LY/T 3141-2024 English PDFUS$369.00 · In stock
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Basic dataStandard ID: LY/T 3141-2024 (LY/T3141-2024)Description (Translated English): (Testing methods for wooden components of cultural relics buildings) Sector / Industry: Forestry Industry Standard (Recommended) Word Count Estimation: 16,132 Date of Issue: 2024-02-07 Date of Implementation: 2024-06-01 Issuing agency(ies): State Forestry and Grassland Administration LY/T 3141-2019: Technical code on appraisal rating for wooden member of ancient timber building---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.(Technical specification for safety appraisal of ancient building wooden members) ICS 91.080.20 P 23 LY People's Republic of China Forestry Industry Standard Technical code for safety appraisal of ancient building wooden members Technical code on appraisal rating for wooden member of ancient timber building 2019-10-23 released 2020-04-01 implementation Published by the National Forestry and Grassland Administration ForewordThis standard was drafted in accordance with the rules given in GB/T 1.1-2009. Please note that some elements of this document may involve patents. The issuer of this document is not responsible for identifying these patents. This standard was proposed and managed by the National Timber Standardization Technical Committee Structural Timber Subcommittee (SAC/TC41/SC4). This standard was drafted. Institute of Wood Industry, Chinese Academy of Forestry, Shanxi Province Ancient Building Maintenance Quality Supervision Station, Chinese Culture Heritage Research Institute, Beijing Jiaotong University, Beijing Institute of Ancient Architecture, Beijing Institute of Construction Engineering Co., Ltd., Ministry of Science and Technology Torch High-tech Industrial Development Center, Guangdong Runcheng Chuangzhan Wood Industry Co., Ltd. The main drafters of this standard. Zhou Haibin, Wang Weibin, Yong Xinqun, Yang Na, Zhang Tao, Song Huijie, Chen Yongping, Zhong Yong, Wang Shuangyong, Wu Guofang, Lou Wanli, Guan Runkai. Technical code for safety appraisal of ancient building wooden members1 ScopeThis standard specifies the terms and definitions, basic provisions, damage survey items and bearing capacity verification items of the safety assessment of wooden components of ancient buildings. Purpose To identify ratings. This standard applies to the safety inspection and appraisal of the wooden members of the following buildings. a) Wooden structures and ancient buildings approved by various levels of government as cultural relics protection units; b) Wood that has not yet been approved for publication as a cultural relics protection unit, but has been registered and announced as a non-removable cultural relic by the district and county government cultural relics administration Structure ancient building c) wooden structure ancient buildings that have not been classified as immovable cultural relics but have been announced as historical buildings by governments at all levels; d) An ancient wooden structure that has not yet been identified as a historical building, but does have conservation value.2 Normative referencesThe following documents are essential for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest version (including all amendments) applies to this document. GB/T 28990 Nondestructive testing procedures for internal decay and elastic modulus stress wave of ancient building wooden components GB 50005 wood structure design standard GB 50009 Load Code for Building Structures GB 50165 Technical Specifications for Maintenance and Reinforcement of Timber Structures of Ancient Buildings GB 50292 Civil Building Reliability Evaluation Standard LY/T 2146 Non-destructive detection method and decay classification of wooden components of ancient buildings3 terms and definitionsThe terms and definitions defined in GB 50165 and the following apply to this document. 3.1 Ancient timber building Buildings with wooden components as the main vertical load-bearing components are valuable buildings for the study of social, political, economic, and cultural heritage. 3.2 Wood unit Single or combined element in the wooden frame of an ancient building. 3.3 Dominant member Its failure will lead to the failure of related components and endanger the structural system safety. 3.4 Common member Its failure will not lead to the failure of the main components, and does not endanger the structural system safety.4 Basic requirements4.1 Identification object The safety appraisal of wooden elements of ancient buildings should be carried out in the following cases. 1) Major wooden components in key maintenance projects; 2) Wooden members monitored regularly; 3) wood elements that change their use or conditions of use; 4) Wooden members found to have safety problems during use; 5) Wooden members affected by major disasters such as earthquakes, wind, floods, fires, and lightning; 6) Wooden members with special requirements. 4.2 Identification procedure 4.2.1 The safety appraisal of wooden components of ancient buildings shall be carried out according to the following procedures. 1) Accept the commission. According to the requirements of the client, determine the purpose, content and scope of the safety evaluation of the wooden members. 2) Preliminary investigation. collect and analyze the original data of ancient buildings, including drawings, building history, past repair data, and conduct Field investigation. 3) Inspection and verification. On-site inspection of the state of ancient building wood components, including. component measurement, deformation measurement, damage inspection, tree species Appraisal, material performance testing, etc., if necessary, instrument testing and structural check calculations. 4) Level determination. conduct a comprehensive analysis of the data of surveys, inspections and calculations, and integrate their safety levels. 5) Disposal suggestions. Put forward principled disposal suggestions for the identified ancient building wood elements. 6) Issue a report. 4.3 Identification requirements 4.3.1 There are two levels of safety appraisal for wooden elements of ancient buildings. The classification and rating standards of each level are shown in Table 1. Table 1 Levels, grades, and standards of safety evaluation of wood members Hierarchical identification object rating standard A survey item a 'has no damaged points, or the original damaged points have been repaired b 'Only minor or suspected damage was found, but it did not affect safety c 'has a moderate damage point, which has affected the safety of the project d 'has severe damage points, which will endanger the safety of the project The safety of a single component a meets the requirements of class a of this standard and has sufficient bearing capacity b The safety is slightly lower than the requirements of level a of this standard, and it has not significantly affected the carrying capacity. c The safety does not meet the requirements of level a of this standard, which significantly affects the carrying capacity d. Safety does not meet the requirements of Class a of this standard, which has seriously affected the carrying capacity. 4.3.2 When the safety of a wooden member is evaluated according to the rating results of the damage survey item, the damage level of the member shall be determined according to Table 2. Table 2 Evaluation criteria for damage rating of load-bearing components Grade standard a component should be a 'grade in the survey project; or no c' grade and d 'grade, only individually b' grade There should be no c 'and d' grades in the survey items of b components, and b 'grade is more than a' c The lowest level of the component survey item is c 'level The lowest level of the d component survey project should be d 'level; or no d' level, but c 'level is more than 50% 4.3.3 When the safety of load-bearing wood components and their connections is determined according to the carrying capacity, the level of each check item shall be determined separately as specified in Table 3. Level, and take the lowest level as the safety level of the bearing capacity of the component. Table 3 Rating of load-bearing components and their connection safety levels according to bearing capacity Component category R/γ0S Class a Class b Class c Class d Main components and connections ≥1.0 ≥0.95 ≥0.90 < 0.90 General components ≥ 1.0 ≥ 0.90 ≥ 0.85 < 0.85 Note. R and S in the table are the resistance and action effects of structural members, respectively, determined according to GB 50009 and GB 50292; γ0 is the coefficient of structural importance, and World Cultural Heritage Land and buildings of national key cultural relics protection units are taken as 1.1, and other buildings are taken as 1.0. 4.3.4 According to the damage survey item and bearing capacity check item, assess the damage level and bearing capacity level of the wooden members respectively, and take the comparison The lower level serves as the final safety level of the wooden members. 4.3.5 The safety level of wooden members shall be used as the basis for judging the maintenance and reinforcement of the members. See Table 4 for processing requirements of different grades of components. Table 4 Treatment requirements for wood components based on safety levels Security level processing requirements a No action necessary b No action required c can take action d must take immediate action5 Appraisal and rating of the damage survey project5.1 The damaged points of the wooden building survey project of ancient buildings shall be divided into a 'grade, b' grade, and c 'according to their degree of influence on the structure and component safety. Level and d 'level. The a 'and b' levels can be judged by the appraiser based on the actual condition, and the c 'and d' levels should be judged by the appraiser. Determine the actual severity. 5.2 The damaged points of load-bearing wooden columns of ancient buildings shall be determined according to Table 5. Table 5 Evaluation criteria for bearing wood column damage Survey item survey content c 'level or d' level Material situation Natural defect Characteristic size of any defect in key stress areas, knots, oblique grains or shrinkage cracks Exceeds the limits in Table 6 with other damage decay When only the surface is decayed and deteriorated, ρ > 1/5 or the remaining cross section is not acceptable When there is only heart rot, ρ ＞ 1/7 or unqualified according to the remaining section Coexisting heart rot, surface decay, and aging Insects bore holes; or no holes were found, knocking empty drum sounds 3 Column damage cracks show signs of fracture, splitting or crumpling within the range of the column length 4 Lateral bending sagittal height δ δ ＞ L0/250 Pedestal and pedestal Resistance The actual bearing area between the bottom surface and the column foundation and Ratio of the original cross-sectional area of the column at the leg Less than 3/5 Eccentric check If the column is an eccentric compression member, the deviation of the center of the actual bearing surface from the column axis should be determined. The eccentricity and its effect on the original eccentricity were unqualified according to the eccentricity check.6 Pillar misalignmentDisplacement between column and column base and column diameter (or Column cross section) the ratio of dimensions along the dislocation direction More than 1/6 Previous reinforcement The original pier joint is in good condition with new deformation or displacement of the column body, or the tenon-and-mortise joint has been degummed, cracked, or the hoop has been loosened Original grouting effect The original grouting slurry has poor adhesion to wood, the slurry shrinks, and there are empty drum sounds when struck; columns Obvious wrinkling or deformation The intactness of the original excavation site has become loose, degummed, or new decay has occurred Note. ρ is the ratio of the area occupied by decay and aging deterioration (total) to the entire cross-sectional area on any section; L0 is the unsupported length of the column. Table 6 Evaluation criteria for natural defects Item natural defect Log Member Square Member Bending member or bending member Compressed member or secondary Bending member Bending member or pressure Curved member Compressed member or secondary Bending member1 knotOn either side of the component (or along the perimeter Length) Any 150mm length The sum of the sizes of the knots should not Larger than the width of the face Log perimeter) 2/5 2/3 1/3 2/5 The maximum size of each knot should be Not more than the log circumference of the measured part long 1/5 1/4-- Twill Average tilt over any 1m length Inclined height should not be greater than 80mm 120mm 50mm 80mm Shrink crack Not allowed on the sheared surface of the joint Attach the sheared surface of the joint Near, its crack depth (the opposite Use the sum of the two when cracking) should not more than the 1/4 in diameter 1/2 in width 1/4 in width Annual ring width Should not be greater than 4mm 4mm 4mm 4mm 5.3 The damaged points of load-bearing wooden beams and concrete of ancient buildings shall be determined according to Table 7. Table 7 Evaluation criteria for bearing wood beam and concrete damage Item survey item survey content c 'level or d' level1 Material defectsdecay When only the surface is decayed and deteriorated, the beam ρ > 1/8 or the remaining section is not qualified. When the end part (within the support range) has surface decay and aging deterioration, regardless of the size of ρ, it is regarded as a point of damage. The existence of heart rot, regardless of the size of ρ, is regarded as the point of damage Insects bore holes; or no holes were found, knocking empty drum sounds Natural defect At critical stress locations, any defects such as knots, oblique textures, or shrinkage cracks exceed the limits in Table 6, and Have other damage2 Bending deformationMaximum vertical deflection ω1 or ω1 ' When h/L ＞ 1/14, ω1 ＞ L2/2100h When h/L≤1/14, ω1 ＞ L/150 For beams and rafters over 300 years, if there is no other damage, it can be judged as ω1 '＞ ω1 h/50 Lateral bending sagittal height ω2 ω2 ＞ L /.2003 Damaged beamThere are cracks or cracks across the interruption lines, but there are signs of crumple on the upper surface of the beam Beam end split (not included Shrinkage crack) End cracks or oblique cracks caused by stress or excessive deflection Non-original sawn, open Slot or drill Failed inspection based on remaining section Previous reinforcement Beam end original splicing reinforcement Intact The original splicing has been deformed, or has been degummed, or the bolts have been loosened The original grouting effect The original grouting body shrinks, there is empty drum sound on percussion, or the deflection of the beam increases Note. ρ is the ratio of the area occupied by decay and aging deterioration (total of both) to the entire cross-sectional area on any section; L is the calculated span; h is the height of the member section. 5.4 The bucket has the following damage and should be regarded as the point of damage. a) Obvious deformation, misalignment or twisting of the bucket; b) the relative deflection of the bending member in the bucket has exceeded 1/120; c) The forsythia is broken, the small bucket falls off, and two consecutive occurrences occur under each one; d) The twist of 栱 is more than 3mm, or the depression of the bucket is more than 3mm; e) Decaying, worm-eaten or aging deterioration of the wood of the bucket bucket has affected the bucket bucket force; f) There are obvious signs of damage at the stigma or corner. 5.5 The damaged points of roof wooden members shall be determined according to Table 8. Table 8 Evaluation criteria for damage to roof members Item survey item survey content c 'level or d' level1 purlinThe material has become decayed or moth-eaten, or is heavily wet The deflection is greater than 1/100 of the span and has caused significant roof deformation The connection between 椽 and 檩 is not nailed, or the nail is rusted2 PurlinMaterial is evaluated according to Table 7 Mid-span maximum deflection ω1 When L≤3m, ω1 ＞ L/100 When L ＞ 3m, ω1 ＞ L/120 Most purlins have large deflections that cause rain. Regardless of the size of ω1, they are regarded as Break point Purlin support length a Supported on wooden members, a < 60mm Supported on masonry, a < 120mm Tendon at the end of the purlin under stress, or the purlin rolls outside, or there is no anchor between the purlin and the beam Melon pillar, horned llama Material is decaying or moth-eaten Slope, mortise, or split in good construction Wing angle, corner beam, Yu Material is decaying or moth-eaten No reliable tie at the fixed position at the rear of the angle beam The damage process of the tail beam of the angle beam and the end of the beam Split or broken The wing corners and eaves are obviously drooping Note. L is the calculated span of purlin. 5.6 The damage points of wooden members on the floor shall be determined according to Table 9. Table 9 Evaluation criteria for floor component damage Item survey item survey content c 'level or d' level 1 Floor corrugated (joist) Material is evaluated according to Table 7 Maximum vertical deflection ω1 ω1 > L/180, or severe somatosensory tremor Lateral bending sagittal height ω2 (Raw joists are not checked) ω2 ＞ L /.200 End tenon-and-mortise condition without reliable anchoring and support length less than 60mm2 The condition of floor wood decay and surface damage can no longer strengthen the horizontal rigidity of the floorNote. L is the calculated span for joists.6 Appraisal and rating of carrying capacity check items6.1 When checking the bearing capacity of structures or components, the following requirements should be observed. a) The structural analysis method used for checking the structural members should refer to the provisions of the current national design code; b) The calculation model used for checking the structural members should be consistent with its actual stress and structural conditions; c) Structural loads shall be implemented in accordance with the provisions of GB 50165; d) the strength grade of wood shall be determined in accordance with Appendix A; e) The geometric parameters of the structure or component shall be measured on site, and the effective cross-sectional area of wooden members with material defects shall be determined in accordance with Appendix B. 6.2 Beam and column members shall be checked for bearing capacity in accordance with the relevant provisions of GB 50005 and shall comply with the following provisions. a) When the beam is excessively bent, the effective span of the beam should be determined according to the actual contact between the support and the beam, and the eccentricity of the support force transmission should be considered. The support member is affected by force; b) Columns shall be calculated according to the hinges at both ends. The length shall be taken as the distance between the lateral supports. Columns with a change in cross-sectional dimensions may be measured according to the intermediate section rule. Inch check c) If the original component has been partially damaged or decayed, it shall be checked against the remaining effective section. 6.3 When checking the wooden structure of ancient buildings, the timber design strength and elastic modulus should meet the following requirements. a) It shall be implemented in accordance with the provisions of GB 50005 and multiplied by the coefficient of structural importance 0.9; there are special require......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of LY/T 3141-2024_English be delivered?Answer: Upon your order, we will start to translate LY/T 3141-2024_English as soon as possible, and keep you informed of the progress. 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