaojin introduced that the airship is too stable and has limited bearing capacity, making it difficult to pull up a 1,200-meter-long pilot cable; the risk and cost of using helicopters are too high; while the use of rockets has the defect of insufficient accuracy. "The opposite shore is so wide, if it is a few meters away, it will basically fail."
Yang Min told reporters that after pulling the first pilot cable across the river through a drone, after 7 rope replacements, the nylon rope with an initial diameter of 2 mm turned into a steel wire rope with a diameter of 54 mm, and the bridge load-bearing structure was initially formed.
"Bridge Craft Expo"
Humen 2 Bridge starts at the starting point of the hub-type overpass called Dongchong Interconnect. The overpass is a transportation hub connecting Humen 2 Bridge and Guangzhou Ring Expressway and Guangao Expressway . When the Global Times reporter came to the construction site, he was dazzled by the various intricate passages in front of him: within a small area, the main line and various approach bridges of Humen 2 Bridge were intertwined with the existing expressway viaduct, Guangzhou-Shenzhen-Hong Kong High-speed Railway Elevator, Guangzhou Metro Line 4 viaduct and multiple high-voltage electric wires. In addition, there is a subway station and a high-speed railway station in the area. There are also three high-pressure oil and gas pipelines buried at no more than 1.2 meters underground...
According to the project personnel, the construction of the Dongchong Interchange part of Humen 2 Bridge was carried out in a nearly instantaneous manner between the existing channels and pipelines mentioned above. According to statistics, the entire construction process of Tung Chung Interchange needs to span 8 existing expressways, 6 high-pressure oil and gas pipelines, 5 subways, and also have to cross once each from the existing expressways and high-speed rail lines. What is even more difficult is that during the construction process, it is necessary to ensure the normal operation of the above-mentioned pipelines, roads and railways.
Zhu Xiaojin told the Global Times reporter, "We have adopted a total of 14 processes to solve the construction environment of 'upper and downward penetration' in the interoperable area. There are so many processes that need to be implemented in the same project, which is also the first time in the world." Zhu Xiaojin said, "With so many processes here, this project is also called the Bridge Craft Expo in the industry."
