BAIJIAN - Third party testing organization
Grid structure has become a very common structural form in modern architecture due to its high stiffness、 light weight、 and good seismic resistance. It is widely used in projects such as roofs、 large public buildings、 and offshore platforms. In recent years、 with the successful completion of a batch of large spatial metal grid structures、 such as the National Stadium and the T3 Terminal of Capital Airport、 grid structures have also received increasing attention from people Therefore、 the safety performance of steel structure grids should be regularly tested and evaluated for safety
The main body of most grid structures is a reinforced concrete frame structure、 and the roof is a curved steel grid structure. It adopts a variable thickness hyperbolic triangular cone grid shell structure、 and the majority is an evacuated triangular cone I-shaped grid shell. The grid shell structure is supported by the bottom chord、 and the cantilever structure of the roof is supported by conical and shuttle shaped steel pipe columns. In order to investigate whether the current steel roof structure is damaged and has safety hazards that affect its normal use、 and to ensure the normal and safe operation of Capital International Airport、 it is necessary to conduct on-site inspection and testing of its damage situation、 evaluate its actual bearing capacity、 and propose corresponding treatment suggestions based on the evaluation results、 providing reliable and accurate technical basis for subsequent safe use
The main contents of grid safety inspection include appearance inspection and inspection、 material and corrosion condition inspection、 structural displacement detection、 stress detection、 etc
2.1 Appearance Inspection and Patrol
The main purpose of appearance inspection is to check the main structure of each grid frame for obvious signs of abnormalities、 whether the connections of each node are intact、 whether the auxiliary facilities are complete and effective、 and to determine whether the main structure support is normal、 and whether there are obvious modifications or structural adjustments.
. Patrol inspection is the main daily work in the engineering management process、 and records need to be kept Visual inspection is the main method of appearance inspection、 combined with the use of simple inspection tools such as a level gauge. Before conducting appearance inspection、 it is necessary to have a detailed understanding of the daily maintenance and upkeep of the building、 understand the existing problems、 their causes、 and solutions、 and identify and judge potential risks in the future 2.2 Material and Corrosion DetectionDue to the complex structure and large system、 there are inevitably situations where the raw data collection is unclear or incorrect. Therefore、 material testing should be carried out on the components in question. Destructive sampling is generally not allowed for testing. During the testing process、 a comprehensive analysis method is used. Chip samples are drilled from non stressed parts of the component to analyze their composition、 and the material and its grade are determined through comprehensive analysis based on their hardness、 tensile strength、 and other values More importantly、 corrosion testing is carried out on metal components. Due to the corrosion of metal structural components、 the emergency cross-sectional area decreases、 leading to an increase in cross-sectional stress、 thereby reducing the stiffness and strength of the entire metal grid structure、 and ultimately affecting structural safety. The main methods for corrosion detection include ultrasonic thickness gauge direct detection method、 special vernier caliper combined with corrosion curve judgment method、 and other different methods、 which should be selected based on the actual situation
2.3 Structural Displacement Detection
Due to the complexity of the building structure、 it is difficult to avoid minor local or overall deformation. However、 if the displacement continues to occur or exceeds the safety value、 reinforcement and other work need to be carried out、 otherwise it will endanger the safety of the entire building structure.
. The general methods for displacement monitoring include embedding detection probes、 which are common engineering detection parts. The current application of new intelligent sensors also provides more options for structural displacement detection methodsFunction of testing report:
1. Project bidding: Issue authoritative third-party CMA/CNAS qualification report
2. Online e-commerce platform entry: Quality inspection report recognized by major e-commerce platforms 3. Used as a sales report: issuing legally effective testing reports to make consumers more confident 4. Papers and research: Provide professional personalized testing needs 5. Judicial services: providing scientific、 fair、 and accurate testing data 6. Industrial problem diagnosis: Verify the troubleshooting and correction of industrial production problemsinspection and testing process:
1. Telephone communication and confirmation of requirements
2. Recommend solutions and confirm quotations 3. Mail samples and arrange testing 4. Progress tracking and result feedback 5. Provide reports and after-sales service 6. If urgent or priority processing is requiredTesting and testing characteristics:
1. The testing industry is fully covered、 meeting different testing needs
2. Fully cover the laboratory and allocate localized testing nearby3. Engineers provide one-on-one services to make testing more accurate
4. Free initial testing、 with no testing fees charged
5. Self service order delivery for free on-site sampling
6. Short cycle、 low cost、 and attentive service 7. Possess authoritative qualifications such as CMA、 CNAS、 CAL、 etc 8. The testing report is authoritative and effective、 and is generally used in China