Accident treatment of the pre-buried construction of anchor bolts of a steel structure column of a certain project Chen Jianyuan (Fujian Geological Engineering Company, Fuzhou 350002, Fujian) management method.
Compared with other material structures, steel structure has the advantages of high strength, good plastic toughness, high construction accuracy, short construction period, and relatively low cost. It is especially suitable for large-span factory buildings, warehouses, public buildings and high-rise buildings. Ordinary steel structure buildings are generally composed of structural columns, frame beams and horizontal and vertical support systems. At the site, the above components are assembled into the spatial structure system of the building, and then the spatial structure system transmits the load received by the upper part to the foundation and foundation, and finally realizes the use function of the building.
The work of closely linking the upper steel structure system to the foundation is done by anchor bolts pre-buried in the foundation. The anchor bolts fix the superstructure on the foundation and transfer the load received by the superstructure to the foundation to ensure the spatial integrity and stability of the superstructure. The pre-buried construction of anchor bolts is the first process of on-site installation and construction of steel structures. The quality of the anchor bolt construction will directly affect the quality of the steel structure installation project. Therefore, the quality control of the embedded construction of steel structure anchor bolts is the first issue that should be paid attention to in the construction of steel structure engineering.
1 Project Overview The project of Fujian Zhengsheng Commodity Co., Ltd. is located in Gaishan Investment Zone, Cangshan District, Fuzhou City. Among them, 1-7 workshops (warehouses) are composed of 7 single-story steel structures with the same structural quality, with a total construction area of ​​6048m2 , The foundation uses deep cement mixing piles.
2 Quality accident and analysis of pre-embedded anchor bolts 1 After the construction of the concrete accident foundation and foundation beam of the quality accidents is completed, through the inspection and review of the pre-embedded anchor bolts, it is found that the position of individual anchor bolts is skewed and the exposed length is insufficient , Affecting the installation and construction of structural columns.
22 Reason Analysis The occurrence of the quality accident of the embedded anchor bolts, in addition to the quality of the embedded bolts, is also related to the construction quality of the embedded bolts related to the construction process (the embedded anchor bolts in the foundation concrete are related The construction process is generally as follows: the foundation steel bar is bound, the foundation template is installed, the foundation anchor bolt is embedded, and the foundation concrete is poured and cured and the mold is removed.
22.1 Factors of the construction quality of the anchor bolts embedded in the ground bolts are not accurately positioned and laid out during the installation of the anchor bolts. When the installation is in place, there is an error in the spatial position and geometric dimensions, and the installation is not securely fixed.
22.2 Quality factors related to the process of anchor bolt embedding construction 22.21 The quality of foundation template installation and construction is the most important factor that affects the quality of anchor bolt embedding construction, and also the main reason for the construction accident of anchor bolt embedding quality of this project. A major process in concrete construction. Through the spatial positioning of the formwork, the plastic concrete is shaped into a certain shape and size according to the design requirements of the accident treatment of the pre-buried construction of the steel structure column anchor bolts of a certain project of Chen Jianyuan. It is also an operating platform and safety guarantee for concrete construction. The pre-embedded anchor bolts can be pre-embedded and checked according to the geometric dimensions and spatial location of the template installation. The formwork is a model for cast-in-place concrete molding. In order to ensure the accurate shape and size of the structure and components, the formwork system must have sufficient strength, rigidity and stability. Therefore, the anchor bolts must be reliably fixed on the template to ensure the accurate and firm installation of the anchor bolts. Therefore, the quality control of the pre-embedded construction of anchor bolts depends on the quality control of the installation and construction of the embedded concrete member formwork.
The construction site of this project was originally a pond channel, which was formed by backfilling. Because the original backfill contains a lot of domestic waste, such as waste plastics and old tires, the composition is complex and the nature is extremely unstable. When installing the foundation and foundation beam formwork, the side form supports are fixed on the foundation slope and the foundation pit edge wood. The slope of the foundation pit contains a lot of backfill garbage, which seriously affects the stability of the soil and weakens the strength of the soil, causing the lateral support of some templates to fail, causing the template to deform and move under the load of poured concrete, which directly leads to the pre-buried anchor bolts. Deformation of the position. The failure of formwork workers to improve the construction process according to the construction site is the main reason for the embedded quality accident of this project.
2.2.2.2 Foundation concrete pouring and ramming construction will also affect the anchor bolt pre-embedded quality. Concrete pouring and ramming are generally carried out by inserting vibrating rods and flat plate vibrators. If the construction staff does not pay attention to the protection of the pre-embedded anchor bolts during the pouring and construction process, rough construction will cause the deformation and displacement of the pre-embedded anchor bolts, which will affect the embedment quality of the anchor bolts. Failure to strictly control the pouring of concrete, resulting in overfilling of the foundation concrete, is also the main reason for the insufficient length of the anchor bolts exposed in this project and affecting the installation of the structure. More importantly, if the pouring of concrete is not strictly controlled, serious quality accidents such as vibration leakage and honeycomb holes will occur, resulting in unacceptable acceptance of concrete members, and the embedded anchor bolts cannot be put into use, which will also lead to the embedded anchor bolts Failure of construction. Therefore, the construction quality of foundation concrete will also affect the construction quality of embedded anchor bolts. Therefore, in the process of foundation concrete pouring, the anchor bolt pre-embedded team should send someone to follow the whole process, cooperate with the concrete pouring and stamping construction personnel, and find and deal with the sudden factors affecting the quality of the embedded anchor bolt in time, which is also very necessary and Effective pre-control measures.
2.3 Treatment of quality accidents The deflection of the anchor bolts in this project is not very serious, and the maximum deviation is within 1mrn. When the skewed anchor bolts can still meet the requirements, the straightening treatment is adopted. For displacement affecting the installation of the structural column bottom plate, after the bottom plate is reamed, pads with the same thickness of 50X50mm as the bottom plate are added to the column bottom plate, and welded to the bottom plate, and then the anchor nut is installed. If the exposed part of the anchor bolt is insufficient, it shall be treated separately according to the review of the exposed elevation of the anchor bolt. If the exposed part is insufficient due to overfilling of the foundation concrete, it is sufficient to remove the overfilling part of the concrete. If the exposed part is insufficient due to the sinking of the anchor bolt, the inner bolt can be processed to connect the anchor bolt ().
Anchor bolt offset processing indicates that the main reason for the pre-embedded quality of this project is to strengthen and improve the support system of the foundation formwork, properly encrypt the support system of the poor soil section, ensure the support strength and rigidity, and improve the overall stability of the formwork system. Strengthen the confession before the class for the personnel who participate in the concrete pouring, enhance the awareness of the protection of the finished anchor bolts, and improve the construction quality.
Through the above measures, the sheep were repaired, and the management of the follow-up construction was strengthened, so that the subsequent pre-buried construction of the anchor bolts of the 2 factory buildings was progressing smoothly, basically eliminating the hidden danger of quality accidents, and ensuring the smooth progress of the project construction.
3 Summary The pre-embedded construction of anchor bolts is a major process of steel structure engineering, and its quality control should be the whole process and all-round control.
31 Quality control of raw materials The selection of qualified raw materials is the basis of the quality of any project construction. The steel used for manufacturing and processing anchor bolts in the project shall provide a factory certificate and meet the design requirements and the "Code for Construction and Acceptance of Steel Structure Engineering" (GB50205-2001), and strengthen the acceptance of raw materials. When there is any doubt about the quality of steel products, samples shall be taken in accordance with the provisions of the relevant national standards to conduct mechanical strength performance tests, and chemical composition tests shall also be conducted on imported steel products.
She 3 2 Likou's quality control of finished products 77 pages) Ye Xiangming talked about the overall plan for the development and construction of intelligent communities in residential areas. It can be seen that the installation of the security precaution system in the residential area has become a very important part of the intelligent residential area.
Security systems include home security systems, community security systems and fire alarm systems. The home anti-theft intrusion alarm system in the security prevention system of residential quarters is a kind of system unique to intelligent residential quarters, which is quite representative.
Existing anti-theft and intrusion alarm systems are roughly divided into two categories. One is an anti-theft and intrusion alarm system that is independent of other residential community networks. When it encounters an alarm, it directly connects to the alarm management center or rescuer's phone, pager, and mobile phone through the local telephone network. Alarm, this form is suitable for already built houses, easy to install; the other is the anti-theft and intrusion alarm system that alarms the duty room of the community security management center through the community network bus when it encounters an alarm, which is convenient for unified management.
The anti-theft intrusion alarm system consists of an indoor alarm controller and user equipment terminals. The indoor alarm controller is used to receive various signals from the user equipment terminal, and after certain analysis and judgment, it is sent to the alarm center, so that the alarm center can monitor the series of states of arming, disarming, alarming, testing, and faults of each user in real time. And control it, it also has the function of allowing users to perform remote operations through the Internet. The user equipment terminals of the anti-theft intrusion alarm system include door sensor, window sensor, glass break detector, infrared / microwave anti-theft detector, emergency call button, sound and light alarm, temperature and smoke detector, combustible gas detector, operation Display disk, etc. They can be divided into two forms: wired connection and wireless connection with the indoor alarm controller.
The current indoor alarm controller is only limited to the realization of home security protection alarms. Although there are indoor alarm controllers integrated with the stair intercom system or the remote meter reading system, only a part of the functions of home intelligence are realized . The ultimate development direction of indoor alarm controllers should be home intelligent controllers. The home intelligent controller is the core of home intelligence, and is the link between the user's home and the outside world for video, audio, and data communication. The future home intelligent controller should have functions such as security protection, remote meter reading, and video intercom, as well as TV and telephone transmission, network interconnection, and intelligent control of household appliances. Especially after the realization of "first-line entry into the household", it will become the veritable "brain" of the home intelligent system, and its status cannot be ignored. It is believed that with the development of science and technology, an appropriate, more scientific, more convenient and more humanized living community in China's intelligent residential communities.
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