API STD 4B-1952 WOODEN DERRICKS (Fourteenth Edition).pdf

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3、leum In!IUtute 2 Atnerira Pt:troleum Iniltltute -=“= TABLE 01 CONTENTS Foreword - . . . . . 3 Sect. I: Scope . . . . 4 Sect. II: Material _ . 4 Sect. Ill: Design Dimensions 4 Sect. IV: Design Loads , . 5 Sect. V: Allowable Unit Stresses 7 Sect. VI: Workmanship - 7 Sect. VII: Marking : - 8 Sect. VIII

4、: Inspection and Rejection - 8 Appendix A: Safe Load Capacity . 9 Appendix B: List of Atthorized Manufacturers lO Appendix C: Use of API Monogram 11 Note fhb edltioft aupenedes tbst nqultemeote on .oodn denieb aa ILlJNG UDJC 0 UD“ u UDOORe“ u “ of “ of . “f . CALtiOA“IA CCM91_ TION OAILLikC. CA8LE T

5、OO_ DRILLING PRODUCTION d. Requirements on standard rigs are ven-in API Std. 4A, Specification for Steel Derricks (Including Standard Rigs). e. Recommended practice on the erection, care. and use of steel derricks as given in Appendix A of API Std 4A includes some suggestions which are applicable to

6、 wooden derricks, particularly to derrick founda tions, and should be consulted by users of wooden derricks. Amerleaa Pt.troleurn ln9titute SECTION I SCOPE I. This specification covers requirements for wooden derricks, including atipulatiom1 on materials, design fontures, londlngs, and allowable str

7、esses. Rec.: ommendations on safe load capaciti.ea for wooden dew ricks are included ns an appendix. .1 2. NoJ.ing contained in this specification i5 to be constru,d as .a-ranting any right, by implication Of otherw e, !or manufacture, sale, or use in connecw tion lh any method, apparatus, or produc

8、t covered by lea:ers patent, nor a5 insuring anyone against liaw bi!it for infringement of letters patent. SECTJ ,;-f TI M.ft.tERIAL 3. Structural L:mber. Lumber used in construc tion of wooden denfcks shall conform to the manufac turers nssociatlon grading rules under which the material is Jurchase

9、d and shall be grade marked or accompanie by n manufacturers association certifi cate of inspection. SECTION III DESIGN DIMENSIONS Definitions of Measuremnts 4. Derriek Size. The si7.P.s of wooden derricks shall be as specified 111 Table 1. The si1:es may be referred to by number1 nnd eaeh size shRl

10、l have only the partic ulnr combination of height A, base square B. and water table opening D, lS given. 5. Derrick Height. The height dimension A shnll be measured Rlong the neutral axis of the derrick leg from the top of the nte-r of Drill Holt. For stTaiht cable-tool drilling the center of the dr

11、ill hole shall be 6 in. from the center of tht derrick base on the center line to8 wards the samson post, with a t“lerance of :!: in. For combination cble and rotary tool drilling, and for straigh. rotary drilling. the center of the drill hole shall be at the center of the derrick base, tolerance %i

12、n. 1U desl. bisrber iio poln may be e:u.red oD apt“Cial ordt. Spllc11lion for noden Derrlk 5 SECTION IV DESIGN LOADS 12. Ma:dnium Safe Load. he maximum o;afe load of a wooden derrick, exprssea in pounds, sh1.1l be the total sole load of the derrlek and shall be pecifled on the name plate. 13. Maximu

13、m Safe Load Determinations. rrhe maximum safe load of a wooden derrick shall be d,ter mined by multiplyin,.- the maximum safe loef the der-rick ulting (rom the pArticular point of nneborA.ge , 54 mph. An actual wind velocity of 54 mph. is .equivalent to 10 mph. indicated velocity as de t,rmined by t

14、he Robinson fou-rcup anemometer. w;,d velocities TepOTted by the u. s. IVeather Bureau. stations are currently determined on more accurate iustn,ments and are within. ap proximately .1 per cent of the actual wind velocities. 16. The wind-load area of the pipe setback shooo 83 7,980 WI SA 1136 5 8 8,

15、900 22.5 5 8“ X 90 510 8,720 6,000 83 7,980 lA-,plJN to 136ft. rlenlck with either 26lt. or 30ft. baae. 2132 atands (12 taDda ( 9 stan.U lly 10 stands). 6 Ami!rlcnD Pftroleum lnttltute NOTE: In prev1ous editions of this specifica tion, aasumed pipe setback weights and wind areas were established in

16、, -:der to pTovide for standardized derrick designs. In th:is editicnt thesa assumed loadings have been retained, in order to Tetain ezisti-ng designs. In Table :1, these a18Utned ladinB ate exprmid in term of total length of pipe, weight per foot, and dimenmons ofpipe Sf!t back. (Pipe sizes, total

17、lengths, and 1ueights pe-r foot haue. been adjuaeed to confurm to current field practices and because of this their relation ship to wiml-load areas are only approximately equivalent.) If th.R c:sumed setbnc:k load c;ondi tions shown in Tabls are ezceeded, ptroper pre cautions should !Joe takm to pr

18、otect the derrick muler conditions oj high wind loads. NOTE: The wind-load anc. of the 1ipe setba. 1“-ind load on the Pipe setback, hori:ontal compo-:umt of the weight of the piOB ,-;etback, and the comoined resultmtt of these two loads, all Cl8 given in Table JJ, are based on the following assumpti

19、on and compr.tta ttons. a. lYind-Load Area of Pipe Setback. The area. for wind load ina /01 pipe setbacks qiven in Col. 7, Table 3, are based on the usm1.med heights of stands, number of stand., and arrangement of st.tnd.-; shown in Table 2. b. nind Load on Pipe Stback. The wind loads on the pipa se

20、lbuck at the point ol ongin, as given in Col. 9, Table !, are based on the area of 11ips set.back (Col. 7, times specified -minimum unit wi-ncl load (Par. H). Example (1S6-It. derrick): 510 X 11.76 = 6,000. c. Horizontal Component of 1Vei9ht of Pipe Set back. The ho-rizontal C()mponents of the uei!J

21、ilt of r.pe setback at the point of origin, given in Col. 8, Tab e 2, are based on the tota.lnumber of feet of drill pipe in the setback (Col. 4), tf,e weight per foot for the par ticular size (Col. 5), aml an angle. of mclitta.tion of 2% deg. The 1Veiffht valitM shoum are a . sumed acting ut the ap

22、pro:riniate center of gravity of theJipe setback, at a height above the de7“Tick floor equa to one half the lenath of the stand, measured parallel to tl1e slope. The 1Ueight of pipe, shown in Col. 5, is the nominal :u;eioht of threaded and coupled external-upset tubin,q or of drill pipe with 11 tool

23、 joint at each connecUon. for the pipe sizes shown in Col. 3. Example (136-ft. derrick and 5-in. drill pipe): Horizontal component at point of origin, in pounds, equals the total number of feet of drill pipe in setback (8,900), times weight per foot (22.5), times sine of 2 deg. (0.04362). 8,900 X 2.

24、5 X 0.0.4:l62 = 8,7;20 d. Combined Resultant Load. The combined re sultant load3, at the pomt of suppned resultant load at the finger bo.ard of the horizontal component of ptpe W81ght and ths 1vind load on ths pipe setback. a b 45 :-. (8,70 + 6,000) (-) 88 = 7,890 /b, nt lh finger board. whe in: T:

25、z = hoJ“i:ontnl conlpVtent of clad uMi,Qht of pip6 at pvint of o-rigin (Col. 8, Table 2). lV2 = wind load(;“;!; setbnck at point of origin (Col. 9, 1uble :!). a = one-half the height of thiJ pipe setback (., the heigilt yiven in Col. 6, Tahle ll). b = finger-board hei9ht from derrick flow (Col. 10,

26、Table 2). 19. Le: Members. Whtmever load is to ba trans !erred by end bearing, the ends of the abutting leg members shN.tl be properly faced to give uniform bear ing throughout the derrick. In naile laminated con struction there shall be at least 2 ft. between the splices of any two planks with rela

27、tion to any of the other planks making up the leg section, so that the nailed laminated leg shall b.e a continuous member; The connecting members shall be so fastened ns to hold the leg sections accurately in alignment under a combined safe workiug load and wind load equal at least to the specified

28、capacities.-20. Joints. Girts, and BraceM. Joints, girts, and braces shall be tlesignP.d to sustain safely the stresses imposed by the load conditions stipulated belcw, applied with proper dh;tribution over the entire struc ture, properly guyed and anchored. Each of the two toad conditions shall be

29、considered as actin sepa rately and the members and their connections designed on the basis of the maximum stress. All girts nnd braces shall be classified as secondary members. The load condition that hall be considered “ as follows: a. A load equivalent to the windload capacity as stamped on the n

30、ame plate which load is to be determined by the proV:sions in Par, 14 16, together with the pipe setbak load as specified in Par. 1118. b. Three co-acting loads as follows: (1) a con centric crownblock lPnd eoua1 to 1. times the max. imum safe load capacity as stamped on the nam.e ph e, the assumed

31、load to be taken as acting con centric with the derrick; (2) the horizontal com ponent of the weixht of the pipe setback load as given in Table 2 and applied in accordance with Pnr. 18: (3) n horizontal load of 3,000 lb., or 0.01 times the safe load capacity of the derrick (as stamped on the name pl

32、ate), whichever is the least. applied at the top of the derrick leg at one corner of the derrick, in the plane of the derrick side anrt in thf! same direction a9 the horizontal component of the weight of the pipe setback load. NOTE: 1he load under which failure of a. wooden derrick ma.v be erpected,

33、 asm1.ming the fo!tr derrick Ieos to be loaded unifonnly, ca7t be oi1.1en on.lu as approzimately 2 times the mnz imnm 3afs load, b11.t this information shall not appear en the name plate. -21. lfaximum Safe Load of Gin Pole.l The max imum safe load of the gin pole, expressed in pounds, shall be dete

34、rmined in accordance with the formulas and provisions of the 11National Design Specification for Stress-Grade Lumber and Its Fastenings (Revised 1948) ,“ for strength of compression members. (See Par. 401 of that specification.) Spedfes (Revised 1948).“ L = the length of the beam between “work ing !

35、JQi_nts“. in inches. b = the width o! the beam at the section under consideration, in inches. h = the df.!pth of the beam at the sertion under consideration, in-ln.Ghe.sc W =the weight of beam, in pounds. S=the section Mad Capicity _ MiJes Per Hour (Aetual Veloclb) (11.7. Inpt:ction Notke. V:here th

36、e inspector repre senting the purchaser desires to inspect this material or witness these tests, reasonable notice shall be given of the time at which the run is to be made. 36. Inspection. Lhe inspector representing the pur chaser shall have free entry at all times. to all facili ties which will co

37、ncern the contract while work on the contract is being performed. The manufacturer shall afford the inspector, without chrge, all reasonaole facilities to satisfy him that the material is being manufactured in. accordance with this specification. A-ll inspections should b made at the place of origin

38、 lrior to shipment, unless otherwise specified on the purchase order, and shall be so conducted as not to interfere unnecessalily with the operotion of the facilities. 37. Rejec:tion. ll:J.tcrial which shows injurious de fects on initial inspection or subsequent to final ac ceptance, or which proves

39、 defective when properly applied in service, may be rejected and the manu.fal! turer so notified. 33. Compliance. Tho? manufacturer is responsibla for complying with all of the provisions of thi specificab. n. The purchaser may make any investiga tion nece-ssary to satisfy himself of compliance by t

40、he manufacturer and may reject any material that does not comply with this specification. -.-t.“-t.U. tn llod. t.l.e.m. selves.rnto each other l-shaped columng, such as used in oil derricks, if made of clear wood, would he limited in strength by torsion of the section when the rul:io of width to thi

41、ckness tf the component pieces excee1:ts five. When the width of the leg is six times its thickness, such a section may be expected to fnil by twisting at about 67 per cent of the expected strength of clear wood in direct compression. When the ratio is 7 to 1, the failure will occur nt apprc.ximatel

42、y 56 per cent of the expected trcncith of clear wood. c. The strength of such columns is decreased proportionately bv the percentage of knot area permissible in the material by reason of its commercial grade. _ A 2. The nhove facors nre not cumulative, but the atrenth of the column is governe-d by t

43、hat factor givin.s the lowest strcs value. A3. The short column te“es shall not ?oly when the /,fr of the L section formed by two planks e“ceed 38. If the Lh of an individual L of the leg sec tion exceeds 38, the !=;tresses must be reduced in ac cordnnce with the formulas in Par. 401-E-2 and Appendi

44、x D of the uNational Design Specification for Stress-Grade Lumber and Its Fastenings (Revised 1948)-“ In applying the formulas to L sections, the numerical a.lue to be used for the least dimension d in the column formulas is the least radius of t:YlStion ,. of the L section divided by 3.46. A .f For

45、 exnmpl: If :. com,Prcinl gr3din rule ner mits knots not m()rn than 2 in. in diameter in a lO in. plank, or, in ()ther words, calls for not less than 80 per cent of the cross section to be of clear wood, and the length is not sufficient to exclude it from the short column class, the strength of the

46、column will be lim ited by a 75 per cent factor for imbedment of .en grain. If the grade call for not more than y hAe determined that aa.0 vorking _:trcnca for timber sub_jected to short time load!ng (such ns is character!stie of the maximum loads in oil der ricks) may be considerably greater “;han

47、those for long time loading. The relationship of .dlowRble stress to duration of load is given in F1g. 1 of Supplement No.2 (June,1948) to U.S. Department of Agriculture Miscellaneous Publication No. 185 .-Guide to the Grad ing of Structural Timbers and the Determination of Working Stresses,“ availa

48、ble from the U. S. Forest Products Laboratory. 61, tile. u.to.t. “-o.t !.14. !-“-“-“- “-“-“-.to . _m is assumed to be full nominal size (cross section) except for usual cut reducing depth of beam at end to one half the depth at ter.ter. e. Weight of wood is assumed to be 38lb. per cu. ft. d. Weight of beam is calcula.ted on the basis of full s tion and full length. e. Weight of %-in. sucker rods is 1