Godfrey, H. J.

Lyse, I.

English

Lehigh University: Lehigh Preserve

Lehigh University
Lehigh Preserve
Fritz Laboratory Reports Civil and Environmental Engineering
1935
Investigation of web buckling in steel beams, Trans.
ASCE, Vol. 100 (1935), p. 675, Reprint No. 5
(33-3)
I. Lyse
H. J. Godfrey
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Recommended Citation
Lyse, I. and Godfrey, H. J., "Investigation of web buckling in steel beams, Trans. ASCE, Vol. 100 (1935), p. 675, Reprint No. 5 (33-3)"
(1935). Fritz Laboratory Reports. Paper 1144.
http://preserve.lehigh.edu/engr-civil-environmental-fritz-lab-reports/1144
Fr.II:.. ... vd
L_ J I {
BETHL[ntl11, Pt.111 ~,{LVANI .
r d Y r
0 to t r Its o -
1 b t
0 1 1-
e t10 ot t u
to
-
1 t 1
or t 0 or t
us tu ch t tl c-
-
10 u 0
t t or
t r 1- S c
r 1 r
, ' ~ .. ·2
, 'relatively sma.lltillets,," Fig." 21' also ahows thet .the :com-
putedst1"8$Se~ 'at tbe 'y,leld1.ng ot',tb.'e llea~i tnstead of" belns '
greater. ,as tber should aecord1ngto ~easrs.J!ooreendHart- ,
mann's disoussion.are leas thantheyleld...polnt stresses ot
the web '&terlal.
, '
,One- halt ot tbe'beams repoJ"ted,by¥essrs. MooJ"e and
Hartmann taIled by what has been', termed, web' cripplIng.' Au
,investigation of web "Crippling '1I'A8 ' also 'carl" led out at Lehigh
Unlver31'ty ,,1th the co.operation or'the Bet,hlehem Steel Com- '
panl ana ita subsidIary 'the I;IcClin:tlc-f~e.rsb,&llOorp0J;atl0n.'
at '~be time of' th.e tests.of ,\feb, bucklIng. , 'rhe results were, ,
. .. . . .'
,not ·Included in. the~aper 1n' order tom_ke a deti~1te dlatina";'
. tloD batween the two t;Jp~sor s:trEHlsco~d1.tlon.The7 are
there1'ore presented herewl~h.
Webo.rlppling Is prlnclpallya"iocal't'nliureproduced
,', by exc0aslve, compressive stresses, and ,tb.~ Ptobl~ of prevent..
beal1u~' supported on aeatanglea.. , The,41Ja o~ the investigation
, , ,',,$ to es't~bll8h the.$tress at 1tb1ohY.1eld1Il&due to web crlp-
p11ng'took plaoe.
Tho progrma 'Included the'"temt:ltl5 of six Bethle,hem'
B!2...58 rolled beams,. tourot whioh "recut from" the ~e..e
. "
section and two from another 3-6otlon. 'The infomation1:or
"" the~e, beems"hleb. had' an hIt ra,tio cif ahout 52.1s. 81"611 in. ,
"
Table, III. Three ot the beams .8~, ..4e$1~ ",'tot'ei1 at ~he,
t>'". ". ~ . 3
pcdnt 'or 8PP~lcatlon ot the. loa.d and the otber tbree. ~o fail
. . .
a't the supports. _~e nominal betu"lng lengths were? and 11
. . ". . . - .": ". .
inches ~or tho CGnterr~1lures. 8n4_3-l/~ and 5-1/2 inches ror
the end fallures. . -
I~ ortler .to. prevent't'ailure due to end twisting, steel
plates were welde4to t.be bottc)ttr t'lange ,at each e.nd or the
" " "
beam.' In'eaoh end plate, at,ahe1ght ev~n with the top:rlange~
, " . "
tl:uu:e' tmsa slotwhloh serve4 as l!1 guIde: tor,'bars welded to the
. .
canterot the top t'lange. Thlsarrangernent, 'Qsshown i~ ,Flg.26
allawed the top tl~utge to deflect ve:ttlcally bilt,restralne4, It
rrom moving laterally'.
"All the beams were 'supported by rollers and loaded at",'
'the center of tbe span. A roller 1I'8S81$0 used tor the appl1-
~tlon_of tbe load torbe8J'fl(4'No. l,and 2. but a spherioal
'bearing ,b~O~k was em}?loyed tor this purpose in the testing, of '
. -
t~e- remaining tour beams. ~teGl bearing p~ateB ot ,the' proper ."
length were usE:td 'to'· transfer the load, tram the, rollers sud
bt,ari,ng block $0 the beat!. Vertical deflections an~' strain
. gage observations_ere "taken on 811b~ams. EXcept-rorUeam
No.1,' allbcw', .ere 1fhlt~'tfa8he4 'before' test1ng~,'
, Strain lInes' 'in the ,.eb. appeared at both supports at
" . . -.
a load or 115.000 lb•• lU':ld at th~ ceaterat 'Q' load ot' 200,000 "
lb~ -, At a' load'or ,190,000 lb., the str~1ns in Beam No.,lln-
creased greatly. indicating that the actual yieldil'lS Qt the
be_ occurred. . ~he atra:lnsobserv9d at a po1nt .1Jule41at.ely "
'. :'.-
aboTQ 'the riange Indicate tha~ 'they-ield point or- the
_terial ira: 'the ..._yeareached at considerably lower loads.
. . .
HOlfeveX'. this local 71eldtng.dld'J1Qt.have any'et:rect on the
. .. ,. .. .
be",88 a.mole.!h.e· baeaCllontlnued to taka loa4 util a
llax1.mlD1 ot 202.000 lb. fta r4la.ehed 8;' whleh time 'the web
. . .. .
erlPJlled ai 'the .Jld.·ushoR '1n '11£. 276
In ~utll16 the ~etualbearing l<mgt;b' at the root
of the web, it was aS8U1led "that the atre" was 41s·t:r:lbuted·
.tliroqh the f'1.ange all. an. angle -or 45-.' The total'bearlns
length 'thus eqqala the lena'h of the bearIng plat. plus
twice thethlekn.eu·· or· the tlJ.tn&G at' the .r-OG'ot the "b.~ .
'l'hetblekn.ss ot the flange was measured by miorometer.at .
. .. . .... .
a poInt next to the ttlle' as lndleatectin Table I. 'fhe
leqth or the bearlDSPle.~. was 3-1/1 Inches at.thesuPPol"t$ .
wnora the baa .was .d.al~d to ,t'~114> . '1'1\. C<Hap~.lu~lYestresa
at the root of ~ha web' at 'the ,.ield pOint C>f'·th.. bes was
50.50(') lb. per. aq.ln..•• Whlch:ooapares Ye~ .ell lflththe a...-
vq_ ~.n!lil~ )'~.ld-polnt lSt-ress or 49.000 lb. per aq.lJ1~
tor the web '_t.:rillll~ The fu.111ield-pol1'lt stress o~ the
web '88 tbu. utilized in this bew.~
SeQ· No.2 was designea 1".0 rail at the loading point
wnere,tbe lengthot. ~hebearlng plate.wae s~ven l~ches.
. ~. .
St1"libt I1n8$ .appeared e~ the supports at a load'or '100.000.
. ..
l\). and at the loading po1ll\at 140.000 lb. Since thehl1-
ure ot' this bea. oeourredat the loading polntno tile-finite'
- :5
. indIcation ot yielding could be obtainedfromthedetlectl()D
0\1"88. ne ~traln gage results shQwed that the 8$rnlns near
the-root _ot the web laereased at -flh1ghrete above -a. load Q.t
120.000 lb. !'h$ stralrUI Ileiuilsred 'a'tthe,eenter c.t the web _'
. ' .
, indIcate-de. yielding et 8 load or 160.0001b.; .10h ns
take. a.a theyleld-po.1n:t. 1004- ot the \)tuim. - The be_ oontin~
ned. ~o take load until a aax1llluln ()~ 223.000 11')~_s reached.-
at whleh tao-the w8bcr.1.Pl'le4 s:t the loadblg poL"1t tUI abo_
brig.,28.
At tb81iel.4 point of the beam the maximum ceJlpres-,
sive s":recss at the rOf.>t·of t,.fo}e yah ft8 49.000 lb. per sq..ln••
Or the: eame -•• 'tb;e tcudle yle14....pQlmt&~:rftsS of the web
metertill. '
Beam.c. 3 was t\esf.gneQ. to' fall at' the auPPt?rts- where
lensth of the berm« plat~s 1Jl1lf ~l/a ll.'lc!u~s,,.~;;,.p~.ent -
faIlUre 'at-thec.n~er';.~lfteit.r$ ,,:er$'"~lded to b0tb.s14es
or ,,"b-eweb at' thi.pQ,1la'\ .•
!l'1e r1rst8t.~a1n lines .pp,c&r~i:l 111. the web near the
.eater at a load of 60.'OOO,lba , The atn1n lines continue"-
to torm"aad. at' Ii 10440'1" 110.000 lb. they-appeared 'in the
, -
web at- the $u.ppor't$S.'lh& obtJ$'1'Ved, '.tra11'ls, indicated 71814-
, 111& ata load ,ot !20.0001b•• 'whick..,aa 't~en.ae the yield,
point of t.he ~_.' 'Wblie the' 'detleotloneurves ina,tested
yielding at 8 load or 230,000 lb. 'At the aaxima load O"r.
'231,500-1b. tltewe'b ,'orippled,at one of' tne, supports, as
- 6
shown in Flg. 29. The bearing plat.euaedtor ihis beam was
too tbin for effectiye dlstribu,tloQ. ot the lO(l1d trOll the'
, ,
rollctr to the.tl~$ or the b._ and couequ$ntlycontrlbuted
to a coneelltra:tlon ot:strees at t~. ,center f?t 'the plate, caus-
Ins local refluX:. a't' low .verage stres8.
The _x~um comp~es$lYe.t~ss8tth€t noot of> the web -
_s' 41»000 lb.'per aq.ln. 'e.~- the yield po~tot the _au.
'This Is. i)()Jlalde1"ab1y less" than the tensile yleld-p,?lnt:a"tre.. ,
or 50,OOOlb~ per'sq~1n. tor the aater1al in th. '••b.
" ,.laDeam,lto., 4 WliS designed to t'$11 at.the center.
. '
atlfttnler•. wer...ldea to th.e we:bat' the euppo:rtf9 ~ The
legtb or the bearlq,plate ~t the center 'of this beam -!l.'
,11 Inc~&s.
./
Th& tlratetra1n. line$appearea In the web at the
lSupportsat e. l~.d or' 90,000 lb. and at ,120,000 1.b. they ~p-'
, '
pearea unde1"tha load1nlg ,potilt • The ' ob.-el"'1'ed, s\ra1ns lad!.. ·
. eate4:l& yielding at 8 ~ load .ot 210',000 l~. wb.i;eh ..as taken a8
, '
the yield-polnt loetlo£fhe beam cootll\t\:led' ~o teke load until
,. ' ., ."
a ,-X,1aUll of 26ol.400 lb. ft8r$8ched, at whiehi1iae ,t.he ..b
eripp1e4 at tbe c·enier of the O$d 4S aho.nm :rlg~'30. 'The
. ,
bearing pla'te •• 't,oo 1th1a also tor th18.1>e. tor .itom
dfa~rlbutlon 01" .be load.
At the. yleld-point load ~1l9 Jliixtatml OO1'IlPte8s1ve '
strese' at ':t~e rbot ot the web, 1f'~S43.200'ib.P&r 'sq~1n •. ~'
whIch 'Is cona14e:rably lees ,than .the •"tensile"yield-po.!»t,
, ,
st.:re.. ot the web aaterlal.
, . Bes !loe' 5 was sbl11ar to l3eam 110. 1, haYing a
boariDg length ~t 3-1/2 tn'cnes at the 'SUPPQrts .-ber.· It ,~
, W88deslped to tal1~' Thetlrat strain 11n.e8 appeareir1l1 ' .
the web at th~ supports at' •. load'. ot 60~000 Ib~ 'and at t~. : .
loadli1g poln~ 2:" '$1084' et 130.000 U'. The 'Yartlcal de-
fleet,lons .& ••11 a8 tihe straius, 81),0••4. that the b.,.
.,.. .
yIelded at 8 load o~16C,OQQlb. '. slicht crippling otth.'
web at· the auppO~ft.. nQte4 at 190,000 lb., utftit .. loa4
of' Z05.000 I'D 0- the web, crlpplGd.
At the Yl$ld-polnt load'of 160,000 lb. \h$ cOlIpute4
stress at tberoo't of the' web was 41,.too Ib-. per eq.ln.,
" .. '. .
, , .
Which ,e01lp.ru tavor!1~ly wS:th tbe ,,.1~1d-~polnt stress o~,
4:4.660- lb. per, aq.ln. tor the Yeb ...terl8.l.
Beam. 110. '6 ft$ similar to Beam No. '2. hav.1.ug a bear....
. - . '. .
, 1DS lengt.t1 orsnen 1nebes at the load1nc 'po1ut. As 'thi.
be•• 1'elied at, theceB~r,'tl1eve1;'tlea:l derle,ct.loJ'!.$, In~l-
. . . '. .. . - ..
, .
oated. 'tbat 'there .as no y;.ld!ng ot tbs be_ a.3 • whole.
1.'be atraU'CUM'$s, ~o.eT.rt indicated a bendIng tfindeBC'y
in the ,web &t ahloa4or 00 ~op~, lb. 'fhc&rmte or strains in-
,creaaedssbSJ"ply 'at ,8 lOlld ot liO.OOO--lbe: wh1dUWelS, taken as
the yield-point ot~h$ he_. The beam continued to' take load
,_·s
thewel) crippled und,er the e--en,ter. . ,
At tllsyield-po!tlt los4 ,ot· tneb5Qm tho maxi..
00lll,r.8-81..-& StJ;'8S8 etthe' rootQt tb,e 1r.b was a5,OOOlb.
per, .q.ln. which 1$ vary ~1oee to the yield-point stress
. ~ . - .
of' 44,.660 lb. peraq.ln. for, the web_terlaL.
'Both.tbe'tlex.u.alend sh&.rlna'st~esses..ere ,loll' 1ft'
81.1 ot' tb€uiJe beau, ao there wRattoindltlat.1oQ· of 1'!.elii11lg
due to t,hese str...es.
SInce 001'1311 baams weret&lStetl in thle lnv9.s'tlga-
,t1otl ll no general cOBelus1ons can be <lraB. ,B'owever$ the.
'res'lllts indioate ~ba't:
. ," .
1. The a,ppearoc@ ot the first ~strain line's· baa
no relation to the yielding of t,he bas••8 Dolebui Is
aa l:ttdl(tation -or hip loe,a1: st'resa.
2•. ?he oompreasif-e,stre-sset the'rootottheweb'
at· the 11,.14 ptk1nt or'!h. 'bed. c()r,r~$p()-l11u'very .ell ·wlth
..
, the' tansile Jleld-p.o1n~ stress ~ot the,_t~ial tor properly'
deslgned pearlng plates.
3.'ne yIeld1ng WlAS e:tlused b7.the compressive
~ . . . .
8t~ess.$at the root of the web.
'. 4. -, The .tOl.1:0wlngtormula ifuiy be used in c01llPut1:na
~he compressive atress .~ the root ot the web1
t • 1t~fA+aB)
nere:
f • coapreSS!V8 S~re86
B • load on bearIng plate
't • "th1cJtnessof .eb
A"a leagth or bearf,ngplate
If - thlcnea8 ot' flange "at edge or fillet
-...- .. -.............


Investigation of web buckling in steel beams, Trans. ASCE, Vol. 100 (1935), p. 675, Reprint No. 5 (33-3)

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Investigation of web buckling in steel beams, Trans. ASCE, Vol. 100 (1935), p. 675, Reprint No. 5 (33-3)

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