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Millimeters achieve million meters of wisdom achievement boutique

Public number: Coastal plate construction headquarters Source: Time: 2020-02-21 01:49:51

Millennium Tongzhou vitality north stream

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(Transportation Tourism Herald Engineering Department)

Millimeters achieve ten thousand meters

They are pioneers!

The short-line method of matching section beam bridges, as the mainstream bridge structure design today, has been widely promoted around the world, and it is still in its infancy in Zhejiang. Whether Yueqing Bay Sea-crossing Bridge No. 1 and No. 2 can achieve a precision of less than 20 millimeters for the Wanlong Bridge is decisive for promoting this process in Zhejiang and even the whole country!

They are challengers!

4,200 section beams, more than 1,500 workers, and more than 6,200 sub-item structures, corresponding to more than 5,000 test data ... but also self-pressurizing, less than the stringent requirements of national standards: the precast control accuracy of section beams is ± 1mm The finished product acceptance accuracy is ± 3mm, and the assembly error is ± 15mm.

They are innovators!

They have also felt pressure because they have never done the construction of segment beams, but this elite soldier will forge ahead the formed iron army, seek benefits from management, seek development with innovation, create quality with ingenuity, and realize technological revolution through technological innovation. Create smart construction sites through BIM and other methods, create industrial workers through standardized management of teams and groups, and launch an impact on "quality engineering".

They are even more successful!

At present, the total length of the 28-segment beam of the 10,000-meter bridge has been erected for a total of 2490 榀, which surprised the industry: under the control of the gasketless assembly process, the deviation of 2464 matching joints is less than 1mm; the deviation of 140 joints and 280 joints is all Less than 15mm, 5mm smaller than the national standard requirements, reaching the domestic leading level!

The project is planned to be completed by the end of October this year, and CCCC First Office has won 56 project management, QC, construction methods, patents and other honors!

Just after the Yueqing Bay Bridge successfully achieved precision control, bridges designed with segment beams in Zhejiang also began to spring up. Yueqing Bay Bridges No. 1 and 2 became a model for the construction of segment beams in the province and the country. The achievements in management modernization and innovation have won the first and second prizes at the ministerial level and become national benchmarks.

They have resounding names-China Communications First Office!

Dream · Ambition

1

Millimeter-level precision control national pilot

Entering the construction site of the Yueqing Bay Cross-sea Bridge-Bridge 1 and Bridge 2, the majesty of the bridge has begun to appear. The classic pictures of CCTV's famous documentary "Super Project" flashed in my head. If time goes back quickly, the segment beam assembly construction here will also be a very shocking picture!

Section 1 and 2 bridges are constructed with segmental beams for 10 kilometers, which is the core and most characteristic of the Yueqing Bay Bridge. In short, this construction process is to implement the factory prefabrication of the box girder backyard and the front yard assembly. Because of the high degree of standardization, controllable quality, much less construction time than on-site beam and slab pouring, and environmental protection, it has been widely promoted in global bridge design.

Yueqing Bay is one of the strong tide bays in China, with a maximum tidal range of more than 8 meters. On average, there are 3 typhoons "patronizing" each year, and it can reach 6-7 in many years. It is also one of the areas most frequently affected by typhoons in Zhejiang. A rough estimate is that under the premise of ensuring the safety of construction, the effective construction days here are less than 250 days a year.

The No. 1 Bridge is affected by the local newly built Xuanmen Bay dyke. The length of the tidal flat reaches 2940 meters. Almost all the materials and equipment used in the construction of the maritime bridge are handled by ships. The effective operation time of the construction is further reduced, and the safety risks are also significantly increased. These have also become important reasons for the use of segmented beams for the main bridge.

However, segment prefabrication and erection need to achieve millimeter-level accuracy, and accuracy control is a national problem. The main bridge of Yueqing Bay has a span of 60 meters, and each span is assembled by 20 beams. According to the procedure, first assemble 30 meters on each side, and then dock. This means that two "big guys" with a width of 16 meters and a height of ten floors need to complete the docking, and the combined error of these two large concrete components must be less than 20mm according to specifications.

In addition, if there is a 1mm deviation in the initial 0 # beam segment during assembly, even if there is zero error in the subsequent segment assembly, the maximum cantilever of the assembled T structure will be enlarged to a deviation of 27.55mm. If the segment accuracy is not high, it will lead to the accumulation and amplification of assembly errors, and the deviation will increase geometrically after closing.

There are 19 types of section beams for single approach bridges, and each beam is unique. In case a certain beam is not 100% accurate, the entire hole must be pushed down and reworked. The construction period is delayed for at least half a year. 4200 榀 section beams, more than 6,200 sub-item structures ... These make the accuracy control even more difficult.

Before 2010, of the tens of thousands of bridges across the country, only more than ten were constructed with segmented beams, and the accuracy of the domestic cantilever segment beams was not very satisfactory, and Zhejiang was still in its infancy. The heavy tasks of the No. 1 and No. 2 bridges of the Yueqing Bay Sea-crossing Bridge are: whether the precision control of the segment beam construction can be successfully achieved was of decisive significance for the promotion of this process throughout the province and even the whole country!

China Communications Construction Group No. 1 Highway Engineering Bureau Co., Ltd. (hereinafter referred to as "CCCC No. 1 Public Administration Bureau") is facing such a challenge and feels pressure. Management innovation .

Dream building

2

Technological innovation realizes technological revolution

Technical research and technological innovation are the cornerstones for achieving overall controllability of Helong.

The influence of the accuracy of the dragon is firstly reflected on the top of the pier. According to the existing measurement process, CCCC First Office calculated that once a deviation of 1 mm occurs on the top of the pier, the error will accumulate in proportion to the maximum cantilever of the T structure. The deviation of 27.55mm, the specification requires that the accuracy of Helong be controlled within 20mm. In the harsh measurement environment at sea, considering the error of the instrument itself, the control of 1mm is almost impossible.

In response to this, CCCC No. 1 Public Office adopted the “Space Cartesian coordinate system-based segmented beam cantilever assembly pier top block installation and construction method” to develop a “axis system interchangeable measurement method” and introduced a “space Cartesian coordinate system” ", The rotation of the pier top block is controlled through data conversion, and the error magnification is reduced to 1mm: 6.8mm, which truly achieves the positioning accuracy of the pier top block of ± 2mm.

In terms of segment assembly, CCCC No. 1 Bureau has also innovatively adopted the "prefabricated segment beam advanced span-by-T assembly construction method". By optimizing the application process of the segmented epoxy glue and adopting a temporary prestress-oriented adjustment process, it has achieved "Sectional beam fine-tuning process without epoxy patch".

At the same time, they carried out a full set of optimization of the girder equipment to realize the function of the bridge crane pier top load and the overall adjustment function, and adopted the "advanced span T-frame assembly" and "side-span overall adjustment" processes, under the premise of ensuring the assembly quality , Which saves the construction period to the greatest extent.

The prefabricated pedestal is the key to achieve high-precision control of the finished beam section. The single-segment segment is 16.05m in length, 3m in width, 3.6m in height, and an average weight of 100t. If such a large segment is cast in one shot to achieve millimeter prefabrication, the entire pedestal must reach the level of a finishing machine. The difficulty lies in the fact that the entire prefabrication plant is located in the tidal flat area and has a soft silt foundation of nearly 30m. How to ensure that the entire platform is not displaced during the prefabrication process is the key to control. The foundation of the project department alone is over 10 million yuan. 22m deep CFG piles are installed in the entire platform area according to the 1.6m plum pile spacing to form a composite foundation. Overloading and preloading are carried out before the formwork is assembled. Currently, prefabrication has been achieved. Zero settlement during the period.

Secondly, the template is used as a finishing machine. It is designed with the most advanced concept to ensure sufficient rigidity. At the same time, the internal and external molds are fully hydraulically controlled, and the template adjustment accuracy reaches 0.5mm. In order to ensure the organic unification of the internal quality and external taste of the segment beams, CCCC also carried out a series of small technical reforms and innovations. For example, the design of some gaskets, plugs, and connecting pipes used in the prestressing system ensures the straightness of the pipeline connection between the sections and the overall linearity of the prestressing system is controllable.

As one of the cores of segment beam accuracy control, the measurement tower is also strict. In order to ensure stability, 37m deep pipe piles were set and wrapped with geotextiles. At the same time, a color steel plate shed was built outside to reduce the impact of temperature on accuracy. Moreover, the settlement observation of the measuring tower was carried out weekly, and a deviation of 1 mm was found, and the control network was retested.

In addition, in order to ensure the safe use of bridge girder cranes, CCCC First Office has also developed a “four-dimensional matrix 4DM safety supervision system for bridge cranes”, which solves the “inadequate” and “professional” of ordinary bridge crane monitoring systems. Problems such as “not strong” and “fundamental lack” improve the safety of bridge cranes in all aspects.


Cinema seats

The No. 1 and No. 2 Bridge Project Department of CCCC No. 1 Bureau has obtained 49 technological innovation achievements, including 16 QC achievements, 7 construction methods, 12 patents, and 2 scientific and technological innovation achievements of China Highway Association.

Dream building and innovation

3

BIM management leads smart construction sites

In the nearly two years since the construction of the Yueqing Bay Bridge, the construction of the main bridges of No. 1 and No. 2 bridges has not caused any rework due to data or quality problems. No one beam has been prefabricated incorrectly. It is rare in similar projects across the country.

Accuracy is higher than the specification, and "zero error" can be achieved. The main reason behind this is BIM (Building Information Mod⁃eling), a management achievement ranked by the Ministry of Transport as the top ten innovative technologies.

Without much experience to draw on, CCCC Public Office integrates various relevant information of the project through parameter models according to the needs, and gives the model functions according to local conditions, and realizes visual management with big data, bringing intelligence, Precise selection, to achieve precise control, improve work efficiency, save costs and shorten the construction period.

In addition, CCCC No. 1 Public Administration Bureau integrated BIM into every construction content of the main bridge to achieve full life cycle management. The systematism and meticulousness of applying BIM technology are at the forefront of the country.

The major function of accurate correction of BIM big data is to preview the situation of structure and structure collision. According to statistics, with the help of BIM visual inspection, there were 81 "collision corrections" in the main structure and temporary structure of the Yueqing Bay Bridge. In addition, in each process, the BIM technology platform uses the deduction of three-dimensional solutions to visualize and make precise decisions to technicians.

The reporter at the prefabrication factory saw that the system platform was equivalent to the electronic brain of the entire prefabrication factory, which controlled the construction equipment, materials, products and operating personnel information on site in real time. Here it is as fine as each bundle of steel bars, each package of materials, as large as each device, each beam, and has its own QR code, which means that the information from the material to each product has its own "electronic ID card". Formed millions of databases.

Site managers and workers can quickly find the location information of the target segment beam on the screen. For example, if the beam is to be displayed 4 days on the day, the corresponding position model on the screen will be displayed in red, and the beam information label will be automatically generated at the same time. Similarly, the basic information of the tire frame and pedestal of each production line in the construction, the current process, etc. are all directly reflected on the system, and the team leader can efficiently organize the workers to carry out the work.

Sixty to seventy percent of the project's funds are used for materials, whether the materials are qualified, the use is standardized, and traceability can be traced everywhere. There are more than 40 sets of large-scale equipment with more than 100 tons at the peak time of bridges 1 and 2. It is not only important, but also a major source of danger. The use situation and when to maintain can be viewed and retrieved through the platform or mobile app, or reminded by the system. Where does the beam plate exist and how long it has been stored? Whoever operates and so on can be checked at any time, as far as possible to ensure that there is no problem with each beam, or that problems can be corrected in time.

With the support of BIM technology, precise control of construction costs can also be achieved well. Before the start of the project, the project department calculated that the bridge construction needed to invest 3.33 bridge cranes, that is, 4 equipment. With the help of BIM calculations, the project department only needs to increase the assembly efficiency by less than 10%, which can reduce one bridge crane and save nearly 20 million yuan in equipment investment. Another example is how much paint is used on the surface of steel anchors. Now, the surface area and thickness of the steel anchor box are accurately calculated through three-dimensional solids. Naturally, how many barrels of paint are actually used can also be calculated.

In September last year, the China Highway Society's "BIM Promotion and Application Technology Exchange Conference in the Transportation Field" was held in Hangzhou, representing the most advanced and high-end level of BIM technology in China. What's even more gratifying is that at the end of last year, the results of BIM-based multi-dimensional information collaborative management won the 15th ministerial first-class national transportation enterprise management modernization innovation achievements.

Dream Building · Transformation

4

Standardization of teams to create industrial workers

Bridge No. 1 and No. 2 run through "two or three places". At the peak, a total of 1,524 workers were working on the site, and the scene was spectacular. Such a 10,000-meter bridge has a large number of construction sites, a wide area, and a large number of people, and it has become very difficult to manage. To achieve the most accurate control in the country, the management must be more sophisticated.

CCCC No. 1 Public Administration Bureau has actively implemented the new concept of personnel management proposed by the Yueqing Bay Project Construction Headquarters: promoting the standardization of 6S team operations, and transforming migrant workers into industrial workers.

According to the relevant person in charge of the project department, according to the traditional model, the management team is not detailed enough, and it is not realistic to directly manage front-line migrant workers. Teams are the smallest units to complete sub-items. Even if teams are changed, the impact on the project is relatively small.

To meet the standards of industrial workers, excellent technology is the key. While promoting the standardized construction of teamwork, the first bureau of CCCC also actively implemented the "first team system" regulations. For example, the team doing the pillar must make a qualified pillar before they can continue to do it; if it fails, the training will be dismissed if the training is done more than 3 times.

Since the start of construction, there have been 64 teams and bridges in Bridge 1 and Bridge 2, and 15 teams and teams have been eliminated. The headquarters has also used 5% of safety funds to promote team standardization. Deterrence and rewards are two-pronged, and the teams working here are increasingly meeting "high requirements."

In addition to technology, the project department also requires rapid improvement of the quality of migrant workers. The way the project department wants to benefit from management is to strictly implement the "6S" process management of the team. For example, the rebar processing plant covers an area of 4,100 square meters and is divided into five areas: raw material storage area, rebar processing area, semi-finished product area, waste area, and safe passage. Factoryization and assembly line production are implemented. Workers are strictly required to organize and rectify the construction site according to the process, reasonably set up related facilities, equipment, and material areas, and use spraying marking lines or making signboards to effectively mark the site in an orderly and tidy manner.

There are also special people to urge the team to implement the "6-step walking" daily cycle operation process, that is, pre-shift reminders, pre-shift inspections, intra-shift inspections, post-shift cleanups, post-shift transfers, and post-shift summaries to maximize the requirements of industrial workers.

Such strict requirements make the qualified rate of the component size reach 100%, and the accuracy of the reinforcement processing can reach an angle of 0.5 ° and a length deviation of 1mm, which has become an important guarantee for the accuracy control of the broken beam.

The “Standardized Management of Team Operations” implemented by the project department also won the 2015 Second Prize of National Transportation Enterprise Management Modernization Innovation Achievements.

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