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GB/T 51422-2021: (Technical Standards for Testing, Appraisal and Reinforcement of Building Metal Sheet Enclosure System)
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| GB/T 51422-2021 | English | 2059 |
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(Technical Standards for Testing, Appraisal and Reinforcement of Building Metal Sheet Enclosure System)
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GB/T 51422-2021
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PDF similar to GB/T 51422-2021
Standard similar to GB/T 51422-2021 GB 50205 GB 50017 GB 50755 GB/T 51434 Basic data | Standard ID | GB/T 51422-2021 (GB/T51422-2021) | | Description (Translated English) | (Technical Standards for Testing, Appraisal and Reinforcement of Building Metal Sheet Enclosure System) | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | P26 | | Word Count Estimation | 103,114 | | Issuing agency(ies) | Ministry of Housing and Urban-Rural Development of the People's Republic of China; State Administration for Market Regulation | GB/T 51422-2021: (Technical Standards for Testing, Appraisal and Reinforcement of Building Metal Sheet Enclosure System)
---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
1 General
1.0.1 This standard is formulated in order to achieve technical reliability, safety and applicability, economical rationality, and quality assurance during the inspection, appraisal, reinforcement and transformation of building metal plate enclosure systems.
1.0.2 This standard applies to the detection, identification, reinforcement and renovation of new or existing building metal plate enclosure systems.
1.0.3 The detection, identification, reinforcement and transformation of building metal plate enclosure systems shall not only comply with this standard, but also comply with the current relevant national standards.
2 Terms and symbols
2.1 Terminology
2.1.1 metal building envelope system
The prefabricated enclosure with the corresponding functions of the building is formed by using the pressed metal plate or the metal surface sandwich panel as the main plate of the roof, wall and other systems, connected by supporting components, combined with waterproof, thermal insulation, heat insulation, steam insulation and other structures. protection system.
2.1.2 profiled metal sheet
Sheet metal is rolled, cold-bent, or bent to form a shaped sheet metal with a continuous wave or other shaped cross-section.
2.1.3 Appraisal of reliability
A series of activities such as investigation, detection, analysis, checking and evaluation of the safety and usability of building metal plate enclosure systems.
2.1.4 target working life
Identify the expected useful life of building sheet metal envelope systems.
2.1.5 assessment assessment
According to the results of inspection, testing and analysis, the safety and usability of the building metal plate enclosure system are evaluated in accordance with the specified standards and methods.
2.1.6 Assessment items items of assessment
A program for assessing the reliability of building sheet metal envelope systems and their components.
2.1.7 Appraisal unit
According to the structural characteristics of the certified building metal plate enclosure system, the enclosure system is divided into one or several sections that can be independently identified, and each section is an identification unit.
2.1.8 component component
The components of the metal plate enclosure system can be divided into components, connections, etc.
2.1.9 Component members
A single component that bears various functions in the containment system, or refers to a certain component of the system. Including sheet metal, purlins, wall beams, etc.
2.1.10 connect connect
A system that uses special brackets, self-tapping screws, rivets, nails, bolts, welding, occlusion, etc. to combine components together.
2.1.11 Attached facilities
Maintenance access, ladders, fall prevention facilities, snow protection facilities, lightning protection facilities, photovoltaic systems, decoration systems, etc. for building metal plate enclosure systems.
2.1.12 Strengthening of metal building envelope system
Measures such as reinforcement and partial replacement are adopted to improve the reliability of the building metal plate enclosure system, so that it has corresponding safety and usability.
2.1.13 Renovation of metal building envelope system
Renovate or replace the original enclosure system to meet the functional requirements of the transformation.
2.2 Symbols
2.2.1 Main symbols of structural performance and action effect
M—the design value of the maximum bending moment borne by a section;
Mu - the design value of the bending capacity of the section;
Mx, My——the sum of the design value of bending moment before strengthening and the design value of bending moment after strengthening around the x-axis and y-axis of the centroid of the reinforced section, respectively;
We—effective section modulus;
φbx——the overall stability coefficient of the beam;
η—reinforcement strength correction factor;
ηm—correction coefficient of strengthening strength of bending members;
γ0——structural importance coefficient, whose value is consistent with the main structure.
2.2.2 Identification Rating
au, bu, cu, du—the safety level of the component or its inspection items;
Au, Bu, Cu, Du—the safety level of the identification unit or a part of it;
as, bs, cs—serviceability level of the component or its inspection items;
As, Bs, Cs—the usability grade of the identification unit or a part thereof;
a, b, c, d - the reliability level of the component;
A, B, C, D—the reliability level of the identification unit.
3 Basic Regulations
3.1 General provisions
3.1.1 When one of the following conditions exists in the building metal plate enclosure system, reliability appraisal shall be carried out.
1 When there are quality defects or corrosion, leakage, damage, deformation, etc. that affect safety;
2 When the designed service life is reached and intended to continue to be used;
3 When the conditions of use or the change of the use environment are unfavorable to safety;
4 When a comprehensive overhaul is required;
5 When you intend to continue to use it after suffering a disaster or accident;
6.When routine maintenance checks find potential safety hazards;
7 When making modifications or alterations.
3.1.2 When one of the following conditions exists in the building metal plate enclosure system, special appraisal should be carried out.
1 When there are special requirements for maintenance and reconstruction;
2 When there is local damage affecting its normal use;
3 When there is doubt about the integrity and durability of the metal plate or when it needs to be dealt with;
4 When the supporting structural members, connections, etc. are subject to general corrosion, damage or other problems;
5 When there is vibration effect;
6 When long-term monitoring is required.
3.1.3 If the building metal plate enclosure system is identified as not meeting the requirements, it shall be reinforced.
3.2 Appraisal procedures and work content
3.2.1 The reliability appraisal of the building metal plate enclosure system should follow the clear appraisal purpose, scope, content, investigation, formulation of appraisal plan, inspection and testing, reliability analysis, reliability appraisal, submission of appraisal report and other workflows (Fig. 3.2.1) Proceed.
3.2.2 The purpose, scope and content of the appraisal of the building metal panel enclosure system shall be determined according to the reasons and requirements of the appraisal put forward by the entrusting party and the current status of the building metal panel enclosure system.
3.2.3 The investigation should include the following basic contents.
1 Review drawings and materials, including special reports, as-built drawings, as-built materials, inspection and observation records, maintenance records, drawings and materials of previous appraisal reinforcement and transformation, accident handling reports, etc.;
2 Investigate the historical situation of building metal plate enclosure system, including construction, maintenance, reinforcement, transformation, change of use, change of use conditions and disasters;
3 Investigate the site, investigate the basic situation, actual situation, use conditions, internal and external environment, accident records of the building metal plate enclosure system, check the problems that have been discovered so far, investigate or listen to the opinions of relevant personnel, etc.
3.2.4 The appraisal plan should be formulated according to the characteristics of the appraisal object, the investigation results, appraisal purpose and requirements, including the basis of the appraisal, work content and methods, work schedule and preparatory work to be completed by the entrusting party.
3.2.5 For inspection and testing, the following items should be selected according to the actual situation.
1 Check relevant documents and materials;
2 Material performance testing and analysis;
3 system performance testing and analysis;
4 Support structure inspection and testing;
5 Inspection and testing of connectors and panel systems;
6 Inspection and testing of auxiliary facilities;
7 When the deformation or damage of the main load-bearing structure or the foundation affects the building metal plate enclosure system, check and test according to relevant standards.
3.2.6 The reliability analysis shall be carried out according to the inspection and testing results, including the analysis and calculation of structural bearing capacity, the safety and usability analysis of the building metal plate enclosure system, and the cause analysis of existing defects, corrosion and damage.
3.2.7 In the reliability appraisal of the building metal plate enclosure system, if the inspection or testing data are found to be insufficient or inaccurate, supplementary inspection or testing should be carried out in time.
3.2.8 The reliability appraisal of the building metal plate enclosure system should be divided into two levels of components and appraisal units; the appraisal rating should include safety, usability and reliability grades; safety should be divided into four grades, usability should be Divided into three grades, the reliability should be divided into four grades, and should be evaluated according to Table 3.2.8.When it is not required to assess the reliability level, the safety and usability level assessment results can be directly given.
3.2.9 The appraisal procedure of the special appraisal can be carried out according to the reliability appraisal procedure, and the work content of the appraisal procedure should meet the requirements of the special appraisal.
3.2.10 A report should be submitted for testing and identification, and the preparation of the report should meet the requirements of Chapter 10 of this standard.
3.3 Identification and Rating Standards
3.3.1 The grading standards for each level of safety appraisal and rating of components and appraisal units of the building metal plate enclosure system shall be adopted in accordance with the provisions in Table 3.3.1.
3.3.2 The grading standards for each level of the usability appraisal and rating of components and appraisal units of the building metal panel enclosure system shall be adopted in accordance with the provisions in Table 3.3.2.
3.3.3 The grading standards for each level of reliability appraisal and rating of components and appraisal units of the building metal plate enclosure system shall be adopted in accordance with the provisions in Table 3.3.3.
3.4 Reinforcement and reconstruction requirements
3.4.1 Reinforcement and modification of building metal plate enclosure system may include reinforcement of enclosure support structure, reinforcement against wind exposure, reinforcement against trampling, anti-corrosion treatment, function modification of enclosure system, etc.
3.4.2 The reinforcement and reconstruction design of building metal plate enclosure system shall meet the following requirements.
1 The design scheme should be determined according to the influence of site conditions on the construction method and reinforcement effect;
2 The reinforcement should work in harmony with the original structure;
3 For structural damage caused by different influencing factors, corresponding prevention and control countermeasures should be put forward in the reinforcement design.
3.4.3 The design service life of reinforcement and reconstruction of building metal plate enclosure system shall be determined according to the following principles.
1 The design service life after reinforcement and reconstruction shall be agreed upon by the owner and the design unit, and should not be lower than the original remaining design service life;
2 In the case of local reinforcement and reconstruction, it shall be determined according to the influence of the original remaining design service life of the enclosure system structure on the design service life after reinforcement and reconstruction.
3.4.4 The acceptance of metal plate enclosure system reinforcement and reconstruction works shall be carried out after the construction is completed.
4 On-site investigation and inspection
4.1 Data investigation
4.1.1 Data investigation should include project overview, original design documents, special reports, as-built drawings, project acceptance documents, reconstruction data, meteorological data, etc.
4.1.2 When the information is incomplete, on-site investigation and actual measurement should be carried out.
4.2 Use load investigation
4.2.1 The standard value of self-weight of components shall be calculated and determined according to the standard value of self-weight per material unit according to the actual size of components and connections. When the information is complete and there is no significant deviation between the actual component size and the as-built drawing, the calculation can be carried out according to the as-built drawing.
4.2.2 Other standard values of dead loads borne by components shall be determined through on-site investigation.
4.2.3 The standard value of variable load borne by components shall be determined according to relevant standards such as the current national standard "Code for Building Structure Loads" GB 50009 and corresponding special reports.
4.2.4 The investigation of variable loads should still be based on regional characteristics. In areas prone to heavy snowfall, the local accumulation and sliding effects of snow loads should be investigated; in rainy areas, the water load of gutters caused by poor drainage or failure should be investigated ; In areas prone to strong winds, the effect of strong winds on unfavorable parts such as corners or overhangs should be investigated, and the influence of the dominant wind direction and the surrounding environment should be investigated; industrial plants that generate a lot of dust during the production process should investigate the dust load and local accumulation effect.
4.3 Status check
4.3.1 The status inspection shall include inspection of components and their connections, performance inspection, structure inspection and inspection of auxiliary facilities.
4.3.2 The inspection of components and their connections shall include the inspection of metal plates, purlins and wall beams and their connections. Inspection items should include manufacturing and installation deviations, corrosion defects and corrosion, component deformation, cracking or breaking, connection defects, etc.
4.3.3 For coastal areas or other areas prone to strong winds and atmospheric conditions, the connection status and local strengthening measures of edge parts such as gutters and cornices should be checked; for industrial plants, the connection status of the gable parts of the plant should also be checked; In areas subject to heavy snowfall, focus should be placed on areas that are prone to local loading, such as low-span roofs where high and low spans are connected; for structures located in corrosive, high-humidity, and coastal areas, emphasis should be placed on checking their anti-corrosion measures and component corrosion.
4.3.4 The inspection of anti-corrosion defects shall include the integrity of the topcoat, primer or coating and the percentage of damaged area.
4.3.5 The performance inspection shall include the waterproof, lightning protection, thermal and wind protection of the enclosure system, and the performance inspection shall meet the following requirements.
1 Waterproof inspection shall include metal plates and their joints, waterproof layer, flashing boards, ridge boards, corner boards, deformation joints, roof drainage systems, etc.;
2 The lightning protection inspection shall include air receptors, lead wires, grounding resistance, etc.;
3 The thermal inspection shall include metal plates, joints and expansion joints, etc.;
4 The windproof inspection shall include metal plates, flashing boards, detail nodes, etc.
4.3.6 Structural inspection shall include component and connection structure, waterproof structure, thermal insulation structure, vapor-proof structure, sound-proof structure and wind-proof structure.
4.3.7 The inspection items of the connection structure shall include structure layout, support system and connection structure of each structural unit, etc.
4.3.8 The inspection of auxiliary facilities shall include items such as structure, connection, impact on the safety of the main structural system and use functions.
5 detection
5.1 General provisions
5.1.1 The engineering inspection of the metal sheet enclosure system can be divided into the inspection of the newly built sheet metal enclosure system and the inspection of the existing sheet metal enclosure system.
5.1.2 In the following cases, the new metal plate enclosure system shall be inspected.
1 When using new materials, new installation techniques and new structural forms;
2 When the sampling test results of the construction quality fail to meet the design requirements;
3 When construction quality inspection is required;
4.When there are doubts or disputes about the quality of the project and further verification through testing is required;
5 Design or other conditions stipulated in relevant standards.
5.1.3 In the following situations, the existing metal plate enclosure system shall be inspected.
1 When conducting safety appraisal;
2 When carrying out reliability appraisal before overhaul or reconstruction;
3 When the design service life of the building is reached and needs to be continued to be used;
4 After major natural disasters or severe environmental erosion, it is necessary to assess its impact;
5 When there is doubt or dispute about reliability.
5.1.4 The engineering inspection of the metal plate enclosure system can be divided into laboratory inspection and on-site inspection, and the inspection at each stage shall comply with the requirements in Table 5.1.4.
5.1.5 According to the safety and functional requirements of the building metal plate enclosure system, the testing items should meet the requirements in Table 5.1.5.
5.1.6 After conducting the investigation and on-site investigation, the inspection unit shall formulate the inspection items and inspection plan for the metal plate enclosure system project according to the characteristics of the project and the requirements of the entrusting party.
5.1.7 The testing plan should include the following main contents.
1 Project overview;
2 The client's requirements or testing purpose;
3 Testing basis, mainly including the standards and relevant technical data on which the testing is based;
4 Test items, test methods and test quantities;
5 testing personnel and equipment;
6 testing progress plan;
7 The work that requires cooperation;
8 Safety and environmental protection measures during testing;
9 A description of the degree of local damage that occurred during on-site inspection, including a repair plan if necessary.
5.1.8 The tensile performance test of the connecting part of the fixed bracket between the metal plate and the supporting structure shall meet the requirements of Article 6.2.2 of this standard. In addition to the rivets, self-tapping screws or nails used for the tight connection between metal panels or between metal enclosures and supporting components in building metal panel enclosure systems in windy and coastal areas, they shall meet the requirements specified in Article 6.2.3 of this standard. In addition to the requirements of the article, it is also advisable to conduct laboratory tensile performance simulation tests.
5.1.9 The specifications, models and materials of the test pieces for new projects should be consistent with the construction drawings, the test pieces should be representative and typical, the installation should meet the design requirements, and should be the same as the on-site installation.
5.1.10 The instruments and equipment used for testing shall pass the inspection or calibration and be within the validity period, and the accuracy of the instruments and equipment shall meet the requirements of the testing items.
5.1.11 The on-site testing work shall be undertaken by two or more testing personnel, and the testing personnel shall be trained before taking up their posts.
5.2 Testing method and sampling plan
5.2.1 For the detection of the building metal plate enclosure system, the corresponding detection method should be selected according to the detection items, detection purpose, current situation of the enclosure system and site conditions.
5.2.2 The on-site inspection should adopt the inspection method that does not damage the metal plate enclosure system. When the sampling detection method of local damage is selected, it is advisable to select the part of the load-bearing member with less stress and the part with less impact on the use function, and the safety of the containment system must not be damaged.
5.2.3 When the newly-built metal plate enclosure system is tested according to the inspection batch, the sampling test ratio and qualified judgment shall comply with the current national standard "Steel Structure Engineering Construction Quality Acceptance Standard" GB 50205 and "Profiled Metal Plate Engineering Application Technical Specifications" The provisions of GB 50896.
5.2.4 In the testing of the existing metal plate enclosure system, the minimum sample size of the testing batch shall comply with the provisions of the current national standard "Technical Standards for Testing Building Structures" GB/T 50344.
5.2.5 In the following situations, full testing should be adopted.
1 When detecting appearance defects or surface damage;
2 When the scope of inspection is small or the number is small;
3 When there is a large difference in quality status;
4 When the damage of the containment system is detected after the disaster;
5 When the entrusting party requires full testing.
5.3 Material inspection
5.3.1 The samples for engineering testing shall be sampled on-site according to the same manufacturer, type and variety, and re-testing shall be entrusted to a testing unit with corresponding qualifications.
5.3.2 Mechanical properties, anti-corrosion properties and weather resistance properties of metal plates, mechanical properties, water vapor transmission rate, impermeability, low-temperature bending properties of waterproof and breathable materials, mechanical properties of purlin and wall beam materials, thickness of metal plate coating And unit quality, etc. should be sampled on-site for laboratory testing.
5.3.3 Density, thermal conductivity, combustion performance and other items of thermal insulation materials should be sampled on-site for laboratory testing according to the current national standard "Construction Quality Acceptance Standards for Building Energy Conservation Projects" GB 50411.
5.3.4 On-site testing of materials shall comply with the following regulations.
1 On-site inspection items should include size, plate thickness, coating thickness and coating adhesion, corrosion, etc.;
2 Size, plate thickness and coating thickness can be tested according to the current national standards "Technical Standards for Building Structure Inspection" GB/T 50344 and "Technical Standards for On-site Inspection of Steel Structures" GB/T 50621;
3 Coating adhesion can be measured according to the provisions of the current national standard "Cross-cut test of paint and varnish film" GB/T 9286;
4 Corrosion can be detected according to the provisions of the current national standard "Visual assessment of surface cleanliness of steel surface treatment before coating" GB/T 8923.
5.4 Static detection of wind resistance
5.4.1 The test box should have sufficient strength, rigidity and overall stability, and should meet the technical requirements of the experiment.
5.4.2 The quantity of witness sampling and testing for new projects shall meet the design requirements; when there is no provision in the design, at least one specimen shall be tested for the same type of system.
5.4.3 Engineering test specimens should be installed according to the actual structure and construction method of the project.
5.4.4 The testing steps of the test piece by the static method for wind resistance should be carried out according to Appendix A of this standard.
5.5 Dynamic detection of wind resistance
5.5.1 In windy and coastal areas, in addition to the static test of wind resistance, the metal plate enclosure system of buildings in coastal areas should also be tested for the dynamic performance of wind resistance by simulating dynamic wind loads in the laboratory.
5.5.2 The technical requirements for the inspection box, the requirements for the number of new construction witness sampling and the requirements for inspection specimens are the same as those in Section 5.4 of this standard.
5.5.3 The design value of the wind load should be taken for the dynamic wind load detection, and the detection steps of the dynamic method of wind resistance should be carried out according to Appendix B of this standard.
5.5.4 The test results should at least include the following.
1 The dynamic wind-resistant unloading load adopted for testing;
2 The damage or failure of the test piece after the specified number of cyclic wind load tests;
3 Dynamic wind resistance test results.
5.6 Watertight performance test
5.6.1 Metal plate enclosure systems with waterproof requirements shall be tested for watertight performance.
5.6.2 The watertightness test of the metal plate enclosure system can be divided into on-site water spray test and laboratory test.
5.6.3 On-site water spray testing shall comply with the following regulations.
1 The on-site water spray test should be carried out under suitable meteorological conditions. The outdoor temperature should not be lower than 5°C, the outdoor wind force should not be greater than level 3, and there should be no rainfall during the test. The temperature, air pressure and wind speed should be recorded during the detection.
2 Sprinkling water can be sprayed with nozzles at the design specified pressure 0.5m away from the water spraying part, and the spraying time should not be less than 5 minutes. At the same time, the indoor leakage should be checked, and the leakage location and leakage situation should be recorded.
3 When water leakage occurs on site, the cause of the leakage should be analyzed, repaired or replaced, and re-tested.
5.6.4 The test pieces for the watertightness laboratory test of the metal plate enclosure system should be placed horizontally. The preparation and installation of the test piece shall be consistent with the actual project.
5.6.5 The watertightness laboratory test of the metal plate enclosure system should be carried out according to Appendix C of this standard.
5.7 Airtight performance test
5.7.1 When the metal plate enclosure system has airtightness requirements, the airtightness performance test shall be carried out.
5.7.2 Metal roof test pieces should be installed horizontally for air tightness test.
5.7.3 The air tightness testing device should consist of a static pressure box, a pressurization system, an air flow measurement system and a pressure measurement system.
5.7.4 The test method for the airtight performance of the test piece should be carried out according to Appendix D of this standard.
5.8 Thermal Performance Testing
5.8.1 Thermal performance testing can be divided into laboratory testing of heat transfer coefficient and on-site testing of thermal defects.
5.8.2 Laboratory testing of heat transfer coefficient shall comply with the following regulations.
1 The testing equipment should comply with the provisions of the current national standard GB/T 13475 "Determination and Calibration of Adiabatic Steady-state Heat Transfer Properties and Protected Hot Box Method";
2 The production and installation of the test piece should be consistent with the actual project.
3 The test sample should be able to represent the thermal performance of typical parts, and should include thermal weak parts.
4 For the same type of system, at least one set of laboratory heat transfer coefficient tests shall be carried out.
5.8.3 On-site detection of thermal defects shall meet the following requirements.
1 Thermal defect detection should be carried out by infrared thermal imaging camera;
2 The test should be carried out in suitable weather, the outdoor wind force should not be greater than level 5, the test should be carried out in the heating period in severe cold and cold areas, and it should be carried out at night in summer in other areas;
3 The surface to be inspected should not be exposed to direct sunlight, and the inner surface should avoid direct exposure to light;
4 The temperature measurement range of the infrared thermal imaging camera should meet the requirements of on-site inspection; the temperature resolution of the infrared thermal imaging camera should not be greater than 0.08°C, the uncertainty of temperature difference detection should not be greater than 0.5°C, and the resolution should not be lower than 76800 effective pixels.
5.9 Sound insulation performance test...
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