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

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. 



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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* 



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-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 — *~~ 






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Conn pu for ion5 for a 



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Af*MOU/* //VST/TL/T~E: or-TCCrt/S/OL.O&V 



C/-"C<4&0, /L.L. 



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^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/ . 



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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 



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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. 



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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. 



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VV Z - At' = 76-+ L*Z£- 
W* ~ t./ X/O-Q \3X <Qj - 

Wf = XA /-./A JOO A 3 32 



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== / 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 



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P.L Ma^r. =• JZl* * 44>ao*/6M/6 _ j/zjBG** 
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r~rorr? handfroo/C J. for a <?-2* /S~" I beam 



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We/orrf of- /7oor s-ys/errr 



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br/dje =z m ;z/ X/f>s jeer fA of truss. 



MAX. END 5 tlZ:^ '/? ON r/QO^S^^M /Live /oaJ) 





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jE^cJ shea a- = /3,/oo VaJue of ^r fillet '* bectr/**} 



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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 

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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 



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r or co*yf 



if>ress/orr Ji? <* /zooo - £& 

tCeao/red area for ¥&tis/o*7 — ££££ - /■4-.S' 
C Sx'ZS 

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DESIGN or 5TirrE'Klll\J& r/TU^S (con*) 



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/.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" 

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/or comr>re35/or? J = /oooo - **3*y <~ y -\. 

/ f 

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/.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. 



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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~ 



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area = /o. tz 
2 ri^eSs : 74 



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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&.*- 



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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 



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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 . 



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D£5J6M Or" 5T/r-/=~£:U//V& TRL/S3 (coh/~.) 



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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