Editor's note
July 15th is the first day of the ambush, and there are a total of 40 dog days this year, and we will usher in a sunny, hot, and sunny high temperature "baking" test. At the construction sites of major projects in our city, under the premise of taking precautions against high temperature weather, the construction time is reasonably organized, and the builders are fighting on the front line of construction to promote the project progress in a steady and orderly manner. From now on, this newspaper has launched a special report, and the reporter walked into the site of the major project to record the construction situation under the "baking" test.
On the morning of the 15th, the reporter saw at the construction site of the new Jingpingshan Bridge (hereinafter referred to as the "new bridge") that the main project of the main bridge of the new bridge was completed with the last cubic concrete poured into the Helong section through the sky pump. While successfully completing this construction node, the workers carried out the follow-up construction of the bridge deck in an orderly manner in the scorching sun, so as to "accelerate" the completion and opening to traffic by the end of the year.
Project Profile
The demolition and reconstruction project of Guilin Jingpingshan Bridge is a major transportation project coordinated and promoted at the autonomous region level, and a groundbreaking ceremony was held on January 5, 2022. The main bridge is a three-span variable section continuous beam bridge, with a length of 320 meters, a span diameter of 310 meters, a bridge section width of 50 meters, and a two-way six-lane road, and non-motorized lanes and sidewalks to realize the separation of machine and non-machine. The new bridge is in harmony with the surrounding environment in terms of bridge type selection, bridge details and decoration, and the design respects nature and integrates with the landscape environment to achieve overall unity.
At present, the main bridge of the new bridge has been successfully closed, and the follow-up work of the bridge deck, ramps, street lights, and greening construction will be promoted to ensure that it will be completed and opened to traffic before the end of the year.
Xinqiao Helong construction site.
Visit: They sweat like rain under the scorching sun and work in full swing
A few days before the main body of the new bridge was closed, the reporter came to the construction site to visit.
It was about 4 o'clock in the afternoon, although it was past noon, but the construction area was open and unobstructed, and the reporter began to sweat on his face when he walked from the entrance to the construction area of the Helong section on the north side of the new bridge.
At this time, the construction workers working in the Helong section are tying up steel bars in preparation for the final concrete pouring of Helong. Rebar binding looks simple but is a meticulous job, and it is almost entirely freehand, and the tools are just small rebar hooks in the hands of workers. I saw the workers squatting down in the Helong section, bowing their heads to fix the steel bars, getting up and moving a position to continue the same operation, a few "squatting" and "getting up" down, their faces were already sweating like rain, raising their arms to wipe the sweat a little, and continuing to work.
At the same time, a worker holds a welding torch and welds the rebar joints one by one. Electric welding operation is a special type of work, and the safety protection requirements are high. In order to avoid being injured by flying welding slag sparks during the welding process, the workers are "fully armed", and there are many helmets, gloves, and protective masks. Under the scorching sun, the outside temperature was high, but he focused on the welding work. Each solder joint only lasted a few seconds, but the high temperature and sparks made him face a double "baking" test. When he took a break for a while, he took off the protective mask, the beads of sweat on his cheeks kept falling, the clothes on his body were already soaked, and the rubber gloves stuck to his wet hands, and it took a lot of effort to take them off.
On the morning of the 15th, the reporter came to Xinqiao again. Due to the strict temperature requirements for the micro-expansion concrete used in Helong, the construction site was busy at 6 o'clock in the morning. The concrete truck drove into the bridge deck on the south side of the new bridge, and poured one cubic cubic of micro-expanded concrete into the 10.5-meter-long, 2-meter-wide Helong section through a long "arm" sky pump. After three hours of hard work, 26 cubic meters of concrete have been poured. With the last cubic concrete poured into the mold, the main bridge of the new bridge was completed.
At the same time as the closure was working, the scorching sun rose high. After staying at the scene for more than ten minutes, the reporter was already sweating. On the south side of the bridge deck, a number of workers carried out the binding of the bridge deck steel bars in the sun, and the whole field was tense and orderly, full of enthusiasm. The reporter saw that under a helmet were dark faces, beads of sweat on their faces, and beads of sweat on their arms.
The relevant management personnel at the scene told reporters that in the dog days, they also took sufficient heatstroke prevention measures and prepared heatstroke prevention and cooling supplies and medicines. The working hours of the workers have been adjusted accordingly to avoid the hot periods to ensure safe production and everyone's health.
Workers push the sky pump to pour concrete on the Helong section.
Progress: The main body of the main bridge of the new bridge was completed
Jingpingshan Bridge is located in the southeast of the city, across the Li River, connecting Huancheng South Road in the east and Huancheng South 2nd Road in the west, which is one of the important passages connecting Xiangshan District and Qixing District.
Laojing Bottleshan Bridge is a 5-span prestressed concrete continuous beam bridge with a total length of 277.6 meters, which was completed and put into use in 1983. In 2017, the old bridge was found to have a major safety hazard during regular inspections. In 2020, the Guilin Municipal Government approved the demolition and reconstruction of the original site of the Jingpingshan Bridge, and the project owner is Guilin Nanfang Road and Bridge Construction Co., Ltd., the main construction content of the project includes bridge demolition engineering, new bridge construction engineering, road engineering, temporary bridge engineering, etc., as well as supporting construction of water supply and drainage, lighting, greening, transportation, electricity, communication pipe group and other ancillary projects, with a planned construction period of three years.
The groundbreaking ceremony of the project was held on January 5, 2022. On June 15, 2022, the old bridge was officially closed for two-way construction, and the temporary steel temporary bridge was officially put into use.
On the afternoon of July 19, 2022, with a loud "bang", the old bridge, which had accompanied the people of Guilin for nearly 40 years, completed its mission and collapsed.
On April 15, 2023, the water piers of the main bridge were all completed before the flood season; On August 10, 2023, the construction of 80 piles for the main bridge was completed.
On January 31, 2024, the cast-in-situ box girder of the right auxiliary road bridge of the new bridge was poured in closing.
On July 15, 2024, the main bridge of the new bridge was closed, which also marked the completion of the construction of the main body of the new bridge.
"The new bridge has been closed, and I can still recall the scene of the blasting and demolition of the old bridge two years ago. In a few months, the new bridge will be open to traffic. An on-site construction worker said with emotion.
Highlights: The deepest pile is driven 66 meters, which is equivalent to 23 stories high
The construction process of the new bridge is a process of continuous optimization of the construction plan according to the actual situation for the builders. And in the process, they also encountered some problems.
"The geology of the construction area is complex, and the loose pebble layers and karst caves have brought great difficulties to our pile foundation construction." Tang Yujian, chief engineer of the Jingpingshan Bridge Demolition and Reconstruction Project of China Construction Eighth Bureau Second Construction Co., Ltd., told reporters that because the loose pebble layer is prone to collapse in the process of piling, they drove the first pile for 4 months. "Normally, the construction time of a pile is one month to one and a half months. Based on the actual situation here, we can only ensure the smooth development of the pile foundation construction in the loose pebble layer area by pouring concrete around the pile foundation and the variable section casing. ”
Karst caves are also a common problem encountered in the construction of bridges in Guilin. There are many underground karst caves in Guilin, even after preliminary exploration, it is difficult to make the underground karst caves in the construction area "clear at a glance". As a result, new karst caves are also encountered during piling.
A relevant person in charge of the construction site headquarters of the Jingpingshan Bridge Demolition and Reconstruction Project in Guilin City participated in the construction of the Longmen Bridge. He told reporters that among the more than 200 pile foundations of the Longmen Bridge, about half of them encountered karst caves during construction, and many of them were vertically "strung together" like sugar gourds, and the deepest pile foundation was driven to more than 50 meters below the riverbed. ”
During the construction of the Yangshuo Fuli River Bridge, a group of bead-shaped karst caves was also encountered, and the deepest pile was driven to 35 meters below the riverbed.
"During the construction of the new bridge, a pile was driven 66 meters below the riverbed, which is the deepest bridge construction in Guilin in recent years." Tang Yujian said.
What is the concept of 66 meters? According to the relevant regulations, the floor height of a house cannot be less than 2.8 meters, and 66 meters is equivalent to a 23-story building.
Although there are many difficulties in the construction, with the continuous optimization of the construction plan according to the actual situation again and again, from the early full casing follow-up construction to the variable cross-section casing follow-up construction, and then to the combined construction technology of grouting reinforcement geological auxiliary construction and full casing follow-up around the pile hole, the efficiency of pile foundation hole formation is greatly accelerated, so as to ensure the smooth completion of the construction of the cushion cap and pier stud in the water on schedule.
In the construction of the main bridge body of the new bridge, the continuous box girder adopts the hanging basket method to construct 13 standard sections and the closing dragon section, and the approach bridge part adopts the support method.
Tang Yujian told reporters that the cantilever construction of the hanging basket method is generally used in the construction of bridges across high-speed railways and highways, and is rarely used in the construction of bridges across the Li River in Guilin. "According to the span and construction environment of the new bridge, although the cantilever construction period of the hanging basket method is long, it is the construction scheme of the optimal solution."
Now, with the closure of the new bridge, the next step will be to promote the follow-up work such as bridge deck, ramps, street lights, and greening construction to ensure that it will be completed and opened to traffic by the end of the year.
According to the relevant person in charge of the on-site command center, the new bridge is the same width as the road on the east and west sides, which can effectively alleviate congestion. At the same time, the lights of the new bridge will be carefully designed to create a night view that matches the surrounding scenery. "At the end of this year, Xinqiao will start to 'work', taking on the important task of connecting Xiangshan District and Qixing District, and becoming an important channel for Guilin citizens to travel."
Source: Guilin Evening News