# Full text of "Design of highway suspension bridge across the La Grasse River at Massena Center, St. Lawrence County , N. Y."

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Illinois Institute of Technology Libraries AT 315 Stewart, John L. Design of highway suspension bridge across the La Grasse DESIGI Of A Hig hway Suspension Bridge Across The La Grasse River At Massena Center: St. Lawrence County; g. Y. A THESIS Presented By John L. Stewart. Orville C. Badger. To The PRSSILEUT AETD FACULTY Of ARMOUR INSTITUTE OF TECHNOLOGY For The Degree Of BACHELOR OF SCIENCE LIT CIVIL MGIE3ERITTG Having Completed The Prescribed Course Of Study In Civil EgGiESERnrG 1913 Approved:, ILLINOIS INSTITUTE OF TECHNOLOG Y g^kJ ^ T7^ PAUL V. GALVIN LIBRARY ^fJ 42J CP ^6^T S5 WEST "3RD STREET v^f m , W\ *^~^^ -HICAGO. SL 60616 . (X~ <?• Jifn^? S?35EISIQg BRIDGES. Suspension Bridges may "be classed under two main heads :- ( a ),'- Those composed of a light platform suspended from a cahle , the loads passing directly from the floor to the cahle. f "b ),- Those consisting of a roadway supported "by a truss which is hung from the cahle "by means of hangers. Structures of the first class are called Unstiffened Suspension Bridges. Because of their lack of rigidity, structures of this type are limited to short spans and light loads. Structures of the second class are called Stiffened Suspension Bridges. The applied loads ere taken up hy means of the stiffening trusses and distributed to the cahles "by means of hangers. Dae to the rigidity of the trusses heavy concentrations or symmetrical loads are distributed over the cahle approximately as a uniform load, so that it does not vary greatly from its original shape. Stiffened suspension bridges can he constructed rigid enough to ca*ry railway and heavy city traffic. Such men as Joseph Mayer;' Gustave Lindenthal; and George S. Mftrison,' have from time to time puhlished articles in yhe leading Engineering Magazines on"Suspension Bridges", ana it is due to their efforts, that this type of triage has come to he recognized as an economical structure for long spans; 5 hoth for heavy railway traffic and light foot traffic. -2- 3US! 8 E 3 S I E B E I D G E LA Over GRASS E S I V E R MASS At EIA C E IF T E R -0 -1_ I. , Y. The site of a Suspension Bridge over the La Grasse River at Massena Center, IT. Y. The La Grasse River is a tributary of the St. Lawrence River and is navigable to a point about three miles above the site of the bridge. The river also serves as a tail race for the power plant of the St. Lawrence Power Co; The War Department required a 35 foot clearance for a distance of at least 250 feet at ordinary high water during the season of navigation,' which is at about Elev. 160.00. The design of the bridge provides a 45 foot clearance for a distance of 250 feet in the middle of the channel. This was deemed enough to take care of all emergencies that might arise locally. This bridge is designed for highway traffic. The bridge consists of three spans; a central span between towers of 400feet; n and two side spans of 100 feet each. The central span is divided into 36 equal panels'; the end spans into 9 equal panels',' all spans being suspended from two cables The anchorage roadway of 40 feet on each end makes a total length of 680 feet excluding grade approaches. ' -3- SUB4-STRU CIUEE The highest water level on record being at 183.5;' this height was fixed as the top of the masonry piers. These piers are the tower piers and they run down to Elev. 154.66. The cable anchorages which also form the approaches are built of concrete. The space between the two wings is not built of solid concrete; but is left open and filled in with earth and stones* On the Horth side of the river; soundings revealed a continuous bed of coarse sand and gravel. Onthe South side a gravely hardpan was encountered. SggER-STRUQTURE. Each of the two cables is made up of 7 bridge cable strands 1 1/2 inches diam. each. Each strand has an ultimate strength of 267800#; equivalent to a unit strength of a little more than 200000# per, sq. in. Their modulus ^f elasticity is about 20-000,000. The main span cables are cradled to a batter of about 1 5/32 inches per ft., and the plane of the land span cables is coincident with that of th* corres- ponding main span cable. The versine of the main cables center to oenter of towers is 38 feet at the assumed normal temperature;' at which there is no stress in the stiffening truss due to lyye load. The main supporting columns are vertical and spaced 25 foot centers.. Each column or leg is anchored to the corres- ponding masonry pier with 2 l/ 2 inch steel rods embedded 8 feet in the masonry. .. • ' -4- The stiffening trusses are 16 feet on centers and are 8 foot yf — 2 inches deep; back to tavk of chord angles, LOADING A IT D ST R.E SSES. The estimated dead load was 780# per lin. ft. of "bridge";' and a live load of 51#tper sq. , ft. floor area, (Class "C n Specifications for Highway Bridges.), on a 14 foot roadway. The eables,cable fastenings, etc., were designed for a maximum uniform live load over the whole bridge at a minimum temperature which was assumed at 40 deg. F. The floor was designed for a load concentration equivalent to a 15 ton road roller. The limits of maximum stresses in the towers and anchorage steel, including "bending stresses in the towers due to temperature changes is about the same as that of a live and dead in the trusses. The maximum unit stress in the cables under the extreme lull load on the entire bridge at minimum temperature is less than 49000# per sq. in. That of the suspenders,' which are made of the same grade of steel wire; is only 17000# per sq. in. The estimated cost of this bridge complete is ahout |4E000. Articles on the estimate and construction of a bridge for this site appeared in the "Engineering Record" Oct. 5 and Hov. E; 1912. -5- spECi Frcrrro i s ." Coopers Specifications Class "C? will govern this design, (1) The loading used in designing the floor sywtem was according to Coopers Class "C" Spec* A 15 ton road roller was also designed for* (£) The live load to he used in designing the stiffening trusses will he the uniform live-load for spans of 200 feet or over'; as given by Cooper in his Spec, for Highway Bridges* (3) Temperature and wind stresses will he negleoted if they? combined, amount to 30<% or leas', of the combined dead and live load stresses in the ohord members. TSis is according to Coopers. (4) Steel for the cables will he according to the spec- ifications of John A. Robling's Son's Oov; Trenton S". J.*; steelto have an ultimate strength of S50,C0C# per sg* in* A factor of safety of 4 will be used. (5) The floor of the bridge is to be of 5 inoh long leaf yellow pine plank. Guard rails 4x6 inches are used* . — - -.'.;;■■.. ■ : • V . I .: - '■ ■J • '" - 2 . '. - . :■ i„ , .;.-.•' .*'-"■' . _ ; ill "-'-'- - ■ r 1 ' . t Cj 30 ,"": >i . -■-- ; J.' ' L _.;.'- : . . . . -'. I - - . - ' • ' - iO..:j - Zl ... : -" . - ; -6- DESIGCT OF FLOOR SYSTEM. The design of a floor system for all types of gri&gee is practically the same, so no lengthy discussion will he gone into in designing this floor system. It will "be designed according to the "best modern practice, THE STIFFECTIITG TRUSS A three hinged stiffening truss will he designed, as this type is much more satisfactory and has a greater carrying capacity than two hinged trusses. The trusses are placed 16 '-0 1 'center to center and are 8 , ~g~l7 t g' ' deep, hack to hack of chord angles. The stresses in tjre truss were determined according to Johns on, Bryan and Turneaure's "Modern Framed Structures,' Part 11". According to their theory, the cahle always remains a parahola with its vertex at the center of the span,' there-fore the hanger stresses are uniform over the entire span. There is no stress in the truss, due to the dead load of the bridge . The end trusses were designed on the assumption that the cahle was a parahola. This assumption is not exactly correct",' hut as it gives stresses that are on the side of safety this method was used. Temperature stresses were calculated according to Eerriman and Jaeohys* "Higher Structure s"';' page 159. Lateral stresses due to wind were calculated according to Johnson ; Bryan and TuroeaureV "Modern Framed Structures,' Part II" page 521. All similiar members were made of the same section", as this is considered "best practice in modern suspension "bridge design. -7- SUSPE1DER ROM. The suspender rods; 1 which transfer the loads from the truss to the cables were designed in accordance with the theory advanced in Johnson, Bryan and Turneaure T s "Modern Framed Structures,? Part II. DESIG1 OF OABIES. After the trusses have heen designed and the dead and live loads estimated,' we can then proceed with the design of the cable. Specifications say that the cables must "be designed for the maximum tension to which it will "be sub- jected. This condition occurs under full dead and live load. Thevmaximum tension for one cable in this "bridge is 730,000#, thus a cable area of 14.6 sq.. in. is required. Seven strands of 39 wires each 1 ; of ¥o.2 steel wire were used. Clamps for connecting suspender, rods were designed according to experience and precedent, they cannot be mathematically designed. All suspender rods are fitted with standard clevises* There is a cable deflection which is due to temperature and live load. The sag increased by temperature and live load. In order to take care of this sag the maximum de- flection was determined, and in oftder that the bridge would never drop below the horizontal, the trusses were given a camber of about 5 feet. THf cables were cradled as this gives a greater resistance against lateral wind pressure. -8- DESIGN OF TOwERS . The towers were designed according to Johnson, Bryan, and Turaeaure T s "Modern Framed Structures'; 1 Tart II". They were designed with three panels,' the top and "bottom panels "being X braced^ and the middle panel thru which the driveway passes is portal "braced. For cable seating see detailed drawing. GABLE ABCHORAGSS. The function of the cable anchorage is to provide weight enough to counter act the tension of the arables. The bottom and side walls of the anchorage are built of 1:3: 5 concrete,' and the space between the side walls is filled with stones and earth. Thus a cheap and stable anchorage is obtained. See masonry drawing for details of the anchorage. LOADS . Floor system- — -.232 Kips/lin. Ft. Cable. Truss .200 n " " ■ Suspender Rods — .005 ■ " n ; " live Load .480 ■•■■»■ Dead Load -«««*--*.-,— .jbg " " » " Cable — — ~ .050 * n n » Total 1.297 * " fr — *~~ . Conn pu for ion5 for a U~J. Af*MOU/* //VST/TL/T~E: or-TCCrt/S/OL.O&V C/-"C<4&0, /L.L. ./. ^ssurrte width be/ween Wringers . 2-9" 3 * ~-~ M * ~~- 3 = /ooo* for ye/ low pine c = ~- .*. d ' st viLfZl /A ssurrte roller distributes we/phi over 2 plants each /z" wide. Then b=>24-" and d = \l 3x-rsoo*33 =. 3,34-" f^lanKing wilt be ' ?x/ooox2+ " " ,, / / - 3X/2 since the wesa/fT" of rotter ts probably distributed over o /arger area and Specifications art /3. state that f/oor pIciriH. shall hay* a thickness jh /ttches at least eaua/ to the distance a&arf of beams. l/y<s/ahf of f/oor. Weight of yellow pine 3.***joer ft. board measure r/oor area m &ooa /+ ~ 3400*' #440 X 3. SUT3 - 39200 \4/beeJ guarefs 6x«?- ' Zona teat ye//o w Pine 600 XZ A3.? X.5*<*r =■ 3+00 Tot ut * &3ZOO -r&tOO =» 36600* or /t&o per pane/ . 2. D£SI6/V OF STf?JMG£T/Z. Q r ' 5H 'r- K //./ ** 7? f = 7? 3 =■ 3.75" K/'pz J-.L.M- 3.7? X5-.5SX/2 - 24-3.2 Kjt?- )H. D.L.M- - ■4r' w * 20 per ft wesyfif of str/naer » Z22 * + c/ead Joad of fJoor on str/rtger- //./A 33 'A 3 6 - ^ 320 * Tbfa/ (V = &4-2 , „ _ 6V^A///A/^ s.o K/f>- IH ToJ-oJ M - 2+92 + 90 -=■ 2S&2 AT//? Jrr. = 2S&, 200 //*- 3 * 13000 (art 4£- Sjoec^ M, . X = £££*££ = fSL9 5 C /360O 'rvt+t hand boofc — for a 9 U - ^s^ J 4>eaw c - 20.4 .". Use for a// sJ-r/rryers 9" a) 25* per ff; I beams. DESIGN or rLOOfZBF^M. I * i si \ - v/./ / // -to — & — vaa Concentrated load / 5 tons on two o*/es io' centers • and upon the reniai m nq portion of the r/oo^ a load of /oo of f/oor. K ~ > |\ «6 «£5 s^> % %£>,' /~o ^ ' " K, W = Sx//./ A IOZ>.+ X 32 VV Z - At' = 76-+ L*Z£- W* ~ t./ X/O-Q \3X <Qj - Wf = XA /-./A JOO A 3 32 - S. // AC . == / 57 /t - / 66 A. • DESIGN Or ^LOO^BSr^JM (cortt) Moments about ^ % t = A66x/ + S.//A j.s + /.s/a 6.s~ +s.// x S.S +4/6 */3.<T -i- /6 = i2 ~ a - /O. &/ K. Arfow. a hoof W 2 /o.Sf x 6.S - 4/6x4- Max. L.L. Mo**r. =» S3. S3. KjO.f-t-. m 64-2 2-40 £>./-. morn, floured frort>f we/ohf or? r~/oor-beor+r. / floor bean* /& ' a) so ■ Boo F/oor } yvheeJ auords - /790 defa/fe /o <?<Z&o.$~ P.L Ma^r. =• JZl* * 44>ao*/6M/6 _ j/zjBG** s <? ~7ofu/ Alow. =r 6422«lO+-/f23ZO = Tf+tto"* I_ _ £L - 7S~+60O _ /fooo J& r~rorr? handfroo/C J. for a <?-2* /S~" I beam — 5~8.& .'. Use tor a// f/oor beams /s'oO^z per //. I £>eo*t*s, We/orrf of- /7oor s-ys/errr ■&600 oer t>a*?e/ ■4-6 //■/ »/- .-« <<sf>s oer- //£ o/^ br/dje =z m ;z/ X/f>s jeer fA of truss. MAX. END 5 tlZ:^ '/? ON r/QO^S^^M /Live /oaJ) J , ) t. 1 1 ' 'I / a /&—o _L_ ) — <¥. A- - — — .* — /// *« /c ■ T' T / •/ 1 Momerj/s aJjour 1 - /? z f?tX/6 = 3SXJ.5~t8JJX8.S~-<-3/x//.S * 3. // X /-?: i? K - 2Q3.2 /3J J</'&s wc?a . e/?c/ shear. *. f^ivefs ifi connect /on <^s fo fl. beams jE^cJ shea a- = /3,/oo VaJue of ^r fillet '* bectr/**} it -~ pJ. ~ 67SO /3IOO 6 7 'SO = 2 ri ise rs h design or ^TrrFEMMG t/xuss^s. >H ~,~>uryir>tior> ryiaJe -/-bar trusses w/ if riot be stressed uhjc-r dead loud . L.L. = SO w= 60 A /x J& =■ % 9& Kips per fr. „ * brjdge - .-4-8 */&$ per rruss . V* ^L ■ *2*+2S. = 32 . Kips 6 6 1 Max. AW = J2f£ S3 Merr/man «* Jacohu. f^art Tg. , 43 X 400X^00 = y+ So /c ip .-f+ % 53 ' i?ec. & * /,2/ rbr a// dtaaona/s . ( mo/i* st>an\ A/ax. 5/iear - 32 X/&s . £}<e5/ar?ina stress * /.2/X32. <- ^/T:* A'f>3. j^or a// chords , /twain s&an\ LSes/anma ry7C>mer?t == /*?-5~o K/&. ft Lses/an of CAord ^ect/on. for fen 5 /on a//oired stress = /2£oo =*a r or co*yf if>ress/orr Ji? <* /zooo - £& tCeao/red area for ¥&tis/o*7 — ££££ - /■4-.S' C Sx'ZS fry j2 ^s <s^6x^ area - /a. /a, ! ><> r/\re/s /<4Z /6. 76 v .: a*: . DESIGN or 5TirrE'Klll\J& r/TU^S (con*) ss/ " " J 3 " /^or corytjpress/on — 5 =■ /2000 — -^p- . r fo r 2 <c.s ex<SX ■— - A82" /- S:Sirx/2= 66.6* 3= /2000- ss '***■$ . = /.82 joooo .*. ■ ^ =• /£./* read area . 8x joooO c .'. f^or L/e>t?er and /ower chords ( ma/n st>an\ use Z Zs 6X6X~~-. J^/agor?aJs lOesJarnr/a srress - 37.5" x/ps. for ^errs/or/ read. 37.'*' a " T ' " " t " a" area = — — = 3.oo /ry 2 Zs <9-X3J<-%- area = 4>f /or comr>re35/or? J = /oooo - **3*y <~ y -\. / f « /oooo- "* *'***!+ - * 3 oo* a " ^Irea rea'd = %£- = /.2S < 5.& a " / " " " 6.4-f .: 0./< Use 2 Zs -4-A3X-Z for d/ayo/ra/s (rvra/rr and errd s^>ar>J. For ertd d/agor/a/s 2 Zs 6~X3x jr **v// £>e used. yerhca/s are used Jo rvaXe She urpsuj^aor^ed Je/7p-fri oS c bored Sryta/Zer. /Z z^xjg'x^'kY/// be used. s. pes 1 6 is or STirrEsiii*4& truss ^o^t) Chore/ Sec t 'ion (end spans) Max. moment = ^L = ~x &s*20o*= 725 </b ft S3 $3 For le»sior? = 72f a reod area . Try 2 Zs 6X6x~ 8A12S area = /o. tz 2 ri^eSs : 74 *"f 6 ^ , c- ■ <- 5S / O.K. tor corn press /on - D - /2000- ■^~ = /2000 - **.***■* = /oo+o ai read, area = '?££ - so*" .'. Use for both cUorc/s 2 sLs 6X6X^ Weight of Truss . Chords. ^4LS bxex yf- //. / a? 31 * **//./x 3/ = J37&.*- * // * Uja<jona/s—z/-5 +x3x% 9.74- a) //./ = 2x 2 X9.7+X//./ = 4324 Verticals— )jl zi*zfx~ a) ^.*s'^ 2X8***i = 66* To fa/ we/p/?/- f>er f?ane/ - /3Z6.^--r-*32.'9-^-sa + /o 0/0 for detai/s * 206Z or- 2.1 X/ps ~£- = /9 K/ ^ ^ £ ^ -ft, of truss. ** DESJ£J\I Or ST/rrErJV/r^G TfTUSS (co*Aj /Tii/ets /n Try 55. ( -zf r/fe+s\ •Phear «■ /oooo LJear/ng = /3000 5/nqle shear ~ *W3 dovb/e shear * 8836 /"or c/iagona/s - Stress * e.s x S78 =37.7 KJps (coyytp) __^. a 5 rivets 23ear/ng on -x- ' o/aie ^73"o for tens /on stress =• /2.SX6.06 * rsis x/ps. ^tjL /3 J 2 r/wets. Pear in j on /g" pi. * //.^? ^/>e»5. /^z" cnorcfs - /Far /ens/os? f/na/n spar?) stress- = /6.7-4-x /2& = 209 X/ps 7?<h * /S rivets. r~br corn/?, stress- /s ' /8 x /oooo - /8/.a *:/ps j~- =» ;e r/ye+s for ten s /on (end span) stress * S.<44>x/2.s = /03 /cips g T 2 " '4 rivets re per/ red. F~or corn press /on- stress = /o.szx /a. 04- = so/.? /</ps ^f* /S n * e * s f^or vert/ cats use & rt vers . /o. D£5J6M Or" 5T/r-/=~£:U//V& TRL/S3 (coh/~.) f = rov/3ion fc v/3tori ror ex. Ypartsjon for a change of ± 70°/=\ from normo/ '. Elx/pomisjom coeff/'c/errf for steel = .0000065" L - e {J =• .000006S XTOX^OOX/Z = Z 2./S ,\ a"" w/ 1 / provide for fofaf ryiovetnenf ( 'was/? span) for end span - /. = . 00000 &if x 70 x /oox /x ~ ±.545~ .'. ijf. wj // ' oro wde for +r?ov&tr?er}f flinges. find h/*?ges - £~rrd shear - /& Ar/^s for orre fruss. f/i area - j§r ~ A 6 or a /jjr f/j?. x4 Zy p/rr mf/ - he used- £er?fer A/nge - Ce/tfer shear = 6 s</i?s t>er fruss /A7 area = j-r- s .6 or a / jP/rr. sd x^ J?'n m//// be used for a// &//is. //. £>£^/6fij Or S'T/F-rf/V/MG TTFUSS . (com*) ~~fe ' ™/?^^/v'l&--J2z±'€ s - s J&C \ _ ~7f^ f££' O s Temjs>erafctf*& stress fJ?s. t?er so./ +7. s =• saj rot to = . 09S~ e= coeff/c /er>/ of expa^s/or? - .00000 6S~ for /">T f * fas-r^e of re**?£?er'afc/y& - 70 1 '/? fro^n /7or/*7o/. £f= moc/o/c/s of e/asfc/'ry = 30,000^,000 d = det>J-h of y fuss = &-o" / = /ertgrh of S£>a*7 J7__ (<?+-2.4 X.O~ff6~J OOOOO 65 X70X 30,000 j OOO Jr 3 /C X.OSS X^f-OO -£. 26fO *tr& /2. 5trd5~> in Choreas. . v 7= bertd/^a mowen-f due /a umtorryi w/wd Joad '. p - L'n/fory*i n'/yid load per un/r /ena^k of f/- /J^e . X = dsfu+rce *~o sec f /on a£ wh/cfi ,V7 /s des/r<sd . h = d/sfa^ce from £ of ^ower /o £ of- //./vs. t * base fo /\/<j&er/ a n fou a rjtf >+is M=,JL f / - g / g ( ''* )c 7 (Jo/txsom framed 5+rocf) 7J where c' = f ( »+ H»± f- 5Qq of cab/e J-f = due fo w/*7<d /oacd //- <due fo deacf fo&c/ Hr' Zf "- modo/c/3 of e/asf/c/Jy I = /+*&*** en f of ;*rerr/c< of ~trc/5s.( I of chords ajyoo/ fro-ss £\ x-x. I - (I c -t ad )2 d**6.z I c = fo/- z £.s ^yror/fy = 2x-jaoa If* 6X6 k -£- abour cerrfer of < //■*■ C = A 0002*f- = 6&/^ & = /&/& / " 2 C&0./Z +■ 'S./8X -&&z) — T77SO 3S [38*] -<?£> x &OO0OX7773O SX.osf = x oaooooO s-97 /V &/■'// be footed for She &o/r?f of sncrx . /../.. M, /3. ^<? C /^ ^"- ^X ^y €» * .000 24 X "23.2,* &■&*■ = .//6/2 fog of / 3065 (e <C ~*) Jog e **- <?(/-**) Jog e " .0002^ (3676-8) (.43-<?) - . 33237 Jog Of 2. +'64- (e c ) Jog e c => c/ /og /0 e * .00024-* -t-soo x,^-?- — . 43336 Jog of 3./620 yy or P = 300 + 30 = 330 jrfrf: 39. ,5fex:'f/c.0f/0*r& OOOOOOO S37 L /+ 3. i£ZO J //# 000 Lot 1 era/ truss = /<z,'-o" <Jaez>. cftorcf stress - —7 2SOOOO d ^3poo,ooa „^^ * — '— '- * J '6 0,0 00 /6 Jt /2 ' ita Z8./8 - J 3 TOO Jjtice rh/s stress eAceeds 300/0 of the of/owed dead aid f re Jo ad stresses ff w/J/ J>e cotisjJerec/. V- <=, - c I C, e -c~ <?' / John sot? , f3r~yo*7, Tur/ieo-cre /4. / 330 C, ~/T f-=~Z 7 =" //0 , 5~OO t OOO <£, = 3. JS2 X % OooooaoS37 *- J //O t SO 0,000 =" 3-&9 } -<?0/ } 00 y= — .0002*? [ //o f S-<TD,#VO - J^Sj^o/oool - T o~7S~SO f=~ J / ^ 4TTST&0 „ a" /or a/aqo//a/s area reaa. = — = 3.2 J I /Sooo Try 2 Z5 4-X*9-x-^ area = 3.7f / r/iser ,44 _ „ cr j 1 ' / " » „ 3.3/ ° 0<- /or fate rats use ^.jr-*x£ froth t+ra/*7 ana/ e /id 5 pais. tj *'ye/s /t* fateraJs. S/Pr^/e shear s -44-js cq/i J?e /*rcreasea / fa crfo r4rt S3 ^j&ec/f/car/o/rs 3t, - 3 nrets 7jt?ec/r/caf/o/*s Csfress* 1 3.3/ x 'Sooo - sssoo SSSOO -a- fledes/fti of ^/tor^s for Truss . cf/ord area /wcsf J>e /Mcreasect oto accooif of w//7d / ar/d fern^eratore stresses. The a //o wed wf stress car/ pe wcreased Jyy sotfo whe/i mva' ar>c/ temperature Stresses are covs/cfereaf. /sooo +3o*/o = za*?oo w/tt be oftotveat far the c/^/f stress t?er so. //f- /£■ D£S/GN Or LATERAL. SYSTEM (co»*) \A//r>d stress = 2S0000 L. L. =• /a/25'o * // Tern&e ro fure sfress = £6-9-0 4 re* for chords = * SP** *'"*«* - 20.3 « " 23+00-26+0 , " " " « Try 2 as 8x6x~a~ - 22 9s a 2J. 2 a .: O.K. /or end smarts— Sxex-lr" xls Witt he used. /( / rets in Chord Ofress = 2A2 x 207*0 = 4.^0000 0ear/rt& or? ■£- t?/are of /3000 - 7/3/2 -4*40000 _^ / v = 37 rivers (/na/r? span) 1/3/2 find spar? — vS~ = /2.62 x /2S~oo - /s-7SO( /S7SOO 6 7 SO = ;?<*• rivets /€. DE5I6N OF AUSTEN PER RODS. Where the distance between cah/es and -floor he cms /s short stee/ roc/3 \a//'// he used as suspend&rs . ^-i r a// other- po/nrs suspenders cons/sf of h/gh strength steet rope strands . f^- hanger pu/f per J/n.fh H = hor/zonta/ component- ot cah/e stress, /= /er/afh h - center ctef/ectton of cab/e s » -j- r= *3Lj**p± =, .S3 «'PS per /'*>- & -ZOO * ' ' / per panet ** //.j#.88* 3.7r *csps F* per hanger = "Z38 *'ps s4rea rega. =» —= % so$ Use ^r <p rods area - .S068 ° Longest rod about- 44 ' Zona . We/ghf = /.0+3 x -9<> = 4-8 per ferret = 94* jf^ » 3.65 per ft: of truss (majc.) Assume 5~ per hn. ft of truss for n/e/ohf of hangers a net c/e fa//s . f^r cah/e we/ghf assume 5~0 per //n. ff. /7. PESIG/V OF CA&l-ES. Total Load on Cable. r~~/oor system = .,2^^ Kips / ft of cob/e. Truss <*D uspender rods /_/ve load Wind load Cabfe .20 " = .00s " .4-8 - .33 = \o*_ 7b+a/ /.297 Kips / ft. of cabfe 7~= max . tens /on in cah/e . ti - horizontal corn/?. of 77 /= span . h - cabJe sag at center, s = -t~- / w/ T~ s jr- V/+/6S* - fi \f/*-/6s* Aferrsrna*? * UacoJsy. ( 7=2i *■ fur.) ft* **9tx+oo_ ^ 683 - -r s 6Q3 fr~J^* = 3JC.095~ ' 683 X /.or — 730 Kips. LJ/f/mafe strength of cabfe ■it a " Wire «• 200000 rhetor of safety « -?- WorKtng strenyfn = Sb.ooo*" sd reo read. = ^^§g f '** £/5"<? 7 strands of 33 wires each of A/0.2 steef wire. /rom 7?oeb/mg s w/re cata/o^ue /a. <a DESIGN Or CA3L.E5. (con-h.) re a of fto. 2 yv/re = .0&4-3 7x33 = 273 w/res a" ^ ,OS~4-3 X 273 - J*fr3 .'• O.K. CsracJJing of Uab/e . b* /are rat crad/ina of cab/e . h * saj as assumed in o vert tea/ p/one. dh = decrease //1 saa due to crad l/ny . dh ~ ^ - f/?-h* =■ 33 - J 33*- 4-* = . 2/ ' b= <4--o 7~/j/s chaise //■? sag J nc reuses the oab/e tehs/o>? a&out ./ of / rfo. fierr/mai i daco&y. ( 7=brrttz.) CabJe £2e/ : /e cftor)s. (Loads a*?d tetrrp.) C= length of ca b/e c= t (/-t-^s*- ~- s% A - too // f -j-x.afs- - ^-x.ogfs ) - 4-07. 3S2. ' kef ween to wers . f^or ^em&er&tL/re — ~ ^ ~ = 3 X .0000072. X 7(2 X 4-073&JL . ^^ ' /6X.O&S- /=br //>*? toads - \dt> = £^ dc= ^ //- 3 3 >) T dve to J/ve toad 0»/y . //=- -£^ = f****? m ** 8 ^ ~&xp9S~ 25~3 K/'pS / = /.07 /7 '- /.07JX2S~3 =2 7/ /</pS. _^^_____ _?■ OFS/6A/ Of* 6^&L-iz5 (co**:) Jc _ *_y&22Y,-A.« J 5S?) -./##' ^- -£ri^ . 3 _, 7 ' /+.& *30000 K ^ y /6A.035 Aierr/ryiar> t, ^Jacoby . (T^rt jjz.) 7~o/ot/ deflec-rjon » .-4-05- +.36? — .772 J bis is pro is j dec/ by comber ma trusses. 7~bey wtlJ be cambered to a rac/;c/s of 6os/ or about 7-4- /„ 60 o . zo. D£SI6Asl O/^ TOWZr/^S. r= /I [, +( +*»«, r *£)*]* = /29.7*X /.«?-/ - /33 K/&S " X /33 =» /*-?■ K/f>S // • fO X S3 3 =r £2 K/PS ,,,.3 /,/.& K/ps * 730 =■ 1/3 KS/?S *8 * SFS'4' K/£?S V* » - 02-/36 *■ „?/^ A-z^ir & ear //>,<? s^rea fo r fos/s . s4//owed beanng or, masonry - ^oo ^rea reyc/ . = —£■ = S+f a s4 p/a/e +& x*i " w/'/J be usee/, ^ rea * /aoe a .; <?. /C /Lena// ? of C7ab/e . A^V>7 Sf?art - «?-07.332 /l rt<J 5/3MS - £_ = ?,(, + &-S*+ -fow, ■y L = /oo ( / + £ x.si^-h £) = //6,s- To/a/ /er/gJ-h = *?az3& T2x //e.S = 6^o.3s' £~y*/jr-e /er?^/h w/// be a boo/ 6TS 2/. J 3endmg /foment in ~7~o we/5. A/ s Q/+ \/d Johnson , J3ryan, ~T<jrneaure . far / XT. O' load with V caus/no a def/ect/on d ]/ = vert tea I load /- height of tower 3 H A */ ^ ~ 7? "Wt ^ ' ^ or J' Y e }°°d (rna/r> s/?ar?.J £ * /r?odi//c/$ of e/ast/c/fy J~ hio/ne r?-r of tru^s (end s&an^ Q - Va>c r=j, J for tower-. = +9+30 fl* *L = *pm_ = &S 3 X.09S I = (33. 32 + 11.5 x *&32 *J 2 J „ S X 2fO x(/2.fx/2)x /OOX/2 11 ^^° K 'f s /? X 30 , OOO x <?9430 2/3 C r 30 000 X-4-BOO _ 2/3 X 2,OZ X PO/2B G* - .00000/5/ c = .00/2.3 - / /s~i K/'/os /.<*2& - ,96~S ran c/ = 5Z3X.OO/2 3X6S-X/2 =■ ss a +01 ct = /. *-*a ct = , 00/2 3 X 6&X/Z = ,959 /V * A/ff-X 44"JC /jg + 2/3 x 2.02 = /3*o *'/? /n. Z^e5/c/x7 of fosh Y TT J ^ s4 SS c/ m ed S ec tion : " " 7 " <-?—> // 2 fr/s. 22 x # J *'/*?*- **■*&' = 2+,75 = 2/00 Y Tote?/ * 5"Z27 22< D£S/GA/ OF TOWF/T5. — j . * / a boo £ x-x OJfS/S - I, = J~X 22 A JL + 2-9:7S~X /2.2a = /6 29/0 3 A To fa/ - 2S/Q +f04-i- /397 = <4S// u+ /39T r * V. SZ27 *''* . 3 I about y-Y axs/'s - I, = It* %■* 2Z = 5 '°° J, = J-xz+xHZ- + 2J * j^l* = /OfO I 3 =4(3.26+2,38 X 3~&*) * U fb - 3S3 ■v ■* To-ha/ - 5~oo + ;o5~o -r 3*~3 - 2<4-o3 6200 &a >y - V 7TT7 m *»+ a — = -r=~ = i 3 ^°. = 2,/e ~3ec//oA7 yHodu/us rego/re-d. C 5 62 < ?*iL = 386 = J. usee/. .: O.K. J 2.43 7 C 5/ B> ' r^sses ^jn_ f[ £JV£f_ J ~>r&cmQj v> /4rf.<?o. ^pec/f/'caforts ~ /a/era/ j arejjsure = /oo t?er i/erf/ca/ fr. ■f- O d - "S~0 +■ /c/fera/ con*/?, of \ cab/e stress due /o crad/sucf s= //S~0 +■ 730 COS <¥ =■ //3V '*■ /4-600 - / S7i>~0 5_^_ Cc =* //S~0 +2300 = 3*-5~0 yA <J - //-5~0 + 2300 + '800 ■*■ 65~0 = &900 34?- f<?A<?5 reacf/or? of $f /ff &{?'"$ \ /russet. 23. DE5J6/V Or TOWFffS. H // for £)ct -try 4-jJs 3x2-£-xjg w/th /c?c/r?cf t?etweer? 5; /<. r» 2.26 fcrc/r?a stooo- Z°l / = r 23 ~ =282 S = ,6000 - ***3§± - 7260 ■*fa 4 re a re* ><&. - '-¥& - 7260 s4 rea (/sect ■ 6 S2 .: or. for £c use same w? — sect/or?, for ^4a -4-4-5 sx3r^~ Z5 // be c^ect 22 t>acX to bocK of z.'s. '$***■■ **^~~1 r* 25Z •^ * ?6000 - — * &/6Q ita- Cd= Oc - 5/ s4rea re<sct. - - - ,^?5* .'. cl/<, res 5 = //5-<2 sec o = //so a: /. 3? = /fso j*4b - a 3 - 3 tress - S2&o sec e, * s-*s~ox /./2 = S88o ' J ' " *r- " ror these members use 2 4-s s*3* — /6 >4rea read. = S880 _ /6COO 36 7 : <a/r. K^H L ?e"/?c//*7cy t£L2l*2i 0/n &b > V^ ^ / /f- react /or? of trass for ryro/r7 s/?an — /X — **g£o=^ s ^. for er,o\spor, t?~ *%£+= '«*« *&oo 24, DESIGN OF TOWERS Morn. • 3.5 X 29- tOL 5 re/'/? ft = t, 220,000 //*• Jject'/ort modu/us react. - {,2,20,000 __ ^^ 7^ ^ ' /So 00 ofs. 24-x g- , 4- 2L5 3X 2-£r x jg . >4rea - /<? y-^.sve =24*2 r "i •* — ^4~ — L J I about hor/zon+a/ axs/s, J for ph. =■ & * ■§• * **■ x 2 = ^^ I ror Z.S =4(/.<?2 +■ /.63 X //.07)~ 802 Section n?odu/u^ =• — =■ /3g , ; O.K. L.ac/*7g used between Z.5 . f3rac/rta //? Sc be C^o repress /art or tens /or? /n brace = -5£' /=?*,' too ."s4rcA. Ena". = i+2L**3 m ■#■ / / ' " " S~ " a" £000 (dse Z ^.5 <4X3Xj£ area - -4/& r~ /.*•? . Z? - /6000 - 7Q x 4.3S x /2 m /2.730 ^T = &?■ area - JJ? fZ730 read C/se tb/s sect/on for o// braces. /T'fvers - Pd and Cc - 7 I^SJf±£? - // "~— " 44fa s4ct _*"°*»'++ m 2f 4b and Cd = 't>ooox«S2 _, /g 44/ & 42 2 S / os ^§ = r e ra c,„ 9 ;„ 0c» c - /6 %tT' 3 - /6 44 J 8 - t/a/ue /*? &/tiq/e sheor-. ■4-225' = beor/*f<p or> — pj '. DA/ £ /f/J C£A/ /&/3. 7^/?WW^^ %oo ■ o- ^^m^ 7 ^ L-- ^x — >-• 4& o > AJ "T Jan. 2Q, 13/3, ^ -fo O +-* THESi: ^L^L^k^ ~ 2S8 JZf^r. fnfer-secrson o/ SUSP£N5/0/\/ Br=UO&£ LA 6r/?A55E /f/Xf/T X 7- £r Ord/rarr 5 rape of ftii/er /oO.O frbd/c-j o £ Camber of Spar? s af /Vecro 7e/77/i < - (,08/ /o 3orrom C/iord. C/ /S-f.6b AIT Jan. £8, 1313. 33 W/r^z ><? •••••*• ••••• t • ••••• • AJX ,4pr,/ /^ /9/3 ) J p K ! THEei OV£f? La A7a3 AffMOO'te y<r+ « A- $Z<LU5^f. £2^ck&!^ -^. t&tz^f&Z'r^ //V.5 T/ TO' T£ 6r f?A 55£ r?/ I/Fft SEA/ A C£NT£R,MY or T^CHA/otoar Hfil.r ifvrnn i IS/env. ' Afa/Lr J^cr/c/v A-A £/. f VA r/0f er 7b W£f? /^/£j^. a'-a- 3-> 3'6'M . =i Ji, 9 '- o -- f/7e t^-e/'f/fr 1 of fthe , £7/7CS?e>s-i?ye sw&sjt' At/ive & /rt //?e ca£/e /c/~ tf s/^/0 of e-ges// fosses*??. 7"- /SSo.ooo*' I hST fftg'd — 3 360, OOO* i*/e/<?Af of coster*/* =■ 'fJV " ^?er Cf. /*>? = -^e>^c-"^er c~^ ftt. 3,36O,ooO-l-*t0£>0= &d& Cts. ycf$ /?e#c;/s-0<f. per Ct4S*. ^s/Zmored vo/tssw e\cf rlicfiaro oe •= /-POO Co- yds f^LA/V Pr~ Tew^S? f^/^rT J / » '"* » n 8 L 0- — a ,1 o 7 J ■? \ ' I CONCftETF 0i~ m I; W \ '•", NT ■ii- V» ■1 ' At I, >M;V »; *■'■'"■' ; j.. •:-" ■ * '.■.'■■'.-.. ■■.■ ; -' t -1 ~«_ TH PA/ J3 '^/O/V sJO/A W*43 A/ L OWFK o/^ 7>- = Chord C?p// { 2 * ' ach chord THE3D! suspensions/ bridge over l-4 ^ff^)55f xj FfMOISf? INSTITUTE OE 7~E£f-/A/Oi-06V j &f%*-. ibL *fli**sasd. C?l*-l^G I «-G©-G-0 OO-G-O- M^/N SfsdM 30 X 9^-X £ /3 faiy /ea/ ye? //oh P'le £>/ctnH /3 /J"iy 'ear ye* //on £>'*7e f/a**rT 2x-> se&orofdkr, ■2-3X/-&5*-£ | • • • • •'* • • • • 4 • • • •• •• •• •+- ' ' 1 ' 1 1 !.....*{- Chord 5p/>ce (**?arn soar?) //>/3-7Jta"x^-. S3f>/'~ctt //7 *?aerh chord. W/r>0 Anchorag e £^nd f! be urn ■9 — & i 2£ s ex 6xJ- £/. '$8 3o 2£.S 4-X j„ — -? r" W/* /2 /« rrlasOr"- 1 5 ho re end / '/ Or Tress 6*4xj- 4. 4" Vio/es for £ :A///V^ J-ffU&SFS sQ/dO Z^tLOO/^ '-. 5T g '4 »., r ~T J f and T russ /^ocKer ^ rrn _ N — ft 3~S* B* + " 5cv/e -4". /' both p 1 t ; ^} •# Truss /r'ou.Aer _ ^-Jr. c/f Mc/frt Tower /O tver end Chord 5o//ce ( end s/roisj £>/. S~7A #'*7 ■ * S/dtee tr? each chord y ^ho/es to* #■ 6&/r$ .V* stored f" JoiylivJuty m m