April 11th
At the confluence of Kunshan's "mother river" Loujiang River and Qingyang Port
A 1,750-ton oversized steel arch tower
Under the action of traction equipment
It blooms like a "and dilian" on the clear waterway
It marks the construction undertaken by China Construction Seventh Bureau
The highest inland river bridge in Suzhou - Kunshan Zhenchuan Bridge Project
Smooth vertical rotation
Witnessing the Seventh Bureau of China Construction and Kunshan City
Work together to promote the upgrading of Kunshan's waterway industry and human settlements
Go hand in hand, and blossom together.
Kunshan Zhenchuan Bridge Project is a major traffic and water transportation project in Jiangsu Province, and is an important part of the waterway improvement project of Qingyang Port section of Shenzhang Line, starting from the level crossing of Heilongjiang Road, spanning Qingyang Port on the route, with a total length of 931 meters, of which the bridge is 507 meters long and the main bridge is 230 meters long. As an important part of Kunshan's "five districts and one line" planning, the project is difficult to construct, install, hoist and turn, and will make the Qingyang Port channel have the transportation capacity of thousand-ton container ships, effectively helping Kunshan's "urban living room" to build and improve the comprehensive transportation system.
The volume is large, challenging the most in Jiangsu Province
As a "star project" in Suzhou's bridge industry
Zhenchuan Bridge is currently in Jiangsu Province
The rotating weight of the steel tower of the same steel structure cable-stayed bridge is the largest
The bridge is a cable-stayed bridge with asymmetrical steel arch towers
The total weight of the large and small steel arch towers of the main bridge is about 3,100 tons
This puts forward extremely high requirements for the bearing capacity and construction technology of the bridge foundation.
The project team sought a breakthrough from the technical level
After many in-depth discussions and repeated demonstrations
Facing on a river channel more than 200 meters wide
The main bearing platform with a total amount of concrete to be poured exceeds 4,000 square meters
It was determined that "the substructure pile foundation cofferdam built the island."
+ cushion cap steel sheet pile support + main pier shaped steel mold construction".
The construction personnel planned and organized in advance
Continuance of Overcoming Geographical Conditions
Fill the river 90 meters on the east side of the river with clay
Use an excavator to dig the earthwork in the steel sheet pile of the cap to a depth of 10 meters
The cushion cap formwork uses ordinary large steel molds
Crawler crane is used for hoisting.
Operators enter the foundation pit in Hanoi to carry out manual bottom cleaning
In the face of its internal steel and steel structure intricate,
The situation that the concrete vibrating is inconvenient
Binding of rebar and pouring of large volumes of concrete in batches
The "prototype" of the bridge foundation was successfully completed.
The main pier in the pit is a special-shaped variable cross-section
The construction is complex and extremely difficult
The requirements for installation control and positioning accuracy are extremely high
The project strictly debugs and controls the mix ratio of concrete
Externally, self-compacting concrete is used to pour in three phases
The condenser tube is set up to cool down according to the scheme
It adopts rigid skeleton, Fengzi board and prestressed material
Lay a solid foundation for the completion of the main bridge.
It is difficult to hoist, and strive for perfection to create a new landmark in Kunshan
Zhenchuan Bridge is the history of Suzhou
The most difficult steel tower cable-stayed bridge to construct
The main body is composed of two parts: "steel box girder + steel arch tower".
If the steel box girder is the "torso" of the bridge deck
The steel arch tower is the "soul" of the bridge.
The steel box girder is divided into 27 segments
The large and small steel arch towers are divided into 13 and 11 segments respectively
Its construction and installation quality and precision control
It directly determines the construction quality of the entire bridge
More than 50 steel structure segments
It is necessary to alternate multiple steps for batch transportation and hoisting on land and water
And it requires accurate installation and accurate points
The difficulty can be imagined.
Due to the large lifting radius of the three sections on the east side
After the completion of the construction of the main pier of the bridge
The project uses a 90-metre-long land passage on the east side of the bridge
Two slides were laid for skid lifting
The 3 steel box girder segments are respectively hoisted to the sliding slideway and slid into place
At the same time, combined with the surface of the floating crane
It took 3 months to finally build a 130-meter-long steel bridge on the east side of the bridge
and the small steel arch tower and the preliminary work hoisting completed.
It is different from the water and land hoisting on the east side
The bridge on the west side is 90 meters long
It is located at the intersection of Loujiang River and Qingyang Port
The water is turbulent, and it is more difficult to float on the water throughout the whole process.
The project stabilizes the idea and divides the construction on the west side into two parts: north and south
After the completion of the steel box girder above the main pier
The lower section of the rotating tower is hoisted by floating crane
Subsequently, part of the steel box girder on the west side of the bridge was hoisted
Ensure that the south section of the large steel arch tower is assembled completely.
After that, the steel pipe support on the north side is completed
Lift the remaining segments of the steel box girder and complete the bridge deck closing
Then hoisting the north side section of the large steel arch tower
Finally, a floating crane is adopted
Interspersed with the upper section of the turret gantry is hoisted
and install a cable wind rope
Make final preparations for the rotation of the small steel arch tower.
New technology, the country's first "asymmetric phase"
The large and small arch towers of the project are 101 meters and 78 meters high, respectively
Tilt 25 degrees to the shore side, respectively
The arch tower is connected to the bridge deck by 30 cable-stayed cables
During the rotation process, the force of the arch tower will follow the progress of the project
and interleaved changes
Therefore, the vertical rotation is also in the process of the construction of the Zhenchuan Bridge
Critical processes with the greatest security risks.
The project team adapts to local conditions
For the first time in the country, the asymmetrical phased rotation method was adopted
First, the large and small steel arch towers will be rotated in stages
Finally, the cables are installed in stages
The small tower is backed by the weight of the large arch tower itself
The arch tower is backed by 4 permanent structural cables
While ensuring safety, it also saves great costs.
Before construction, the project department invites an expert group
Carry out in-depth exploration and research on the vertical rotation process
After more than 10 internal audits, the special construction plan has been continuously improved
During the construction process, the project uses "intelligent + manual" data to collect data in real time
Arrange inclinometers and strain gauges at the root of the bridge tower and in the chamber
Data such as speed and stress are monitored every 5 minutes.
Combined with BIM models
The project monitors stress and deformation of critical parts in real time
Timely warning and correction of abnormalities are found
The attitude error of the steel tower is controlled between millimeters.
The jack works in a reciprocal cycle for 280 strokes
Each stroke averages 20 cm
The maximum tensile force of the steel cable is 729 tons
From April 10th, the turn began
After more than 30 hours of continuous construction
The large steel arch tower finally turned into place smoothly!