SANS 8686-1-2009 Cranes - Design principles for loads and load combinations Part 1 General《起重机 荷载及荷载组合设计原则 第1部分 总则》.pdf

《SANS 8686-1-2009 Cranes - Design principles for loads and load combinations Part 1 General《起重机 荷载及荷载组合设计原则 第1部分 总则》.pdf》由会员分享，可在线阅读，更多相关《SANS 8686-1-2009 Cranes - Design principles for loads and load combinations Part 1 General《起重机 荷载及荷载组合设计原则 第1部分 总则》.pdf（36页珍藏版）》请在麦多课文档分享上搜索。

1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-22603-9 SANS 8686-1:2009Edition 1ISO 8686-1:1989Edition 1SOUTH AFRICAN NATIONAL STANDARD Cranes Design principles for loads and load combi

4、nations Part 1: General This national standard is the identical implementation of ISO 8686-1:1989, and is adopted with the permission of the International Organization for Standardization. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428

5、 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 8686-1:2009 Edition 1 ISO 8686-1:1989 Edition 1 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS TC 96, Cranes, in accordance with procedures of the SABS Standards Division

6、, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in August 2009. . INTERNATIONAL STANDARD ISO 86864 First edition 1989-11-15 Cranes - Design principles for loads and load combinations - Part 1 : General Appareils de levage S Charge suspendue - Principes de calc

7、ul des charges et des combinaisons de Charge - Partie 7 : G b) features not present in the design; c) conditions which are design of the appliance. prevented or suppressed by the If a probabilistic proof of competence calculation is used, the relevant conditions, particularly the acceptable probabil

8、ity of failure, shall be stated. 6 Loads and applicable factors This clause gives loads and ranges of values for the factors used in proof of competence calculations when determining load effects. Individual values for specific types of appliance, selected from these ranges, will be found in the Par

9、ts of this International Standard covering those appliances. The loads acting on a lifting appliance are divided into the categories of regular, occasional, exceptional, and miscel- laneous. Individual loads are considered only when and if they are relevant to the appliance under consideration or to

10、 its usage : a) Regular loads, occurring during normal Operation, shall be considered in proof of competen ce calculations against failure by yielding, elastic instability and, when applicable, against fatigue. They result from gravity and from acceler- ation or deceleration produced by drives and b

11、rakes acting on the masses of the lifting appliance and the hoist load, as well as from displacements. b) Occasional loads and effects which occur infrequently are usually neglected in fatigue evaluations. They include loads induced by in-Service wind, snow and ice, tempera- ture and skewing. c) Exc

12、eptional loads and their effects are also infrequent and may likewise usually be excluded from fatigue con- sideration. They include loads caused by testing, out-of- Service wind, buffer forces and tilting, as well as from emergency Cut-out, failure of drive components, and exter- nal excitation of

13、the lifting appliance foundation. d) Miscellaneous loads include erection and dismantling loads as well as loads on platforms and means of access. The category in which a load is placed is not an indication of the importante or criticality of that load. For example, erection and dismantling loads, a

14、lthough in the last category, shall be given particular attention as a substantial Portion of accidents occur during those phases of Operation. 6.1 Regular loads 6.1.1 Hoisting and gravity effects acting on the mass of the lifting appliance The mass of the appliance includes those components which a

15、re always in place during Operation, except for the payload itself (see 6.1.2). For some appliances or applications, it may be necessary to add mass to account for encrustation of materials, such as coal or similar dust, which build up on the appliance or its Parts. The gravitational forte induced b

16、y the mass of the appliance (dead weight) shall be multiplied by the factor GI, where 1 - = 1 + a, 0 G a G OJ. In this way the vibrational excite- ment of the lifting appliance structure, when lifting the gross load off the ground, is taken into account. There are always two values for the factor in

17、 Order to reflect both the upper and lower reaches of the vibrational pulses. The factor Q1 shall be used in the design of the appliance struc- ture and its supports; in some cases, both values of the factor shall be applied in Order to find the most critical loadings in members and components. Anne

18、x C gives a general comment on the application of factors. 6.1.2 Inertial and gravity effects acting vertically on the gross load The mass of the gross load includes the masses of the payload, lifting attachments and a Portion of the suspended hoist ropes. 6.1.2.1 Hoisting class For the purposes of

19、this clause, lifting appliances are assigned to hoisting classes HC1 to HC4 according to their dynamic characteristics. The hoisting classes of appliances are given in 3 SANS 8686-1:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 8686

20、-1 : 1989 (EI table 2 and shall be selected on the basis of experience. Cor- responding values of 2 and G2 are also given in table 2 and illustrated in figure 1. The selection of the hoisting class depends on the particular type of Iifting appliance and is dealt with in the other Parts of this Inter

21、national Standard. Equally, values of e2 tan be determined by experiment or analysis without reference to hoisting class. Table 2 - Values of 2 and G2 I l 02 Hoisting class of appliance 2 2 , min 1 2, max HC1 02 1 1,3 HC2 04 1,05 1,6 HC3 W 11 19 HC4 03 1,15 22 6.1.2.2 Hoisting an unrestrained ground

22、ed load In the case of hoisting an unrestrained grounded load, the dynamic effects of transferring the load from the ground to the Iifting appliance shall be taken into account by multiplying the gravitational forte due to the mass of the gross load by a factor $9. (See figure 1.) NOTE - The dynamic

23、 effects covered by this clause occur when the drive Comes up to Speed before the lifting attachment engages the load and are the result of the build-up of kinetic energy and the drive torque. The factor 992 shall be taken as follows: 2 = (bz, min, for Vh 0,2 m/s vh is the steady hoisting Speed, in

24、metres per second, related to the lifting attachment, derived from the steady rotational Speed of the unloaded motor or engine; 2 is a factor assigned to the hoisting class (sec table 2); 2, min is given in table 2 for the hoisting class. Where the hoist drive control System ensures the use of a ste

25、ady creep Speed, this Speed only shall be taken into account to cover normal Operation in determining the value of 4!1. Where this is not the case, two conditions shall be considered by taking a value of G2 to cover normal Operation, as in 6.1.2.2.1, and a value of G2 max to cover exceptional occur-

26、 rences, as in 6.1.2.2.2. 6.1.2.2.1 For normal Operation a) Where a steady creep Speed tan be selected by the crane driver, this Speed shall be used in determining the value of G2. b) Where a stepless variable Speed control is provided or such control tan be exercised by the crane driver, the value

27、of 402, min for the appropriate hoisting class shall be selected from figure 1. 6.1.2.2.2 For exceptional occurrences For appliances with control of type a) as in 6.1.2.2.1, the value of 402 max shall be based on a value of Vh derived from the maxi- mumnominal Speed of the unloaded motor or engine.

28、For appliances with control of type b) as in 6.1.2.2.1, the value of 2,max for the hoisting class shall be based on a value of Vh derived from a value of not less than 0,5 times the maximum nominal Speed of the unloaded motor or engine. Annex C gives a general comment on the application of factors.

29、6.1.2.3 Effects of sudden release of part of payload For Iifting appliances that release or drop part of the payload as a normal working procedure, such as when grabs or magnets are used, the peak dynamic effect on the appliance tan be simulated by multiplying the payload by the factor G3 (see figur

30、e 2). The value of G3 is given by tp3 = 1 - om(l +3) m where Am is the released or dropped part of the payload; m is the mass of the payload; 3 = 0,5 for appliances equipped with grabs or similar slow- release devices, = 1 for appliances equipped with magnets or similar rapid-release devices. Annex

31、C gives a general comment on the application of factors. 6.1.3 Loads caused by travelling on an uneven surface 6.1.3.1 Lifting appliances travelling on or off roadways The effects of travelling, with or without load, on or off road- ways, depend on the appliance configuration (mass distri- bution),

32、the elasticity of the appliance and/or its Suspension, the travel Speed and on the nature and condition of the travel surface. The dynamic effects shall be estimated from experi- ence, experiment, or by calculation using an appropriate model for the appliance and the travel surface. 4 SANS 8686-1:20

33、09This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 86864 : 1989 (EI m 4 Figure 1 - Factor 2 2,min 132 2- HL 1,15 Q,8 , HC3 1,l Oh HC2 LOS 0,4 1 , HC1 02 , 1 l - *- 02 1 1,5 vh,m/s Am m Figure 2 - Factor 413 SANS 8686-1:2009This s tandard m

34、ay only be used and printed by approved subscription and freemailing clients of the SABS .ISO 86864 : 1989 (El 6.1.3.2 Lifting appliances travelling on rails The effects of travelling with or without Ioad on rail tracks having geometric or elastic characteristics that induce acceler- ations at the w

35、heels of the appliances depend on the appliance configuration (mass distribution, elasticity of the appliance and/or its Suspension), travel Speed and wheel diameter. They shall be estimated from experience, experiment, or by calcu- lation using an appropriate model for the appliance and the track.

36、The induced accelerations may be taken into account by multi- plying the gravitational forces due to the masses of the lifting appliance and gross load by a factor $I. International Stan- dards for individual types of appliance may specify tolerantes for rail tracks and indicate conditions within wh

37、ich the value of 41 may be taken as 1. Annex C i$ factors. gives a general comment on the application of Annex D gives an example of a model for estimating the value of G4 to take account of the vertical accelerations induced at the wheels of an appliance travelling on rail tracks with non- welded S

38、teps or gaps. 6.1.4 Loads caused by includ ing hoist drives acceleration of all crane Loads induced in a lifting appliance by accelerations or deceler- ations caused by drive forces may be calculated using rigid- body kinetic models that take into account the geometric properties and mass distributi

39、on of the lifting appliance drive and, where applicable, resulting inner frictional losses. For this purpose, the gross load is taken to be fixed at the top of the jib or immediately below the trab. A rigid-body analysis does not directly reflect elastic effects. To allow for these, the Change in dr

40、ive forte (M), inducing either the acceleration or deceleration, may be multiplied by a factor 5 and algebraically added to the forte present before the ac- celeration or deceleration takes place. This amplified forte is then applied to the components exposed to the drive forte and, Drive forte Spee

41、d where applicable, to the appliance and the gross load as weil. (See figure 3.) The range sf values for G5 is 1 1 the value of which shall be selected according to the requirements of the particular application. Using the allowable stress method, the allowable Stresses shall be divided by the coeff

42、icient. Using the limit state method, the loads shall be multiplied by yn. See annex A. 12 SANS 8686-1:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .ISO 86864 : 1989 (El Annex A (normative) Application to the allowable stress method and

43、 the limit state method of design (see clause 5) A.1 Introduction The principles set out in this part of ISO 8686 for determining the loads and load combinations to be taken into account in proof of competence calculations are applicable to both the allowable stress method and the limit state method

44、 of design. This annex describes their application in general terms. A.2 Allowable stress method Individual specified loads, fi , are calculated and amplified where necessary using the applicable factors They are then combined according to the load combination under consider- ation from table 3. The

45、 combined load, Fj , is used to deter- mine the resulting load effects, & , i.e. the inner forces and moments in members or the forces on supports. The Stresses, F, , due to the action of the load effects on a par- ticular element or component are calculated and combined with any Stresses, C2, resul

46、ting from local effects. The resulting f i Fj - Sk design stress Fl should allowable value of adm o be compared with an appropriate Admissible Stresses are obtained by dividing the specified strengths R of the material, such as the Stresses corresponding to the yield Point, limit of elastic stabilit

47、y or fatigue strength, by a coefficient yf, specified in table 3 according to the basic load combination (see 7.1.11, and, where appropriate, by a risk coef- ficient yn (see 7.3.5). Special care is required to ensure a valid proof of competence when the allowable stress method is applied to cases wh

48、ere in- ternal forces are not linearly proportional to the loads producing them or critical values of stress result from the combination of independently varying loads which give Stresses of opposite signs. A flow Chart illustrating the allowable stress method of design is shown in figure A.I. R 0 a

49、nd F 0) b) For event II awM(+ = 0) i-1 r2 r-l q - wmg 1 12 201(rlv f-2 r- ) q + m since il = + 1 (as ti 0 and F 0) jJ(, = - 21fBIr1r2r-1q-1 + wmg 1 12 1 21(t-l- r2 r- ) q- + m since A. = - 1 (as U 0 and F 0) From these results it tan be seen that if ME) = 1 iMB 1, the acceleration Xlf) for event I is less than the deceleration Z(, for event II. E.7 Design load effects in the mechanical components As an example, the tangential forte to be transferred by the gears and to be considered in design, F, is estimated as follows (see clause E.4 and figure