IMAGE EVALUATION TEST TARGET (MT-3) h A y ■%.^ I!! 1.0 I.I 1^ 1^ Hi us ft 40 2.5 [2.2 2.0 18 1.25 U ill 1.6 6" — ^'' ruutOgicipniL; Sdences Corpordtion 23 WEST MAIN STREET WERSTER.N.Y. 14580 (716) 37^-4503 i\ \ » 6^ ^ CIHM/ICMH Microfiche Series. CIHM/ICMH Collection de microfiches. Canadian Institute for Historical Microreproductions / Institut Canadian de microreproductions historiques Technical and Bibliographic Notaa/Notas techniques et bibliographiques The Institute has attempted to obtain the beat original copy available for filming. 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KESllLTS OF EXPEJMAIENTS ON THK STKENGTH OF WHITE PINE, BED PINE, HEMLOCK AXl) .SPRUCE, By Prof. H. T. Bovey, LL.J>., D.C.L. To be read Thursday, llth November, 1897. (Rend before Section G, liritish Associalion, 'J'oronto, Anj;nst, lf;)7.) Ill a paper read bclbro tlie Ciinjidian Society of Civil Euginccrs in ;1895, the results were <;iven of a number of cxperinicnLs on the trun.sver.^e stnnf;th (,i' timber beams; but in the ciileul.itions it was jassunied that the (li>toriiiin, or diminution of iloplli, wt tlio bcarini; isurf'aco was sufticiontly small to bi^ disregarded. It (it'leii l-appens> ihoweviir, and especially when tliu timber eontiiins a lait^e amount of linoisturc, that the change in depth due to con pre.-sion is excessive, pio- 'ducing 41 cbrtespoudiiii; inereaso in the skin-stress. ' ■ • ^ / j This inoreas3 is theoretically 2 ^ A rf, / bein;,' the intensity of the jskvn-slress, d \\\c depth, and A (Z the change in depth, ' Tlie method ol' conducting these experiments was I ully described in the Paper referred to, and therel'ore the following points only are lioted ;-—' I All the transverse tests were made with the Wickstced machine. The midtlle of the beam was sup|iortcd on u hardwood bearing of 44 ius. diameter. The two ends were forced down by rams under hydraulic pressure, which can bo gradually increased at any required rate or can be maintained constant for any given time. The end-pressures were kept normal to the surface of the beam by nieans of spherical joints wliieli allow the end bearinijs to revolve. The elasticity coetticients have beeo calculated fioin the following for mu lie : ( being the length of the specimen, A its sectional areu ;md A ir the increment of force producing il change A Z/ in the length. (/') Coefficients from transverse experiments ; L' A \y 1. being the I'ligth, h the bn-alth, d the depth and A II' the increment of force producing an increment A /■* in the deflect i'ln. An oirnr A'' in the deplh theorelically corresponds to an error iu E, which is approximately measured by 3— ~ \ d. d In previous experiments, the wire used in observing the detloc- tieus was found to bo somewhat coarse, aud a special wire was there- fore drawn of .002-inch diameter. The skin-stresses have been calculated by moan.s. of tlie ordinary flexure luriaula, IK) being the toU:! load on the beam, W-i, the weight of the boam, and y the distance of the skin from the neutral surface. The flexure theory is admittedly unsatisfactory, anil freriuently gives results wiiioh iiro eoutrury tj eiperieuce. J'ossibiy, when a ocrfcaiu 1 # liiiiii liusljoen passed tlicvc is a IcnJoncy towards cquBliznIioii of struKS, iitul tlie socallod ncutriil surCuco iiiiiy be moved towards that portion of tlic bciini which is best able to bear the stress. It may indeed bo more correct to assume that the distances of this surraco from the tension and compression fnces are in the ratio of the ultimate tensile and compressive slren jt 0^ = ^ c >^ »o r-: ri B-~~ r^^s CI .-: ri « s^r '•< '£ Z^ C -x' irj '•' .ti ^ r- .0 1 - -J CI £.= e ci :-^ r^^ •- ^% - 5i- » X 1-/^1 = :,'? = - X .r CI r? ^^ ?^ -t - - .- x s= ^ 1- p X CJ ** l^- .*.-,. — _,.,- f^ i i' ^ ri rt ^ n J^ 1 '^ pr ,V-^ ^ .'^ X 00 c. S5 ■z^ i- •-: 51 c = ■5 wc- ct f« c;, C 1^ *■£ = r*: (ci ffTtrs in' : £*- cici eOr— . ~ ir: « ; 1 ^ c* M d c« c; ~ '■: te to -M ^t e ^~ ^^ "~"^ e m I- 1- ri ci d CI i S ^cifit — cs^ e , c -i -x c: \z •-' ^ * •ic '^ -r « :r 1 s .^ X X r: X a. • "" i - • 1 ^. = >r. r -jt: ci -- 1 - (^ ' CI v. -^ 1 y t — 1-« i« . CD -t OS .-> »C CI CI >n OS r- , — I -- X c» o ^ re -s^ CI 3-. 10 CS CI ifl CJ CI §0 o o o 000 •00 kO W CI ~ * — •0 10 ^ 11^ jai- S iCCItn If: m t- irt " " ■"^ Beams 15 and 16 wi-rj sawn out of trees felled at Kecwatin in 1894, and were received into c Laboratory on the 13tli of December, their weights being 41,"). 75-lbs. anil 457. 78-lbs., respectively. They were both tested on the 2iid of February, 1895, when it was found that beam 15 had lust ;)tj.()9 lbs. or Si? p.e. of its weight, and that 2 XwuM It! Iiii'l lost 4r>.59lbs, or 10.2 p.c. of its wuiiflit. When the l)Liiin.t wore Hiiwii through aCtcr the test thoy wiTo Htill loiiiiil lo be oniiiplcti ly si>;uriil(Ml witli wiiter cxcoptiii!! lor iv depth of 1 imli from the r^iirfiicc. '1 ho heiniis were I'roiii tliu eiiiitral portions of the trren, tlio heart rnn- nln;; from end to und. Bciun!" 28 to -lit were sawn from trees foiled in the water 1803-94 in Quinjiu Liiko Co., F.Q. Tliey remnined in water one year, und were rceeived into the Luhoratoiy on Octoher llie 4th, 18!(5. They wero all first quality linilier, and, generally speaking, .-Iraight in grain nnd free Irom knots and sliakes. In order to dcterniino the cxeess of moisture in the timber, ihrci- ^l!^bH, one near tliu middle and one at each end, wore sawn out of the beams immediately after they had been tested and were at onee placed in a ehamber kept at a temperalnre ol'212^ F. by nii'.ms nf steam pipr~. The moisture was .jIso removed from the whole beam-, by drying them ill the same ehamber. Jieam 3(i failed suddenly under a ver^ small Imid, iln' I'raelnrc eom- meneing at a knot in the tension surlaee. On i'.\amiintii)n it was al>o found that the grain on the face wasobliipie to ihenenlral surlaci , whde there were shakes running from end to end in the ncighbonrhei'd ol'the heart which, on the average, was below the middle of the depth of the beam. The results of this te^^t should be discarded, as the beam \va> not of fair average 3 was cut out of beam 3(1 in such manner that the grain was >traiglit. Iteam 43 failed under a breaking load of S.'i.OOO lbs., but a .some- what long continued and slowly iiiereasing defleiti(m under a load id" 22,00()-lbs. seemed to iirl'eate that at this point the beam failed in compression, although there were no apparent signs ot'crippling, , •.r ri 1^ 1- I- 5 r i" r — o 3 r. i- •/. ■M S £ > 3 S^ ■Is- X * = 7. M rj -„ — r? ^ &j ^-s; ■<: -^ • = si -• I* -^ C; ?M • ro ?: 3j — o • cs ^ r Ml — - ■^ ^*r -m ~M • / 2 X c- X'l -- iv- .~ ; -« - "i • ^ ■^ _ = • ft V t - = >= :^- — ^ 7. '■^ "3 '■E 1- 1- • Hv •J ., ^ V '^ ■/. _ X a -s 1 _^ -.%. O C O O OO O ^ Cv ri -M -r o c^ re -r "-: re re — •-? ri £ ,o 1 - - oj a» r> ^ 7 At y i rs :r'-o -i' ^ "^ tfi 3 Hcni'irkH.—Tho viiluos of £ for spooimons n,, h, c and d Imvo been Ciilciilateil from tlio first series of rondinu's niily, und arc oonsoquently miallir tlian if repeatcj reading's liitd Ik.'cii taken. The mean din'ot tonsile streni,'ih is 2.(!8 limes i,'reiUer tlian tho cal- fuliited moan skin stress of tliu lieani and \i.^ timjs greater than tlio mean eomprcsHivo sirenjitli of tlio timber. Specimens i\ and c, eontain the lieiirt and mIlow tlie least compressive (•tiencftli. Tlie ratios of leiiL'tli to least transverse dimensions in tho compression specimens varied from C.47 to 9.46, and the failure iu caeh case was duo to direct criishin(;. The sliearinji stren^rtli of the rouml specimens is 1.42 times grcaUn- than that of thi; flat specimens. The several specimens had lost considerahly in weif,dit during tho interval of their preparation f'ro;ii the beam atid the date of test. Tetision specimen //, after the first, series of readings, was entirely relieved of loail and was alloweil to rest fur two hours. Between the two series of readiiiL's, cnnipro>sioii specimen /; remained under tho load of 50,0(11) lbs. for sixteen lumrs, the final reading vary- ing from .01117 to .01 172. n ca iz; 9-c B o OS CO :^. »-^ u 09 la I ^ x c: i.*: c. t >.'; lo ?5|e K » = S rj d^ e^ —. r^ rj ^ ^ •i!'^'^ a soa,©^!^ »}•. Sri) £" • *r: ..-1 — -^ o .r^ ■ r- — -^ '-r — — t: o -y. I - re ^ -*< r- "/. • . ?C "C re -M c. / c-> I- j^ re ffi r^ — c^i X ri ^ I-, -M I— c: o X r- o r 5: X O O O O o o o »- r* 1 «T re -^ I.-5 o I to X ='- •* - ''■•■J h " T *■ '^ • •' e .o w "c X ■**, Rfinarls. — The values of J? for specimens a, c, f? and /have been calculated from the first series of readings only, and are conse^iuently stnallcr than if repeated readings had been taken. men iitly .■al- tliu (ivo tho la'li I tor tho ■oly led '■y- Tho mran ilircct tensile «tionutli is 2.21 limes grtator tlian the Oftl<'ulato(l mean skinstresM of tlui lituu unJ 27 limes gtoaliT lliaii the UK.Mii i'(iiii|iii!!*>ivt) slriMij.'tli of tlio timboi', Spt'cimi'iis (|, I3, i,i, contain tlK-li'Mft, ami tlio lieart alsopisHosalonR nnn siiln of Hpooiinoni 31, jj, .'/:i. TIu'hi! xpreiuioiis hIiow tlio loaMt sti'ciialli . Till' ratio dl' li'iiutii to iea-t iranHVcrsii (iimcn.'ticaH was 37.1 tor i/i, 2i;.7:! lor ;/j, lU.lT)? for ."? = = — 2 o '*• ^, -i ^I ^! '": '^ ' ? c o c = o — e - ^ r; — -.i •— -r — ; I*. .— r- I-- I - T -* ^ M f^ .S -i ri ?i I -M ri ?^ '^i • T^ JM T^ r I r- o --2 = ' y ir ci ■^" ^t ^ i_f '"' -2 o -3 «-: r-' '-: ^^ i^ 0000000 • * yr^ r-. X cs X « (V, "1 7 t£> i* _ -^ / ■^ r- CM •^ i—t p- 1 — « "^ ^ -■ ^ •~z> t- -f. Cl — ' r) TC "V ■': -.= t - X Itiwirks. — Tliu mem direct tensilo strcni^th of tlie air-dried spcci- nipii-: was ].!) times y;rcat''r tliiin tlie c:ileul!ilod moan skin-stros.s of the jio.nn and 2. lit times creator than tho moan comprossive strength. By the kiln-dryina;, the mean co-cffioioDts of elasticity wore increased and tho mean com press I vo stienuth was also inercasoil more than 79 pi r cent. The mean sliearinj.' strorifjlh was reduced more than Wi per C(Mit., and there was a slight diminution in tho moan tensile strength. 'I'lie ratios of tho loiiijlhs of the compression specimens to the least tr:i!)svp,r.soil!nipnsiiin varii'd betweon 6.49 and 7.43, and tho failure w.is in every case duo to direct crushing. 5 'I'hn iliffi'niR'o hitwion llic ^pccillu wri:;lit> ol'llit' iiir mil kiln ilriil ("in'ciimiim wiiH iiotgri'ni. 'I'lio i-iirritiu wi'iulit of the bciim was J or I lliit. per cubic loot ^jrt'ulri' tli in ili ii nl ili "Z •£ -S ri ?i -M ri ri ri ^ T" r 9. IIWA -^ X --« r: TI :c :* w ?c Ix* '* -f •ji X. a -_- 'Ji <: — ! '. I ' — ■" y. 5 );;■ a ^ ••••?■( -^ H -J a^ H \ 3 !v ; : ; ;(]■ E •ji i 7 ji » — '. 1 : *. — ^ r^ r— 2 "v •" ! t '■ I "* F"» — "rt* % R 1 f ■I t S : : : .3 — • ' • • -n^ 7. §1 ■ S I 1 *''iJr £ 5 i i : :^ 71 7 '^^^ ^fj ^^ I I I i "" ri -^ rP v^ 1 •__• • • ^ 1 5-« -r^s'^r s" «« u • 1 o 2J Ji ■ w Oi CO r:iS a s •.t% u ?:rUi x, s ".^i-fi b S a 4%^B Tl T t? r. -a •■: c- -+• — ' -J a: 1 *.5 — " =r rT -/:- => S"- ^ ■< J c c> c* •_J ~ — i- •:^;r5 a tJ ~ 3 ~ 1 •• '3 S « -J ^'' 11^ i*l5'-"U" £ •yj t p-.' -J ^ — * M -^ r? V ■i o ' 5 .2 -; =■ o = ^- I; X' = = u i_ c- 1 M 1 " t - f Q ■ •. • - Is £ b r-- Ji O c-i -r r-: ri 5 — -T 1- coi--^ • I s-s « /ii/;Kr (■/.•.<. ^Tlic iiu'iirrilirect tensile stron^lh of tins air-drioil .--pii'i- niinis was 2.99 tiinos tho iiilmii coinprossivu slrcnuth iinj 1.0 liiiie!< iln' calcnliitcd mean skin-sin si ol'tlio beam. 15y tlie kiln-diyii-n', tho L'oc'fKcionl.s of elasticity were incnvi.soJ ami the uiean coniprossive strength was inofeasi'J inoro than .'{.>, (> p. c. There WHS also a sliulit iiicicase in llio mean tcnsilo .strcnglli, but tlic shearing strength was diniini^hcil more than ID.l p. 0. The ratio of the loiijih of llip compression .spocimens to tho least transverse ilimen.sion varioii bL'twceii 2.02 ami 10. 1, and the failure wii< in every ease due to direct crushinir, exceptini^ in the case of spociinen h. ill .. .lioli the ratio wsw 20 and the failure was partly due to bcml- iiiL'. Tho injured portion was reninvod from specimen g, whioh was then rctcsted after it had lost in weight 1 .08 lb. per cubic foot. Its coni- pres.sivc strength was found to be 673.'} lb,s. per square inch, or 1.8ti limes as great as in the first tckt, 6 ■I'l- 111(1 I*. tllr 'i'lio dilfuruiiuo butwecD tlio HpculAu wciulitH of iho nir unJ kilu-Jriivl «|ii'i'iiiii'ni4 wuM not ("it'iit. Till' »'|M'ci(l(' wi'i^ht nl' tlio licaiii wi«i from 2 to I Ibri, [lor cubic I'uiii groiilci' tli.m timt nl' tliu H|io('iim!ni. ^ . ^ 'i 35 — '^ — ** M 1- «' f ri 0« TO **• I- ^1 r- '■* ^ T « « !• ». I. !• -i — * 1-.^ — n'i, i-. rt A ?i ti T» r* T^ ?"i fi ti 7i ft ?» ri M fi ?i ^* ?♦ 7i _ — e 1- ■- Ti -t -/ t<^ i- o / r. •»• I' p: fi r> to »5 ift r'l r' r.- "f x I ■■ '4 X '** ' • © T; "f '*» » • ^* ffi r4N rJfi»i*-i ?* ri« ti ri *i ri mM ri ff-i U. M ri H a S a Ed H a js a o a: b. «3 V5 3R u a. a a a ^£^^ i. h. »t 4 ^ <» I J S" rt M X c " " X I- — X ffv ri r. o c', - (T X M- C-. -^ — X ?^ I - r* r-. -T T TS tQ ?fl Ci "M T X I - ^^ •1' c^* I - i I '3 s o o ^ . o c o r O -T C « I-- ■^ *c c . X o -r ri a o — o6tc : r^ i2 " X , -f O CJ c^ X ; — "-^'- - Ol -* "- • I OS s X 'I r^ ; -t'i-TiO x" . -r" w ?*j ct Jii imirks. — Tiic co-i'ffieienis ol' I'hisiicity, toiisilu and compressive sInn 'til of ttii.s kilii-ilriod beiiin arc till small, possibly on uccouut of tlio obli(|uity of the firain in tlic timber. Tho compressive strength, iiuwover, is aj^'ain muoli greater and the shearing strengtli much less than the corresponding strengths in similar air-dried specimens. Owing to some inherent weakness wliieh could not be determiuod, specimen c failed under an abnormally low load, and before the exton- annuter liad been taken oil'. ast leii n.l- Uil )in- M Hi c c 5 C 3 ii as : :~ ; ! : .2 !'■ t I -1 c 3 3 a.r" ■i.K fj }*■ -3 3!" 5^ i ■" *• •* - 03 I .;• * s i "-' "' ~ .'.' ,"■ 5 "J f^ ^ M s 2 ■: -.' '.; •:• < • ;^ - -f .-. ♦; ~ -• Ti -^ r. •- s ,- Tj 5 -r I- s ,T 5 s z ; •i n :;: -3 , ■^ ri s Ti » r. -^ t. / f. /. J \ 1 1 *' ■J fi s r? _ -»• y Ti Tl 1 Tiri Tl •5 ;J ii 1*1 3^ 1- ■5 • X X X X / ' ."" _-_ -r 1 ^ ri ■/ /. T* 1- •— • .- _ ■ t r 1 ^ !■• 7. Xi O t(^ »■: . -. ~ "^ "^ T ;?<^i AVm'(/'K_IU.ani,s 17 ami 18, cniitaiiiiii- tljc heart, «vio cut IVum tiTcs liUod ai Kctwiiliii in 1894, and wciv ordinary 1st quality liinlMT. Tlicro were shakes in Beam 17, reaeliin- the heart at [mints. The irraiii on the hiwcr hall' ol tlie beam was -traight. hut ran crosswise on the tensiou surliiee. From tins time tlie beam was neeivcd into llii; Laboratory to tin" date ol'tho test, a period of 57 days, the beam lo.t 13 P.O. ol'its weiirlit. After thetest a :! ineii sbib waseut out, and the 'V i-ht oC this «lab nn I'Vb. ITith, 1S!)7, by wbieb lime the' nalnr,,! diyiiiL' ean be eonsidere.j to have been eompleled, Ha> |;,iind tn l,e -iS.(il!7 lbs. per culdo loot, iieam 18 wu.s tested after remaininLr in the liaboralorv 12 (biys, in wbieli time it was found lo iiave lust 8.711 p.e, ol' its weiu'bt. It tailed by cripplinir and lon:.;iludimil .shear, siuiultaneously. Tlie urain Ibr about 111 incites ou eaeh side of the centre was clear, straij;lit and I'lee fiom knots. The loj;s from wliicb IJeams 31 to H) were .sawn were felled in the Homiecbi'i-e di-triet in the winter of ISl'l '.I."), and remidned in the water lor six months. They all cuntailted the heart, and were ordiiiiiry Isl-quility timber. Beam 32 failed by longitmlinal .sliciir along a ..hake in the neiuli- bouvbood of the neutral surface, but there were indications that Ihi.i bad been itumcdiately preceded by a slight cripplini;. ' 8 Rciin 11 wM Rtntinht Kwinoil, but conliiinml l«rge nimko* on tliu »iili'K nnil on (lie cnniprpiiiiion mirfiimi dun to noiisoiiinjf and dryiriK Ituiiiii44 wiiii«lmi({litKrnin«d kml .Diiipafiiiivply (rco Irom knolii, but poiilniiicd xliiikcii whiuli siiiwrpntly oik-nded Crom dm hoart niitwnrd In llii! iiidi'H. Aftiy 2.'»,'t dayit it liiid lost 22. 1 p.e. of itx wi!i; wax a dcimo timber orcxetHont i)iiiility » itb "liiiltcn ncrurriiig inturmitli'iilly. A ooDHtBiilly inurunnin); dcflootion indiciiiril ibiit prip- plinK liiid litkt'M pliici' iindur u loud of 70 no lbs,, ulijiim-ii ijir nipplinii wiiH notiippuri'iii iinlil iIh: loud wih S(I(I0 IIi^. Il AVmar/i's. — The mean ilircct toii-ilc ^trtiistli is LM2 tiiiio> i;iout(r lli.'iii tlie ciilt'ulalcd iiioiin skin :.':ko 1- X cj CM 5M n CI CJ 5^1 xS.sS" (M -* -»■ X — 1- 'sTi •*♦ -M — h- X r- T- — -f M -r^ r- ^1 -s| 5SJ c: rc 'J ^ -x ;£ — ^ ,x M -^ 1- n M I - - ^ rt n X ro r-. c-j :-: vr ri x x ri x i ^ 3 -^ -* r^ r- r- r-; M fc fc iM cc .._J 1 '09ds fO -t O "X r- X ai C — iTJ fo — « — ^ — ^ -.J J,l -.l J-I s* u* ' ..;-£§ d=^i •^^ "• -r 7^ f* u sM^i H ^ "" H«£:5cr ■ ri'M'"- C ».£ • i i • — o • ri X 1 1 . I- o ' c^ x" •03(1 S i = -= i — rs /. -^ r; ^M - — ri 3^1 e «r '*« '^'~' "J", '-^ cc X — 3" I- erTcc I t ,..,ig li'iifii/.-ti. — Tlio iiiPiui (lirocl tonsili; stronirtli is 2. Si times irroater than tlii'c;ileiiliitcil \w-.in -kin >trcss oftlie boitiii and 3. 03 times fro:ucr t!.,in till' mciin ilin'ct ounipri'ssivc^ sti'('n2;tli. S|ieoimen 11 (■onttiinci! tlic heart ami -licws the loiist coiiiprossive ■•ireniitli. The i-atina of \i'Uis\h t" liM-^r transverse cliiiieiision wvic G.43 I'.ir specimen 11, ami tl.Vl lor .-pLriinen 12. In raeh case the failure was dm tn ilir'>ct eni.-hiii^. The coetiieients (ifi'Lisii.'ity lor sptcimens 1 , 2, 1-} 4 G 7, S 9 w.'re ealcuiated Irnni the tirst -iries of readin},'.s only, and are eon.sequeutly -nnller than if repeated readini»s had heen taken. The shearing strenj,'tli of the ronn 1 specimens is 1.79 times the mean :hoarit)g stren'.;th of the flat specimens. The timher of the beam in question w.is unusually dense, and the mean .specific v/cight of the beam does not seem to have been much ,-,'reater than the mean specitie weights of the eo;npre.».siou aud shearin-,' t". sf5 S.'S . CO = « = tf COO-*M X — rv T '.-tads •'^Si-i*'*- s < 'A w a 09 i5 M Q •3 Is : Ss S3 ; ^ 3-^2 w Tt r^ ?? a ^ o hi . _. — ■- — - — - o c - » = c^ r"; I-- ri^' « c-Tcim"*! ^^ o e = «e ^ 1- ■/- ^:; X' tc £ rrc^s^rTrT ■^•^-fe'^''^' 1- •n C;^ — ^" = 1= '.KM 100,1 « 7-1 — X ^S^" -^ o ^ = c ■rT = c^ licmarks, — The inciin direct tensile sticnutii is 1.65 tiiiios greater tlian the calciilateil mean slcin-.'itrosscil the lioam ami 1.55 times i^reater than tlie mean direct compressive streiiLitli. Uy the kiln-drying; the tensile strenj;tii was diminished, the eoiu. prcssive stren;_'tli was largely increased, and the shearini;- strength was diimni.shed by 2t.l p.c. The ratios of the length to the least transverse dimension in the com- pression specimens varied from 5 to 10, and in each case the failure was* due to direct cru.shng. Specimens h\ and /(.. contain the heart and .shew the l^ast compressive strength in the w and kilu-dried conditions, respectively. The lossof weiglit in kiln-drying varied i'rum 1.344 lbs. to :!.0O3 Ujs. per cubic it. 11 ^ 8 2 u 1 01 0,1 Of c-a',T .S-.e-c ;juH r 5i i- '"t s^ cc o I ? I H S r- = • i I .5 ~ xr.""« c -5 J — 5 y= O' Of ft> "tfc u^ ^ a« 04 b _HHJJ_ 3 ■§ ooo o »f: o —(CM to — — SS5 CO •* -^ 30,800 ; 21,000 22,000 /. Cr -/ A /: - •M :7 "7 a ^ — o Av„,.o-fa._|ieum.s 22,2,} and 3:., containing tlio hoait, iiiid lain in tl].' water (ill- a consideraljle time, and were coinpletoiy water-soaked. When a.stod, lieanis 22 and ;!5 wore found to be hard i'ro/.en. Beam 2;! Wasal^^M lVo/.ii, but not thinu-hout, as was shuwn when the licaii. was .nt in two at theecntro. Beam 22 was straiglit-grainod, free from knots, and fail,.d with a suddcMi -harp IVaeturo. Incipient decay had coin- menced near the heart of Beam 23, wliieh, however, was rct,'arded as a fair -pecimen of ordinary commercial .(uality. It was full of jar-e knots and the grain was curved from cml to end. Jtaim 35 was strai-lu- urained, ,-lear, .•on.parativoly free from knuts and of exceptionally -ood -luahty; beam 4(1 was cut out of beam 35 after the latter had been tested. Beams 25, 20 and 29 all contained the heart. Beam 25 wa.s a good specimen, and was completely water-soaked. Beam 20 was saturated throughout, excepting for a depth of U inches from surf.ice, and. •■dthon-h an apparently poor specimen, was considered to be of ordinary commercial (juuliti', It was full of knots and its grain was curvcl. 12 1 s 1 « = ■: =-. x «^ x_ i?I in o y» 1' 1- o — / — -* o 1- 'M r' m o >-: J - — o iM r; • 1 - — o X x « — :■: re r: rft r- r: :■; re ro :^ -^ ce T »o fta'araoo'5ia^oi»!c?iK ao-** t, :!s I X — ^ "-■ :: CQ US 7-\ -M "/ 00 X r": o ri — 1- T ' — oooe o c. (ir; c: in — ' '-C X -r ?; ^ D 1* to as a S ca &< c o ■oads ;'-r-^ s — I- I- I- X !•- W X I- ex — tn ^* * ~~ ® "* -rOCOOOOCO _ ^- I- n TJ »n X — ,r / -r ?e X c-1 rl rt I -. QU — c -r: :=) — ri I _ : I ]{ciii'tr\'s. Till' ineuii direct teiLsile .stroiii;tli is 1.43 (iinos great. 'v tliiiii ilu- cMlculatcd mean skiii-stivss o!' the beam and 2.31 times <;ieatiT tlian tiie moan direct compressive stronuttli. Tiic shearins streni,'th of the round >i)eeimeii is 1.52 tinie-^ -reater tliiui the mean sliearing strennlli of the flat speeimcns. 'I'iie ratios o!' length to least transverse dimensinn in the eompression specimens varied between 5. "5 and ~ ■-' , and th.- failure was in each ease dec to direct erushin;;. The eompression speeimens had the appearance of bein<; fmzen, but tlic frost ill the tension and shearing; specimens had tliawed, althouijh thev still remained very cold and water-soaked. In fact, the speeitio weight of several of the .specimens was oven greater than the mean >iie- .'itic weight of the frozen beam. 13 < u o -9 o a; s Q »2#i I : : : • • = 5-5 2 ■ ■ °^."'.'^. 'V-:-.'1^=^ . . . . ; " s —C jr ^, ~ re o s o ■J^ o M 1- vs r ; ; ; I ^5 [ _^_ : : : : : »»-j ( ~ -. ■•, "T" - :■' I- •M « ct r- fi :-. = .'rs m , '* '" - " -o 1^ - _ ^ rr 1^ ^ r^ ^ - ;j5 ;2 aS** I ■ ■ ';~~ ' i-« o -. -r Ti X = C-, — — - ? "'o i ^5 -^ ^ iZ^ H j£ 1'; ^ — — — a' '-"3 -•' r^ ri » i'A;> :'COs ;i'i'^. .«.! ■a « I i.T .- ^ - - ■ - i 1 I 22 3Sg ==0 == ? -o o = 3 -, '- ;- s '/ T •r ,t o^7o,- .;^;::£ Vil:i ; : ; ; : ; £^1 ■C-^ "^ - A ■; X 1- _ o ; !>• o X oc ?c rT : — — Ci ; ? : ?^!?§Si£ 22S2S : : : : • ^ " -, ^. °^ <^ I -. 1^ f^ rj vr M .-■; -• I £,'5 = 2 = = = 000 = 0". :::::■ [^ I ' V ii , fc "~", ~ — ^ C_ O^ Cl^ '"O , , , * * *i AVw,n-/.-,,._Th.. n,oan .liroot tcn«ilostronsth is 2.1 times greater ll,a,. t he cnlculatcil mean skin-stress of ti.u beam at,,! 3.:!:( times -neater that, the tnoaa cou.pressive strcjrth. The tnean sl„.,ri,„- stret.-^th of the round s,^d,nens i« 1.50 times greater than the mean shearin.. strength o( the flat speeimens. The ratios of the length to the least transverse cliu.ension varied e ween 6.08 and 0. ,;, ..d .,.« failure was in eaeh ea.c due to direct e.ush.ng. The results tndtcate that the tutsile and shearin,. stren-ths arc greatest tn titose speeitnens of the greatest speeific wei-ht ° Several of the ..peoit^ens had u greater .specific weight than the mean specific weight of the beam. Tension specimen i' after tho first series of readings, was left under 00017 "■ "' ""'^ '■'"'^"•= ^■'"•^'"= '■'■"'" -O'^oas to 14 < a ea M o 3 a a a a i CO 2! ca a Ei) Oi o I t i : ilia II iiter iigdi rini; ricd irect ;ths leau ader I to Compression specimen g, attcr tlic first sorias of rcadiims, was wholly relieved of load for IJ liourR. Compression specimen * -x ^ fc 1 - i^ c> ' ■: -JL — (M — ■M — — -to — 030^ r ».= ^ ^OOOO-'O OOOOOO C t, i, — r-t^O— •l-.Z— — J-ICCMJO m t • - 1- r. r-T-r ^t r- - — 'O i- i — r -t^r^ U r-l— > — — — •--<*|t— !•-■•— — r-iM^-*?^ l-H —1 (M x cor^oooo,^ 30^^000 - ^ f 3 V V- rt rj M -/J c^ T 1 - r. — - - — n ? 1 ', ^ — — •-•t' "- --^ >.<;•- ^ A Ed :^ ■-4 a, V3 /I'cimir/.-.H. — Tho mean ilii'cct tciisiK' stroni^th was more than 2.J(i times as great as the oalcuhited moan skiii-streas of tho Beam and ."J. II times li-rca'or than tho mean coniprcssive stron<;th. The kilri-driod spoeimen showed a eninprcssivo strength more than double the mean eonipressivo stronu;th of iho air-diiod spccimons. 'f ho ratios of tho leni^th to tlio least •limsvorse dimensionsin tin.' oompression members varied fiom 2.5 tn 7.8. an J tho failure was ineacli case due to diroot crushins*. JJotwccn the first and second series of readings, h remained under K)0 lbs. (or \ti hours, tho final reading varyins; from .OOiST to .0037U. Between tho second and last scries ^f i'^i'dings th( specimen was loft under 400 lbs. for 4"i hours. Tiio i\n. .mg varied from .001 to .00398 in tho first two hours, and tho oxtensomoter was then reset at zero During tho next hour it varied from zero to .001; and the final reading before recommencing tho tost wag .00082. The average time occupied in each observation was about cae minlite. The varia- tion in the value of the coefficient of ela.sticity was due to the gradua drying of the specimen, and also to the varying liygromstric condition of the atmosphere. I 16 Specimen/ was left under the load of 400 lbs. for 17 hours after tl.e first series of readings, the final readinj; varjiing from .OOliS to 01064 After the .second test it was left under 400 lbs. for 2;i hours the fii.ui rt...d>nK v:n7inj; from .OOL'81 to .00995. Between .he third and fourth series of reading's the spccimon wi.s hh ui.dcr 400 lbs for .'► h. iMH, the finul leading varj-ing from .001C,3 to .00284. The varia- tion of the riiadiug was due to the gradual drying of the specimen i.iid to the ..hungiiig hygrometric condition of the atmosphere. I'.ctwetn the two scries of readings for specimen / there was an intorvai of 90 hours. The small tensile strength of the specimen was chiefly duo tn the fact that the grain of the specimen was slightly obliijue to the axis. The compression .specimen ps was left under a load oir.,000 lb- after the first scries of readings for 42 hours, the final reading varyin.> from .00081 to ^00;|98. After the second series of reading, it roiiiaii.ed un. cr 5,000 lbs for 48 hours, the final reading only varyin.^ fVom .00401 to .00398. ' -"^ " The compression .specimen s was left under 5,000 lbs. for 18 hours after the first series of readings, the final reading varying from .0026 to .00208. After the second scries of readings it was left under 5,000 lbs. lor4J hours, the final reading varying from .00278 to .002805 After specimen p2 had been tested the' injured portion was removed and the romi.inder rctested when it had lost 2.4 lbs. per cubic foot of Its weight. It* compressive strength was 4,097 lbs. per square inch n » o o a u n o en s w a, rc — r»i ■ ■» '^ . - jj , - -^ M IM C^ C-» -/i '^ U 1- r* c o :g u UJ d r<: ■— I r-H = o o =; 5^1 cri I- o — . T fC o C"= v-^ ! yif. 16 §'i=.r o = I vs o o 2 cc ~ . S r- C % — j ; -/:' CM -^ , i/ 1 ; r — — * ^ s o -T /- .— or. Im •,-.-: : •>}■ T •»■ : >«<•-«: ■~''i-'^ 7 ' <1 Id 33 O a: .: - . -J 'M c^ M ri r-. J-- o t- • i- *i^ O M — - oo tc T (^ o - -ft r^ .- -v -f — ti^ '- «:^ 7J r^t^ (M ■-»« to — — « »rt oa '- — = ?i- 1- X — i - :- I — * =^ ^tz^ _ _ -^ — — — oooooooc OD 3 * , ooooooooeo V ^ E ^ 1 *: v; cr •* /: x >;7 • ■; rf — ^ O iti 6 K ^^ ,^ ^ _^ ^ ^ t!-C>-C (J W-^ ■« •*^^>. 'J i; z ;i3 a t: ^ — ^- T"! — -/. - / "i -rr f i -/. 5 ^ ?i 7 — -T '•: — ' ~* *. -^ '/ J* rr T^i ri M ?i fi ri Mr) -* r- t - ri o i* '■^ ft s'l X r-: -r r^ -f » -c -f %5 ri .;' i -A — r. ro ;_^ ".' A •'• '=■' - - -r. /- .. •-k -^ "^ "^ ^ — 5 ir^o — r. ri r. — X 1 - t* 1- t.*; u* ,-' Tl Tl ?J M ri li i. 11 1? .. --i r. -^ -/ • X t -r ' ' ^ — ----- 0^03:= o o — ^ ^ o r^ ri r- o :- rJ X, :":^rj.<= e ri M — '3 ii i. ' ~ - '■ o « *i * V ' V " , ~ O 'T "^ ^ — ^-» __^-_ ._. o c: o e c c: o c — — ,- ;r. — _ - O 3j 2 o Ti I -n- 0,01^'* '-'; ^; •s r^ TTy-: =-rv- -— -T "■: Xj - i^ 1: ' - ' ' 2£ O i— — < *f. - -_- * >•( ~ •»« .-. . CI ;) .« -<■*:•'-•* ■^ ^ -»^ ^ -• — O .- "/* CI — pt ?■: ri — T 1 'LO 1 - '.r -r -- ,- 'J;' •ri -N rJ ri M ■ri ■fl r^ 1- r*i 1 - r^ o — — o 1- r. = o Ir (J -H o — r- -r 1- /- 1- '-i 7 *' ^ = =-o o ^ o ?? ^ r^ |'^ ri cj — r'^— "*-, »--5^ •M 1- .rf cTxVr r- X' tr^ y: o •M -1 CIO I- i « ^ ^1 H« >-<*>] ph —M '~* o o = c: o O O y. - - O T^ — TI X — X^i * -- Oi^ C\ -* r^ x'o'-i" 1 - X -I* X ;/. -M o (- o o '*.»«* I »i 5^1 t— . — C-l — " "■ ji .. CI ^, t: i ^ lift 17 Ri>m c impression specimens varied between 4.43 and 5.57, and in each caso the failure was due to direct crnsliiiiL'. After /i-j had been le^ed, the injured portion was ronioved, and the siieeimen wasdried at:il2 ° V. ami n'losted with the following result'* : — eooffieiont of elnsii(iiy=:l, 511,000 (lorwaid), 1,517,H.'10 (return) ; compressive stren^ith ~ /lU". 8 lbs. per square inch; specilie wcij:hi = liV.Ol" 111', per culiie foot, Aftei Ir: hiij been tcstiMl the iiijiired portion was removed and the >pecimen was allowed to dry i.'radiiiilly in the laboratory for about a month. It was then re-tested, with the tiillowing results: — eooflieieni treni;tb = 3G3t!,3 lbs. per .-quare incii ; sjK'Cifie weight = 38.07 lbs. per cubio foot. After /■ had been ti'ited the injured portion was removed and the sjiecimeii was imtnedialoly iv-tostecl, with the following results: — <■■ efficient of elastiiity = l,t'08,5li(l (forward), 1,615,3110 (return) ; o.iuipnssive streuixth = 3502.5 lbs. per (-([uare inch; spocitic woisrht = 52U2 lbs. per cubic foot. The injured portion was rcninvod, and the specimen dried at 212 ° V. when it was re-tested, with the follnwini; results: — coefficient of ehv^- tieity — l,f>fi2,5U0 ( forward), 1, (157. IKIlt (return) ; eomprcssivo strength = 624tilbs. per square inch: s|ieei(ic weight = 25.33 lbs. per cubic fnnt. Jo till' caso of specimen /,. Aftei' 1st series of readings it was loft imdcr 20,000 lbs. for 18!l li'urs, the fmal readiut; varyin;; from .00755 to .O076ur.s, the liiiiil rciidiiiL' v.iryiii'_' iViHii .00723 to .0072(). After 4th series of readings it wa- left uiiiler 100 lbs. for 17| hours, thi' final reading vi.ryiti'.' from .00140 to.OOl-s. After 5lb series ol readings it was left under 100 lbs. for S.j hours, the final reading varying l'nim.OOI7ti to .OOISS. After /', had been tested the injured |icirfiou was removed ai^d the s). 'cinieii immediately re-lt.'sted, with the following results : — eoctti- cient iit'elaatieity = 1.2^4,450 (forward). 1.27S, SCO (return); eom- lO'i'Siivo strength = 31 .328 lb", per sq\nirj inch; specific weight = t6.61 lbs. pi-r cubic font, 'i'lii' injured portion was removed and the specimen dried at 212 - ]•'. and re-tested, with the I'ollowing results : — I'rom 1st scries of readings, eoetlicient of elasticity r (forwird), 1,503,030 (return). From 2nd series of readings, coefficient of elasticity : (forward), 1,»59,920 (return i. from 3rd seiies of readings, coefficient of elasticity = 1,471,140 (f.irwaid), l,473.2Sl) (return); the compressive strength :== 7021.6 llis. per cubic font ; the specilic wei'jhl := 24.00 lbs. per cubic foot. Between the Isl ini 1 2nd reailings the speeinicn remained under 100 lbs. for aboutj hour, the final reading varying from .00043 to. 00021. Between the 2iid and 3rd readings the specimen remained uiulcr 100 lljs. for about 1 hour, the final reading varying from .0007 to .00050. l,49d,940 : 1,405,810 i a i •3 a ttl •EX 3 I Gc 1 ••9 1 o'' :- ■ * ■ : _ r* H -3 ri ?i o ii •rs- ' ■ • ■ ' ■ ■ «S /. S « >. !x '^ H n ^ .11 Tl '* "I ^ ■- T — C in^ —T— *? ;u i - -3 -f] 1 = 1 - cv — H 1 J '■^ eu .z y •". /_ IS ■ -^ '-y r: -i. 3 1 s«g."'^ ^ 1 J2 "N t/- ' - /. j 5s: ta -^ t- S e I 00 I* ? 3 , I 7i,m<-r/.-s. -Benin 24 was ^vot, but w.s in ^..nd roiuhlion and com- paratively iVeo Irom knots. l!oan> U7 ^vas of ordinary connnoreial unality, with fairly straight gr.in and [a lar.. niunbor of small kn,..s. Boan. :!0 was of ordinary con,m.idai:.|uality, l.ut «,tl, largo >l,ak. s runnin..' from cud to cud and dividing the bean> praotic.My n,to lour soctionl Beau. IKl was wator soak.d and hard frozen «hcn tosted It was of exceptionallv uood ,,<'ality, IVco frou> sbakes and liad eloar straisht grain. U.an, 'M «as cut out of H.an. 33 aftor tlio latter bad been tested. Ii> < •A ■A a. OS 3 aa i e -^ M 9> or -^ CD r- t- 1^ • • X -f'fri ® — "4 O V r- t-. r-« I-. fj T) a> vr -t •- f JJ >; M I -■■:•*-.' CO ij c; ■* i — — M ;■: fo I - I - r- I - c; ri si •^' -t r-. .;' ri t* r»^ i I ' i 4' i" s" r ^' ;Ca: ^ >ircc4'~J' mi ^ ^ :■: — .• .— 1^ r. 1- ri _ i Ti s I - I - r. ? 1 'X '/ r t rj ?< D ;- ri Ti r-: •M r: • - -i S ri ?. ^ 'l; ' •; O v.^ ?i^ -r_ -•^ — fi fi -^ |r ^ ;•! ;i ^ Z-^\ t. A r- — r^ "^ c :c i-i ri " \-\ -3 '"^ '"^ •'* I - ? I I - vr -i* — * ' -t c: ■- t: — r-' /* — * •-* X vc ^ . I =5 O -T I- t r- -^ o — I - =1 — X M — ■/. — — -r — -M --*—■/ C Ci •- ?i— :^ — Ow Mi-r: rcn — ri TJ * '" — ''^~ f'v "i^ " *' "t."^ -« "x: . • -T / ao ^ -^ " ^- I - - ^' "-■ 5 — — f* TI 1^ / a £i ri ?1 X' t~ — ' -/:' c" — "■; ■-' cTi - y^'X —T -^J ^ ,; r- r^ — r_i i^ ri ri X -r :- I - i - Tr~tirrTi — — 'ri rTri ^".-T— T I -" " ♦ /iVhi'(,/,v. — Tlic uic:in ili. t tunsilc >trfiintli was moi'c tliiin douhli' tlio eiiltulatoil mean skin stress aij I- -- c" ?-*■ I - Ci x" I - ■/' cT T- c -c « r^ « rv r-- '/ -9 ■/3 •VI -/. 5> '^ ;- r; 5 I- y- - { I Itiiinirl.-H. — Till' mean tensile stp'ti^tli ni' die air ilcicd s|ii'riiii(>ii-i Was iiioru liiaii double tlic caleulaled mean siviii-stress iil' rlic Heam aIlc^ 'l.Cil times tiic direct mean conipiessive stroiigtii. By kilii-dryini,' lliu tensile streiip;tii was diminished, and the mean (;iim|iressive streiiL;th Was inereased mure tiian (if) )ier cent. Spoeiinen 3, alter the first series of readings, was left under 1(1(1 llis. I'lr 4t; hours, and chirini; this interval tliu final reading ordy varied f'rcim .0(t2r)>S to .OO'iCO. S|j(cin!i 11 f(,, afti'r tlie first series of readiiiLfs, was lot't under 400 llw. fur 22 hours, and durim; this interval the final readiii'^ varied I'niai .l)(i;!7S to .OlTMu. Tin* ratios (if the loii'^tli lo the loast transverse dimensions in tiie eompressiou monibers varied between 4.2'! and 8.80, and in caeh case the failure was due to direct crushinu;, exee|itiiii; in tlie cases of speei- mens 5 and (!. in which the ratios were 18.70 and 14.;j2 respectively which failed to some extent from bendiiii;. Specimen c.,, helwccn tiie two sets of readinits, was left under 5,00(1 Ihs. tiir 41 hours, the final reading varjing from .OOOtO to .dOlO:!. .'Specimen (/-, between the two sets of ieadint;s, was left under 5,0(i0 lbs. for 41 hours, the final reading varying front .00128 to .00070. After compression specimen 2 had been tested, the injured portion was removed and the femainelcr re-tested, when its specific weight was 21 '.Tt.lHlft 11)1 pir vMv t'lMit mill it* uitiiipruwivi' utronaHi 4Ht',t \lt. ppf n|iiiiru inoli. Tho iiijiinul portion vt»» rriiinvid Iimhi t\\\% liii»l. mid the imiiiiiniliT ii'jiiin IcHtnl, wlii'ii its wciiilii wii* 'itl,o:»» lli^. por fiibb litiit uikI it> l'Hl|||lt'l^H,•livo stiviij^lli tlCr.'l 'i IIh. per ,«i|iliilr illl'll. S|iuciiin!iii 3, i-„ !•„ •■ 1, nil niiilniii llir licurt mul »liuw tlii! loiiit uom- pi'i'i'iivi.' itirtn^tli. I 3; 09 /. o as SB •/, M T^ CJ T* _^ '/R-l' 1 ntim'i * ^SW-*" I.I- .•: ri -J fJSt'S^ ; -f I 5> *> ta — : i it ■^ C V i.*'«». •i i « l^sSi'^ ■?i f tf» « c' s^ cj — ri re n t^ ri rt s rt r: c 1- — ^'2 i- S^'i!^^:-: "', ^ • V » • - • V r^ M at; ? 1 -^ -^ " V I r p- ^ : 72§5f £ >i ~".,^, -."". ^^1 k. . - »i -^ ^ X -f ■5 ; s?3S:2.::r2 Jl '- rrc-irrri rTc-r 00 = so = ' • Tl -i;,*^, *','*, is /' i~ r* r'l I* - Z r. V, ^ -^ -» y, 5 •• _M W W »! Tl P . ii !£ y' — '"* 3 H N fi R S n ■f • H H ♦ t% y -^ o ■M ?* f I -M ri f- :: r> r- ji — I- 0=0 c-i n -^ c r^^ I— — o -J I- -^ C*J t*: -T •* RimiirliS. The niuaii iliri'Ct tensile stieiigtli of iln' iiir il.icil rcri- mens was :«.'.• tiiiius tliu ealculiitcJ iiieaii fikiiisli'e!.s ol" tlit bciiui, uml 2 :{5 limes tlic menu ilireet (ompressivo streii^jth. l!y tliu kiln-itryinL', llie meiiii tensile stroiiglli st'eiii> tn have 1 n liiereascd, but H]icoimcn <;,, lailcd under an abnoruialiy small loud, pinbably because of some inherent weakness. Tiie compresHive .siieiii'th was increased 77 pi'r cent., imd the mean shcariiiit strenirtli U;T'iinisbed mure than '^'1 per cent. The Vii'io of the length of d to its least transverse dimension was The ratios of the length to the least transverse dimension in the rciiiainder of the compression inembeis varied between 2.00 and 10.1, iiiid in each ease the failure was due to direct crushing. 9. m V. I 1 - - — '4 -^ ■/ r. Tl M»l I'J ■; 55 S ?^jy M / i ^^" ?> U ii >- «'Lf • *i .5 i.-r- ,17-53.7-1 ri i 1- ;-. s nn -.'-.'*,~ * o V •. "r ■- « * * * * /?,mar/,v-Tlio .n-.u. ,iir.vt i.Misil.' stro.,.tl. ut ilu, Hatur.U.a .spcn- ...enswus ...uHy .i-.l.!.. Hu, o.l.ul.u.a.nean .kin-..r.s, of .ho bcu.u and W 88 times tbo 11.0111. comvv's.v ■>w\viK\\. T3v t),o kil»-a.7i"^'. tl.o tousilo ...•o„«th s,..M„s .,, hav.- be.,. .li|;l. -l,..;,ri..s; .s..c.fjtl> w;,- .lin.i„isl„..l ,....•. tl,a,. 12 ,,er cent 1 h- ■<.. The ratios of .1.0 le.„tl, .n ih. I..- .runsv.-.. .lm.o„.„m ,n ,h .o,..pr,..sio„ .ae.„l....s va.-ioa iVom-UlT .., ^.85, and l:,>Un. wa> u. ..:al, I'lhO ih.e li"lii'''Ct I'l-l.shiii;;. . . , ■ ^ftcrco,n,„c...in.. sp.,i.....n 1 ha.l h-.n t,..,.! the ,n.,a.v.l pov...... .,. ..cnovo,! and .h. nMnainder .•e-t-.toa, whc.. '<«;l'7 i;-;;; " ;;; ■17 4,Mll..re.- euhie .1,,.,, its eneffieient ol ci..t.c..y 1,..J.^'0 ( <>- ^^..„.j. ,„,, ni;.,,,9.U) (.v.u.n). an.l its ,.o>np.vss,v.. .........h ...00 ib> ,:,. 'ua.-,. inch. Tho i„,iu>o,l ,..r.i..n was ren.ovo,! IVo.n ,|.,s la., an,l ing results — Cc.L-ftiL'ie.it "f olasli/itv from 1 st se.-ios of .■c:..l...,iSS _ 'j.40-2,7iu (I""v;um1). '~'.HI0,:!K» (.etiirn"). Coefficient ofolastiei.y IV.un 2nd seri.- ol .vadin;^s = 2,415,(VJ0 Cforwaril), 2,tll,S10 (^r.'tuin). Coefficient of o'lastiehy fiMin \\n\ sciios of .endin.^s __ 2_410,0-H> ifoiwaiil). '-'.f-'l^itlO (.etuin). ' 2;; B"twccn the first and socimil rradings tlio spccimon was iiudor 100 lbs. for ;5 hours, the final readin'j: varying from - .01)005 to h .00002. Betwopii tlio second and tliird roadinirs the upecimon was loft under 100 lis. for 25 minutos, the rfadiiis varyiiii; tVom - (lOIIOS to i .0^002. Tlio s|ii)c''!if woiij;litof llicdriod speeinun was ;J2.r),")9 lbs. per cubic foot . AfUr /,, bad been tr-^tcd the injured jiortion wa-^ roniov"(l and tile remainder retestcd, with the foilowini; ri',uits : — Coefficient of oiaslicily =ir I,;t72.;i!t0 (forward). I,!>(i2,02i» (return) : compressive s'.-.-enptli = 3521.4 lbs. pi'r s(iii,'ire inch; specific weiiiht 1= 30.777 lbs. jier cubic foot. After 2 had been tested the injured iinrlinn w !,~ reninvcd and the remainder re-tcsted, with the l()llmviiiL; results : - Coefficient of elasticity .-_; i .73:5,4.-^0 (tin w.ird ), 1,727,0(10 (return) ; compressive strength = 37.''>l'i.7 lbs. per si(uare inch : specific weight = 37.1)02 lbs. per cubic loot. The injured portion was removeil from the last and the remainilcr dried i.t 212 ° F., when it was te-teil, witli the fullinviiif; results : — Coetficieni ">' ■ l;-:' jity ^r- 2.(i'MI,l:!0 (forwa'd), 2,(i;)!),970 (return) ; compressive s;».ceni;fh = 8465 lbs. pir si|uare inch; spL.:iti foi-w;n-iI r.-turn , , "'■ pr'-s>Hit' .r ret:iti\^ II. « loading'. I't'/Htillg. I..il)Mratnry. vitponi. lulllllilitv . |."inl. i — ri'.ll.TOi i:ii- ."iT2 2s s to. ■tin •1 llil'.l.l y.i ii'.i'.i , itiT 4.-. ;i t...iii s .•Jl.vj --.li "li ■* Ttir..i:.:i Till, n;:! i;s 1 to iis':i 1 .i" riss.iMi ilss. |7."i 117 4 to iW 1 .17'':; —7 .1 ..| - fi":i.'.i."is iiTH.d :« iiiH7-5 1 .111-2 -:i.ii ! v.k: i;ki;..') I'lSti.oiid Ii7' to lis .170 '.•:i.7 ■ .'ill.:; i;>'.-..in (is.'t. ;! i;i .". ; .l!7:; 1 '>'i (;70.(i."> lull. -J.". ;!t ."i to:i7 > ) ' 1 "" ()i;:i..'. li(i!l..-> :;:< t..:iri ;) f . 1 2(rj s!t (-,.--■.>..-. ii.-2. i; I tci 117 ■• . 1 .-,.-,7 >'.' i "Is ■; I'lTs:.^.'!? tiiS . 22s lir. 2 ; .1 1'.IS -e, 27;:! i;iii;.i(;'.i iii;i;.i4- .■!.•>' .l;i>2 -II i,').:> i.Tti.iw:: (i7i;.ii3 111'.-, 71.7 t ■J'cnsile strc i};th of spcciin '11 -- I2.2:it lii^ 24 per S(]. inch. Sl'UlMKM H, Si'KeiMi:N 12, lllU.'. > ur 2-! 2!l 2lt :'iO Mar. 27 ■' 2.S " 28 H. SPECIMENS 01-' KED I'INH MARKED GI. (KILNDKIED). SrniMKN 1.— Sect, area ■-= .G874 sq. ins.i f-y. wt. = :!0.9 lbs. (ler culi. ft. ; (ensile siriii;.'tli ^ 1 1,(')20 Ibf". per wq. Id. Si'Kc imi:n 2.— Sect, urea = .71"".') .si|. ins,; f\\. wt. = 311.17 lb?, per enb. ft. ; ti'ii-^ile uringth •- 12,'t2;! llis. per sq. in. .•SPECIMEN 1. iiiii... > ur 2-! •ill 2 It Tt'iiip. (Falir. Nm. Ill MiNiji foi wtlt'tl Mi'ftii ii-tiiiii reHUiiigs. reading, i reading. 1 I li.-. t .'V t 4^ t;iii.2-< 2."i (;,'J0.:!2 6.-ii :i/7 iu!i..')i; (i')(i. , "f .Menu pvcssuro .M»'aii roliiiiv. Iti-w I.iiboratojy. , of vapipur. i Imiuiilily |.i.iiit. .")5' to Ii4' 2.S toHd' 2.V J to 27 SPECIMEN 2. . (i:i !,• ■Vi.fi i:.i> Mar. 27 ■ ' 2.'< " 28 22 , liiij.:* 42 ' i;ii().i;2,') 21 ; (JU.i;-) (i4.:2 \:\\v i;(iii.:!0!i 27 .j Ull',.9,'< U."> I .(IS2 .ll'.M"! I:!.:! 17.0 Attain, a kilu-driod tension specimen, with a scctioMMl :ire;i of .15.58 square inclio-i, was placoil in the testing mnchinc on April llic lOtii. 1891), nnd was subjected to w lo:ul wliicb wasgradnidly increased up to 1000 lbs. Under tbi> load, tlie extension durinjr the, first day was at llio rate of ti.l hiuidrcd-tlionsandtbs of an inch per hour, < bi every succpedinif day this rate diniinisbcd, but irreunhuiy, until tiie test piece bad reached its nornial slate. At this point, the slii;htest ciianiio iu tiic humidity produced a ■■orresponding ehann'e nf length in test piece. The maxiniiuu amount of extension, viz., .00708 irich, occurred on the lllh of JIay. The ijreatest observed rates of extension and recovery per iiour were 7 and 8 one hundred-thousandlbs ol' an inch, respectively. On the IGth of -May the load was reduced to 200 lbs., when the extension was also reduced to .0024 inch. One hour later the reading hail fallen to .0023;! inch, hut an increase in the humidity then caused a corres- ponding increase in the ixtensioo of .00017 inch. In the tran.sverse experiments tb.c greatest possible eare was taken to increase the load at liic same nniliirm rate, the average time oeeu- pied in adding each inercinent and in taUing the corrr ponding readiii'.' being sligblly greater tlian 1 minute. In many cases the beam was loaded, then relieved of loul, and reloaded again, the readings in all c;"^e,s biung carefully noted. This operation was sometimes repealed uierc than once. Wbenevcf a beam or a specimen under tension m- compressiou was subjected to repeated loadings, the tirst series of rea ,4 inch. In lieam 17 the increments of deflection under the lir-t ami sec^'iid loadings were exactly the .same, viz., .41,") inch for an increment of 7,000 lbs. iu the load. Wlien the load, after tlie first series of rcading.s was reduced to 500 lbs., there was an apparent Met of .005 inch, which wculd iiave certainly disappeared had the beam been uUosved to rest for a few minutes. In Beam 24 (Spruce) for an increment of t),000 lbs. in liie load, the increment of deflection was 1.04 in. in the first loading and 1.0:!4 ill. 25 iu the second. Upon being onlirely relieved of load, th-re was an ap- parent, but evidently only apparent, set of .01 in. , . , , , In Ikam 25 (Hemlock), for nn increment of 6,000 lbs. in the load, the increment of deflection was 1.165 in, in the first load.nc; and 1.155- inch in tho second, the apparent set when entirely relieved of load bein;: .01 inch. ■ , v \ ^e In Bo>im27 (Spruce), after being loaded and then entirely relieved of load, there was an appaiont set of .005, wiiich in two hours had fallen to .002 inch. ,• i In Beam2C (Hemlouk), after bein- loaded and then entirely rohcvcd <,f load, tl,cro was an a|.p:.vont set of .004 inch vhieh had entirely d.s- ayiiicared ailcr an interval of about two iiours. Lithe caseof Ih-am 28 (White Pin.) thee were three ?cts of load- ings, tlic ineroments of drfloetion corresponding to an increment of 11,000 His. in the load being; — .238 in. and .234 in. f'U' tlie first sot. 237 in. and .232 in. for the seiiiinl set, 237 in. and .232 in. and .232 in. for tlu> third set, When the Beam was entirely relieved of load alter the first sot, there was ati apparent sot of .002 !.,., which ha,l entirely disappeared in -;) n,inute< The second s,t ofl-adings .•ommeoeed after an intervrd ol IS hours. The tnean incen.ent ..I' defl.'eti..n = .2344 in. ; the mean con.piession = .0327 inch, and, UMUg the ordinary forninla, the coi responding valua of E =i: 1,00(!,980 lbs. The increment., of .leflection for repeated loadings corresponding to an increment of G,()00 lbs. in the load were :— .675 in., .660 in., .650 in. for Beam 29 (Ilendock), .335 in.', .330 in., .337 in. for Beam 30 (Spruce), 49" in 485 in., .487 in. for Beam 31 (Red Pine), '675 in*.', .655 in., .6.-)3 in. lor Beam 32 (White Pine), 313 in 308 in., .305 in., .SOf. in. for Beam 49 (Red Pino). The increments of defleetioti for repeated loadings, corresponding to an increment of 7,000 lbs. in the load, were :— (;'>5 iu 620 in., .620 in., .625 i.i. for Beam 33 (.Spruce). The increments „f deflection for repeated loadings, corresponding to an inei-ementof 5000 lbs. in the load, weio ; — 590 in., .556 in., .555 in. loi Beam 35 (Ilendock). For beams dried at 212-' J'., tin; it.erements of deflection for repeated loadings were;— ,«',., .420 iu., .400 in., .405 in., .405 in., .405 in. for Beam ..6 (N\ lute Pine) and an increment of 6,000 lbs. .178 i„., .173 in., .r.3 in. for Beam 37 (lied Pino) and an mcre- iiioiit of 4,000 lbs. .039 in., .042 in., .040 in an increment ol'300 lbs. .048 in., .048 in., .048 in increment of 300 lbs. .071 in., .070 in., .070 in., .070 in. for Beam 40 ^Hemlock) and an inerement of 300 lbs. .36.5 in., .358 in., .35S in., ,36,3 in. for Beam 41 (Bed I'lne) and an iiieroment of 1,200 lbs. .669 in., .672 in., .675 in. for Beam 42 (Wiiite Pine) and an in cr.'inont of 1,200 lbs. .411 in., .416 in., .408 in., 102 in, an increment of 6,000 Ihs. .243 in., ,240 in., .238 in., increment of 6,000 lbs. From these results and from the further observations up t» tho point of fracture, tlie following inferences may be at once drawn :— {„) The inerement of deflection diminishes and therefore tho eo-efti- cicnt of elasticity increases with the elimination of the moisture from the beam. {!>) The increments of deflection are much more uniform in amount in the case of kiludried beams. 26 ,040 in, lin' Beam 38 (White Pine) and .0.49 in. fn- Beam 39 (Spruce) and an or Beam 43 (Wiiite Pine) and ,241 in. for Beam 44 (Rod Pino) and an 'J'uiiip, 'I'l'ini*, -reliil.. ■[■■■mv '(', '.I :; V, 8 It is, of course, impossible to uiniotain a beam in a kiln-clriod stato. As soon as it is exposed to tlic iitinosphcre, it at once commences to absorb moisture, nnd tlie absorption continues until there h an equili- brium between the hygrometrieooiulitions of the beam and atmosphere. The beam is then in its noimi.l state, imd the cxpeiinieuts indicate that the inci-ements of deflection, corrcspondinj,' to this state, are approxi- mately uniform. The rate ol absorption depends essentially upon the nature of the timber, and proceeds more slowly as the density increases. Thcwcifihtofacciitral2 inch sl;ib of beam 30 (spruce) increased 3.6 per cent, in 24 days and S.5 jior cent, in 47 r example, between .09 inch (in August 24th, and .0S2 inch on SepteadxT 211(1, the i;reator deflection oi' course correspond iii.t; to an innease .if moisture in the atmo.spherc. On the 4lli 7 7." ^ il-T T ;» .ils< i T.v;! .Os'.i Cldiiilvan erv. 7.1°9 .08S Clou.lv. 74^0 .OHS iMue. .o,s,s .OSC, .OSS .OSS .iisi; . O.S.) Stormy. II i( Fine ami .-.liowery Dull, colli anil >liuwerv. Temp. ,.or. Komaiki. 70 t .OS,-. Dull, .'ol.! an showery. 70'(', .000 Continuous rain. 72°:; .0>0 Shiiweiv, llieu line. ■ 72'.-. .oso Fine. 7H s .OS!l ■' 711! .(ISO 71 :! .0>0 Dull an.l cool. "."("."l .0S2 Fine. 71 !) . t)S(i Sli.iw.ry. I NDKI! A LOAD <>F 2.ooo i.liS. DrUIXti SFl'TEMHEIl. Remarks. Clou.l I-J7 I2'.i 120 120 120 I 1211 120 CliMI.lv. [{niri ine Storniv m.l 7ro lis '7.'i f.s'0 (iO a Oil i;o 4 tlO'O n 1 eol.l I' Mie an.l warm. Fin.' an.l eol.l. Fine ami warm. .120 Clou.lv .120 .I2.'i I . 1 211 .121 .121 .I2J T,-lu|i. Dif. 7r:i .120 77\'t .12(1 :\ :> .ris 71 . 1 20 7ni .I2S 7110 .I2s (17° 1 .128 lifi 8 .120 l£.-iii;irks. Fine ami warm. Fin.', I'lit CO.. lev. Wei an.l .-lorniy. Fine. 27 UNDKIl A LOAD OF 2000 LBS. DURING OCTOUBR. i;,vo (WO llli'i! iWi i;,-) '0 7U'0 117 '0 .127 . 1'25 A'l:, .\'>r> .123 .12J .125 .125 Dull, cold and showery. Fine and warm. Dnll and cn)d. Laby. healed. Hull' and cold, fjaliv. heated. 75'0 ti5-8 i;n ii(> 1 (i7°(( (15 '8 {W .') .12» .12:! .1211 .120 .120 .122 .120 .120 (i8°0 1 . Il" Fine and cold. Stormy. Fine aijd cold. CH'O f,\°H G;1'6 (iS'O i;.VO ils-() C.'J'O .m; . 1! '.I .1111 .114 .115 .115 .111 Ilani|> and colil. Fineimd ciild and drv. (iO'O I .120 j «5°0 i .120 ' i;H'2 ! .120 UNDEU I'OOn LKS. Dl'HING NOVi;MBl':i{, (IS -) -O'O 5>i"(i (in-O (I7"3 (WO (Ki-S i;o (I 5:h (t 57 '0 uS'O .115 .111 .114 .115 .115 .115 .12(1 . 1 W Alti .122 .120 Rain. (Ilondy and cold. Fine and cold. Ifiiin and warm. Laliy. door open. Coiiiinnon-i rain. ■(;°o (i7°5 ilrt°(l 5^0 I2n no Cloudy and cold. (12°0 (i(;"0 .lis .115 Cold. Lahv. heated. Snow, "" " 110 11!) 11 '.1 1 20 120 Fine and cold. Rain. Fine and warm . Fine. Dnll and wet- 57"^ (;o°o I17°5 (10=>7 00=0 .120 .115 .IIS .lis .lis Fine. Snow. Rain anil warm. Clondy ic warm. Fine and warm. 120 120 Rain and warm. Clonily anil wurm i'i'.p:', 70°0 .lis .115 Fin.'. Fine and cold. 120 Snow and cold. UNDER 2000 LBS. DURING DECEMBER. IVlnp. (;o" (12''5 (14°5 (;i°(i (;s=(i (■,1°5 o;°0 Ivoniiirks. .113 Pine and cold. .115 Snow-tnrm. .115 Pine and C(dd. .114 ii " ,115 (.' tt .115 Snow and (jiildc .115 iO of strength in compression due to kiln-drying midit have be( n naturally expected, as in the jiroccss of drying the w.iUs of the cells are stift'oned and hardened, and thu.s become better able to resist a compressive force. The walls, however, arc at tb.e same time much more brittle, nnd it is possible that a sudden blow might cause the failure of a kiln-dried column, which would have remained uninjured had the moisture not been eliminated. It may also be of interest to note that in the re-tests of specimens after the injured por- tion had been removed, the compressive strength was, almost without exception, increased. 28 11(1 Cfllll. |. mill colli. imJ culd ami .Laliv.lientoil. I mill wHi'iii. Illy it ivin'iii. ■ ami wiiriii. ami colli. Honco, by kiln-ilr'^inii .1 tw.ini its ofinipro.s.sivo strongtli is iimdc to approxiiimtc nioiv; I'inscly tfc its tcii.Kilc sti'cujjtli. uiifi itH transvpr.so strength is conswiiuiitly son^timcs consiiiei'ably iiicroascd. It iiiu.st be remouibcreil. liowcver, tliat this kiln-dryins! invariably liirj;ely diminiNhos the shcarini!;strena;th, and therefore proportionately 'nereaacs the tendeney to slienr lonuitudinally. Thus, of tlie nine kiln dried beaMLS in the procedini; tables, only one failed by oripplincr while /b«r failed by fracture on the tensile side iind four I'liiled by lonsiiludinal shear. Indeed, i:c iicrally speaking, ki.n-dried beams will fail either by a tensile friietnre or by a longitudinal shear, and this result has been further verifi<'d liy experiments subsequent to thn.se referred to in the present I'nprr. [n practice, of course, beams cannot be maintained in a kiln-dried state, but they rapidly pa.ss into the normal state. The question of how far it is dosiiiibli' to eliniinate tlie moisture depends issentially on the bulaiice to In' niainlliilied between the ten.sile, shearini; and com- pressive strenntlis, and :i beam should always lie placed .'o as to O.xcrt its relative strenijihs to the best advantage Kiln-drying, unless some speciiil method of prevention is adopted, develops shakes in the timber and causes existing shakes to becdme more pronmuK^ed. Some of these shakes often extend to a yreat ilepli: and nin the whole length of the beam, so that it not uifretpienlly lia]ipens that only a slight layer is left to bold the beam together. Such a heiim, although other- wise sound and clear, offers very little nsi'.itance to longitudinal shear, and might n'ore justly be regarded as being made up of two or more superpo.sed beams. Ki'Miiiiks m iiiid dull. Mil" 1 and cooler. 29