The breath of spring is getting stronger and stronger, and on the land of Guizhou, the transportation projects under construction are in full swing.
If you don't see it with your own eyes, it's hard to imagine that on a deep V-shaped canyon with uneven terrain, Guizhou people can build a large bridge project here.
This bridge is the Naqing Expressway Baishui River Bridge built by the Road and Bridge Group, a subsidiary of Guizhou Communications Construction Group, which completed the hoisting of the last bridge deck not long ago.
The Whitewater River Bridge under construction
As a control project of the high-speed and difficult points, the smooth breakthrough of the bridge deck is of great importance to the construction of the whole line, laying a solid foundation for its completion and opening to traffic.
Looking forward to the future, after the opening of the Naqing Expressway, it will become an important road transportation channel for Sichuan and other provinces (cities and districts) in the western part of the mainland to go south to the sea, connecting Guizhou in the mountains with the world outside the mountains.
More than 10 technologies are innovatively applied in the quenching and bridge-making process
With a total length of 833.5 meters and a height of 303 meters, the Baishui River Bridge is a 340-meter-long upward-bearing concrete-filled steel tube arch bridge.
As an important traffic artery connecting Zhangjiawan Town, Nayong County, Guizhou Province, and Jichang Township, Zhijin County, the construction of the Baishui River Bridge carries the expectations of the people.
However, the mountains on both sides of the strait are steep and the construction is extremely difficult, which is another bridge "work" polished by the technical team of Guizhou Communications Construction Group.
There are a total of 240 bridge decks on the main deck of the Baishui River Bridge, and in the hoisting of the bridge decks, the team did not follow the traditional installation method, but innovatively adopted BIM digital intelligent construction technology.
The benefits of this technological update are clear: the efficiency of the construction has been greatly improved, and the number of decks installed per day has increased from 6 to 8 to 10 to 12.
Under the support of this technology, the damage to the prefabricated bridge deck by hoisting construction is also effectively reduced, and the precise installation and positioning of the prefabricated bridge deck is realized.
It is the bridge that is built, but the technology and ingenuity that are tempered.
In order to successfully complete the hoisting of the bridge deck, the construction personnel conducted a comprehensive review of the installation position of the steel beam, accurately controlled the longitudinal and horizontal deviation and the deviation of the top elevation, clearly marked the hoisting position of the bridge deck, and ensured that the shear nails entered the reserved groove smoothly. Zuo Qing, project manager of Naqing T5 standard of Road and Bridge Group, a subsidiary of Guizhou Communications Construction Group, told reporters.
Whitewater River Bridge deck hoisting
"The construction conditions are difficult, the construction technology is complex, the volume is large, the construction period is tight, and the technical difficulty is high. This is the first experience of the project participants on the Baishui River Bridge, but it also forces them to work hard and innovate and work hard to promote the continuous leap forward of bridge construction technology in Guizhou.
To this end, the technical team actively applied more than 10 key technologies such as BIM fine modeling, deepening design of steel structure processing drawings, intelligent cable hoisting of Beidou system long-span bridges, monitoring and monitoring of cable hoisting and buckling system, and one-time jacking and pressure injection of self-compacting concrete, and a series of innovative breakthroughs and scientific and technological support to ensure the smooth construction of the bridge.
"The bridge is located in a deep V-shaped canyon, and extreme weather is frequent. The project team continuously optimizes the construction plan and provides guarantee for the project in terms of technical level and safety plan. Xia Wanwu, deputy manager and deputy chief engineer of the Naqing T5 standard project of the Road and Bridge Group under Guizhou Communications Construction Group, said. In his opinion, for Guizhou, the bridge museum, although the technology for building mountain and valley bridges is very mature, new technical problems must be overcome every time a new bridge is built.
Develop new quality productivity and realize the "three modernizations" of bridge-building
The high-precision and sophisticated Guizhou bridge has become an important symbol to demonstrate its comprehensive strength, and the construction of the Baishui River Bridge is the same, and the project team will be assembled, digital, and green throughout.
The Whitewater River Bridge under construction
Looking back at the construction of the arch columns of the bridge, zero error in millimeter alignment was realized, which also benefited from the idea of prefabricated bridge-building. To this end, the Baishui River Bridge project has set up a special prefabricated beam yard.
Because the columns on the arch of the bridge adopt a hollow rectangular thin-walled section steel box structure of row frame type, the column limbs of the transverse bridge are respectively fixed on the steel pipe arch ribs, and the columns are connected by cross braces. To this end, the factory is assembled in sections, processing, on-site sectional hoisting and welding.
According to the height of the column, the column cross-sectional dimensions are 1500×800 mm, 1300×800 mm and 1100×800 mm, and the wall thickness is 16 mm. Each column is composed of a number of 8-meter-long standard sections and less than 8-meter-long non-standard sections, and the whole bridge has a total of 56 column foot sections, 100 standard sections, and 56 non-standard sections, which are divided into 42 combined sections according to the lifting weight and lifting length, and the millimeter-level accurate hoisting is successfully completed.
In the current construction of large-span bridges, most of the bridge positions are distributed in mountainous areas and rivers, and it is difficult to transport large finished steel structure segments. Therefore, most of the construction of steel structure bridges need to set up an assembly yard at the construction site and pre-assemble in the assembly yard.
"Due to the limitations of the site environment and other factors, prefabricated bridges are more suitable for large steel structure bridges in mountainous areas, which will make the construction more accurate and more environmentally friendly. Ran Maolun, general manager of Naqing Company, a subsidiary of Guizhou Communications Construction Group, believes that this is also a concrete embodiment of the development of new quality productivity in accordance with local conditions.
It is reported that the main bridge of Baishui River Bridge adopts the form of bolting and welding, with high manufacturing and installation accuracy, and the bridge is located in a complex terrain, and the main bridge adopts cable hoisting and cable-stayed buckle hanging method construction. To this end, the project has carried out the application of "arch bridge cable-stayed buckle intelligent monitoring and visual intelligent cable hoisting system".
In this application, the symmetrical synchronous tensioning of the buckle cable and the anchor cable is realized, and the self-balance of the buckle tower is maintained during the construction process. At the same time, the automatic control and visual operation of cable hoisting realize the whole process monitoring of the cable crane, and the monitoring system comprehensively and accurately grasps the operation status of the structural system such as the cable tower, sports car, main cable, lifting and traction, etc., to ensure the safe and orderly hoisting work.
At the same time, the Baishui River Bridge is located in a water source protection area, and the project requires environmental protection measures in the whole construction process such as excavation, welding and painting, and strives to achieve zero pollution to the environment.
Building bridges in Guizhou is by no means an easy task, just to go to sea and cross the sea
After experiencing the highway transportation network from scratch and from there to the whole catch-up, Guizhou's Wanqiao flying frame has created a high-speed plain.
But that's not enough. In Guizhou, the Naqing Expressway under construction is one of the projects with the most complex topography and geology and the highest proportion of bridges and tunnels among the expressways under construction in China.
As a representative control project of the Naqing Expressway, the powerful force in the backbone of the builders of the Baishui River Bridge continues to breed, accumulate and explode with the advancement of the construction of this bridge.
The Whitewater River Bridge under construction
In other words, every time this bridge "grows", it embodies the "multiplication" efforts of countless people on the front-line "battlefield", in front of and behind the scenes.
During the period when the main arch was in the stage of construction with a large cantilever, it coincided with the rainy season. "I dreamed that rain poured in and filled the arch ring, causing the buckle cable to increase significantly and the bridge was at risk of instability. As the person in charge of the main arch hoisting site of the Baishui River Bridge, he is often disturbed by the continuous wind and rain and cannot sleep.
After waking up, Luo San adjusted his mind and analyzed calmly, and quickly went to the scene for on-site inspection. After careful observation, he found that the actual situation was not a big problem, because the arch foot main was not yet closed, and the rain could not accumulate and stay, and this discovery relieved him. Not only him, but at that critical stage when the main arch was not closed, the pressure on every participant in the construction of the bridge was enormous.
Zhao Hui, who has extensive experience in bridge construction, is the surveying leader of the Baishui River Bridge project. However, the construction of the Whitewater River Bridge presented him with an unprecedented challenge. For the first time, he independently undertook the measurement and lofting task of the concrete-filled steel tube arch bridge in the large-span mountainous area, covering many key links such as arch foot embedding, main arch installation, column hoisting and bridge installation.
Looking back on the whole process, Zhao Hui also faced great pressure. At the beginning of the project, he found that there was a big discrepancy between the calculation method of some of the data and the actual situation, and although he conducted in-depth research, he still failed to find the root cause of the problem. In the end, under his diligent research and leadership, as well as the multiple efforts of the entire project team, the construction accuracy of each link of the Baishui River Bridge achieved a major measurement result of zero error.
Today, with the construction of the Baishui River Bridge, a modern highway with a total length of 162.167 kilometers with perfect functions has become clear after the joint depiction of the Nayong-Xingyi Expressway (G7612), which connects the main lines of national highways such as Hangrui, Xiarong and Shanghai-Kunming.
Its construction is conducive to the penetration of six vertical channels in Guizhou Province, strengthening the north-south transportation links in the western region of Guizhou Province, forming a fast channel connecting Guizhou with the neighboring Sichuan and Guangxi, and once again allowing the open channel to leap from the drawings to the plateau, leap into the mountains, and leap into the happy life of 40 million Guizhou people.
Source: Guizhou Road and Bridge Group Co., Ltd. Tianyan News