Long Bolted Joints. Proc. ASCE Vol. 89 (ST6) December 1963 Pub

7/27/2019 Long Bolted Joints. Proc. ASCE Vol. 89 (ST6) December 1963 Pub

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Lehigh University

Lehigh Preserve

Fritz Laboratory Reports Civil and Environmental Engineering

1-1-1963

Long bolted joints. Proc. ASCE, Vol. 89 (ST6),December 1963, Publication No. 231 (63-17)

R. A. BendigoR. M. Hansen

J. L. Rumpf

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Recommended CitationBendigo, R. A.; Hansen, R. M.; and Rumpf, J. L., "Long bolted joints. Proc. ASCE, Vol. 89 (ST6), December 1963, Publication No. 231(63-17)" (1963). Fritz Laboratory Reports. Paper 1733.hp://preserve.lehigh.edu/engr-civil-environmental-fritz-lab-reports/1733
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of the eonnect1on. If the ne t atea lavery large tbepl$te stresses andstrain are negligtb1.e and the ; late functions practically a 1'ig1dmember. AfiJ a result tbe "Mean Curve" shown in Fig. 8 (or Fig. 14)become$ borbontal tbrough an unbuttoning fat tor of 1.0. On the otherhand U th e net area is reduced tll11l'kedly the plate strains become verygreat thuf)bastening the p r c m a t ~ r e . f a U u r e of the end faateners. In t h ~ scase the ''Mean Cuwet ' takes a steepel' slo,e.

T h ~ b o l t ~ d jo in ts reported by C b c s ~ o n had At/An ratios ranging from1:0.65 to 1:O.. 88whe'reas the t ' M ~ ~ u l : C u t ' v e u of Fig. a i s for joints havinga ratio of IfL10. ;rhus it i s 't? be expected that ~ ~ P l o t t e d ~ o t ~ t sfal l below this 11ne ae they do. Similarly for the riveted connectionswlg;;;tf!>C;he A,/An rati.o ranged ftom 1:0.65 to 1:0.70 whereas t he limited. . . " .. ". ,Lehigh University riveted eonneetioQ$ h $ ~ 1:'titios 0. .1:0.76 to 1:0.78. Use, . ' . 1 . .,of the a n a ~ y t . i < : a l m e t h o d - n o t e d - in the f irs t paragraph shows C h ~ s s o n ' 8expel'i.illMtal'work to fa l l ~ l o s e to t he p redie ted value s. (See Flg. 9, Ref.22). '. - , ' .

'-two other items prevent G direct comparison. In the connectionS- . (1) . I .' '. (2)reported by Chesson 1 t b ~ bolU ~ h e ~ n ' e d t h r o u g h th e th re ad s and ~ the_ io .....I..rs ",ere .f!!ighe. 8tromsfh A7 8 t " , , ~ .. ?' h l g ~ ~ t r e " g + / ' + ~ A7~ ~ - - - " ' - - " " ::::.====:::::::::--- . .. nUhaXt should ~ e ' n o t e d that ' the fIlualyti.calaualysi$of flat pla!:!! joints r'

of Refs. 15 and 22 i s not lim ited to e q ~ ~ -inner and ~ u t e r ply d ~ n s i o n sBS ~ t a t e d b y C h e s s o ~ ~

'J


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;;

Lidt of References(Where a reference has been used before 1n the original paperor the three discussions the _same number bas been assignedin th is c losure .)

In order, of appearancEt in closure .a. December 1963 by Robert A. Bendigo, Roger M. Hansen, ' andJohn L. Rumpf (Proc. Paper 3727)

, t I ~ ' ,eo. Professor ,and Head, D e p a r t ~ e n t ofClvl1 E n g i n e e ~ DrexelInstitute of Technology, Phil adelph ia . Pa.'19.'rOOc19, A. J . , "TbeBehav1or of Aluminium Alloy Riveted,i!oblts" t Research Itpt. 15, Aluminium Development

Association, London, 1953.15. Rumpf. J . L., ''The Ult1mate Strength of Bolted ConneCtions",Ph.D. Dissertation, -Lehigh University, 1960.,21 . FishEll", J. W. ,"he' Analysis of Bolted Plate S p l 1 c ~ s " ,Ph.D: Dlseertat'1on, Lehigh UniversltY,1964.22. Jllsber ,J. tv., and Rumpf ,"J. L.. lithe Analysis of Bol'tedButt Joints", Report 288.17, Fritz Engineering LiaboratQ1"Y,,Lehigh University, 1964.23 . Chesson. i , .J r . t and Munse. W,; H.. "Behav$.oro/lJf RlvetedTrQGs-Typo Connections.",Transactions, ASCE, Vol. 123 11 1958,p. 1081. .24. Munee, , W ~ H and Chesson. B., J r . ,"Riveted and BOlted Joints:Net" Section Design,n Journal of the Stl'uctull'al Divislon,ASCE.'

VoL 89. No. S T 1 , ~ PJ'oe.Pl1per 3413, Febr:uary, 1963. '

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Jsnuary20, 1965

Mr. I rv in J .Semrartz.Editor t Tecbn$,cal P u l ' > l , t e ~ t l o n $ pAmertesl1 Society of c iv i l Engiaeers345 East 47th StreetNew York 17 p ~ e t 1 York

'Re: Digest for TRANSACTIONSPape!!, 13727,Dear Mr. Scbwart2:

Bnclosed find two (2) copies of the digebt ofProeeedtnga Paper 13727 e n t t ~ l a d "Long Bolted J o i n ~ e . nVery truly yours,

John L. Rumpf\ \ Professor and HeadCivil Engineering and Meehanies

JLR:ell

Inc losures (2) ~ . / .. ...cc : J. tf. Fisher ' ,


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' l ~ D ) ! o a tG13ttll ~ , P 1 tventy lon3st'l'w:tural ~ p u . c : e $ of 1 A 7 I $ t ~ $ 1 .plste c : o n o ~ t e d ~ ~ t b high stweaath bolts provide b ~ c : k g r o ~ ~ ~ rpu t s of Q:he G p G c i f i c : ~ t i . o l l of the a e f l ~ " b C o U n e t ~ o i \ 8 ~ v c t ~ ~ ~ ( )Bolted S t i i ' U f : t . ~ l ' $ l J o ! ~ t o f o r tlle U D e m b ~ y of G t J r U C t u r ~ l ~ . e e t . i o n 8 .

u s i ~ .uZ5 ,bolte. The. pi\'l.j.p@l i t e m u n t l ~ 1 l ' l ~ v e a t ~ a , r u . o n u lj , t h ~effec:tof the 10ftgtb o ~ the joilllt on thGultim.g,te s ~ t G : 1 D g t h of. ' , .. ,beewlO$-typeeODnGCttone but v4Juable i ~ f o ~ t i o ~ t ~ e d e ~ i g nof f J r i ~ U . o n t y p e conuectlo1l'1$ was c I . e t ~ l l : a l l : a e d $180.

The tesQ:El UluslttrQted agalca the phenomeno/Q of p X ' a o o ~ u r eunbuttonirtg""type failure of the Qnd fastelllarLiB 1n long COllUlec3t!Oit\$.Sht,)r;t cOtmeetlou ofapP1'OICtmately 16 inches. i l l l ~ D 3 t b . t'4U,l.ed by ,(:jbeuillg of bolt$ at an. average sbe$lr stress ~ 85%oftbeQ t r e Q 3 ~ h of a etnale bolt. f o ~ & c o ~ n e c t l o n with 16 bolts tn lineand an ovefall l ~ n g t h of 52.S1Cc:hea thE! lllverllige shest a t failull'eWa& ~ e d u e e d to only 60'ZH C o 1 \ i t d ~ d . n g l!O al1ov_la dC$l$n "beartE;itrema VV' C;!1 2 2 k ~ i the factor of $Q.fsty$3tli.taat f e . U ~ r o torShort connectS.oQ is about 3.0 but tbis d e e r e ~ s e s to about 2.1 forthe long eOltUlectlom" A fsw.comp.nrtson tests r t v e t ~ cOJmec:tionseho""3d $imU$1l:' ~ b 6 1 v t o T C . Cotnpal'lC::lC;lIi of .several comtaetlon.s t i l thVE11r!OW pitch dimeD$tone skou$ tlUi' G i , h . 1 J i \ b 1 . l e : ~ O l 1 i n g ( ) i _


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The A3Z,bolta ~ i 8 h t e n e d by the t U ; D O ~ ~ ~ t m e ~ h o d e o a a i G t $ ~ t l ybed tensions of f4Ppron1l:n&tely 1.30 ti,$4'!$ tbe proof ltl&! of ~ h e bolt .No d e t l " i m e D t ~ l G l b e $ 1 ' bebavf.or o f $ cOQilfacU.oa w u a x p ~ r t $ l ' ! C o d

~ e a u s e of ellia higb 1.Ditltd. t ~ t o n ~ Jouts tI1th t 1 g h ~ mill scalef t ly i . . , u r f t i 1 c e ~ sUpped batobe$lrlDg at v a 1 u e ~ 0 average $bea1l'

1..0e t ~ e s $ Kcess of Fv ~ 1.33 x is ~ A k a i for 4ead'and Itveload

p l ~ u $ wind. Theeetelllt$ indicat.ed 0.35 as e . r e 4 $ ~ n l l l b l $ l tower Hlllit.fo r tbeeoefficient' of slip. .

Joints v t t h ' $ e m l ~ p o l l s b e d $ u , f a c e s o b t $ 1 n ~ d b 1 ' t ~ n g 3 1 1mill $ c ~ l e witb a power tool ~ l ! p p e d at aD average shear $tresegreater than 1S kat but les6 than 20 kat 4l1.d acoeff:f.ctellt o ~ 8 1 1 ,of 0.20.


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I ~ ,

LONG BOLTED JOINTSaClosure by John L. Rumpf

J. L, Rumpf 30The authors wish to acknowledge the contr ibut ion of Professor (19),i'flancis to the l i terature on th e behavior of structural connections.

Rather than escaping the notice of the authors his work provided a(15)valuable basis for the analytical work carried on simultaneously(a)with the e ~ p e r i m e n t a l work to which this paper was confined. Theanalytical solutions have now progressed to computerized form ~ d assuch have become successful in reducing the amount of costlyphYs1cal(21,22)testing of large joints I t is expected that the analyticalwork will be ava il ab le in a more readily obtainable form in the nearfuture so that engineers may compare the analytical and experimentalresults in detail . At this point we will simply state that thecorrelation has been excellent.

Professor Chesson has tried to correlate tests of the connections(23,24)., ,.of various truss type members haVing fastenets in single shearwith the results of the double shear plate splices reported in thi$ paper.While i t is true that the truss type connection is more complex in i tsmethod of load transfer than the f l a t plate sp lic e th is is not the wayto e ~ p l a i n what may appear to some to be a large deviation from theresults of this paper. Chesson has failed to recognize the effect on theunbuttoning factor of varying the connection geometry (TiS rat io). theTIS ratio may also be expressed as As/An where the nunlerator representingthe bolt shear area is usually expressed- as I, 'and where the denominatorrepresenting the net area of . the plate .indicates the relative proportions


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of th e connection. If the net area is very large the pla te s tresses andstrain are neg ligible and the plate functions practically as a rigidmember. As a result the "Mean Curve" tilhown in Fig. 8 (or Fig. 14)becomes horizontal through an unbuttoning factor of 1.0. On the otherhand if th e net area is reduced markedly the plate strains become verygreat thus hastening th e premature failure of the end fasteners. In thiscase the "Mean Curvelf takes a s teeper s lope.

The bolted joints reported by Chesson had As/Au ratios ranging from1:0.65 to 1:0.88 whereas the "Mean Curve" of Fig. 8 is for joint;s havinga ratio of 1:1.10. Thus i t is to be expected that the plotted gointsfa l l below this line as they do. Similarly for the riveted connectionswW8;the A s / ~ rat io ranged from 1:0.65 to 1:0.70 whereas th e limitedLehigh University riveted connections.,had ratios of 1:0.76 to nO .78. Useof the analytical method noted in the f i rs t paragraph shows Chesson'sexperimental work to fal l close to the p redi ct ed values. (See Fig. 9, Ref.22)

Two other items prevent a direct comparison. In the connection(1) (2)reported by Chesson ~ th e bolts sheared through the threads and the

main members were of higher strength A7 stee l .I t should be noted that the a n ~ l y t i c a l analysis of f la t plate joints

of. Refs. 15 and 22 is not lim ited to equal inner and oute r p ly dimensionsas stated by Chesson.


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List R ~ f e r c n c e s(Where Q r e f ~ r e n c 0 haG bean U D ~ d before in the o:iSinal paperor the t h r e ~ d l s e ~ s s 1 ~ ~ s the,seroe number bas beeneeligned,in this closure.) , . "

a. 'Deeeu'.oel' 1963 by RoQ$t'1% A. Bendigo a a"3Gf: M. H.9nsen. and~ o b n L . , Rumpf (PrQc. V Q P O ~ 3 1 ~ 7 )

50. P.rofeesor, and BMd, ~ p o l ' t m e n t of Ca.vtlb01noer. DIrexellustU:1Jteof Technology, ehUad.elpbla, 11'4.19. 1 ? t ' & n Q l ~ . A. ,3., ' ' 'The Stifnavlor of Alumtni.wn 4UI)'1 t U . v ~ t $ d

~ 1 ~ ~ o u ~ . ! ~ t u ! r c h . R"pj"'Y'l... J l ~ M U l U i f i i U t n D e , \ 1 e l ~ J t ' ~A ~ o Q c i $ t 1 o n . Loudon. 1953.

lS. llumpfjl J . L. D n . r h ~ U 1 t i . o o t : e Strengt.h of ~ l t l S d n n n e e t ' 1 0 t W t f . "Ph .D. J)lasertaU.ou. Lebigh UniV'ersltY$ 1 . ~ 6 0 ~21. Pleber, J . W ''The Analyel& of Bi.,lt.ed 1 P l a t ~ S p l 1 < : Q S " ~l'h.D. Dts$ertatioD, Ulbl$l.i UnlvOf:Gity,1964.22. llioher'ja J. e . , aud Rumpf, J. L", tithe ~ l Y l ! i l a of Bolted!lut.tJi)1nts"" R { p o r ~ 288.1,. 1!ritE !ngU1e0.Jt1ug L a b o r ~ t ( ) \ 7 .Lehigh Ul)lvereity,1964, '23 . C t u ~ G $ o n . n. lI' 31:: .. J ~ n d MUn3$) W R . ~ lfiel'ulV1Gi."Q_f i U . v ~ t ~

T ~ U $ 6 " ' T y p e Co_ect1olul,u tr.epSi!cti91l\t!1l ASCI. '01 .. 123, 19S3)p. 10S7. '24. Mun$e, B I.lS).d C h ~ s S Q n t 5 . , Jr ' j ' . 1 v e t ~ d $ n d Bolted JOlnt$:Met S e c t ~ n O $ 6 1 J , g l l . n Journal ofthetntetu,:al.Divi., 103b ASClhvoL ;89 . NQ.$' fl . P r o e > ) ? a p c r 3 4 1 3 ~ rebruaty, 1963.

>.:...


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1 9 4 ~ l111e20should rQad . :u1tl:m4te ehGsr stfength of


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AMERICAN SOCIETY OF CIVIL ENGINEERSUNITED ENGINEERING CENTER

345 EAST FORTy.SEVENTH STREETNEW YORK 17, N. Y.

.. ~ Q y . ~ ~ ~ ~ ~ ~ . L . ~ 2 ~ .Th' '11 k Id ' ... d d Nov. 7, 1963IS WI ac now e ge your commUnIcatIon ate _ .Please be assured ~ p . a t this matter will be given our carefulattention.

Technical Publications DepartmentI, I


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I!

-- - . _ - - - - - - ~ - ~ ~ - -

( TH I S SIDE OF CARD IS FOR ADDRESS )

- ~ = = = = = = = : : : ; - - II

Mr. John W. FisherDepartment of C ivil EngineeringFri tz Engineering LaboratoryLehigh University:Bethlehem, Pe!ll'lsylvania


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', : ..,

November 7. 1963

288.1 Ref: 16-2-4.B

Mr. William D. FrenchAssistant EditorTechnical PublicationsAmerican Society of Civil Engineers345 E. 47th StreetNew York 17 J New York

Dear Mr. French JYour communication addressed to Mr. Robert Bendigodated October 28. 1963 reached us on November 6, 1963. Uponreceipt of the edited photocopy we have revie\vec1 your editorial changes and have the following comments:On page 1, the loca tion should be given as New Yorkfor reference number 4. References 10 and 11 need the appro. pr ia te date .snd ci ty of pub licat ion inse rt ed . Reference 13has a word deleted from the t i t l e .Several corrections have been made to tables 6, 7,and 8 . Several of the sub-headings have been modified. Intable 6 we have completed the column labelled gri.p. Thel a s t column of table 8 has been de.Leted.On pages 12 and 14 we would prefer that the allowable shear stress be included in the text and not centered inthe page.


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Mr. William D. French

-2-

tiovember 7, 1963

The intent of the summary and conclusions is modified1f ' 'bearing-type joints:! and IIfr1ction-type joints li are centeredand capi tal ized. These are intended as sub-headings. We wouldprefer to see them i talicized as the other sub-headings havebeen.Several other minor modifications have been made onvarious pages of the photocopy. The other edi toria l changesyou made are satisfactory.If we can be of further assistance please advise us.

We have certainly appreciated the work you 'have done in gettingthis manuscript into final form.Sincerely yours,

John H. Fisher . / 'JWF/vacc: L. S. Beedle

J . L. Rumpf


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REVIEWER I S COMMENTS ON THE PAPER "LONG BOLTED JOINTS" BYBENDIGO, HANSEN, AND RUMPF

Reviewer A

Reviewer B 6K ;- C 9 ~ "'" ~Specific r e c o m m e n d a t ~ would improve value. Figure 3,Col 3, not clearly identif ied. Ref. 9 and 11 not readily avail-able. Conclusion on Ks 2: v. "3.:;-"may be q U e s t i o n e d . ~ ." ~ c . e . 14 rO ~ ~ + b

Since o th er d at a suggests that a somewhat different picture p.of behavior could be obtained i f other heats of steel from other '\ 'VOmills had been used, i t would be desirable for the authors to CN...c.t rqualify their conclusions to indicate this fact . The application ~ ~of the data reported without consideration of the other data in 'I ~ c . -kthe l i terature could provide structures on the unsafe side in-sofar as slip of the joint i s concerned. ~ ' - .:q .u,;!> IS S~ e Re-surel.. C

I ' I v ~ O'UJ- &"'- "WI.Jh Ih . s r e, f'

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k '(ck ~ 3 ~ ~ -


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(7.2) F RAME S TAB I L IT Y 7.4

of the two types of problems. For the case where th e frame is loaded by th edistr ibuted load, a l l th e members in th e frame are subjected to combined bendingmoment and axial force, whereas in the case with the simplif ied lo ad ing condi -t ion only axial forces are present in th e members a t the ins tant of buckling.In general , th e p re sence of bending moment in th e members causes only a smallreduction in the buckling load for por tal frames considered here. Detaileddiscussions of th e effect of bending moments on elas t ic frame ins tab i l i ty canbe found in Refs. 7.3 and 7.4. In the fol lqwing i t wil l be assumed that thesimplif ied loading condition is applicable in determining the elas t ic bucklingload of th e frames.

tr I ql Ie. Ie. FI G. 7. 3P = wLg2I. L97.2.2 Methods of Buckling Analysis

Numerous methods have been developed and effect ively used in solvings tabi l i ty problems re la ted to building frames. They resemble very much thosemethods ordinar i ly used in analyzing s ta t ica l ly indeterminate s tructures , ex-cept that some modification is made to includ e the bending effect of the axialforces. Essentially there are three different avenues of approaches that arenow in common use. These are , 1) th e analyt ical methods including the methodsof s lope-def lect ion and four-moment equation, 2) the moment dis tr ibution method,


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271.18 -2

~ q u s l the tensile capacity of the net sect ion of the main material. Testsof c o m p ~ c t bolted jOinta(6) established the balanced design tension..shearratio' A7 steel and A325 bolts a t 1 to 1.10. Xn other worda, equal

, u l t 1 m a & : ~ strensth will result i f the area; of the main material and boltaare chosen so that th e average tensile streGS on the net sec tion and theaverage shear s ~ r e s s on th e bolta are in the ratio of 1 to 1.10., ' ) ,In d e a i g ~ > c Q l c u l a t i o n s for riveted and boltedt,york i t is assumed thateach fastensR' carries an equal share of the load. Booever, analytic;sl

(7 8) . .tvork ' has shown that in long c o n a e e t i o n s ~ ~ d , t h a ll parts behavingelastically, the end fasteners carry amucb larger proportion of the loadthan do the:! inner fsstenegos.. But, e ~ e f C ' i m e n t a l t l 0d t with riveted connections(9)haa shown that successive yietdlng of the outer rivets p r o ~ u e e o a redistribution of load so that at failure a more uniform distribution exists than theelastic analysis indicates. In the case of hot driven rivets, it usuallyhas been assumed that the e q u a l l ~ a t i o n of load is complete enough that nochanges in design procedure need,be specified fo r long connections.

~ e ~ a m o u n t of redistribution of load depends upon the ability of thefsstene!fS to undergo large shear deformations without failing. Because theproperties of high strength bolts differ from t h o a ~ of rivets, it t180 deemedadvisable to conduct tests of b o l t ~ d jolntain o r d ~ r to m 2 4 a U r ~ the abilityof the bolts to redistribute.load, and to determine i f long bolted connectionsdesigned vlth Q tenaionQshear ratio of 1 to 1.10 st i l l provided a reasonablefactor of sefety. This uork ~ a s s t a ~ t e d in 1958 ~ n d y p ~ o v i d e d furtherbaekgll:'ound for the formulation of portions of the"specific8tions of the ResearchCounciloh Riveted and Bolted Structural Joints.

6. nStat.icTension Tests of Compact B.olted Joints lJ lI by R. '1'. Foreman, J . L,Rumpf, ~ a n s s c $ i o n a ASCE, Vol. 126p Paper No. 3125, p. 228 (1961)7. tI'lhe Part,1tiol'. of Load' in Riveted .:vointe" p by C. Batho p Journal ofF r a n l ~ l l n X n G t : u : u t e . Vol. '182, p.. 5SS (1916)8. liThe i'1ork of Rivets in RiVeted Joints l l , by A.. Btrennikoff, TransactionsAGeE, Vol. 99, p. 437 (1934) .9. u'X'I9ns1on Tests of Large Riveted JointsH , by It .. E. Davis, G. B. Woodruff,Davis, U. E. , Transactions ASCE, Vol. 105, p. 1193 (1940)


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1. The following symbols have been adopted for uae in this paper:

IlIll number of bolte

= the'Qverage bolt shear stress in the bolted conneeUOll6

allowable sheor strese

e number of ahesr planes

o net tenoi le aree of the pl4te= bolt shear &rea (for butt-type splices the re are two ahear p l ~ G )

= unbuttoning fQctor for length , L= tfi.'1nimum tGlWUe BtrC:lngth for A32S bolt

= the unbuttoning factor defined as the ratio of thee . v e r ~ e bolt shear stress in the connection when the f i rs tbolt sheare to the ultimateetrength of So single bolt .,oJ thee ~ lot and of the same grip . ,

IlIll averQge ohear otrength of a single bolt

= major eUpload= ratio of the tensile stress on the net sec tion of plate tothe shear strese on the nominal area of the f$stenere ( ~ / A n )CI averoge ,i.nitial bolt tension

colip coefficient

.2. The fol1ow1l.ng ,

~AsrvKamnPeTIS

TiU

~ UtO'mln' \ 'u'\'1

Tbe transverse spacing of the boltsGripPitch

'!'he thickness Of the plate material in the connectionThe longitudinal epacing o f ' t h ~ bolts

$nug The expremeion used to dsacr1be the t ightness of sbolt before beg1tming the tum of the nut. "Sn\lgn ieindicated by the impact wrench when impacting begiue

Unbuttoning Tbe aequential failure of fmsteuers whicb progressesfrom the en4s of e j o u t inwer4.! . ;


27/74

1, The following symbols have been adopted for USe in thie paper:

co number of bolts

,"

terms are used:

The loligitud:Lnal spacing of the bolts

The transverse spacing of bolts:"The thickness of the plate m a t e r i a l . ~ ~ the conneetlon

.} "

G$geGripPU:ch

2. The f o l 1 ~ i l n g

CI major sl ip load

.... .tllS bolt a ~ e ~ r area (for butt-type splices th ere are ~ o ehear planes)

~ y ' e r ~ e ohaar atrength of Q single bQlt

.-::0 net tensile area of the plate

::0 the unbuttoning fector defined as the r$tl0 of theaverage bolt shear stress in the connection w b . ~ the f irs tbolt shears to the ultimate strength of a single bolt: ,.,oJ thesame lot and of the same grip .,

c slip coefficient::0 number of shear plQnes

allogable shear stress

a unbuttoning factor for length, LG m i n ' ~ tensile s t r ~ n g t h for A32S bolt

= ratio of the tenoile stress on the sec tion of plate totheehear stress on the nominal area of the fasteners (AsiAn>= a v e ~ ~ e ini t ial bolt tension

AuAs'vr.tsmnPmTIS

TiU

~ ULaminTuT1

Snug The expression used to describe the tightness of abolt before beginning the turn of the nut. ,t'SnugU :1.8indicated by the 1 m p a c t ~ w r e n c h when impactlng begine

~ l " , '

U n b u t t o ~ l n g The $ a q u ~ ~ t l a l failure of fastenere ~ i c h progresceofrom t}ie ends of a joint inward

-.......


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ABSTRACT:

LONG BOLTED J O ~ S

50 t:1ord ABSTRACT fo r Civil EngineeringTension t e s t s o f long structural s plic es o f

A7 st e e l provide background for portions of th especification of th e Research Council on Rivetedand.Bolted Stru ctu ral Joints fo r j oi nt s using .A325 b o l t s . Data on the, slip resistance andul ti mat e s tre ng th o f connections ar e given.

~ _ . J@ ~( . ~ . , "-" ---! /\! I I\ \ ./)\ ,.__ / /' - ~


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..

INSTRUCTIONS FOR PAl'F:R\ 'f :.. .1. ~ i g u ~ e e S11OU1d be interspaced with the t f t ~ t t e n t e x t ~ An approximateloca.tion of each is noted i n pencil .

\ . ... F i g u r e ~ ~ i t l e s are to be set in type aa shown on the copies ando n . _ t h ~ enclosed Ust. .

Figures 4 and 5 contain tabub.ted data which should be set intype i The eronll tll:Qcings heading these iigull:es are ~ n ~ l o f ) e d .(271.168, 271.169 and 271.170) \\4. I t would be d e s i ~ a b l e U: a l l Figures except Figs. 6 and 7 appearedin th e not'll'lll positiOn in 'V1hich tbe journal is held, All Ff,gurel:1can be reduced without impaill:ing their understanding,S. The following 1s a tabulation of the- Figs,

Figure1234567891011121314

I:>1617186. Figures t, 2, 3, 4, 5, 6, 7, 12, and 13 conta in tabulated data whichshould be set in type.


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mSTRUCTIONS 'FOR PAPER0 '.1. 1113111;'es should be intcrapaced ~ - i l t h the ut:u:een text. An approximatelocation of each is noted in pencil.

\

2. P i g u T . O ~ t l t 1 e s are to be set type as shown bd the copies andon the enclosed l i s t . '

ira inL _~ ~ 2 7 1 . 1 6 8 " , , )/ / ' \ Jab1es1'/ !obles" V


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F ! g ' ~ 1Jtig'. 2-fig. 3Fig. 4Fig. 5Fig., 6l l i g ~ 7Fig. 8Fig. 9. F ; i ~ h 10 ..11ig. 11Fig. 12. F i g . U SFig . ' 14F ig . 15 -, i g . l6Fig. 17Fig. 18

FIGURE TITLES

Nominal Dimensions of Bolted S ut t J oi nt sProperties of PlatePropel'itao o f Bolteilominal Dimensions of Bolted Lap .,Joint!!Nominal Dimensions of Riveted Butt JointsTest Results Bolted Butt JointsTest ,Results ... ~ o l t e d Butt JointsLoad ... Elongation, Curve co Joint D91Load ,.. Elongation Curve . . J o i n t D901Saued Section co J o i n t b61Sen-Jed Section ... Joint DR7iTe$t Results '!" Bolted Lap Joints'lsst Results -Riveted Butt Jo i sUnbuttoning FectorComparison of Ultimate and WarShear StressSlip R e s i s t Q n ~ e of B o l ~ oints ightenedby/1furn..of",titut !4eth........Faetor 0,, S,afety Aga1nst ~ l i p for ' ad an dL i ~ e J..oad$ Fv co s f : )' act o r" o f -Safety ,1n l i p fo1' Dead and: lg ' v ~ 2 0 k 6 i ''u/

\


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FlGUBE TITLES

,,-

r i g ~ 1rig. 2Fig. 3Fi8. 4Fig. 5Fig. 6Fig. 7Fig. 8Fig. 9Fig. 10rig. 11FiS. 12. Pig.1l3Pith 14I, Pig. 15Fig. 16Fig. 11FiS. 18

NomiMl Dimensions of Bolted Butt Joi.ntsProperties of PloteProperites of Bolts.Nominal Dimensions of Bolted Lap JointsNominal DimenGione of Riveted Butt Joints-Teat Results Bolted Butt Joints[ Teet Resul ts- Bolted Butt JointsLoad Elongation Curve a Joint 91Load Elongation Curve Joint D901Soued Section - Joint D61Saeed Section .. Joint DR71T e s t . ~ 8 U 1 t a a Bolted Lap JointsTeet Results .. Riveted Butt Join. Unbuttoning Factor . ...;' Comparison of Ultimate and Work

Shear Stressby Turn-of.l3utHethod . -cFactor of S a f a t Y A g a ~ t " s l i P for d ondLive, L o ~ C ! D .flv Cl 15y.8i _r a ~ t o r of Safe. ty ~ ~ n s ~ s . ip for Dead andLive plus Wind ~ ~ ) \ f ~ = 20 ke1

. / ~ ~ , ' " "-( ( ~ " \ \ "",,>- I ) )

/ - - - - ; , \\._--_.-/ /( Q ~ /


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LONG BOLTED JOmS

" 175 word INFORMAnVE ABSTRACT for information-retrieval program!KEY '-lORDS: Connections, bolte, strength, sUp, s teel , tes ts

ABSTRACT:

"ITension tests of long s tructu ral butt splices o f A7steel connected with 7/Sll high st:rength bolts provide

b ~ e k g r o u n d for portions of the specification of the~ ~ a r c h Council on Riveted and Bolted StructuralJoints for structural joints using A325 bolts. Jointsproportioned for a tensile stress of 20 kst and a shearstress of 22 ksi produced a balance ultimate strengthdesign fo r short connections approxiJDately 1611 long.In longer connections end bolts sheared before allbolts could develop th eir fu ll shearing strength. Inshort connections the e v e r D g ~ s h e a ~ s t r e s s was Sbou,t85% of the strength of a single bq but bolts in 852.5" (16@ 3-1/2") lOng,connectto, ,eveloped only 60%., Joints with tight m i l \ : . : : : . s c a t " B J f ~ i n g surfaces andbolts tightened by the t u r n - o f - n u ~ ~ o d s ~ i p p e d into

bearing Bt, a lower ~ ~ ~ l i P cOs flcient of 0.35.Uhen the ,mill scale" 8 d with a power tool thesUp coeff ic ient wa 1y .0._0 . , } -, /Limited t ~ s t S ~ b ~ l ( e d lap joints provide,information qn ! t b e ~ n - V l ~ ~ o f bol ts in s ingle shear .Several testf pf r i v e ~ e connections give interestingcomparative ~ ~ a . )

.----., \ , ""---.----/// , . - . / ".....-----( / / \ -\ \ J)\ ' ,,____../i )

' - - . - . . . ~

{,.I


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AMERICAN SOCIETY OF CIVIL ENGINEERSUNITED ENGINEERING CENTER345 EAST FORTy-SEVENTH ST.NEW YORK 17, N. Y.

....__.JU!-L26, _:l;963 ..,.--.This will acknowledge your communication dated .... .J.uly..23J:d.Please be assured that this matter will be given our carefulattention.

Technical Publications Department


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/-_- - - - - - - - - - - - - - - - - - - - - - - r = = = = = = = = = ; _ ~I

( TH IS S IDE OFC ARD IS FOR ADDRESS )

Mr. Lyrin S. BeedleD ~ p a r t m e n t of Civil EngineeringFritz Engineering LaboratoryLehigh UniversityBethlehem, Pennsylvania

. ~ i- - - - - - - -


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LONG BOLTED JOINTS

by

......>- ...

~ ~ ' ' ' ' ',

Robert A. BendigoRoger M. HansenJohn L. Rumpf

This work ha.s been ca.rried out as part of theLarge Bolted Joints Project sponsored f inancia l ly byThe Pennsylvania Department of Highways, the Department of Commerce - Bureau of Public Roads, and theAmerican Inst i tute of Steel Construction. Technicalguidance is provided by the Research Council onRiveted and Bolted Structura l Joints .

Fri tz Engineering LaboratoryDepartment of Civil EngineeringLehigh University

Bethlehem, ..Pennsylvania

January 1963Fritz Engineering Laboratory Repor t No. 271.18 Revised


37/74

271018 Revised

LONG OOL 'rED j O I ~ T Sby

Robert A, Bendigo1 9 Roger M., Hansen2 , and

SYNOPSIS

Tension test.s of long st ructural spaces of A7 s tee lconnected with high strength bolts provide background forportions of the spec:Hicati.QIll1\ of the Research Counci l onRiveted and Bolted Structural J.QIints for st ructural jointsusing A325 bol ts , The inHuel:11ce of th e len gth of the jointon the ultimate strength of bea.ring-'type connections i s de-terminedo Data on sl ip resistance also is o bta in ed fo r usein deslgning fr ic t ion-type connections 0

lBethlehem Steel Co, ~ B e t h l e h e m 9 Pao; formerly. Research A s s i s t a n t ~ Fri tz Engineering Laboratory,Lehigh UniversitY9 B e t h l e h e m ~ Pa ,2Contract Coordinator 9 Worden-Allen Co" Milwaukee, Wiso;formerly Research Assistant, Fri tz Engineering Laboratory,Lehigh UniversitY9 Bethlehem, Pa,

3professor of Civi l Engineering, Drexel Ins t i tu te of Technology,P h i l a d e l p h i a ~ Pao; formerly Research. I n s t r u c t o r ~ FritzEngineering LaboratorY9 Lehigh University, B e t h l e h e m ~ Pa ,


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271018

LONG BOLTED JOINTS

INTRODUCTIONWhen the A325 high strength bolt was f i r s t introduced i t was used as a

1 for 1 replacement for r ivets made of A14l s tee l ( l ) . Eventually, as theconcept of the high strength bol t became accepted, i t was feasible to tryto refine the design of bolted joints to take a d v a n t a g ~ of the greaterstrength of th e bol t , Under the guidance of the Research Council on Rivetedand Bolted St ruc tu ral Joint s research was conducted a t several universi t ieswhich led to a specification(2) acknowledging the different behavior offriction-type and bearing-type connections,

In the fr ict ion-type joint movement of the connected parts unders ta t ic , impact or cyclic loading is not tolerated because of the detr imentaleffect on the behavior and configuration of the st ructure, In this case,sl ip consti tu tes fai lure and working loads must be res is ted by fr ic t ionwith a reasonable factor of safety against the occurrence of s l ip .

On th e other hand th ere a re many connections that are erected in a"sl ipped" position with the bolts bearing against the sides of the holesin ' the same way that they will bear under service loads. In such. a bearing-type connection i t is th e s hearing of the bolts t ha t c on sti tu te s f ail ur eand allowable st resses are based on the ultimate strength of the bol ts . I tis in th is case that the g re at er s tr en gt h o f the A325 bol t can be ut i l ized

~ ~ ? u l t i n g in ,the use of fewer bolts than hot driven r ivets ,In 1956 work was begun at' Lehigh Unive rs it y t o establ ish the balanced

design shear s tress for A 3 2 ~ bolts in bearing-type connections, For balanceddesign th e capacity of th e cross sectional area of the bolts in shear should

-1 -


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r

27L 18 -2

equal the tensi le c apac it y o f th e net section of the main materialo Testsof compact bolted joints (3 ) established .. the balanced design tension-shearrat io for A7 s tee l and-A325 bolts at I to 1.10. In other words, equalultimate. strengths wil l resu l t i f th e are as of the main material and boltsare chosen so that th e average tensi le stress on the net s ec ti on and theaverage shear stress on th e bolts are in the rat io of 1 to L100

In design calculations for r iveted and bolted work i t is assumed thateach fastener carr ies an equal share of the loado .However, analyt icalwork(4,5).has shown that in long connections, with a l l parts behavingelas t ica l ly , th e end f as tene rs car ry a much larger proportion of th e loadthan do the inn er fasteners. But , exper imen ta l work with r iveted connections(6)has shown that successive yielding of the outer r ivets produces a redis t r ibu-tion of load so that a t fai lure a more uniform dis t r ibut ion exists than theelas t ic analysis indicates. In the case of hot driven r ive ts , . i t usuallyhas been assumed that the equalization of load is complete enough that.nochanges in design procedure need be specified for long connectiqns.

The amount of redistribution of load depends upon the abi l i ty of thefa sten ers to undergo large shear deformations without fail ing 0 Because theproperties of high s tr ength bol ts differ from those of r ive ts , i t was deemedadv is ab le to conduct tes ts of bolted jotn ts in order to measure the abi l i tyof the bolts to redistr ibute load, and to determine i f long bolted connectionsdesigned with a tension-shear rat io of 1 to 1.10 s t i l l provided a reasonablefactor of safetyo This work was.started in 1958,and provided further back-ground for the formulation o f p ortio ns of the specif icat ions of the ResearchCouncil on Riveted and Bolted Structural Joints .


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271.18

,SCOPE OF PROGRAMThe research program described in this paper consi st ed o f s tat ic

tension tes ts of sixteen double shear b utt jo in ts with three to,sixteen7/8" diameter A325,bolts in l ine. Widths and thicknesses of the platematerial were varied to maintain the tens ion-shear rat io a t approximately1 to 1.10. These tes t resul ts are supplemental to the resul ts reportedin Ref. 3.

,For comparison three r iveted joints of the same type were tested,and tes ts of four bolted lap joints provided data on the behavior of boltsin single shear.

BOLTED, BUTT JOINTS

-3

Dimensions - The sixteen double shear ,plate spl ices, are conveniently groupedin t h ree categor ie s as follows:

. D Series $)Part a - Cons tant . 4 inch grip , varied widthPart b - Constant width, varied gripPart c - Constant 8 in ch g rip$ varied width

Nominal dimensions are tabulated in Fig. 1. With one exception (D13A) thepitch was held at 3 .5 i nche s, hence th e jo in t length and the number of

..bolts in l ine w e r e ' d ~ r e c t 1 y related. The th ic k g rip s were attained byusing ei ther 4 or 8 pries of plate .

. Plates - The one inch plates for the joints of Part a and c were cut from.,24" x 1" uh' iversa1 mill plates rol led from the same heat. The plates of ' ...

various;ihlcknesses used in Part b joints were 10-1/4" wide un ive rsal mi ll,.

plates from a different . heat. Finished widths ,were achieved by roughburning ,and then machining to the f inal dimension. All plates werestructural carbon stee l meeting the requirements of ASTMA7(7) except for

....


41/74

th e yield point of the 1 11 plates, Results o f s tandardcoupon tes t s aresummarized in Fig, 2,

Bolts - All bolts were 7/8 11 diameter with regu lar semif in ished heads, Twoquenched and tempered washers and a heavy semifinished hexagon nut completedth e bolting assembly, The length o f thread, .2 11 or 2.25'.', was standard forA325. bolts a t th e time this research was in i t ia ted but longer than the1-1/2 11 th re ad leng th now s p e c i f i e d ~ ~ 8 ) The bolts sa t i sf ied the proof load(36,05 kips) and minimum tensile strength (53,15 kips)., requirements ofASTM A325, Tension-elongation curves were establ ished for each lo t ofbolts by pull in g bolts in d ire ct tension and by inducing the tension bytightening the n u t ~ 3 ) ,These curves were used to determine the clampingforce of bolts instal led in the tes t jo ints , Shear tests(9) of singlebolts were conducted to provide a comparison with the behavior of the boltsused in the jo ints . A summary of bolt properties is given in Fig, 3,

. Fabrication - Fabrication was done by a local fabricator, The plies ofmaterial were clamped together and the four end holes were subdri l led andreamed, Fit ted pins were inserted in these holes and the remaining holeswere dr i l led through a l l plies of the sol id m a t e r i a l . T h u s ~ a l l holeswere aligned.

Fabrication instructions for preparatio n of the faying su rfac es o fthe plate cal led for removal o f g re ase with solvent and hand wire b rush Ingto remove loose mill scale only. This procedure was followed except in thecase of Joints n3l to 101 where an ambi ti ous ironworker removed a l l millscale with a power tool, The resul t ing surfaces were quite shiny andhereafter will be designated as semi-polished,


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271018 -5

The lamina of plates and the f i l l plates were welded together near theends where the test ing machine was to grip the specimen.

Assembly - A f ie ld erection crew of the fabr icator bolted the joints with


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27L18 -6

Because the inherent eccentr ici ty of lap joints causes them to bend,an external bracing system was used to res tra in the rotat ion of the c o n ~. d . (11)nect10n ur1ng t e s t . The bracing system simulated the effect of the

diaphragms often used by designers in conjunc tion wi th lap type jointso

RIVETED BUTT JOINTSAlthough some experimental work on long r iveted joints had been done

previously(6) i t was not p os sib le to adequately c or re la te th at work withthese tes ts on bo lt ed j oi nt so For that reason three double shear platespl ices were fabricated and machine r iveted with hot driven rivetsoThese connections were designed for the balanced design tension-shearrat io of 1 to 0075 for A7 plate and r ivets made of A14l steelo Nominaldimensions are shown in Fig. 5.The 1" plate was the same as that used in the bolt ed jo in ts o Tensile

tes ts of the r ivet bar stock gave a yield point .o f 3601 ksi and a tensilestrength of 5707 ksio Double shear tes ts of ~ i n g l e r ivets driven a t thesame time as the r ivets in the joints gave an ult imate shear strength of55.3 ksi .

TES1'INGInstrumentation - Instrumentation of the tes t specimens included SR-4 s t ra ingages, a mechanical extensometer, and dial gagesoA few SR-4 s t ra in gages on the p la te s out si de of the connection proper

were used to detect any eccentr ici ty introduced by improper gripping andto pick up the onset of y ie ld in g o f th e g ro ss sect ion.


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2710 18 -7 -

The elongation of each p ~ t c h was measured along the edges of the platesby a hand held sl idebar extensometer. These readings were valid in both theelas t ic and plas t ic range. They were used primarily in the experimentalconfirmation of an analytica l solution for the load part i t ion and ult imate

h f b 1 d .. (12)s trengt o ' 0 te Jo:lnts .Dial gages (0.00 I") were used to measure the overal l elongation of .the

connec ti on , t he reby p roviding a general picture of jo in t behavior includings l i p ~ yielding and bolt fa i lures . Others were mounted a t xhe ends of themain plates and the splice plates to re co rd the relat ive movement or s l ipof the pla tes , and in the jo ints with laminated splice plates dia l gages(0.0001") were used to detect re la t ive movement of these lamina.

Testing Procedure - The jo ints were loaded in sta t ic tension by a 5000 kipuniversal tes t ing machine using wedge grips . The tes t ing procedure wassimilar to that described in Ref. 3 except that in most cases the tes t ingmachine was unloaded af ter one or several bolts had sheared. This permittedexamina tion and disassembly of the in tact connection, and provided valuableinformation tha t would not have been avai lable had complete destruction ofthe jo in t been accomplished.

TEST.RESULTSBolted. Butt Joints _. The results of the tes ts of 16 bolted but t jo ints aretabulated: in-igs . 6 and 7.

JThe s l ip of the jo ints with semi-pol ished faying surfaces was usuallyg r a d u a ~ and occurred in steps as load was applied as shown in Fig. 8, thet e s t curve for joint- D91. However, joints with t igh t mill scale surfacesexperienced a sudden and complete sl ip accompanied by a loud noise. Fig.9, the tes t curve for jo intD90l, . i l lus t r a tes th is type of instantaneous


45/74

271.18 -8

s l ip . In viewing Figs. 8 and 9 it should be noted that the re la t ive move-ment of the gage p oin ts , x , inc ludes ,pla te strains as well as the r igidbody displacements of the inner and outer plates .

Joints D3lto , D6l fa i led by excessive t en si le s tr es s on the netsection. In two cases actual tearing occur re d but in the other 'two. it waspossible to unload the test ing machine af ter the ult imate load had beenreached bu t b efore rupture occurred. Although bol t f ai lu re s did not occur,c al cu la ti on s o f average shear s t ress and examination of the in tact jo in tsindica.ted th at b olt fa i lure was imminent. Fig. 10 i l lus t r a tes this byshowing a sawed longi tudinal se ctio n o f jo in t D6l. ,The high s t ress on then et s ec tio n is revealed by the great elongation of the end h o l e ~ > and theinnninent bolt fa i lure is indicated by the large shearing deformation of theend bol ts . The inner bol ts show practically no deformation. For comparison,Fig. 11 shows a sawed section of r iveted jo in t DR71 with the end r ivetssheared. The inner r ive ts show a measurable deformation.The longer jo in ts fa ile d by t he s he ar in g of bolts . In a l l cases the, '

load a t w h ~ c h the f i r s t bolt sheared has been recorded as the ultimate load.However, in several instances the jo in t was reloaded following the f i r s tfa i lure and then o th er b olts fa i led in a sequential fashion. The sequentialfa i lure of fasteners in long connections has been called "unbuttoning".In some cases a sl ight ly greater "ultimate ll load was required to cause thefai lure of a succeeding bol t as shown in Fig. 8.

Bolted Lap Joints - The results o ft ,h e te sts of bolted .. lap jo in ts are summarized Fig. 12. All lap jo ints sl ipped in a very gradual fashion,under increasing load, unt i l the bol ts came into bearing. U n l ~ k e thebolted but t jo ints no sudden movement or loud noise occurred . Therefore,


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27L18 -9

for purposes of computation, th e s l ip load qa s been taken as the f i r s tmarked change in slope of the load-elongation curve,

F ai lu re o f these joints occurred. by shearing of th e boLtso BecauseL10 was made with similar dimensions, from the same plate . and from boltsof a strength level comparable to those in butt jo in t D10l. these twoconnections may be compared direct ly, L10 failed at 748 kips, almost

~ x i ! l c t b , half of the 1506 kips fai lure load for DlOLJoints L5 and L7 cannot be compared direct ly to D5l and D7L because

of the d i f e r ~ ~ t tension-shear ra t ios ,

Riveted Butt Joints - The resul ts of the tes ts of the three riveted jointsare tabulated in Fig. 13. The r iveted j oin ts f ai le d by shearing of endrivets whereupon the tests were stopped and the joints kept in tact forexamination 0 The general behavior of these joints was very similar tothat of th e b olte d joints. but direct comparisons cannot be made becauseof the different tension-shear ra t ios .

I t should. be noted t ha t r iv et ed joints often experience sl ip despitethe customary assumption that hot driven r ivets f i l l the holes comple te ly .In these tes ts sl ip amounted to about 0.02 inches, which is about 1/3 to1/4 of th e ,slip experienced by th e bolted jo ints .

ANALYSIS OF RESULTSUltimate Strength - The a ll owab le shear stress for bolts used in bearingtype connections is based upon the ultimate shearing strength of the connection. As explained in the introduction, a prime.purpose of this tes tprogram was to see i f long bearing-type connect ions designed with a tensionshear ra t io of 1 to 1.10 have an adequate factor of safety against fai lure ,


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Four jo ints , D3l !:o D6l i nc lu si ve , f ai le d by te arin g o f the platethrough the n et s ec tio n thus corroborating previous work(3) that establishedthe 1 to 1.10 ra t io for balanced design of short bolted jo ints . However,the longer butt j oi nt s f ai le d by shearing of the end fasteners due to thebolts I inabi l i ty to deform suff icient ly to equalize the load among,all. thefasteners. The longer the joint the lower the average shear s t ress a t thetime the f i r s t bol t fa i led.

Because bolts of several different lo ts and strengths were used, itis best to represent the average shearing s t ress a t fai lure in non-dimensionalform. _ Since the "premature" fai lure of end fas teners has often been called"unbuttoning" th is non=dimensional quantity is called the unbuttoningfactor .. The unbuttoning factor is defined as the average bolt shear st ressin t he connect ion when the f i r s t bolt shears (1"u) divided by the ultimateshear strength of a s:l ..ngle bolt of the same lo t and of the same grip (1"1).Expressed m . a t h e m a t i c a l l y ~

(1)

The unbuttoning factor i s an e ff ic ie ncy f ac to r that measures the abi l i ty ofthe connection to develop the ful l strength of a l l the fasteners.

The unbuttoning f a c ~ o r s f o r a l l th e b olte d but t jo ints (includingcompact jo ints(3)) with a tension-shear rat io of 1 to 1.10 are plottedin Fig. 14 using the le ng th o f the jo int as an a rgument. JointsD:n toD6l are shown although they fai led in tension. Their plotted pointsrepresent a lower bound for unbuttoning factors. The lap jo ints andriveted joints are also plotted a lthough only LlO had a tension shearrat io of 1 to 1.10.

The plotted points define a fair ly l inear re la t ionsh ip between averageshear st ress and length of jo int . This relat ion extends from U = 0.98 for


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j o i n t L2 to U := 0.60 for jo in t D16. th e lo ng est connection tested. Theo-r e t i ca l ly . jo int L2 , being s ta t ica l ly d e t e r m i n a t e ~ should have an unbut-toning factor of 1.0. Join t D16 shows tha t in jo in ts of tha t length,52.5 inches, the end bolts may be expected to fa i l when only 60% of thejo in t carrying capacity, based on the strength of an individual bol t , ha sbeen real ized .. The unbuttoning factors for lap jo1nts L5 and L7, having. tension-shear ra t ios of 1. to 1..29 and l to 1.55 respect ively, fa l l abovet he gener al band of values. This is to be expected because the excess platearea resul ts in less plate s t ra in than in a balanced design jo in t and theconnection approaches the Itr igid p la ;t e" theory used by t he des igne r whenhe assumes that each fastener carr ies an equal share of the load. I t hasbeen shown analytically(12) tha t the ult imate strength of a bolted jo in tis a function of these plate s t ra ins as well as of bol t deformation.

The r iveted jo in ts show that the same unbuttoning t rend holds forr ivets . Rivets made of A141 s tee l apparently possess a l i t t l e more de-formation capacity and thus are able to redistr ibute load to a greaterextent than A325 bolts . However, it must be remembered tha t a fewernumber of bolts in a shorter connection wil l sustain the same load as agiven number of r ivets when design is for bearing type connections.

In order to determine the minimum factor of safety against ruptureit is conveni en t to conv ert th e unbuttoning factor data into terms of theshear strength of bolts that jus t meet the minimum s t rength requirementsof the A325 specif icat ion (8). As a resu l t of previous work(9 ), the ul t i -mate shear s t rength of a single bol t is taken conservat ively as 68% ofthe tens i le s t rength . Thus, for a minimum s t rength bol t in a connectionof length, L

(2 )


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where UL is taken from the mean l ine in Fig. 14. This information isplot ted in Fig. 15 for 7/8" 1" bolts with 0min = 115 ksL

The horizontal l ines in Fig. 15 represent th e allowab le sh ea r stress. for A325 bol ts in. bearing-type connections in b u i l d i n g ~ ~ namely:Fv = 22 ks i for dead plus l ive load only, and Fv = L 33 x 22 = 29.3 ks ifor dead plus l ive loads in combination with wind or earthquake loads.The ver t ica l dis tance between the horizontal working s.tress l;D,nes and thesloping ult imate s t ress l ines represents the margin of safety.

For very shor t join.ts under dead and l ive loading the factor of safetyagainst: a b ol t f ai lu re is greater than 3, .bu t a t a length of 52. 5 in ch es(16 in l ine a t 3-1/2") this i s reduced to .. 2 .L The minimum factor ofs af et y aga in st a tensi le fa i lure of the net section of A7 plate is60 = 3 i f t he a ll owable s t ress i s 20 ksi and i f net sect ion eff ic iencies20greater than 1 are not considered. The factor of safety against yielding

33of the n et s ec ti on is 20 = 1.65.Under w ~ n d loading qjti:ditions the factor of s af et y a ga in st a bol t

fa i lure in the 52.5" long jo in t i s only 1. 50 but: even this is greaterthan the factor of safety against yielding of the ne t sect ion,

331.33 x 20 = 1.24.

E ffect of Pitch - The pi tch was held constant a t 3-1/2" (4 bo l t diameters)for a l l joints except D13A where the pitch was 2-5/8", the minimums p ~ c i n g of 3 d iameter s a llowed by most speci f ica t ions . Nevertheless,some interes t ing observations can be made concerning the effect o f pitchby comparing, DlO, Dl3A and D13. DlO with 10 bolts a t a 3-1/2" pi tchand D13A with 13 bol ts at. 2-5/8" had the same overal l length of 31-1/2 11 DBA and Dl3 had 13 bol ts in l ine but the i r overa l l lengths were31-1/2 11 and 42 11 respect ively .


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The efficiency of these connections may be compared. by examiningthe unbuttoning factor p lo tte d in Fig. 14 . Joints DlO andD13A had a l-most ident ical unbuttoning factors of about 0.70. ,This points out thatthe tendency of end bolts to fa i l "prematurely" is a function of thelength of joint rather than of the number o f f as te ne rs per se. Onemust be careful not to construe this to mean that the carrying capacityof the connection with 10 bolts in line is equal to that of the samelength connection with 13 bolts in l ine , for although both membersdeveloped the same uni t shearing s t ress , the la t te r carr ied 1.30 asmuch load.

Comparison of DBA and DB shows unbuttoning factors of about.0.70 and 0.65 respectively. The shorter jo int was more eff icient anda 7% increase in load car ry ing capaci ty was achieved by decreasing thepitch from 4 to 3 diameters.

The conclusion might be reached that it is desirable to make a l ljoints as short as possible. However, other research(14) has shownthat to obtain the greatest s tr ength o f the, connected material this maynot be the best prQcedure. In some types of connections, such as bridgehangers r iveted or bolted to gusset plates , a l onger connect ion maybenecessary for the stress in an unconnected web to. be developed byfasteners through the flanges and gusset plates because of. the phenom-enon known as shear lag.

Long Grips - Spec if ica tions (13) for riveted construction require thatr ivets carrying calculated s tre ss s ha ll have their number increasedone per cent f or each 1/16" that the grip exceeds 5 r ive t diameters.Nothing in these tests indicated a need for a similar provision forhigh strength bolts even though grips ran higher than 9 bol t diameters.


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Joints D10l, D100l and DIO, had 10 bolts in l ine and grips of 4",6-3/4 11and 8 11 respectively. The unbuttoning factors p lo tted in Fig, 14 showno subs,tantial spread ~ n d indicate t ha t var ia ti on of grip is of negli-gible importance in determining the ultimate s t r e n g ~ h of bolted joints.

Slip Resistance - This tes t program was designed primarily to provideinformation about the ultimate s tr ength o f longboltep. jo ints , butvaluable information about sl ip also was obtained.

~ e s i s t a n c e to sl ip is dependent on the fr ic t ional forces that canbe developed on the faying surfaces, Although the bolts are notactually acting in shear, i t is c o n v e n i ~ n t to ~ e g u l a t e the design offr ic t ionallowable

type joints by specifying a tension-shear ratio(2) or an, (13)shear stress for the bol ts . The bar graph i ~ F i g . 16

shows th e average shear stress per bol t existing a t the t:Lme majorsl ip occurred, The two horizontal l ines cutting across the barsrepresent the a llowab le uni t shear st resses ~ r i c t i o n type joints

(13) ,in buil din gs ' ,i. e. under dead and Hve load s, Fv = 15 ks i , and underconditions of dead and. l ive load p lus wind or s e i s m i ~ loading, Fv =1.33 x ,15 = 20 ksi .

The high clamping force produced by the turn-of-nutmethod t o g e ~ h e rwith t ight mill scale fa,ying surfaces produced sl ip r es is ta nc e in excessof the specified shear stresses, The joints h a v ~ n g th e semi-polishedfaying surfaces with pract ical ly no mill scale sa t is f ied th e workingst ress for dead and l ive load, However, two of them slipped a t anaverage stress less than the increased stress permitted for wind loadingconditions. This i l lustrates the impQrtance of faying surface infr ic t ion type connections.


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A better way of expressing the role of the faying surface alone isby means of the sl ip coefficient , Ks , given by the e x p ~ e s s i o n

= (3)

In making this computation Ti has been obtained from a torquedtension bolt calibratiop curve using th e average elongation of a l lbolts in a jo int(3) . ': The values of Ks are tabula ted in Figs. 6, 7and 12, and the high and low values are also shown on the ba.t..gr.aph inFig. 16.

The sl ip coefficient for t ight m ill s ca le surfaces ranged from0.34 to 0.57 with a mean value of 0.46. This mean value c o i n c i d ~ s withthe mean value of sl ip coeffLcientfor mill scale surfaces as reportedpreviously for compact bolted jo ints(3) . For t he semi-poli shed surfacesthe range was from 0.22 to 0.36 with a mean value of 0.29.

In addition to surface condition, f r ict ional resistance depends uponthe bolt clamping force. The mean value of. Ti for a l l 7/8" bolts usedin these tes t joints.was 47.8 kips, Thus, for the type of bolt used,th e turn-of-nut method produced t e n s ~ o n s equal to 132.5% of th e proofload--the specified minimum tension(2). If nuts are tightened by thecalibrated impact wrench method i t is l ikely that the wrench will haveto be se t somewhat above the proof load in order to insure that a l lbolts reach the specified minimum tension.


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271.18 -16

..

The inter-relat ion 6 f s l i p coef fi ci en t, bo lt tension, the allowableshear stress and the cross-sectional area of the bolt is given by thefollowing equation for the factor of safety against s l ip .

F. S. = Total Slip ResistanceDesign Slip Resistance = Ks m.n TiFv m n Ab (4)

To i l lus t ra te the range of the factor of safety against sl ip thatexists in f ri ct ion -type jo in t s that are designed for a specific allow-able shear s t ress , Fig. 17 has been plotted from Eq. 4 for Fv = 15 ksiand for 7/8" bolts with Ab = 0.6 sq . in . The values of Ks ' shown assloping l ines, represent reasonable lower l imits for the surfaceconditions found in these tests . The value of Ti represented by, a sol idhorizontal l ine a t 1.30 PLrepresents the value of i n i t i a l bol t tensionobtained by th e turn-of-nut method in these t es t s . The dashedhor-i"'ZQnt;al l ine indicates the proof load , t h e specified minimum tension.Fig. l8has been plotted from Eq. 4 for Fv increased 33% as permittedfor conditions of dead and l ive loads plus wind loading.

These two figures i l lus t ra te the importance of making sure thatm ill s ca le faying surfaces remain in tac t and unpainted in fr ict ion-typeconnections. Fur thermore , they po in t out th e desirabi l i ty of achieving

.a high clamping force by a t ightening procedure that will develop highi n i t i a l stress in the bolt . The combination of t ight m ill s ca lefaying surfaces and bolts t ightened by the turn-of-nut method shows amargin of safety against s l ip , even under wind condit ions, of 37%. I fa l l bolts in a connection are t ightened jus t to the proof load thefa cto r of safety against sl ip may approach unity under wind conditions.


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271.18

SUMMARY AND CONCLUSIONS

-17

The following conclusions are based on the resul t s of 20 tes ts oflarge bolted joints conducted a t Lehigh University and described herein.Certain of these observations are reinforced by the resul t s of previoust es t s described in Ref. 3. The jo in ts , consist ing of plate spl ices ofA7. s t ~ e l connected withA325 bol ts , w ~ r e proportioned for a balanceddesign a t ult imate strength with a tension-shear rat io of 1 to 1.10.The principal item under investigation was the effect of the len gth ofthe jo in t upon the ult imate strength of t he connect ion . Valuable information also was obtained on the turn-of-nut method, the effect ofsu rf ac e cond it ion on s l ip resistance, single shear versus double shear,the effect of pi tch , and long grip bolts . Tests of several r ivetedjoints permitted a comparison of the behavior of riveted and boltedconnections of similar geometry.

Bearing-Type Joints1. Joints of A7 s teel and A325 bolts proportioned a t a tension

shear ra t io of 1 to 1010 produced a balanced des ign a t ult imatestrength for connect ions about 16" or less in length. In longer c o n ~nections the di f feren t ia l s tra ins in the connected materia l caused theend bolts to shear before a l l bolts could develop their fu l l shearingstrength. This "premature" fa i lure of end bolts is cal led unbuttoning .

.2 .. The "unbuttoning factor" (U) i s used to measure the efficiencyof a connection in uti l izing the fu l l shearing strength of all the. connectors and is d e f i n e d . a s ~ the average shear stress . when the f i r s tbol t in a connection fa i l s divided by the ult imate shear s t rength of as in gle b olt . These tes ts show that U decreases in a fa i r ly uniformmanner as the length of t he connecti on increases.


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Theoretically U should be 1.0 for a s ta t i ca l ly determinate connection with two fasteners in l ine and the t e s t of one lap jo in t (L2)corroborated this with U of 0.98. The tests show tha t for shor t compactjoints with 3 to 5 bolts in l ine and lengths up to about 16 11 the unbuttoning factor is about 0.85. For the connection with 16 bolts a t apitch of 3-1/2 11 , an overal l length of 52.5 11 , U decreased to about 0.60(Fig. 14). In other words a connection of that length ut i l izes only60% of th e fu l l c ap ac ity o f a l l the bol ts before an end. bolt shears.H o w e v ~ t , since the a ll owab le shear stress for A325 bolts i s based uponthe p'erformance of the compact. joints (3) it should be noted tha t thedecrease in the unbuttoning. factor from 0.85 to 0.60 is a more per t inentrelat ionship.

3. The unbuttoning phenomenon can be expressed in terms of theaverage shear s t ress in a connec tion using A325 bol ts that jus t meet thes t rength requirements of the ASTM specificatic)fi -


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of load among t he f as te ne rs takes place. Nevertheless a reduction in thefactor o f safety also occurs as r iveted jo ints become longer. For yearsAmerican r ive ted cons truc ti on specif icat ions have t ol er at ed t hi s reduc-t ion in the factor o f safety without comment.

These tes ts showed that for a r iveted jo in t 42" long (13 in l ine a t3-1/2") the unbuttoning factor was 0.75 whereas a bolted jo in t of thesame length had an unbuttoning factor of 0.68. However when a bearing-type connection can be used the greater s t rength of high s t rength boltsresul ts in a shor ter bolted connect ion thus n u ll if yi ng t hi s apparentadvantage of r ivets .

5. Bolts used in single shear have o ne -h alf th e load carryingcapac ity o f comparable bol ts in double shear provided the shear planesact through the shank of the bolt . Bending of lap type jo in ts should berestrained by diaphragms or other sui table bracing.

6. P i tch d is tance was held a t 4 diameters in a l l but one casewhere i t was reduced to 3 diameters - the minimum permitted by somespecif icat ions. However comparison of three connections (10 bolts a t3-1/2" , 13 bolts a t 2-5/8" and 13 bolts a t 3-1/2") shows tha t unbut-toning.of end fasteners depends upon the length of the jo in t and. noton the number of bolts in l ine per se.

7 S 'f ' . f . d i (13) . h h. p e c ~ ~ c a t ~ o n s or r1 vete construct on r e q u ~ r e t a t t e.number of r ivets be increased 1% for each 1/16" that the grip exceeds5 diameters. Although bolts with grips up to 9 diameters were used inthese t e s t specimens the t es t s indicated no need for a s imilar pro-vision for high s t rength bol ts .


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Friction-Type Joints1. Bolts tightened by, th e t u r n - o f ~ n u t method(lO) consistently had

tensions of approximately 1,30 times the prbof load of the bol t thusi ' . . (2,13)easily meeting the requirements o f specif icat ions which cal l for

a minimum tension equal to the proof load,2, No detrimental shear behavior of a c o n n e c t i ~ n was experienced

because of this high in i t i a l tension in the bolts ,3, Joints with t ight m ill sc ale faying surfaces slipped into bearing

a t-v alu es o f average shear stress in excess of working s t resses forfrict ion-type connections, namely, Fv = 15 ksi for dead and l ive loads. and,.Fv = 20 ksi for dead and l ive loads plus wind load(13) .

4, Joints with semi-pol ished faying surfaces obtained by removinga l l m ill s ca le with a power t oo l s lip ped a t values of average shearstress in excess of 15 ksi but less than 20 ksi .

5, These tests indicated Ks = 0,35 as a reasonable lower l imit forthe coefficient o f sl ip for t ight mill scale faying surfaces for A7s tee l and = 0,20 as a lower l imi t for semi-polished surfaces withmill scale removed.

6, These tests indicated that for connections with t ight millscale surfaces and bolted by the turn-of-nut method th e factor of safety

ii :\against sl ip under conditions of dead and l ive loads p1usowind loading

may. be expected to be about 1,37,

ACKNOWLEDGMENTSThe wo rk described this paper is part of an invest igat ion of

la rg e bol te d joints being conducted a t the Fri tz Engineering Laboratoryof Lehigh Universi ty. Dr. Lynn S, Beedle is director of the Laboratory.


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,271.18 -21

The project is sponsored financially by the Permsylvania Department ofHighways,the Department of Commerce - Bureau of Public Roads and theAmerican,Institute of Steel Construction. Technical guidance is provided by Cmmnittee 9 of the Research Council on Riveted and BoltedStructural Joints .

The authors wish to acknowledge the guidance and advice of theadvisory committee under the chairmanship of Eo Jo Ruble and of th ela te Jonathan Jones who recognized early th e need for this research.Thanks go to the Bethlehem Steel Company and part icular ly to the following persons for their help !n providing s t ee l bolts and fabrication

f a c i l i t i e s ~ Eo F. Ball , K. de Vries, J. J . Higgins W. R. Penman andA. Schwartz. The cooperation of So J . Errera, R. Harpel and thes taff of technicians a t the Fritz Engineering Laboratory is grateful lyacknowledged.


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271.18

REFERENCES

1. Research Council on Riveted and Bolted Structural Join ts ofthe Engineering Foundation,

S ~ E C I F I C A 1 ' I O N FOR ASSEMBLY OF s:rRUCTIJRAL JOINTS USINGHIGH STRENGTH BOLTS (1951)2. Research Council on Riveted and Bolted Structural Joints ofthe Engineering FoundationSPECIFICATIONS FOR SIRUCTURAL JOINTS USING ASTM. A325BOLTS, Proceedings ASCE, VOl08B, SIS (October 1962)

, 30 F'oreman, R. To and Rumpf, J 0 L.STAnC. TENSION TESTS OF COMPACT BOLTED JOINTS,Transactions ASeE, Vol. 126, Paper Noo 3125, po 22B(1961)

40 Batho s CoTHE PARTITION OF' LOAD IN RIVETED JOINTS, J our nal o f.Frank1in Insti tute, Volo 182, p. 553 (1916)

-22

50 Hrennikoff, A.THE WORK OF RIVETS IN RIVETED JOINTS, TransactionsASCE, Volo 99, po 437 (1934)

60 Davis, R. Eo, Woodruff, Go Bo, and Davis, Ho EoTENSION. TESTS OF LARGE RIVETED JOINTS, TransactionsASeE, Vol. 105, po 1193 (1940)70 American Socie ty for Testing and MaterialsSPECIFICATIONS FOR STEEL FOR BRIDGES AND:BUILDINGS,A7-58T80 American Society for Testing and MaterialsHIGH STRENGTH STEEL BOL'IS FOR STRUCTURAL JOINiS, INCLUDINGSUITABLE NUTS AND PLAIN HARDENED WASHERS, A325-:"6TT90 Rumpf, J . LoSHEAR RESISTANCE ,OF HIGHSTREN;GTH BOLIS, Fri tz Laboratory'Report 271.3, Lehigh University (1959)

Ball, Eo Fo and Higgins, Jo JoINSTALLATION AND. ' l ' I G ~ T E N I N G OF HIGH S'I'RENGTH BOLTS,Transactions ASeE, Vol. 126, po 797 (1961)11. Bendigo, R. Ao, Fisher, Jo Wo and Rumpf, J . LoSTATIC TENSION TESTS OF BOLTED. LAP JOINTS, Fri tzLaboratory Report 271.9. Lehigh University (1962)


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REFERENCES (continued)

-23

12 .

13.

14.

Rumpf, J. L.THE ULTIMATE.S'rRENGTH OF BOLTED CONNECTIONS, Ph.D.Dissertation, Lehigh University (1960)

American Inst i tute of Steel ConstructionSPECIFICATION FOR THE P E S I G N ~ FABRICATION ANDERECTION OF StRUCTURAL STEEL FOR BUILDINGS (1961)

Chesson,E. and. Munse, w. H.RIVETED AND BOLTED tRUSS-TIPE TENSILE CONNECTIONS,. Proceedings ASeE, Vol, 89,.81'1 (February 1963)


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n - 7/8" A325 Bolts per l ine

tgnp = 4t

115/16" Drilled HolesJ.. , ...... - j I I: + T I j ~ e w ~ d t ," j I h ,:.;,;'.:, I-< I ) " " I.,. ,(n-1)pitch = leng h 1 2 pliest = 2 or 4 plies = or

r I VII I I / /U I I I I I I IA-.;

..

Pitch Length Width Grip Gage Shear Area Net AreaMark n (in. ) (in. ) ( in .) (in. ) Hole Dia. sq. in . sq. in . T:SD - S e r i e ~ - Part a (",';:ux(ie.i.. Width)D31 3 3.50 7.00 5.84 4.00 3.11 7.21 7.93 1: 1.10D41 4 3.50 10.50 7.16 4.00 3.82 9.62 10.58 1:1.10D51 5 3.50 14.00 8.48 4.00 4.52 12.02 13.22 1:1.10D61 6 3.50 17.50 9.80 4.00 5.23 14.42 15.86 1:1.10D71 7 3.50 21.00 11.13 4.00 5.93 16.83 18.51 1: 1.10D81 8 3.50 24.50 12.45 4.00 6.63 19.23 21.15 1:1.10D91 9 3.50 28.00 13.78 4.00 7.34 21.64 23.80 1 :1.10D101 10 3.50 31.50 15.10 4.00 8.04 24.04 26.44 1: 1.10

D-Series - Part b (l,\,m:;:b.:i,cL 'c Grip)D701 7 3.50 21.00 9.88 4.75 5\ 27 16.83 19.00 1:1.13DB01 8 3.50 24.50 9.88' 5.25 5.27 19.23 21.00 1: 1.09D901 9 3.50 28.00 9.88 6.00 5.27 21.64 24.00 1:1.11DlOOJ 10 3.50 31. 50 9.88 6.75 5.27 24.04 27.00 1: 1.12

D-Ser;ies Part c f ' . j ' d' W' d h)\;''':,3,::., ,e' '.". 1. t ',D10 10 3.50 31. 50 8.48 8.00 4.52 24.04 26.44 1 :1.10D13A 13 2.63 31 . 50 10.47 8.00 5.58 31.25 34.38 1: 1.10

;Db 13 3.50 42.00 10.47 8.00 5.58 31. 25 34.38 1:1.10D16 16 3.50 ", .52.50 12.45 8.00 6.63 38.46 42.31 1:1.10

FIG. 1 NOMINAL DIMENSIONS OF BOLTED BUTT JOINTS


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-Test No" of Stat ic Yield P " t* ks:l Yield P . t* ks i Ulto 'fBnsile St rength, ksi. o : l n ~ . , O : U l ~ " ---Series Coupons Mean Std . Dev, MEan Std, Dev, Me,an StcL Dev,

Par tsa


63/74

n - 7/8" A325 Bolts per l ine115/16" Drilled -Holes_. I W i d ~ h1age"=b - i l l ) lIT L. Wkith I

(n-l) pitch F'l,ength

Pitch Length Width qrip Gage Shear Area Net AreaMark n (in. ) (in. ) (in. ) (in. ) Hole Dia. sq. in. sq. in. T:S~ 2 3.50 3.50 5.84 2 3.11 2.40 3.96 1: 1. 65L5 5 3.50 14.00 9.80 2 5.23 6.01 7.92 1: 1. 32

. L7 7 3.50 21.00 15.10 2 8.06 8.41 13.20 1:1.57LlO 10 3.50 31.50 15.10 2 8.06 12.02 13.20 1: 1.10

FIG. 4 NOMINAL DIMENSIONS OF BOLTED LAP JOINTS

If//ift///44

-15/16 11 Drilled Holes

u--:width)-t!Ime=

)---.----c ) .. _-( )-. Jfl:. wi th IIfenQ:th1 ,.(n-1) pitch = ( I ee -L--_)1--

2t- - d ~ = = = = I = = = = = = = ' i ~ = = f~ = = = = = = = I==g=r1='====4=t=======t

Pitch Length Width Grip Gage Shear Area Net AreaMark n (in. ) (in. ) (in. ) (in. ) Hole Dia. sq. in . sq. in . T:S, DR71 7 3.50 21.0 8.48 4 4 .. 52 16.83 13.21 1:0.7DIUP.l '10 3.50 31. 5 11.12 4 5.94 24.04 18.49 :1:0.7

. ' , . . . .--DR1n );3 3.50 42.0 13.78 4 7.35 31.25 23.81 1:0.7"

FIG. 5 NOMINAL DIMENSIONS OF RIVETED BUTT JOINTS


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" j ....

e F:!.g. I for nomina l d imens ionsan d pat tern (I f jo:f.nts

No, In HneNo" o f. 7/8 11 A325 BoltsNom:lnal shear. area ("" Actual)

-Actual (measu:t'e.d) widthActual (measured) th ickness 'Act.ual gross areaAc.t.ua1 n et area

\UNITS

1.Doin ;sq. in .sq. in .

D31

367,21

5.831.984110577 .8 5

7.162,000l4.3210.57

..

D51

51012.02

8.471.9961609113.17

D61

61211+,42

9,771,96819" 2315,54

D71

11.131.96421.8618.18

DBI

81619.23

12.421.99224.7421.00

;1

D91

91821,64

13,761.99627.4623.72

DI01

102024.04

140991,982907726.05

s R A ~ r I O (As /An)NominalAc.tual

1:1.10l;1009 1.: 1.101:1.10 1:1.101:1.10 1:1.101:1.08 1:1.101; 1.08 1:1.101.: 1.09 1:1.10 1:1 .101 : L 10 . 1 : 1. 08U}Al) .Fdct . ion ~ r y p e Joint; , Fv ... 15 ks tBearing Type J o i n t ~ Fv 21 ksi

I


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1,\

UNITS Dl01 D8C1 D901 DlOOi DIO D13A DB Dl6e Fig, 1 .EOI' lilomlnal di.mensio!!s Ian d p a t t ~ : r n of jo in ts I

,

N'{.l, in IlJrJ.c 7 .8 9 10 10 1.3 13 16No , of 7/ 8 n A.'325 Bolts 14 16 18 20 20 26 26 32-Nominal shear area ( =Act.ual) sqo in . 16e83 19023 21.64 24,04 24,04 31.25 31,25 38.46

Actual ~ m e a 5 u r e d ) width in . 9,863 9,878 9,875 9,869 8,462 10 ,4.59 10,463 12,40Actual (meas urad) thi.ckness in o 2.410 2.632 3.04 .3.354 3.984 3,984 3., 9 8 t ~ :L98Actual gross area sq, lno 230.11 26000 30.02 33,10 33,71 ,41.61 41,68 49,40Actual D.et. ~ r e a sq , :ttL 19.25 21.06 2'.4.32 26.81 26,,24 34.20 34021 41,93G.dp (nominal) in , 4.75 5.25 6000 6,75 8.00 8..00 8,,00 8,00Iis RA'l'IO (AsiAn)Nominal 1:1013 1:1-09 1 :L11 1 :L12 1:1 .10 l :L lO 1:1.10 I 1.:LlOActual 1:1014 1:1010 1: 1.0 12. 1:1.12 1 :L09 1:1.09 1 ~ L 0 9 I1:1.09IORKING LOADFr iedon . Type Joint . , Fv "" 15 'ks! ki.ps 252. 288 .325 361 361 469 , ~ 6 9 577Bear:Lng ~ r y p ~ Joint : ; Fv ::: 'T ksl kips 370 423 476 529 529 688 688 84 6, ~ , c . ~

L-OAD kips no 610 865 1010 900 792 960 "'Irr.f..Oj.",,Bult sh.e.ar .s trc.f>.S ksi 42,8 31. 7 40,0 42,0 3704 25,3 30 . ? 32.3A'lg, ext. of bol t s in." < O ! ~ O 6 00549 ,0413 ,,0595 ,0162 0 70Zj ,076.7


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:3

I:3

091

x

....

... - --- ~ -X

2:3

:3

Bolt Failure SequenceI 2 :3

Test Discontinued\O . ~ 1.0

DEFORMATION X-X, INCHES

1600

o

(J )a..~ 1200oo...J

F I G ~ 8 LOAD-ELONGATION CURVE JOINT D91

1600 Bolt Failure SequenceI 2 :32

(J )a..-~00...J

.. 400.. Test DiscontinUed\

0.5 1.0DEFORMATION X - X INCHESFIG. 9 LOAD-ELONGATION CURVE - JOINT D901

X

f-- - - - ! - -XD901

I3


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FIG. 10 - SAWED SECTION - JOINT 061


68/74

FIG. I I -SAWED SECTION-JOINT DR71


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;I UNIl'S L2 L.5 L7See Fig. 4 for nominal dimensionsand pattern of jointsBOLTSNo, in l ine 2. 5 .7 10

No" of 7/8" A325 Bo1its 4 10 14 20Nominal shear area ( := Actual.) sq. in , 2.40 6.01 8.41 12PLATEActual (measured) widthActual (measured) thicknessActual gross areaActual net area

Tis RATIO (AsiAn)NominalActual

in .sq. :hLs'lll.. illL

5.800,9935.163,88

1:1,651:1,62

9.790.9849,631.15

1:1,321:1.29

15.020,99314,9213,04

1:1.571:1.55

1501413

1:11:1~ J O R K I N G LOAD - - ,F:I'i.ction Type Joint Fv := 15 ksi kips 36 90 126 180

Bearing Type J o i n t ~ Fv = 22 ksi kips 53 132 185 264SLI.P LOAD kips 62 107 195 350

Bolt she ar stress ks:!.. 25,8 17,,8 2302' 29Avg. ext . 'o f bo l t s in , ,0428 00409 , O l ~ 4 5Clamping force per bolt kips 48,6 48,4 ' 48,1 48Slip coefficient ,319 .221 ,286

TYPE OF FAILURE a l l bol ts 1 bolt al l , bolt.s 1 bsheared sheared sheare.d sheLOAD, AT :FAILURE k1ps 191

~640 748

Bolt shear stress ksi 82.1 76,1 62\ 74.2

FIG, 12. IES'f RESULTS EOL1'ED LAP JOIN1S


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See Figo 5 for nominal dimensionsand pa ttern of joInts

IUNITS DR 71 D&101 DR131

RIVETSNo. in l ineNo. of 1/8 1 A141 r ive tsNomlnal shear area (= Actual)

PLATF;Actual (measured) widthActual (measured) thicknessActual g ross areaActual net area

Tis RATIO (As!An)Nom:i.na1Actual

WORKING LOADBearing Type Joint F v ~ 15 ks!

SLIP LOADRivet s he ar stress

T e n s i o n ~ net sectionTYPE OF FAILURE

.LOAD AT. FAILURERivet s he ar s t ressTension, net sect ion

sq. in .

:hLin .sq. in .sq. in .

kips.K:Lpsks!ksi

kipsks ik s i

71416.83

8.471.0016.9313.18

1 781:0.78

25244426,43306r ive t

73843.955.9

11.11LOO22.2218.4]

1:0.771:0.71

36151821.628:0r ive t

942390251..0

132631,2.5

13.79l .002'7.482J.73

1:0.761:0,76

83026.634.9r ive t

12.1638.951.0

FIC. 1 j l'ES'I RESULTS ,- RIVETED ~ m ' T JOINTS


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1.0

2

o

. .... . ....n- NO. OF BOLTS IN LINE AT 3.5" PITCH

4 6 8 10' 12 14Mean Curve - Bolted Butt Jointswith Bolt Failures

16

, ,-

a: 0.8gu~CD~ 0.4I:::>

0.2

Bolted Butt Joint T: S = I: 1.10, Bolt Failures() Bolted Butt Joint T= S =I: 1.10, Plate Failureso Bolted Lap Joints+ Riveted Joints

o 8 16 24 32 40L - JOINT LENGTH, (n -I)p inches

FIG. 14 UNBUTTONING FACTOR

48 56


72/74


73/74

60CJ)CJ)wa::.....

CJ) 40a:: C/).:J&.a.:-w-:r:....JCJ)CJ)w ~ 20(! )a::w> 0

..VI VI~ C\I ~C\I -r0-

o C\I.. C\I

ti l .. '~ Fv=20 ti l~1-- I - - - ~ - - --- I-- 1-- .... - - - - - - - - - --- ~ - - - - - --- -f-- ~ f - - - '"--- f - - - - ~ = 1 5 ksi f--- f - - - -

60

~ 2 0w(!)a::w~

CJ)CJ)wa::.....CJ) ._ 40C/)a::.:J&. 0 :w :r:....JCJ)CJ)

r'

\J".

r0 V lO to I '- 00 (1) 0Q Q Q Q Q Q Q Q C\J lO I '- 0....J ....J ....J ....JFIG. 16 SLIP RESISTANCE OF BOLTED JOINTS

TIGHTENED BY TURN-OF-NUT METHOD


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o

20

S L I P ~ ~

Fv = 15 ksi~ 8 ' A 325 Bolts

2.0 2.5

IIIII10)

I ~1.0 1.5FACTOR OF SAFETY0.5

PL

U.T.S60

..zoen 40zw~

~o(I I(,!)>

Documents

Long Bolted Joints. Proc. ASCE Vol. 89 (ST6) December 1963 Pub