Independent innovation has supported the world's first --- world's longest span cable-stayed bridge

"People's Daily Overseas Edition" on May 23 With people's attention to the world's longest span cable-stayed bridge Suzhou (Zhou) (South) Tong Bridge, four world records in the history of world bridge construction were also announced: the world's cable-stayed bridge * 5655 main span of 1088 meters, * long cable-stayed cable 577 meters, * 5655 group of pile foundations 131, * 5661 main bridge tower 300.4 meters, becoming a milestone for China to move from a bridge construction country to a bridge construction power. Please take a look –

On the way to the construction site of the Sutong Bridge, a placard with the words "Innovation is the historical mission of the Sutong Bridge" is very eye-catching, although the handwriting is somewhat mottled due to years of wind and sun, but it is still firm.

●The peak of the world's bridge construction technology

The main bridge of Sutong Bridge adopts a super-large span cable-stayed bridge, which is a modern super-large bridge project with a scale of 5655, a construction standard of 5661, a complex technology and a scientific and technological content of 5661 in the history of bridge construction in China. The main span of Sutong Bridge is 1088 meters, which ranks first in the world * 5656 in the cable-stayed bridge type that has been built and is under construction, and the project is faced with four major challenges: poor meteorological conditions, complex hydrological conditions, deep bedrock burial, large navigation density in the bridge area, and high navigation requirements. The all-round transcendence of scientific research and management represents the peak of bridge construction technology in China and even in the world.

Innovation is the driving force for the construction of Sutong Bridge. After more than 10 years of careful preparation and more than 4 years of united struggle, the majority of transportation builders have overcome 10 key technical problems of *5653, and created four world records of * deep foundation, * 5661 cable tower, * long cable and * 5655 span.

Feng Maorun, director of the User Committee of the Ministry of Transport, pointed out that "Sutong Bridge is one of the 5,656 landmark projects in China from a bridge country to a technological power."

●The deep-water rapids do the base of the tower

On the day when the Sutong Bridge began to erect the pile foundation construction platform, it coincided with the astronomical tide, the river was stormy, the tide in the river was surging and waves, and 12 steel pipe piles swayed violently under the impact of the water flow...... What's more dangerous is that at this time, the two unpowered piling ships are still connected to the piles, and Liu Xianpeng, the manager of the Sutong Bridge Construction Project Department who was on board, was taken aback and quickly mobilized a powered barge to pull the piling ship, "If the two ships collide, the consequences will be unimaginable." "The boat was pulled, but the Sutong Bridge *5656 platform erection failed.

"Thousands of high-rise buildings rise from the ground", the construction platform cannot be erected, and the pile foundation construction cannot be carried out, not to mention the bridge piers and towers.

On the way back, Liu Xianpeng was annoyed. At this moment, he received a call from You Qingzhong, director of the Jiangsu Provincial Department of Transportation and on-site commander of the Sutong Bridge Construction Headquarters, "This is God helping us, not a bad thing." ”

A "seminar on tackling tough problems" on the construction of pile foundation platform was urgently held in the small conference room of the project department. Liu Xianpeng was inspired by the hydraulic crane on the bridge deck, which produced a pile foundation guidance device with a slight design modification. To put it simply, it is equivalent to a ring restriction ring that can open the mouth, after the casing enters, the "mouth" is retracted, which basically controls the casing within a small range, and the piling accuracy is naturally guaranteed.

Foreman Li Hongjun is the main manufacturer and user of the guide device, and his experience is deep. "That time it was raining on the river, and the wind and waves were also strong, and a lifting steel casing swayed back and forth in the air, with a range of more than 2 meters, and the rope seemed to be overwhelmed and rattled sound." Li Hongjun recalled that the situation was very terrifying at that time, and some of the workers around him were so nervous that they could not speak. He made a decision immediately, commanded the crane to lift the casing flat into the guidance device, and then quickly closed the dragon, and the casing stabilized at once.

In this way, the accuracy of the casing reaches 1/800 (800 meters of vertical distance only produces a deviation of about 1 meter), which is much higher than the project 1/200 and the national standard of 1/100.

● 300 meters high tree tower

The pylon is divided into 68 segments and has a height of 300.4 meters, which is higher than the Eiffel Tower in Paris.

The north and south towers are the main stress structures supporting the whole bridge. All the power generated by this bridge is transferred to the tower. The unique structure of the cable-stayed bridge determines that the precision requirements for the construction of the tower body are almost harsh.

In the construction of the bridge tower, the layers are superimposed upward, and the verticality error from the top of the tower to the bottom of the tower cannot exceed 10 cm. It's like stacking 10 one-dollar coins on a stack, and it's not difficult to stack 20 coins, but if you stack 100 or 200 coins without falling down, you need extraordinary skill. The tower of the Sutong Bridge is equivalent to the difficulty of stacking 1,000 coins.

The wind has become a big threat to *5656. According to the principle of meteorology, every 100 meters increase in the height of the ground, the wind will increase by one level, the main tower is 300 meters high, if the river surface is 6 winds, then the top of the tower is 9 winds.

The wind threatens personal safety. The project department installed a wind speed measuring instrument in the tower crane with a height of 310 meters to monitor the wind speed change at all times, and once the warning is exceeded, all personnel must be evacuated immediately.

wind, which threatens the quality of the project. The construction of the tower body almost completely relies on hydraulic climbing formwork, but most of the domestic climbing formwork can only resist the wind speed of more than 30 meters per second. Once the climbing mold is damaged in high winds, it will bring irreparable damage to the tower.

On the basis of digesting and absorbing foreign climbing formwork technology, the builder created a hydraulic climbing formwork that can resist the wind speed of 70 meters per second, and independently innovated the use method. During the construction process, the "Sutong climbing formwork" not only rain or shine, but also created an average daily tower climbing limit speed of 1.5 meters.

● "Let the Chinese pump send the concrete to the world *5661 bridge tower"

To build such a large bridge, in addition to technology, it is the equipment. The concrete pump is an inseparable equipment for the construction of the bridge tower, but a concrete pump was carefully sent to the construction site by the manufacturer but did not play a role. A few months later, the pylons were already towering over the river, and the pump was happily pulled away by the manufacturer.

This never-before-used device is the pride of the Chinese company Sany Heavy Industry.

Originally, the construction of the Sutong Bridge pylon is divided into 68 sections, each section is about 4.5 meters high, during the period, the equipment must send the concrete with high viscosity to the top one by one, until * more than 5661300 meters, it takes 7 to 8 hours to pour a section, once there is a failure, the quality will be irreparable defects. Therefore, it is necessary to ensure that there are two pieces of equipment in good condition, one working and one standby. The construction unit knows that the popularity of China's concrete pump is far from the "SEW" brand, and the use of imported equipment is in the plan. But Liu Xianpeng is not reconciled, although foreign products are good, there has never been a successful precedent for a 300-meter-high tower and No. 50 concrete, and China now has good products, so why not let us try it ourselves? So, they "arbitrarily" decided to purchase two pieces of equipment, one domestic and one imported.

Naturally, there are different opinions on this matter, and some people say that this is not honest, because the promises in the tender are all imported. Some people also kindly persuaded each other, "What are you doing with such a big responsibility, if something goes wrong, you will definitely lose your official position and be punished." Liu Xianpeng couldn't hold it anymore, he quietly reported to the headquarters, and Commander-in-Chief You Qingzhong immediately said: "Okay! Tell Sany Heavy Industry that if they have confidence and determination, they will let China's pumps send concrete to the world's *5661 bridge towers. ”

Sany Heavy Industry is well aware of the pursuit of quality of Sutong Bridge, Sutong Bridge bought one, they sent two, one of which is a spare. In the actual construction, the imported equipment bought for more than 2.6 million yuan often broke down, but the equipment of Sany Heavy Industry of 900,000 yuan showed its might. Of course, that backup pump didn't come in handy.