GB 50009-2001 - 2006 Load Code for the Building Design, China
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(2) Notice of Issuing Load Code for the Design of Building Structures JIANBIAO [2002] No.10 In accordance with Notice of Printing and Distributing the Establishment and Amendment Plan of Project Construction Standard of 1997 (JIANBIAO [1997] No.108) issued by the Ministry of Construction, the Load Code for the Design of Building Structures jointly developed by the Ministry of Construction and related departments has been authorized by related departments as a national standard, with the number of GB 50009- 2001 and will be implemented from March 1, 2002. Among which, articles 1.0.5, 3.1.2, 3.2.3, 3.2.5, 4.1.1, 4.1.2, 4.3.1, 4.5.1, 4.5.2, 6.1.1, 6.1.2, 7.1.1 and 7.1.2 are compulsory ones and shall be executed strictly. At the same time, the original Load Code for Building Structures (GBJ9-87) shall be terminated on December 31, 2002. The Code is in the charge of the Ministry of Construction that is responsible for the interpretation of compulsory articles. The China Architecture Research Institute will be responsible for the interpretation of technical contents. In addition, the Code shall be published by China Architecture & Building Press (CABP) with the organization of Research institute of Standards & Norms. Ministry of Construction P. R. China July 20, 2001.
(3) Foreword This Code has been overall revised in accordance with Notice of Printing and Distributing of the Establishment and Amendment of Building Construction of 1997 (JIANBIAO [1997] No.108) issued by the Ministry of Construction and the Load Code for the Design of Building Structures (GBJ 9-87) jointly approved by China Architecture Scientific Research Institute and related departments. During the process of revising, the team has carried out monographic study, summarized design experience in recent years, referred to related contents of foreign norms and international standards, widely asked for opinions from related departments all over the country and finalized after repeated amendment. This Code can be divided into seven chapters and seven appendices. Primary contents revised are as follows: 1. In accordance with the rule of combination stated in Unified Standard for Reliability Design of Building Structures and getting rid of Wind Combination, the combination controlled by permanent load effect was added to the load fundamental combination. In the limit design of regular service, for the short-term effect combination, characteristic and frequent combinations are listed and at the same time, the frequent value coefficient was added to the variable load. For all combination values of variable loads, respective combination value coefficient is listed. 2. Partial adjustment and amendment of floor live load. 3. Adjustment has been made to roofing rectangular distribution live load that permits no person on the roof and provisions on roof gardens and helicopter pad load have been added. 4. Character of service for crane has been changed into work classes of cranes. 5. According to new observation data, statistics of wind pressure and snow pressure from national weather stations has been collected. At the same time, the basic value of wind and snow load recurrence interval has been changed from 30 years to 50 years. In the appendix, the 10-year, 50-year and 100-year wind pressure and snow pressure in main stations all over the country have been listed. 6. One Type has been added to the terrain roughness. 7. For the wind pressure altitude variation coefficient of buildings in a mountainous area, compensation factors have been given for the consideration of terrain conditions. 8. Specific provisions have been made to wind load of envelop enclosure members. 9. The interactive influences between buildings in architectural complex have been put forward. 10. For flexible structures, the test requirements for crosswind vibration have been added. This Code may be revised as required. Information and contents revised will be published on the journal of Standardization of Engineering Constructions. The compulsory articles in this Code shall be executed strictly. In order to improve the quality of this Code, units shall sum up experience and collect background information. For feedback of related opinions and suggestions, please contact: China Architecture Scientific Research Institute (No.30 East Road, North Third Ring). Chief Development Organization: China Architecture Technical Research Institute Participating Development Organizations: Construction Department of Tongji University,.
(4) Building Design Institute, Beijing International Design Institute of China Light Industry, Beijing: China Institute of Architecture Standard Design Press, Beijing Institute of Architectural Design and China Weather Scientific Research Institute Chief Drafting Staffs: Chen Jifa, Hu Dexin, Jin Xinyang, Zhang Xiangting, Gu Zicong, Wei Caiang, Cai Yiyang, Guan Guixue, Xue Hang.
(5) Contents 1. General Principles ................................................................................................................. 1 2. Terms and symbols ................................................................................................................ 1 2.1 Terms ........................................................................................................................... 1 2.2 Main symbols............................................................................................................... 3 3. Classification of loads and combination of load effect ......................................................... 4 3.1 Classification of loads and representative values of a load ......................................... 4 3.2 Load combination ........................................................................................................ 5 4. Live load of floors and roofs ................................................................................................. 7 4.1 Rectangular distribution live load on floors of civilian buildings ............................... 7 4.2 Floor live load of industrial buildings........................................................................ 10 4.3 Roof live load............................................................................................................. 10 4.4 Roofing dust load........................................................................................................11 4.5 Construction and repair load as well as handrail horizontal load .............................. 13 4.6 Dynamic coefficient................................................................................................... 14 5. Crane load............................................................................................................................ 14 5.1 Vertical and horizontal load of cranes........................................................................ 14 5.2 The combination of several cranes ............................................................................ 15 5.3 Dynamic coefficient of crane loads ........................................................................... 15 5.4 The combination value, frequent value and quasi-permanent value of crane loads .. 15 6. Snow load ............................................................................................................................ 16 6.1 The characteristic value/nominal value and reference snow pressure of snow loads 16 6.2 Coefficient of snow distribution over the roof........................................................... 17 7. Wind load ............................................................................................................................ 20 7.1 The characteristic value/nominal value and reference wind pressure of wind loads . 20 7.2 Variation coefficient of wind pressure altitude .......................................................... 21 7.3 Wind load coefficient................................................................................................. 22 7.4 Downwind vibration and wind vibration coefficient ................................................. 36 7.5 Gustiness factor.......................................................................................................... 38 7.6 Crosswind vibration................................................................................................... 39 Appendix A Deadweight of Commonly-used Materials and Members................................... 41 Appendix B Method for Deciding the Floor Isoeffect Rectangular Distribution Live Load... 55 Appendix C Floor live load of industrial buildings................................................................. 60 Appendix D Measurement Method of Fundamental Snow Pressure and Wind Pressure........ 66 Appendix E Empirical Formula for the Structure Which is Natural Vibration Period .......... 108 Appendix F Approximation of the Structural Mode Factor....................................................111 Appendix G Wording Explanation .........................................................................................113.
(6) 1. General Principles 1.0.1 This Code is designed to meet demands in building structure design and requirements of secure application and economic feasibility. 1.0.2 This Code is applicable to the building structure design. 1.0.3 This Code has been made in accordance with principles stated in Unified Standard for Reliability Design of Building Structures (GB 50068-2001). 1.0.4 Effects involved with the building structure design include direct effect (combination of loads) and indirect effect (including subbase deformation, concrete shrinkage, welding deformations, temperature fluctuation or effects caused by earthquakes). In this Code, only provisions on combination of loads are stated. 1.0.5 The design reference period adopted in this Code is 50 years. 1.0.6 Effects or combination of loads involved with the building structure design shall be in accordance with this Code as well as other current national provisions.. 2. Terms and symbols 2.1 Terms 2.1.1 Permanent load During the utilization period of structures, the value of the combination of loads shall have no change with the passage of time or the variation is negligible compared with the average, or the variation is monotonous and tends to the limitation. 2.1.2 Variable load During the utilization period of structures, the value of combination of loads shall be changed with the passage of time and the variation is negligible compared with the average. 2.1.3 Accidental load During the utilization period of the structure, the combination of loads does not necessarily appear, but one it appears, the value is great but the duration is short. 2.1.4 Representative values of a load The value of combination of loads adopted during the design for the checking of limiting state, such as characteristic value/nominal value, combination value, frequent value and quasi- permanent value. 2.1.5 Design reference period The time parameter selected for deciding the representative value of the variable load. 2.1.6 Characteristic value/nominal value The basic representative value of loads refers to the maximum characteristic value (such as typical value, mode, median or some place value) of statistical distribution of loads in the design reference period. 2.1.7 Combination value 1.
(7) The value of combination of loads that makes the load effect exceed probability during the design reference period and make the solitude appearance of the combination of loads has a unified value of combination of loads or make the structure has unified value of combination of loads with reliability index stated in the provision. 2.1.8 Frequent value For variable load, during the design reference period, the exceeded total time is the minimum ratio or the exceeded frequency is the value of the combination of loads of the assigned frequency. 2.1.9 Quasi- permanent value For variable load, during the design reference period, the exceeded total time is about half of the value of combination of loads in the design reference period. 2.1.10 Design value of a load The arithmetic product of the representative values of a load and the partial load factor. 2.1.11 Load effect Reaction of structures or structural elements caused by the combination of loads, such as internal force, distortion and crack 2.1.12 Load combination In the limit design, to guarantee the built-in reliability, provisions for all kinds of design values of a load have been made. 2.1.13 Fundamental combination In the limit of bearing capacity state, the combination of permanent effect and variable effect 2.1.14 Accidental combination In the limit of bearing capacity state, the combination of permanent effect, variable effect and an accidental combination 2.1.15 Characteristic/nominal combination In the regular service limiting state, the characteristic value/nominal value or combination value adopted is the combination of representative values of a load. 2.1.16 Frequent combinations In the regular service limiting state, the frequent value or permanent value is adopted in the variable load is the combination of representative values of a load. 2.1.17 Quasi- permanent combinations In the regular service limiting state, the quasi- permanent value adopted by the variable load is the combination of the representative values of a load. 2.1.18 Equivalent uniform live load During the structure design, the actual load of continuous distribution above or under the floor is always by substituted by the evenly distributed load. The equivalent uniform live load refers to the load effect received by the structure can keep in line with the evenly distributed load of the actual load effect. 2.1.19 Tributary area The tributary area is adopted during the calculation of the beam column members. It refers to the floor space of the calculated member load. It shall be divided by the zero line of the floor slab. In the practical situation, it can be simplified. 2.1.20 Dynamic coefficient 2.
(8) Structures and members that receives dynamic load, when designed according to the static force, shall adopt the value that is the ratio of the maximum power effect of structures or members and relevant static force effect. 2.1.21 Reference snow pressure The reference pressure of snow load shall be decided by the maximum value of the 50-year period calculated from the probability statistics according to the observation data from the deadweight of snow on the local open and equitable terrain. 2.1.22 Reference wind pressure The reference pressure of wind load shall be decided by the maximum wind speed for a 50-year period calculated from the probability statistics according to the observation data of average speed in 10min at 10m on the local open and equitable terrain. Also, relevant air density shall be considered and the wind pressure shall be calculated according to the formula (D.2.2-4). 2.1.23 Terrain roughness When the wind passes 2km range before reaching the structure, the class used to describe the distribution pattern of irregular barriers on the ground. 2.2 Main symbols Gk——characteristic value/nominal value of permanent load; Qk——characteristic value/nominal value of variable load; GGk——characteristic value/nominal value of permanent load effect; SQk——characteristic value/nominal value of the variable load effect; S——load effect combination design value; R——The design value of resisting power of structural members; SA——Downwind load effect; SC——Crosswind load effect; T——Natural vibration period of structures; H——Top height of structures; B——Windward width of structures; Re——Reynolds number; St——Strouhai number; sk——Characteristic value/nominal value of snow load; s0——reference snow pressure; wk——characteristic value/nominal value of wind load; w0——reference wind pressure; νcr——Critical wind velocity of crosswind sympathetic vibration; α——Angle of gradient; βz——Gust coefficient at height Z; βgz——Gust coefficient at height Z; γ0——Structure significance coefficient; γG——Subentry coefficient of permanent load; γQ——Subentry coefficient of variable load; ψc——combination value coefficient of the variable load; 3.
(9) ψf——frequent value coefficient of variable load; ψq——quasi-permanent value coefficient of variable load; µr——Coefficient of snow distribution over the roof µz——Variation coefficient of wind pressure altitude; µs——Wind load coefficient; η——Coefficient of wind load terrain and physiognomy amendment; ξ——Aggrandizement coefficient of wind load pulsation; ν——Impact coefficient of wind load pulsation; φz——Structural vibration mode coefficient; ζ——Structural damping ratio.. 3. Classification of loads and combination of load effect 3.1 Classification of loads and representative values of a load 3.1.1 The structural combination of loads can be divided into three kinds: 1. Permanent load, such as dead load, earth pressure and prestress. 2. Variable load, such as floor live load, roof live load and dust load, crane load, wind load and snow load. 3. Accidental load, such as blasting power and force of percussion. Note: Deadweight refers to the combination of loads (gravitation) caused by the weight of materials.. 3.1.2 During the design of building structures, different combinations of loads shall adopt different representative values. For permanent loads, the representative value shall be the characteristic value/nominal value. While for variable loads, the representative value shall be the characteristic value/nominal value, combination value, frequent value or quasi- permanent value according to different design requirements. For accidental loads, the representative value shall be decided according to the utilization characteristics of building structures. 3.1.3 Permanent load characteristic value/nominal value: for structural deadweight, it shall be decided according to the design size of structural members and the deadweight of unit volume of materials; for commonly-used materials and members, it shall be decided according to appendix 1 of this Code; for materials and members (including field fabricated heat insulators, concrete thin-wall members) with major changes in deadweight, it shall be the upper value or the lower range value according to the advantage or disadvantage state to members. Note: For commonly-used materials and members, refer to Appendix A.. 3.1.4 The characteristic value/nominal value of variable loads shall be adopted according to provisions in this Code. 3.1.5 The design of limit of bearing capacity state or the regular service limiting state shall adopt the combination value as the representative value of the variable loads. The combination value of variable loads refers to the variable load characteristic value/nominal value multiplied by the combination value coefficient of combination of loads. 3.1.6 If the regular service limiting state is designed according to the frequent combinations, 4.
(10) the frequent value, quasi-permanent value shall be adopted as the representative value. If it is designed according to the quasi-permanent combinations, the quasi-permanent value shall be adopted as the representative value of variable loads. The frequent value of variable loads shall adopt the variable load characteristic value/nominal value multiplied by the frequent value coefficient of combination of loads. The variable load quasi- permanent value shall adopt the characteristic value/nominal value of variable loads multiplied by the quasi-permanent value coefficient of combination of loads. 3.2 Load combination 3.2.1 The design of building structures shall be in accordance with the combination of loads arising in the construction during the utilization process, according to the limit of bearing capacity state and the regular service limiting state. The design shall take the most disadvantaged combination for the combination of loads (effect). 3.2.2 For the limit of bearing capacity state, the combination of loads (effect) shall adopt the fundamental combination or accidental combination of load effect. The following design expression shall be adopted: γ0S ≤R (3.2.2) Where, γ0——Structure significance coefficient; S——The design of load effect combination; R——The design value of resisting power of structural members shall be decided by related design specifications of building structures. 3.2.3 For the design value (S) of the fundamental combination of loads and load effect, it shall be decided by the most disadvantaged value from the following combination values: 1) Combination controlled by the variable load effect;. (3.2.3-1) Where, γG——Subentry coefficient of permanent load shall be adopted according to Article 3.2.5. γQi——The ith subentry coefficient of variable load. γQi is the subentry coefficient of variable load Q1, to be adopted according to Article 3.2.5. SGk——The load effect value calculated according to the permanent load characteristic value/nominal value Gk; SQik——The load effect value calculated according to variable load characteristic value/nominal value Qik. SQ1k is the controller of all variable load effects. ψci——The combination value coefficient of the variable load Qi shall be adopted according to provisions in chapters. n——The number of variable loads forming the combination. 2) Combination controlled by the permanent load effect:. 5.
(11) (3.2.3-2) Note: 1 The design value of fundamental combination is applicable to the linear load effect. 2. If the SQ1k can't be decided distinctively, each variable load effect shall be taken as SQ1k and the most disadvantaged load effect combination shall be selected.. 3.2.4 For common bents and frame structures, the reduction rule may be adopted in the fundamental combination and the most disadvantaged value shall be selected according to the following combination values: 1) Combination controlled by variable load effect;. (3.2.4) 2) The combination controlled by the permanent load effect shall be adopted according to formula (3.2.3-2). 3.2.5 The subentry coefficient of combination of loads in the fundamental combination shall be adopted according to the following provisions: 1. Subentry coefficient of permanent load; 1) If the effect causes disadvantages to the structure, ——for the combination controlled by the variable load effect, select 1.2; ——for the combination controlled by the permanent load effect, select 1.35. 2) If the effect causes advantages to the structure, select 1.0. 2. Subentry coefficient of variable load: ——Generally, select 1.4; ——For the characteristic value/nominal value of the live load of industrial housing floor greater than 4kN/m2, select 1.3. 3. For the overturn, slippage or floating calculation, the load subentry coefficient shall be adopted according to provisions in related design codes for structures. 3.2.6 For the design value of accidental combination and load effect combination, it shall be in accordance with the following provisions: the representative value of the accidental loads doesn't multiply subentry coefficient; if it appears together with the accidental loads and other combinations of loads, the representative value shall be adopted according to the observational data and project experience. Under different circumstances, the formula of design value of the load effect shall be decided by contrary provisions. 3.2.7 In the regular service limiting state, according to different design requirement, the characteristic/nominal combination, frequent combinations or quasi-permanent combinations may be adopted and the design shall be carried out according to the following design expression: S≤C (3.2.7) Where, C——The limitation of structures or structural members when they are in regular service, such as the limitation of distortion, crack, amplitude, acceleration and stress, shall be adopted 6.
(12) according to related design codes for building structures. 3.2.8 The design value (S) characteristic/nominal combination and load effect combinations shall be adopted according to the following formula:. (3.2.8) Note: The design value of the combination is applicable to the linear combination of loads and load effect.. 3.2.9 The design value (S) of frequent combinations and load effect combinations shall be adopted according to the following formula:. (3.2.9) Where, ψf1——The frequent coefficient of variable load Q1 shall be adopted according to provisions in chapters. ψqi——The quasi value coefficient of the variable load Qi shall be adopted according to provisions in chapters. Note: The design value of the combination is applicable to the linear combination of loads and load effect.. 3.2.10 The design value (S) of quasi-permanent combinations and load effect combinations shall be adopted according to the following formula:. (3.2.10) Note: The design value of the combination is applicable to the linear combination of loads and load effect.. 4. Live load of floors and roofs 4.1 Rectangular distribution live load on floors of civilian buildings 4.1.1 The characteristic value/nominal value, combination value, frequent value and quasi-permanent value coefficient of the rectangular distribution live load on floors of civilian buildings shall be adopted according to Table 4.1.1.. 7.
(13) Table 4.1.1 the characteristic value/nominal value, combination value, frequent value and quasi-permanent value coefficient of rectangular distribution live load on floors of civilian buildings Item. Type. Characteristic. Combination. Frequent. Quasi-permanent. value/nominal. value. value. value coefficient. value (kN/m2). coefficient ψc. coefficient ψf. ψq. 0.5. 0.4. 2.0. 0.7 0.6. 0.5. (1) Residential buildings, dormitories, hotels, office buildings, hospital wards, nursery and 1. kindergarten; (2) Schoolrooms, testing labs, reading rooms, boardrooms, policlinic rooms of hospitals.. 2. Dining. restaurant,. archives. for. playhouse,. cinema. and. 2.5. 0.7. 0.6. 0.5. 3.0. 0.7. 0.5. 0.3. 3.0. 0.7. 0.6. 0.5. 3.5. 0.7. 0.6. 0.5. (2) Bleachers without fixed seats.. 3.5. 0.7. 0.5. 0.3. (1) Gymnasia and stages for performance;. 4.0. 0.7. 0.6. 0.5. (2) Ballrooms.. 4.0. 0.7. 0.6. 0.3. 0.9. 0.9. 0.8. 7.0. 0.9. 0.9. 0.8. (1) 3. rooms,. general materials; Auditoria,. bleachers with fixed seats; (2) Public laundries. (1) Stores, exhibition halls, stations, ports,. 4. 5. airport halls and waiting rooms;. (1) Stack rooms, archival repository and 6. store rooms; (2) Stack rooms with dense tanks.. 7. 5.0 12.0. Fan houses and elevator towers Automobile passages and parking rooms: (1) one-way slab building covers (the span no less than 2m) Carriages; Fire-fighting vehicles;. 8. (2) Two-way slab building covers (the span. 4.0. 0.7. 0.7. 0.6. 35.0. 0.7. 0.7. 0.6. no less than 6m*6m) and flat slab floor (the dimension of column grids no less than 6m *. 2.5. 0.7. 0.7. 0.6. 20.0. 0.7. 0.7. 0.6. Kitchen (1) Ordinary;. 2.0. 0.7. 0.6. 0.5. (2) Restaurant.. 4.0. 0.7. 0.7. 0.7. (1) Civilian building in item 1;. 2.0. 0.7. 0.5. 0.4. (2) Other civilian buildings.. 2.5. 0.7. 0.6. 0.5. 2.0. 0.7. 0.5. 0.4. 2.5. 0.7. 0.6. 0.5. 3.5. 0.7. 0.5. 0.3. (1) In common situation;. 2.5. 0.7. 0.6. 0.5. (2) People may be gathering.. 3.5. 6m) Carriages; Fire-fighting vehicles. 9. Bathrooms, toilets and wash rooms: 10. Corridors, hallways, staircases: (1) Dormitories, hotels, hospital wards, nursery, 11. kindergarten. and. residential. buildings; (2). Office. buildings,. schoolrooms,. restaurants, policlinic of hospitals; (3) Fire-control fire escapes and other civilian buildings. Balcony: 12. 8.
(14) Note: 1.. All live loads in this Table are applicable for natural service conditions. If the working load is extremely large,. the live loads shall be adopted according to practical situations. 2. for the live load of stack rooms in item 6, if the height of bookshelves is greater than 2 m, the live load for stack rooms shall be decided according to a height no less than 2.5kN/m2. 3. The live load for carriages in item 8 is applicable to carriages holding fewer than 9 persons. The live load of fire-fighting vehicles is applicable to oversize vehicles with the full load of 300kN. If requirements in this Table are not met, according to the equivalence principle of structural effect, the partial load of wheels shall be converted to the equivalent uniform live load. 4. The live load for staircases in item 11, for the precast stair footfall slabs, shall be calculated according to a concentrated load of 1.5kN. 5. All combinations of loads do not contain the deadweight of partitions and the combination of loads for the second fixture and fitting. The fixed partition and deadweight shall be taken as permanent combination of loads. If the position of partitions can be moved freely, the weight of non-fixed partitions shall take 1/3 the weight of the wall as the additive value (kN/m2) which shall be no less than 1.0 kN/m2 of the live loads on floors.. 4.1.2 For the design of girders, walls, columns and foundations of floors, under the following circumstances, the characteristic value/nominal value of live loads on the floors in Table 4.1.1 shall be multiplied by the discount coefficient: 1. The discount coefficient during the design of floor girders; 1) In item 1(1), if the tributary area of girders exceeds 25m2, select 0.9; 2) In items 1(2)-7, if the tributary area of girders exceeds 50m2, select 0.9; 3) In item 8, junior beam of one-way slabs and vittae of trough plates, select 0.9; For girder of one-way slabs, select 0.6; For girders of two-way slabs, select 0.8. 4) For items 9-12, the discount coefficient shall be the same as that of the buildings. 2. The discount coefficient of designing walls, columns and foundations: 1) Item 1(1) shall be adopted according to Table 4.1.2. 2) Items 1(2)-7 shall adopt the discount coefficient the same as that of the girders of floors. 3) In item 8, for one-way slabs, select 0.5; For two-way slabs and flat slab floors, select 0.8. 4) In items 9-12, the discount coefficient shall be adopted the same as that of the building. Note: The tributary area of floor girders is decided by the real area within the range extending 1/2 case bay to both sides of the girder.. Table 4.1.2 Discount coefficient of live loads according to different floors Number of floors above the calculation section of walls, volumes and foundations. 1. 2-3. 4-5. 6-8. 9-20 ≥20. The discount coefficient of live loads total on each floor above the calculation section. 1.00 (0.90). 0.85 0.70 0.65 0.60 0.55. Note: If the tributary area of floor girders exceeds 25m2, the coefficient shall adopt the one in the parentheses.. 4.1.3 The partial loads on floor structures shall be converted into isoeffect rectangular distribution live loads according to Appendix B.. 9.
(15) 4.2 Floor live load of industrial buildings 4.2.1 During the production utilization or the installation repair of floors of industrial buildings, the partial load produced by the equipment, pipelines, transportation tools or possibly-removed partitions shall be considered according to the practical situation and can be substituted by the isoeffect rectangular distribution live load. Note: 1. The floor isoeffect rectangular distribution live load shall be decided by the method stated in Appendix B. 2. For common smith shops, instrumentation production workshops, semiconductor device workshops, cotton spinning and knitting workshops, preparing shops in tire plants and grain processing workshops, if there are not enough materials; it shall be adopted according to Appendix C.. 4.2.2 The operation combination of loads, including operating personnel, general purpose tools, small amount of raw materials and the deadweight of finished products on areas without equipment of floors ( including working platforms) of industrial buildings shall be considered as the rectangular distribution live load and adopt 2.0kN/m2. The staircase live load in production workshops shall be adopted according to the practical situation and shall be no less than 3.5kN/m2. 4.2.3 The combination value coefficient, frequent value coefficient and quasi- permanent value coefficient of floor live loads of industrial buildings shall be adopted according to the practical situation besides values given in Appendix C. However, under no circumstance shall the combination value and the frequent value coefficient be less than 0.7 and the quasi-permanent value coefficient no less than 0.6. 4.3 Roof live load 4.3.1 The roof rectangular distribution live load on the horizontal projection surface shall be adopted according to Table 4.3.1. The roof rectangular distribution live load can't be considered together with the snow load. Table 4.3.1 Roof rectangular distribution live load Characteristic Item. Type. Combination value. Frequent value. Quasi-permanent value. coefficient ψc. coefficient ψf. coefficient ψq. 0.5. 0.7. 0.5. 0. 2.0. 0.7. 0.5. 0.4. 3.0. 0.7. 0.6. 0.5. value/nominal value (kN/m2). 1. 2 3. Roof without holding persons Roof holding persons Roof garden. Note: 1. For roofs without holding persons, if the construction load is comparatively large, it shall be adopted according to the practical situation. For different structures, according to related design specifications, the characteristic value/nominal value shall be increased or decreased by 0.2kN/m2. 2. For roofs holding persons, if they are used for other purposes, relevant floor live loads shall be adopted. 3. For seeper combination of loads caused by the disturbance of roof drainage or blockage, construction measures shall be adopted. If necessary, the roof live loads shall be decided according the possible depth of. 10.
(16) seepers. 4. The live load on roof gardens does not include the material deadweight of earth materials.. 4.3.2 The combination of loads of parking apron for helicopters shall be considered as the partial load according to the gross weight of the helicopter. At the same time, its isoeffect shall be no lower than 5.0kN/m2. The partial load shall be decided according to the practical maximum lifting loads of helicopters. If there is no technical information of aircraft types, commonly, the partial load characteristic value/nominal value and active area shall be selected according to various requirements of light, medium and heavy types: ——Light-type: the maximum take-off weight is 2t, partial load characteristic value/nominal value is 20kN and the active area is 0.20m * 0.20m. ——Medium-type: the maximum take-off weight is 4t, partial load characteristic value/nominal value is 40kN and the active area is 0.25m * 0.25m. ——Heavy-type: the maximum take-off weight is 6t, the partial load characteristic value/nominal value is 60kN and the active area is 0.30m * 0.30m. The combination value coefficient of loads shall be 0.7, the frequent value coefficient 0.6 and the quasi-permanent value coefficient shall be 0. 4.4 Roofing dust load 4.4.1 During the design of workshops that release mass dust and their neighboring buildings, for roofs of machinery, cement and metallurgy workshops with certain dedusting facilities, the roof dust load on the horizontal projection surface shall be adopted according to Table 4.4.1-1 and 4.4.1-2.. 11.
(17) Table 4.4.1-1 Roof dust load Characteristic value/nominal value Combination. (kN/m2) Item. Type. Roofs without breastplate. 1 2 3. 4. 5. 6. Foundry in machinery plants ( cupola) Melting house ( oxygen converter) Manganese and ferrochrome workshops Silicon and ferrotungsten workshops Sintering chambers of sintering plants and primary mixing rooms Propylaea and other workshops in sintering plants. Roofs with breastplate Within. Out of. Frequent Quasi-permanent. value. value. value. coefficient. coefficient. coefficient. ψc. ψf. ψq. 0.9. 0.9. 0.8. breastplates breastplates. 0.5. 0.75. 0.30. -. 0.75. 0.30. 0.75. 1.00. 0.30. 0.30. 0.50. 0.30. 0.50. 1.00. 0.20. 0.30. -. -. 1.00. -. -. 0.50. -. -. Workshops with dust sources in cement mills ( kiln rooms, mill 7. rooms, combined storehouses, drying rooms and fragmentation rooms) Workshops without dust sources in. 8. cement mills ( compressor plants, workshops, material sheds and distribution substations). Note: 1. In the Table, the evenly distributed load of soot formation shall be only applicable to the roof slope α≤25°. If α≥45°, the dust load may be neglected. If 25°<α<45°, the value can be selected using the interpolation method. 2. The combination of loads of ash removal facilities shall be considered additionally. 3. For items 1-4, the dust load shall apply only to roofs within the rad of 20m centered by the stack. If neighboring buildings are within this range, the dust load for items 1, 3 and 4 shall be adopted according to the roofs without breastplate in workshops. For item 2, the dust load shall be adopted according to roofs out of breastplates in workshops.. 12.
(18) Table 4.4.1-1 Roof dust load Characteristic. value/nominal. 2. value(kN/m ) Blast. Combination. furnace. volume ( m3). The distance between the roof and the blast furnace (m) ≤50. 100. 200. <255. 0.50. -. -. 255-620. 0.75. 0.30. -. >620. 1.00. 0.50. 0.30. value Frequent. value Quasi-permanent. coefficient ψc. coefficient ψf. coefficient ψq. 1.0. 1.0. 1.0. value. Note: 1. Note 2 of Table 4.4.1-1 can be applicable to this Table as well. 2. If the distance between the roofs of neighboring buildings and the blast furnace is the intermediate value in the Table, the value can be selected according to the interpolation method.. 4.4.2 For places vulnerable for dust deposition on roofs, during the design of roof boards and summers, the characteristic value/nominal value of dust load shall be multiplied by the aggrandizement coefficient as stated: Within the dispersion of distribution that is twice the roof height difference but no greater than 6.0m in the high-low span, select 2.0; within the dispersion of distribution no greater than 3.0m of cullis, select 1.4. 4.4.3 The dust load shall be considered with the snow load or roof live load but the one with a comparatively large value. 4.5 Construction and repair load as well as handrail horizontal load 4.5.1 During the design of roofing boards, summers, reinforced concrete projecting eaves, rain hoods and prefabricated joists, the concentrated load (the deadweight of people and small tools) for construction and repair shall select 1.0kN and shall be calculated in the most disadvantaged place. Note: 1. For light members or wide members, if the construction load exceeds the aforesaid combination of loads, it shall be calculated according to the practical situation, or temporary facilities like adding backing boards and supports shall be adopted. 2. During the calculation of intensity of the projecting eaves and rain hoods, one concentrated load shall be taken into consideration in every 1.0m of the width of boards. During the calculation of overturning of projecting eaves and rain hoods, a concentrated load shall be taken into consideration in every 2.5-3.0m of the width of boards.. 4.5.2 The handrail top horizontal combination of loads on the staircases, bleachers, balcony and roofs holding persons shall be adopted according to the following: 1. For residential buildings, dormitories, office buildings, hotels, hospitals, nursery, kindergartens, select 0.5KN/m. 2. For schools, dining rooms, playhouses, cinema, stations, auditoria, museums or palaestra, select 1.0kN/m. 4.5.3 If the quasi- permanent combinations of loads is adopted, the construction and repair load as well as the handrail horizontal load can be neglected.. 13.
(19) 4.6 Dynamic coefficient 4.6.1 The power calculation of building structure design, if there are enough bases, shall be calculated according to the static force after the deadweight of heavy objects or equipment is multiplied by the dynamic coefficient. 4.6.2 The dynamic coefficient for starting and stopping vehicles, porting and handling heavy objects shall adopt 1.3. Its dynamic loads can only be transferred to the floor slabs and girders. 4.6.3 The combination of loads on roofs by helicopters shall be multiplied by the dynamic coefficient. For helicopters with hydraulic pressure tires, the coefficient shall adopt 1.4. The dynamic load can only be transferred to the floor slabs and girders.. 5. Crane load 5.1 Vertical and horizontal load of cranes 5.1.1 The characteristic value/nominal value of vertical loads of cranes shall adopt the maximum wheel pressure or the minimum wheel pressure of cranes according to relevant regulations. 5.1.2 The longitudinal and transverse horizontal combination of loads of cranes shall be adopted according to the following provisions: 1. The characteristic value/nominal value of vertical combination of loads of cranes shall be adopted according to 10% the total of maximum wheel pressures of all skid wheels that work on the same orbit. The point of application of this load shall lie on the point of contact between the skid wheel and the orbit, with the direction same as that of the orbit. 2. The characteristic value/nominal value of transverse horizontal combination of loads shall adopt the percentage in the following of the sum of the weight of crane carriages and the load-lifting capacity and then the result shall be multiplied by the acceleration of gravity: 1) Flexible-hook cranes: ——If the load-lifting capacity is no larger than 10t, select 12% ——If the load-lifting capacity is between 16-50t, select 10% ——If the load-lifting capacity is no less than 75t, select 8% 2) For hard-hook crane: select 20%. The transverse horizontal combination of loads shall be allocated evenly on both ends and transferred to the rail head by means of wheels on the orbit, with the direction vertical with the orbit. The skid with two opposite directions shall be taken into consideration. Note: 1. The horizontal load of suspending cranes can be neglected and received by related supports. 2. The horizontal load of hand cranes and electric blocks can be taken no account of.. 14.
(20) 5.2 The combination of several cranes 5.2.1 When the vertical load of several cranes are considered during the counting of bent frames, the number of cranes for the single-span workshops shall be no more than 2, while for multi-span ones, the number shall be no more than 4. For the horizontal load of several cranes, for the bent frames for single-span or multi-span workshops, the number of the cranes shall be no more than 2. Note: Particular instances shall be considered according to the practical situation.. 5.2.2 During the calculation of bent frames, the characteristic value/nominal value of the vertical load and horizontal load of several cranes shall be multiplied by the discount coefficient stated in Table 5.2.2. Table 5.2.2 the discount coefficient of combination of loads of several cranes The number of cranes for the combination 2 3 4. Work class of the crane A1-A5. A6-A8. 0.9 0.85 0.8. 0.95 0.90 0.85. Note: For the single-span or multi-span workshops of multi-layer cranes, during the calculation of bent frames, the number of cranes for the combination and the discount coefficient of loads shall be considered according to the practical situation.. 5.3 Dynamic coefficient of crane loads 5.3.1 During the calculation of intensity of crane beams and their connections, the vertical load of cranes shall be multiplied by the dynamic coefficient. Concerning the suspending cranes (including electric hoists), for the work class A1-A5 flexible-hook cranes, the dynamic coefficient shall be 1.05; for the work class A6- A8 flexible-hook cranes, hard-hook cranes and other special-type cranes, the dynamic coefficient shall be 1.1. 5.4 The combination value, frequent value and quasi-permanent value of crane loads 5.4.1 The combination value, frequent value and quasi-permanent value coefficient of crane loads shall be adopted according to Table 5.4.1.. 15.
(21) Table 5.4.1 the combination value, frequent value and quasi-permanent value of crane loads Work class of the crane. Combination. value Frequent. value Quasi-permanent. coefficient ψc. coefficient ψf. coefficient ψq. 0.7. 0.6. 0.5. 0.7. 0.7. 0.6. 0.7. 0.7. 0.7. 0.95. 0.95. 0.95. value. Flexible-hook crane Work class A1-A3 Work class A4- A5 Work class A6-A7 Hard-hook cranes and flexible-hook cranes with the work class of A8. 5.4.2 During the design of bent frames in workshops, in the quasi- permanent combinations of combinations of loads, the load of cranes shall be taken no account of. However, in the regular service limit design of crane beams, the quasi- permanent value of crane loads shall be adopted.. 6. Snow load 6.1 The characteristic value/nominal value and reference snow pressure of snow loads 6.1.1 The characteristic value/nominal value of snow load on the horizontal projection surface of the roof shall be calculated according to the following formula: (6.1.1) Sk = µrS0 Where, Sk——characteristic value/nominal value of the snow load (kN/m2); µr——Coefficient of snow distribution over the roof S0——reference snow pressure (kN/m2). 6.1.2 The reference snow pressure shall be adopted according to the 50-year value listed in Appendix D.4. For structures sensitive to snow loads, the reference snow pressure shall be elevated and decided by related codes for structural design. 6.1.3 If the reference snow pressure value of cities or construction sites is not listed in Appendix D, the reference snow pressure value can be decided according to the maximum snow pressure or snow depth materials, based on the definition of the reference snow pressure and making analysis over statistics. During the analysis, the influence of sample quantity shall be taken into consideration (please refer to Appendix D). If there is also no snow pressure or snow depth material, the value can be decided according to the reference snow pressure in the neighboring places or long-term materials and by means of contrastive analysis over meteorological and terrain conditions. Also, it can be approximately decided by the natioanl reference snow pressure distribution graph (appendix D.5.1). 6.1.4 The snow load of mountains shall be decided after the practical survey. If there is no survey material, it can be adopted as the snow load multiplied by the coefficient 1.2 in the local neighboring and open level surfaces. 6.1.5 The combination value coefficient of snow loads shall select 0.7, the frequent value coefficient 0.6 and the quasi-permanent value coefficient shall be 0.5, 0.2 and 0 respectively 16.
(22) according to snow load zoning I, II and III. The snow load zonings shall be decided according to Appendix D.4 or Attached figure D.5.2. 6.2 Coefficient of snow distribution over the roof 6.2.1 The coefficient of snow distribution over the roof shall be adopted according to Table 6.2.1 for different roofs.. 17.
(23) Table 6.2.1 Distribution Coefficient of Snow Pressure Item. Type. 1. Single-span, shed roof. Roof Table and distribution coefficient µr of snow pressure. Even distribution Uneven distribution. 2. Single-span, gable roof. 0.75µr. µr is adopted by Item 1. 3. Arched roof. Even distribution. 4. The roof with skylight. Uneven distribution. 18.
(24) Table 6.2.1 (Continued) Item. Type. Roof Table and distribution coefficient µr of snow pressure. Even distribution Uneven distribution. 5. The roof with skylight and breastplate. Even distribution Uneven distribution. 6. Multi-span, single slope roof (serrated roof). Even distribution Uneven distribution. 7. Double-span, gable or arched roof. µr is adopted by the requirements of Item 1 and Item 3. 8. High and low roof. a=2h and 8m≥a≥4m. 19.
(25) Note: 1. In item 2, only when 20°≤α≤30° of the single-span gable roofs, the even distribution shall be adopted. 2. Item 4 and item 5 shall be applicable to the general industrial workshop roofs with the gradient α≤25°. 3. For the double-span or gable or arched roof, if α≤25° or f/l≤0.1, the rectangular distribution shall be adopted. 4. For snow distribution coefficient of multi-span roof, please refer to provisions in item 7.. 6.2.2 During the design of supporting members of buildings structures and roofs, the snow distribution conditions shall be adopted according to the following provisions: 1. For roofing boards and purline, it shall adopt the most disadvantaged condition of the snow inhomogeneous distribution. 2. For roof trusses and arch shells, it shall be adopted according to the snow full-span rectangular distribution instances, inhomogeneous distribution instances and half-span evenly-distributed instances. 3. For frames and columns, it shall be adopted as the snow full-span rectangular distribution instance.. 7. Wind load 7.1 The characteristic value/nominal value and reference wind pressure of wind loads 7.1.1 The characteristic value/nominal value of wind loads vertical to the surface of buildings shall be calculated according to the following formula: 1. During the calculation of main bearing structures, (7.1.1-1) wk=βzµsµzw0 Where, wk——the characteristic value/nominal value (kN/m2) of the wind load; βz——Wind vibration coefficient at height Z; µs——Wind load coefficient; µz——Variation coefficient of wind pressure altitude w0——Reference wind pressure (kN/m2). 2. During the calculation of envelop enclosures, (7.1.1-2) wk=βgzµs1µzw0 Where, βgz——Gust coefficient at height Z; µs1——Partial wind pressure coefficient. 7.1.2 The reference wind pressure shall be adopted according to the 50-year value listed in Appendix D.4 but shall be no less than 0.3kN/m2. For high-rise buildings, towering structures and other structures sensitive to wind loads, the reference wind pressure shall be elevated and decided according to related codes for structural design. 7.1.3 If the reference wind pressure value of cities and construction sites is not listed in Appendix D, the reference wind pressure value can be decided according to the maximum wind speed materials, based on the definition of the reference wind pressure and making analysis over statistics. During the analysis, the influence of sample quantity shall be taken into consideration (please refer to Appendix D). If there is also no wind speed material, the 20.
(26) value can be decided according to the reference wind pressure in the neighboring places or long-term materials and by means of contrastive analysis over meteorological phenomena and terrain conditions. Also, it can be approximately decided by the national reference wind pressure distribution graph (appendix D.5.3). 7.1.4 The combination value, frequent value and quasi-permanent value coefficient of wind loads shall be 0.6, 0.4 and 0 respectively. 7.2 Variation coefficient of wind pressure altitude 7.2.1 For level or small-undulant terrain, the variation coefficient of wind pressure altitude shall be decided according to Table 7.2.1 based on different terrain roughness. The terrain roughness can be divided into A, B, C and D classes: ——A-Class: offing sea surfaces, islands, coasts, lakeshores and deserts; ——B-Class: open countries, countries, jungles, hills, and villages and suburbia with sparse buildings; ——C-Class: cities with dense buildings; ——D-Class: cities with dense high-rise buildings. Table 7.2.1 Variation Coefficient µz of the Wind Pressure Height Height away from the ground or sea surface. Types of ground roughness. (m). A. B. C. D. 5. 1.17. 1.00. 0.74. 0.62. 10. 1.38. 1.00. 0.74. 0.62. 15. 1.52. 1.14. 0.74. 0.62. 20. 1.63. 1.25. 0.84. 0.62. 30. 1.80. 1.42. 1.00. 0.62. 40. 1.92. 1.56. 1.13. 0.73. 50. 2.03. 1.67. 1.25. 0.84. 60. 2.12. 1.77. 1.35. 0.93. 70. 2.20. 1.86. 1.45. 1.02. 80. 2.27. 1.95. 1.54. 1.11. 90. 2.34. 2.02. 1.62. 1.19. 100. 2.40. 2.09. 1.70. 1.27. 150. 2.64. 2.38. 2.03. 1.61. 200. 2.83. 2.61. 2.30. 1.92. 250. 2.99. 2.80. 2.54. 2.19. 300. 3.12. 2.97. 2.75. 2.45. 350. 3.12. 3.12. 2.94. 2.68. 400. 3.12. 3.12. 3.12. 2.91. ≥450. 3.12. 3.12. 3.12. 3.12. 7.2.2 For mountainous buildings, the variation coefficient of the wind pressure height may not be determined by roughness types of the equitable terrain on the basis of Table 7.2.1, but also shall be adopted by considering the orographic conditions compensation and compensation factor 11 respectively on the basis of the following requirements:. 21.
(27) 1 For the mountain peak and hillside, the compensation factors on the top may be adopted according to the following formula:. η B = [1 + ktga(1 −. z )]2 2.5 H. (7.2.2). Where tgα——The slope of mountain peak or hillside on the windward side; when tgα>0.3, tgα takes 0.3; k——Coefficient, it takes 3.2 for mountain peak, and takes 1.4 for hillside; H——Overall height of the peak or hillside (m); z——Height from the calculated position of the building to the building ground, m; when z>2.5H, z takes 2.5H;. Figure 7.2.2 Mountain Peak and Sidehill Schematic. For other positions of the mountain peak and sidehill, they may comply with figure 7.2.2, compensation factor at Part A, Part C (ηA and ηC) is 1, while the compensation factors between A and B or between B and C are determined by linear interpolation of η. 2 For the blocking terrains like intermontaine basin and valley, η=0.75~0.85; For the valley mouth and mountain pass concurrent with the wind direction, η=1.20~1.50. 7.2.3 For high seas offing and insular buildings or structures, the variation coefficient of the wind pressure height may not only be determined by roughness type of A-type on the basis of Table 7.2.1, but shall also consider the compensation factor shown in Table 7.2.3. Table 7.2.3 Compensation Factor η of High Seas Offing and Island Distance away from the coast (km). η. <40. 1.0. 40~60. 1.0~1.1. 60~100. 1.1~1.2. 7.3 Wind load coefficient 7.3.1 Shape coefficient of the wind load of the building and structures may be adopted according to the following requirements: 1 When the building and structures are similar to the shapes shown in Table 7.3.1, it may be adopted by the requirements of this table; 2 When the building and structures have shapes different to those specified in Table 7.3.1, it may be adopted by referring to relevant data;. 22.
(28) 3 When the building and structures have shapes different to those specified in Table 7.3.1 and no reference available, it should be determined by tunnel test; 4 For important building and structures with complicated shapes, they shall be determined by tunnel test. Table 7.3.1 the Shape Coefficient of Wind Loads Items. 1. Type. Shapes and shape coefficient µs. Close-type grounding gable roof The median is calculated by interpolation method. 2. Close-type gable roof. The median is calculated by interpolation method. 23.
(29) Table 7.3.1 (Continued) Items. Type. 3. Close-type grounding arched roof. Shapes and shape coefficient µs. The median is calculated by interpolation method. 4. Close-type arched roof. The median is calculated by interpolation method. 5. Close-type shed roof µs of the windward slope, it is adopted by Item 2.. 6. Close-type high and low gable roof. µs of the windward slope, it is adopted by Item 2.. 7. Close-type gable roof with scuttle. Arched roof with scuttle may be adopted by this Figure.. 8. Close-type double-span gable roof. µs of the windward slope, it is adopted by Item 2.. 24.
(30) Table 7.3.1 (Continued) Items. Type. Shapes and shape coefficientµs. Close type unequal height 9. and unequal double spans gable roof. Windward slope µs is adopted by Item 2.. Close-type unequal height 10. and unequal three spans gable roof. Windward slopeµs is adopted by Item 2 µs1 for the windward wall surface on the upper part of the midspan is adopted by the following provisions: µs1=0.6(1-2h1/h) when h1=h, µs1=-0.6. Close-type gable 11. roof with scuttle and cover Close-type gable. 12. roof with scuttle and double cover. Close-type unequal height 13. and unequal three midspans gable roof with scuttle. Windward slope µs is adopted bt Item 2 µs1=0.6(1-2h1/h) when h1=h, µs1=-0.6. 25.
(31) Table 7.3.1 (Continued) Items. Type. Shapes and shape coefficient µs. Close-type double 14. span gable roof with scuttle. µs for the second scuttle surface of the windward is adopted by the following requirements: When a≤4h, µs=0.2 When a>4h, µs=0.6. 15. Close-type gable roof with parapet When the parapet height is limited, the shape coefficient of the roof may be adopted as roof without parapet. 16. Close-type gable roof with canopy. µs of the windward slope is adopted by Item 2.. Two opposite 17. close-type gable roof with canopy This Fig. is applicable to that with s of 8~20mm, and µs of windward slope is adopted by Item 2.. Close-type pitched 18. roof or arched roof with subsiding scuttle. 26.
(32) Table 7.3.1 (Continued) Items. Type. Shapes and shape coefficient µs. Close-type gable roof 19. or arched roof with subsiding scuttle µs of the second scuttle surface of the windward is adopted by the following requirements: When a≤4h, µs=0.2 When a>4h, µs=0.6. 20. Close-type roof with scuttle wind shield. Close-type double 21. span roof with scuttle wind shield. 22. Close type saw-tooth roof µs of windward slope is adopted by Item 2. When the tooth surface increases or reduces, it may be regulated evenly in (1), (2) and (3) three sections.. Close-type 23. complicated multi-span roof µs of the scuttle surface is adopted by the following requirements: When a≤4h, µs=0.2 When a>4h, µs=0.6. 27.
(33) Table 7.3.1 (Continued) Items. Type. Shapes and shape coefficient µs. This Fig. is applicable to conditions that shape coefficient µs in Hm/H≥2 and s/H = 0.2~0.4. Backing 24. close-type gable roof. Shape coefficient µs：. 28.
(34) Table 7.3.1 (Continued) Items. Type. Shapes and shape coefficient µs. Backing 25. close-type gable roof. This Fig. is applicable to conditions that shape coefficient µs in Hm/H≥2and s/H =0.2~0.4;. with scuttle. Single-sided 26. open type gable roof. µs of the windward slope is adopted by Item 2.. 29.
(35) Table 7.3.1 (Continued) Items. Type. Shapes and shape coefficient µs With. gable. Open. on. in. Shape coefficient µs. Double-side open 27. type and four-side open type gable roof The median is calculated by interpolation method Note: 1 Roof of this Fig. is allergic to wind, so to shall consider the sign reversal condition of µs when designing; 2 Overall horizontal force to the roof caused by longitudinal wind loads; When a≥30°, a is 0.05Aωh When a<30°, a is 0.10Aωh A is the horizontally-projected area of the roof, while ωh is the wind pressure at roof height h; 3 When the interior stockpiled articles or the building is on the hillside, the roof suction shall be increased, and it may be adopted by Item 26 (s).. Semi-open gable 28. roof of back and forth longitudinal wall. µs of the windward slope is adopted by Item 2. This Fig. Is applicable to building with upper part concentrically open area≥10% and≤50%. When the open area is as high as 50%, coefficient of the leeward wall surface is instead by -1.1.. Table 7.3.1 (Continued) Items. 29. Type. Shed and gable. Shapes and shape coefficient µs. The median is calculated by interpolation method. canopy. The shape coefficient is adopted by Item 27. 30. both.
(36) The median is calculated by interpolation method Note: (b) and (c) shall consider Note 1 and Note 2 of Item 27. 3 When the interior stockpiled articles or the building is on the hillside, the roof suction shall be increased, and it may be adopted by Item 26 (a). (a) Regular polygon (including rectangular) plane. (b) Y-shape plane. 30. Close-type building and structures L-shape. +-shape. plane. plane. II-shape plane. Sectional triangle plane. Table 7.3.1 (Continued) Items. 31. 32. Type. Shapes and shape coefficient µs. Members of sections. Truss. The shape coefficient of single truss is µst=φµs µs is the shape coefficient of the truss components; it is taken by Item 31 for shape steel and it is taken by Items 36 (b) for round pipeline members. φ=An/A is the breakwind coefficient of truss An is the net projected area of the truss member and node point breakwind. 31.
(37) A=hl is the bounded area of the truss.. n is the integral shape coefficient parallel to the truss. µ stw = µ st. 1 −η n 1 −η. µst is the shape coefficient of the single truss, and η is adopted by the following Table.. 32.
(38) Table 7.3.1 (Continued) Items. 33. Type. Shapes and shape coefficient µs. Independent wall and fence. (a) The profile coefficient µs when the angle tower pier is calculated integrally. coefficient φ 34. Tower pier. Triangle wind. Rectangle. Breakwind Wind direction ①. Wind direction ② Single angle. Angle. direction ①②③. combination ≤0.1. 2.6. 2.9. 3.1. 2.4. 0.2. 2.4. 2.7. 2.9. 2.2. 0.3. 2.2. 2.4. 2.7. 2.0. 0.4. 2.0. 2.2. 2.4. 1.8. 0.5. 1.9. 1.9. 2.0. 1.6. (b) The shape coefficient µs when the pipe and round steel tower pier is calculated integrally When µsw0d2≤0.002, µs is adopted by the µs of angle tower pier by multiplied by 0.8; When µsw0d2≥0.015, µs is adopted by the µs of angle tower pier by multiplied by 0.6. The median is calculated by interpolation method. 33.
(39) Table 7.3.1 (Continued) Items. 35. Type. Shapes and shape coefficient µs. Rotating umbo. (a) The shape coefficient µs of surface distribution when it is calculated locally. Structures of circular 36. section (including chimney and tower). Values in the table are applicable to surface smooth conditions in µsw0d2≤0.015, therein, w0 is in unit of kN/m2, and d is in unit of m. (b) The shape coefficient µs when it is calculated integrally. The median is calculated by interpolation method; △ is the prominent height of the surface. 34.
(40) Table 7.3.1 (Continued) Items. Type. Shapes and shape coefficient µs This Fig. is applicable to condition in µsw0d2≤0.015 (a) up and down dual-pipe. (b) back and forth dual-pipe. 37. Rotating umbo. µs listed in the table is the same of back and forth dual-pipes, therein, the forth pipe is 0.6 (c) close packing multi-pipe. µs is the sum of all pipes The shape coefficient µsx of the horizontal component wx and the shape coefficient µsy of the vertical component wy of the wind loads:. 38. Dragline. 7.3.2 If the space between multi-buildings, especially dense high-rise buildings is small, the interactive group effect of wind shall be considered. Commonly, the single building coefficient µs shall be multiplied by the mutual interference aggrandizement coefficient which can be decided according to test data of similar cases. If necessary, it can be got from the tunnel test. 7.3.3 During the calculation of the enclosure members and their connections, the partial wind pressure coefficient µs1 shall be decided according to the following provisions: I. External surface 1. For zones with positive pressure, it shall be adopted according to Table 7.3.1. 35.
(41) 2. Zone of negative pressure —For wall face, select -1.0; —For wall corners, select -1.8; —For roofing partial place (fastigium with periphery and roof slope greater than 10°), select -2.2; —For overhung members, such as cornice, canopy and sun shield, select -2.0. Note: If the action width of wall corners and roof partial regions is 0.1 of the building width or 0.4 of the mean altitude of buildings, select the smaller one but no less than 1.5m.. II. Internal surface For enclosed buildings, the external surface wind pressure shall be -0.2 or 0.2. Note: The aforesaid partial wind pressure coefficient µs (1) is applicable for enclosed members with the tributary area (A) less than or equal to 1m2. If the tributary area of the enclosed member is greater than or equal to 10m2, the partial wind pressure system coefficient µs (10) shall be multiplied by the discount coefficient 0.8. If the tributary area of members is less than 10m2 but greater than 1m2, the partial wind pressure system coefficient µs (A) shall be decided according to the logarithm linear interpolation of the area. µs(A)=µs(1)+[µs(10)-µs(1)]logA. 7.4 Downwind vibration and wind vibration coefficient 7.4.1 For building with height of more than 30m, high-rise structures with basic natural vibration period T1 of more than 0.25s and wide span roofing structures, they shall consider the impact of downwind vibration to the to the structure caused by the wind pressure pulse. The wind vibration calculation shall be made according to random vibration theory, and the structural natural vibration period shall be calculated by structural dynamics. Note: The basic approximate natural vibration period T1 may be calculated by Appendix E.. 7.4.2 For general cantilever-type structure, if such high-rise structures as truss, tower and chimney, or torsion-neglectable high-rise buildings with height of greater than 30m and depth-width ratio of greater than 1.5, they may only consider the impact of the first vibration mode, while the wind loads of the structure may be calculated by wind vibration coefficient on the basis of formula (7.1.1-1), and the wind vibration coefficientβz of the structure at height z may be worked out according to the following formula: βz=1+. ξvϕ z µz. (7.4.2). Where ξ——Augmenting factor of the ripple; v——Influence coefficient of the ripple; φz——Mode factor; µz——Variation coefficient of the wind pressure height 7.4.3 The augmenting factor of the ripple; may be determined by Table 7.4.3.. 36.
(42) Table 7.4.3 Augmenting Factor ξ of the Ripple 2. 2. 2. ω0T 1(kNs /m ). 0.01. 0.02. 0.04. 0.06. 0.08. 0.10. 0.20. 0.40. 0.60. Steel structure. 1.47. 1.57. 1.69. 1.77. 1.83. 1.88. 2.04. 2.24. 2.36. Steel structure of building with filler wall. 1.26. 1.32. 1.39. 1.44. 1.47. 1.50. 1.61. 1.73. 1.81. Concrete and masonry structure. 1.11. 1.14. 1.17. 1.19. 1.21. 1.23. 1.28. 1.34. 1.38. 2. ω0T 1(kNs /m ). 0.80. 1.00. 2.00. 4.00. 6.00. 8.00. 10.00. 20.00. 30.00. Steel structure. 2.46. 2.53. 2.80. 3.09. 3.28. 3.42. 3.54. 3.91. 4.14. Steel structure of building with filler wall. 1.88. 1.93. 2.10. 2.30. 2.43. 2.52. 2.60. 2.85. 3.01. Concrete and masonry structure. 1.42. 1.44. 1.54. 1.65. 1.72. 1.7. 1.82. 1.96. 2.06. 2. 2. 2. Note: when calculating ω0T 1, basic wind pressure may be replaced directly for regions with ground roughness of B-type, while for regions of A-type, C-type and D-type, it shall be replaced by local basic wind pressure being multiplied by 1.38, 0.62 and 0.32 respectively.. 7.4.4 Influence coefficient of the ripple may be determined by the following conditions respectively. 1 The condition when the windward width of the structure is far less than its height such as high-rise structure; 1) If the contour and mass are even along the aspect ratio, ripple ratio may be determined according to Table 7.4.4-1. Table 7.4.4-1 Influence Coefficient υ of the Ripple Total height. 10. H(m). 20. 30. 40. 50. 60. 70. 80. 90 100. 150. 200 250 300 350 400 450. A 0.78 0.83 0.86 0.87 0.88 0.89 0.89 0.89 0.89 0.89 0.87 0.84 0.82 0.79 0.79 0.79 0.79 Types of ground roughness. B 0.72 0.9 0.83 0.85 0.87 0.88 0.89 0.89 0.90 0.90 0.89 0.88 0.86 0.84 0.83 0.83 0.83 C 0.64 0.73 0.78 0.82 0.85 0.87 0.88 0.90 0.91 0.91 0.93 0.93 0.92 0.91 0.90 0.89 0.91 D 0.53 0.65 0.72 0.77 0.81 0.84 0.87 0.89 0.91 0.92 0。97 1.00 1.01 1.01 1.01 1.00 1.00. 2) When the width of the windward and crosswind side of the structure varies along the height in beeline or approach beeline, while the mass varies along the height continuous and regularly, influence coefficient of the ripple shown in Table 7.4.4-1 shall be multiplied by compensation factor θB and θv again. θB shall be the ratio between the width Bz at height z and the bottom width Bo of the structures windward; θυ may be determined by Table 7.4.4-2. Table 7.4.4-2 Compensation Factor θυ BH/Bo. 1. 0.9. 0.8. 0.7. 0.6. 0.5. 0.4. 0.3. 0.2. ≤0.1. θυ. 1.00. L 10. 1.20. 1.32. 1.50. 1.5. 2.08. 2.53. 3.30. 5.60. Note: BH and B0 are widths of the structures windward on the top and at the bottom.. 2 When the width of the structure windward is larger, condition for spatial correlation of wind pressure along the width direction shall be considered (such as high-rise building); if the contour and mass are even along the aspect ratio, the influence coefficient of the ripple may be the ratio between the total height H and its windward width B, it may be determined by Table 7.4.4-3.. 37.
(43) Table 7.4.4-3 Influence Coefficient υ of the Ripple Total height H(m). Types of H/B. ground. ≤30. 50. 100. 150. 200. 250. 300. 350. A. 0.44. 0.42. 0.33. 0.27. 0.24. 0.21. 0.19. 0.17. B. 0.42. 0.41. 0.33. 0.28. 0.25. 0.22. 0.20. 0.18. C. 0.40. 0.40. 0.34. 0.29. 0.27. 0.23. 0.22. 0.20. D. 0.36. 0.37. 0.34. 0.30. 0.27. 0.25. 0.24. 0.22. A. 0.48. 0.47. 0.41. 0.35. 0.31. 0.27. 0.26. 0.24. B. 0.46. 0.46. 0.42. 0.36. 0.36. 0.29. 0.27. 0.26. C. 0.43. 0.44. 0.42. 0.37. 0.34. 0.31. 0.29. 0.28. D. 0.39. 0.42. 0.42. 0.38. 0.36. 0.33. 0.32. 0，31. A. 0.50. 0.51. 0.46. 0.42. 0.38. 0.35. 0.33. 0.31. B. 0.48. 0.50. 0.47. 0.42. 0.40. 0.36. 0.35. 0.33. C. 0.45. 0.49. 0.48. 0.44. 0.42. 0.38. 0.38. 0.36. D. 0.41. 0.46. 0.48. 0.46. 0.46. 0.44. 0.42. 0.39. A. 0.53. 0.51. 0.49. 0.42. 0.41. 0.38. 0.38. 0.36. B. 0.51. 0.50. 0.49. 0.46. 0.43. 0.40. 0.40. 0.38. C. 0.48. 0.49. 0.49. 0.48. 0.46. 0.43. 0.43. 0.41. D. 0.43. 0.46. 0.49. 0.49. 0.48. 0.47. 0.46. 0.45. A. 0.52. 0.53. 0.51. 0.49. 0.46. 0.44. 0.42. 0.39. B. 0.50. 0.53. 0.52. 0.50. 0.48. 0.45. 0.44. 0.42. roughness. ≤0.5. 1.0. 2.0. 3.0. 5.0. 8.0. C. 0.47. 0.50. 0.52. 0.52. 0.50. 0.48. 0.47. 0.45. D. 0.43. 0.48. 0.52. 0.53. 0.53. 0.52. 0.51. 0.50. A. 0.53. 0.54. 0.53. 0.51. 0.48. 0.46. 0.43. 0.42. B. 0.51. 0.53. 0.54. 0.52. 0.50. 0.49. 0.6. 0.44. C. 0.48. 0.51. 0.54. 0.53. 0.52. 0.52. 0.50. 0.48. D. 0.43. 0.48. 0.54. 0.53. 0.55. 0.55. 0.54. 0.53. 7.4.5 The mode factor shall be determined by power calculation of the structure. For cantilever-type high-rise structure with contour, mass and rigidity vary continuously and regularly along the height, or the high-rise building even in aspect ratio, the mode factor may also be determined by relative height z/H on the basis of Appendix F. 7.5 Gustiness factor 7.5.1 When calculating wind loads of curtain wall component (including door window) of the blind bearing the wind pressure, gustiness factor shall be determined by Table 7.5.1. For other roof and wall face components, gustiness factor takes 1.0.. 38.
(44) Table 7.5.1 Gustiness Factor βgz Ground level (m). Types of ground roughness A. B. C. D. 5. 1.69. 1.88. 2.30. 3.21. 10. 1.63. 1.78. 2.10. 2.76. 15. 1.60. 1.72. 1.99. 2.54. 20. 1.58. 1.69. 1.92. 2.39. 30. 1.54. 1.64. 1.83. 2.21. 40. 1.52. 1.60. 1.77. 2.09. 50. 1.51. 1.58. 1.3. 2.01. 60. 1.49. 1.56. 1.69. 1.94. 70. 1.48. 1.54. 1.66. 1.89. 80. 1.47. 1.53. 1.64. 1.85. 90. 1.47. 1.52. 1.62. 1.81. 100. 1.46. 1.51. 1.60. 1.8. 150. 1.43. 1.47. 1.54. 1.67. 200. 1.42. 1.44. 1.50. 1.60. 250. 1.40. 1.42. 1.46. 1.55. 300. 1.39. 1.41. 1.44. 1.51. 7.6 Crosswind vibration 7.6.1 For round section structure, crosswind vibration (swirl desquamation) for different Reynolds number Re shall be checked according to the following provisions. 1 When Re<3×105 and the top wind speed υH of the structure is greater than υcr, subcritical breeze sympathetic vibration may occur. By then, anti-vibration measures may be adopted on the structure or the critical wind velocity υcr of the structure may be controlled to be no less than 15m/s. 2 When Re≥3.5×106 and 1.2 times of the top wind speed υH of the structure is greater than υcr, over- critical fresh gale sympathetic vibration may occur; by then, resonance effect caused by crosswind load shall be considered by Article 7.6.2. 3 When the Reynolds number is 3×105≤Re<106, supercritical wind vibration may occur, and it may not be treated. 4 Reynolds number Re may be determined by the following formula: Re=69000υD (7.6.1-1) Where υ——Wind speed for calculation, it may take υcr value; D——Diameter of the structural section (m) 5 The critical wind velocity υcr and structural top wind speed υH may be determined by the following formula: (7.6.1-2) vcr=D/TiSt. 39.
(45) vH=. 2000 µ H w0. (7.6.1-3). ρ. Where Ti——Natural vibration period of the structural vibration mode i; when checking the subcritical breeze sympathetic vibration, it takes basic natural vibration period T1; St——Strouhal number, it takes 0.2 for circular sectional structure; µH——Variation coefficient of the wind pressure height on top of the structure; w0——Basic wind pressure (kN/m2); ρ——Air density (kg/m3) 6 When the structure is reduced along the height section (inclination pitch is no greater than 0.02), diameter at 2/3 structural height may be approximately adopted. 7.6.2 The equivalent wind loads of vibration mode j caused by over-critical fresh gale sympathetic vibration at the height z may be determined by the following formula: (7.6.2-1) Wczj=|λj|vcr2φzj/12800ξj（KN/m2） Initial point height H1 of the critical wind velocity shown in Table 7.6.2 may be determined by the following formula: H1=H× (. vcr 1 / a ) 1.2vH. (7.6.2-2). Where: α——Ground roughness index, they are 0.12, 0.16, 0.22 and 0.30 for A-type, B-type, C-type and D-type respectively; υH——Wind speed on top of the structure (m/s) Note: when checking the crosswind vibration, high vibration mode No. considered is no greater than 4, and it may take the first or second vibration mode for general cantilever-type structure.. Table 7.6.2 Table for λj Calculation Structure. Vibration. type. mode No.. H1/H 0. 0.1. 0.2. 0.3. 0.4. 0.5. 0.6. 0.7. 0.8. 0.9. 1.0. 1. 1.56. 1.55. 1.54. 1.49. 1.42. 1.31. 1.15. 0.94. 0.68. 0.37. 0. High-rise. 2. 0.83. 0.82. 0.76. 0.60. 0.37. 0.09. -0.16. -0.33. -0.38. -0.27. 0. structure. 3. 0.52. 0.48. 0.32. 0.06. -0.19. -0.30. -0.21. 0.00. 0.20. 0.23. 0. 4. 0.30. 0.33. 0.02. -0.20. -0.23. 0.03. 0.16. 0.15. -0.05. -0.18. 0. High-rise. 1. 1.56. 1.56. 1.54. 1.49. 1.41. 1.28. 1.12. 0.91. 0.65. 0.35. 0. building. 2. 0.73. 0.72. 0.63. 0.45. 0.19. -0.11. -0.36. -0.52. -0.53. -0.36. 0. 7.6.3 When checking crosswind vibration, the gross effect of wind loads may determine the crosswind load effect Sc and downwind load effect SA by the following formula: S= SC2 + S A2. (7.6.3). 7.6.4 For the structure of non-circular section, equivalent wind loads of the crosswind vibration should be determined by the tunnel test of the air elastic model; or it may be determined by reference to the relevant information.. 40.
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