,,in/ructions ,,on ,,mod]n ,,am]ican ,,bridge ,,build+4 ,,) ,,practical ,,applications ,,& ,,examples1 ,,e/imates ,,( ,,quantities1 ,,& ,,valuable ,,tables4 ,illu/rat$ by f\r ,plates & ,?irty ,figures4 ,,by ,g4,b4,n4 ,,t[]1 ,,civil ,,& ,,me*anical ,,eng9e]1 ,=m]ly ,*ief ,eng9e] ,u4,s4 ,navy1 & late ,*&l] ,in/ructor 9 ,civil ,eng9e]+ at ,d>tm\? ,college4 ,,bo/on3 ,a4 ,,williams ,,company1 #ace ,,wa%+ton ,,/reet4 #ahgd4 ,ent]$ accord+ to act ( ,congress1 9 ! ye> #ahgd1 by ,a4 ,,williams ,,co41 9 ! (fice ( ! ,libr>ian ( ,congress1 at ,wa%+ton1 ,d4,c4 ,,preface4 ,?is little treatise 0 writt5 = ! purpose ( supply+ a want felt by ! au?or :ile giv+ in/ruction ^u ! subject4 ,x 0 int5d$ = an aid to ! "y ,eng9e]1 & is n to be consid]$ z a complete sub/itute = ! m elaborate works on ! subject4 ,! fir/ portion ( ?is "w m5tions ! v>i\s /ra9s to :i* beams are subject$1 & gives ! =mul us$ 9 det]m9+ ! am\nt ( ^? /ra9s1 toge!r ) a few examples to illu/rate _! application1 & also ! me?od ( calculat+ a simple truss4 ,! second portion names & expla9s ! v>i\s memb]s ( a ,bridge ,truss1 &1 by means ( examples1 %[s ! me?od ( calculat+ ! /ra9s ^u ! v>i\s timb]s1 bolts1 etc41 z well z _! prop] dim5sions2 & gives1 9 addition1 sev]al useful tables4 ,! explanatory plates1 :i* are ref]r$ to freely ?r\gh\t ! "w1 are believ$ to be amply suffici5t = ! purpose int5d$4 ,s mu* has be5 writt5 on ?is subject t x is next to impossible to be :olly orig9al1 & no claim ( t nature is pref]r$4 ,x is simply an arrangem5t ( ideas1 glean$ f ! v>i\s works ( /&>d au?orities1 & modifi$ by ! au?or's practice1 embodi$ 9 book =m4 ,to give a correct li/ ( all ! books consult$ w\ld be simply impossible2--b x is well to /ate t ! ,h&-book ( ,railroad ,con/ruction1 by ,pr(4 ,g4,l4 ,vose1 "u :om ! au?or s]v$ z an ,eng9e]1 has be5 us$ z au?ority 9 _m cases :]e !re has be5 a diff]5ce ( op9ions among o!r au?ors4 ,"s p>ts h be5 quot$ entirely2 b due cr$it has be5 giv51 x is believ$1 :]ev] su* is ! case4 ,x is n claim$ t ?is little "w cov]s ! :ole gr\nd1 b x is int5d$ to describe1 & expla9 ?or\ghly1 ?ree or f\r ( ! m prom95t /yles ( ,truss1 leav+ ! o!r =ms ( ,wood5 ,bridges to a subsequ5t volume4 ,abutm5ts & ,pi]s1 z well z ,box & ,ar* ,culv]ts1 belong+ m prop]ly to masonry1 w be treat$ ( h]eaft] "u t head4 ,iron ,bridges =m a di/9ct class1 & may be m5tion$ sep>ately at "s future p]iod4 ,if ?is small volume %\ld lead ! /ud5t ( ,eng9e]+ to exam9e c>efully ! be/ ,bridges ( mod]n practice1 & /udy ! l>g] sci5tific works on ?is art1 ! au?or w feel satisfi$ t 8 ef=ts h n be5 entirely 9 va94 ,cambridge1 ,febru>y #bc1 #ahgd4 ,,t[]',s ,mod]n ,am]ican ,bridge ,build+4 ,,bridge ,,build+ ,! simple/ bridge t c be built1 is a s+le beam1 or /ick ( timb]1 spann+ ! op5+ betwe5 ! abutm5ts--b ?is is only ( v limit$ application--7only = spans ( #bj feet & less7 ow+ to ! rapid increase 9 sectional dim5sions :i* is requir$ z ! span becomes great]4 ,next comes ! s+le beam support$ by an incl9$ piece f ea* abutm5t meet+ ea* o!r at ! middle po9t ( ! "u side ( ! beam--or1 ano!r arrangem5t1 ( two braces foot+ securely on ! beam & meet+ at a po9t above ! middle po9t ( ! beam1 :i* is susp5d$ f ! apex ( ! triangle =m$ by !m1 by means ( an iron rod--,^! arrangem5ts may be us$ up to #ej feet4 ,= any span beyond #ej feet1 modifications ( ?is arrangem5t are us$ :i* w be describ$ h]eaft]4 ,n[ let u inve/igate %ortly ! diff]5t /ra9s t ! v>i\s p>ts ( a bridge h to be>--& ! /r5g? ( ! mat]ials us$4 ,! !ory ( /ra9s 9 bridge trusses is m]ely t ( ! ,composition & ,resolution ( ,=ces4 ,! v>i\s /ra9s1 to :i* ! mat]ials ( a bridge are subject$--are compression1 ext5sion & detrusion4 ,wood & ,iron are ! mat]ials m g5]ally employ$ 9 bridge con/ruction--& 9 ?is pamphlet we %all take ! foll[+ z ! work+ /r5g? ( ! mat]ials--p] squ>e in* ( section4 ,t5sion4 ,compression4 ,detrusion4 ,wood1 #bjjj #ajjj #aej ,wro't ,iron1 #aejjj #aajjj ,ca/ ,iron1 #dejj #bejjj ,t5sion4 ,if a weight ( #bjjj lbs4 7 hung to ! l[e/ end ( a v]tical beam1 s t ! l9e ( action ( ! weight & axis ( ! beam =m$ "o & ! same /raight l9e--! t5sion on ! beam w\ld be #bjjj lbs4 ,b1 if ! beam 7 incl9$1 & ! =ce act$ 9 a v]tical direction1 !n ! /ra9 w\ld be increas$ 9 ! ratio ( ! increase ( ! diagonal ( incl9ation ov] ! v]tical2--suppose ! beam is #bj ft4 long & incl9$ at an angle ( #de--;& let #bjjj lbs41 z be=e1 be susp5d$ f its l[] end4 ,n[ ! diagonal be+ #bj1--! v]tical w be #ad4jad ft4--& ! /ra9 w be f\nd z foll[s1-- #ad4jad 3 #bj 33 #bjjj 3 #bhed--lbs4 ,! great] ! angle ( incl9ation f ! horizontal1 ! less ! /ra9 f a giv5 load--& :5 ! beam is v]tical ! weight causes ! lea/ /ra94 ,compression4 ,if we load a v]tical po/ ) a weight ( #bjjj lbs41 ! /ra9 ( compression ex]t$ ^u ! po/ w be #bjjj lbs4 ,n[1 if we incl9e ! po/--! /ra9 w be increas$1 z we h %[n above "u ! head ( t5sion1 & 9 l mann]1 dep5d5t ^u ! incl9ation4 ,b :5 wood1 iron1 or any o!r mat]ial is us$ = a pill> or /rut1 x has n only to resi/ a cru%+ =ce1 b also a =ce t5d+ to b5d or bulge x lat]ally4 ,a po/ ( circul> section ) a l5g? ( #g or #h diamet]s w n bulge ) any =ce appli$ longitud9ally1 b w split4 ,b if ! l5g? exce$s ?is limit--x w be de/roy$ by an action simil> to t ( a transv]se /ra94 ,a ca/ iron column ( ?irty diamet]s 9 l5g?1 is fractur$ by b5d+2 :5 ! l5g? is less ?an ?is ratio--by b5d+ & splitt+ (f ( w$ge %ap$ pieces4 ,b by ca/+ ! column holl[1 & swell+ x 9 ! middle1 its /r5g? is greatly increas$4 ,b>l['s =mula = f9d+ ! weight t c be su/a9$ by any beam1 act+ z a pill> or /rut1 be=e b5d+1 is3-- ,,wl bd x #hj ,e ---- bd1 :5ce ,w ----------- #hj ,e ,l ,te,x3 frac,,wl#bhj ,e bd#c1 :5ce ,w fracbd#c x #hj ,e,l#b n[1 hav+ ! weight giv51 & assum+ ! dim5sions ( ! cross-section--we %all h ----- _/ ,,wl ,,wl d _/ -----1 & b ------ _/ #hj ,eb #hj ,ed ,te,x3 d sqrt#c;frac,,wl#bhj ,,eb1 & b frac,,wl#bhj ,,ed#c 9 ! above =mul1 ,w weight 9 p\nds4 ,l l5g? 9 feet4 ,e a con/ant4 b bread? 9 in*es4 d dep? 9 in*es4 ,transv]se ,/ra9s4 ,! /ra9 caus$ by any weight1 appli$ transv]sely1 to a beam support$ at bo? ends1 is directly z ! bread?1 & squ>e ( ! dep?1 & inv]sely z ! l5g?4 ,x causes ! beam to be depress$ t[>ds ! middle ( its l5g?1 =m+ a curve1 concave to ! horizontal & bel[ x4 ,9 assum+ ?is =m--! fibres ( ! upp] "p ( ! beam are compress$1 & ^? ( ! l[] "p are ext5d$--consequ5tly !re mu/ be "s l9e situat$ betwe5 ! upp] & l[] surfaces ( ! beam :]e ! fib]s are subject$ to nei!r ( ^! two =ces1 ?is l9e is call$ ! neutral axis4 ,^! two /ra9s ( compression & ext5sion mu/ be equal 9 am\nt--& ^u ! relative /r5g? ( ! mat]ial to resi/ ^! /ra9s1 z well z its =m & position1 ! situation ( ?is axis dep5ds4 ,if wood resi/s a compression ( #ajjj lbs4 p] squ>e in* ( section1 & a t5sion ( #bjjj lbs4 ! axis w be twice z f> f ! top z f ! bottom 9 a rectangul> beam4 ,! foll[+ table by ,mr4 ,g4,l4 ,vose gives1 ) suffici5t accuracy = practice1 ! relative resi/+ p[]s ( wood1 wr\ght1 & ca/ iron1 ) ! correspond+ positions ( ! axis4 ,di/4 ( axis ,resi/ance ,resi/ance f top 9 to to frac's ( ,mat]ial4 ,ext5sion4 ,compression4 ,ratio4 ! dep?4 ,wr\ght ,iron1 #ij #ff #ij_/ff #ij_/aef1 or #j4eh4 ,ca/ ,iron1 #bj #aaa #bj_/aaa #bj_/aca1 or #j4ae4 ,wood1 #b #a #b_/a #b_/c1 or #j4ff4 ,?us we see t ! resi/ance ( a beam to a cross /ra91 z well z to t5sion & compression1 is affect$ by ! incompressibility & inext5sibility ( ! mat]ial4 ,! =mula = ! dim5sions ( any beam to support a /ra9 transv]sely is #d bd ,s ---- l ,te,x3 ,s frac#d bd#bl ,s ! ultimate /r5g? 9 lbs4 b ! bread? 9 in*es4 d ! dep? 9 in*es4 l ! l5g? 9 in*es4 ,detrusion4 ,detrusion is ! cru%+ aga9/ "s fix$ po9t1 su* z obta9s :]e a brace abuts aga9/ a *ord1 or :]e a bridge re/s on a bol/]2 & ! %e>+ ( p9s1 bolts & rivets1 also comes "u ?is head4 ,g5]al ,ab/ract4 ,! resi/ance to ! above m5tion$ /ra9s v>ies z ! area ( ! cross section2 s t by d\bl+ ! area we d\ble ! /r5g?4 ,any mat]ial w be> a mu* great] /ra9 = a %ort "t ?an = a long "o4 ,! work+ /r5g? ( mat]ials1 or ! weight :i* does n injure !m en\gh1 to r5d] !m unsafe1 is a moot$ po9t1 & v>ies1 accord+ to ! au?ority1 f #a-c to #a-aj ( ! ultimate /r5g?4 ,! ratio ( ! ultimate /r5g? to ! work+ /r5g? is call$ ! factor ( safety4 ,! foll[+ is a table ( ultimate & work+ /r5g?s ( mat]ials1 & factors ( safety3 ,weight ,ult4 ,ult4 ,work+ ,/r5g?s ,factor ,safety4 9 lbs4 ,mat]ials4 ,ext4 ,comp4 ,ext54 ,comp4 ,t5sion ,comp4 #cj ,wood4 #ad1jjj #g1jjj #b1jjj #a1jjj #g #g #dhj ,wr\'t ,iron4 #fj1jjj #fd1jjj #ae1jjj #ab1jjj #d #e4cc #dej ,ca/ ,iron4 #ah1jjj #ajj1jjj #d1ejj #be1jjj #d #d ,lat]al ,adhesion4 ,lat]al adhesion is ! resi/ance (f]$ by ! fibres to slid+ pa/ ea* o!r 9 ! direction ( ! gra91 z :5 a brace is not*$ into a *ord1 or tie beam1 at its foot1 x is prev5t$ by ! lat]al adhesion ( ! fibres f cr[d+ (f ! piece1 to ! dep? ( ! not*1 aga9/ :i* x toes4 ,b>l['s exp]im5ts give ! lat]al adhesion ( fir z #fjj lbs4 p] squ>e in*1 & ! factor ( safety employ$ v>ies 9 practice f #d to #f1 giv+ a work+ /r5g? ( f #aej to #ajj lbs4 p] squ>e in*4 ,,table ,,( ,,compressive ,,resi/ance ,,( ,,timb]4 ,l5g? ,safety ,l5g? ,safety ,l5g? ,safety giv5 9 ,weig't 9 giv5 9 ,wt4 9 giv5 9 ,wt4 9 ,diamet]s4 ,p\nds4 ,diamet]s4 ,p\nds4 ,diamet]s4 ,p\nds4 #f #ajjj #bd #ddj #db #bjc #h #ifj #bf #cid #dd #ahe #aj #iaj #bh #ceh #df #afi #ab #hfj #cj #cbh #dh #aee #ad #haj #cb #bii #ej #adc #af #gfj #cd #bgf #eb #acb #ah #gaj #cf #beh #ed #abb #bj #ffj #ch #bci #ef #aad #bb #egj #dj #bbd #eh #ajf #fj #ii ,9 t5sional /ra9s1 ! l5g? ( ! beam does n affect ! /r5g?2 b 9 ! beams submitt$ to compression1 ! l5g? is a mo/ important elem5t1 & 9 ! table giv5 above1 ! safety /ra9s to :i* beams may be subject$1 )\t cru%+ or b5d+1 has be5 giv5 = l5g?s1 v>y+ f #f to #fj diamet]s4 ,,practical ,,rules4 ,t5sional ,/ra94 ,let ,t :ole t5sional /ra94 ,s /r5g? p] squ>e in*4 a sectional area 9 in*es4 ,!n we h ,t ,sa4 ,n[ to f9d ! necess>y sectional area = resi/+ any /ra91 we h ! foll[+ g5]al =mula3 ,t a --- ,s ,te,x3 a frac,t,s or1 by sub/itut+ ! work+ /r5g?s = ! v>i\s mat]ials 9 ! =mula1 we h = wood1 a ,t_/#bjjj ,wr\ght ,iron1 a ,t_/#aejj ,ca/ ,iron1 a ,t_/#dejj ,b1 9 practice1 ca/ iron is seldom us$ except to resi/ compression4 ,/ra9s ( ,compression4 ,all[+ ! same lett]s to d5ote ! same ?+s z above1 we h = ,wood1 a ,t_/#ajjj ,wr\ght ,iron1 a ,t_/#abjjj ,ca/ ,iron1 a ,t_/#bejjj ,z ?is pamphlet has to d ) wood5 bridges only1 no?+ w be said ( ! prop] relative dim5sions ( ca/-iron columns to su/a9 ! /ra9s to :i* !y may be subject$1 b a table ( ! /r5g? ( columns w be f\nd fur!r on4 ,transv]se ,/ra9s4 ,let ,w break+ weight 9 lbs4 s con/ant 9 table4 b bread? 9 in*es4 d dep? 9 in*es4 ,l l5g? 9 in*es4 ,!n1 = ! p[] ( a beam to resi/ a transv]se /ra91 we %all h1 #d sbd ,w ------ ,l ,te,x3 ,w frac#d sbd#b,l ,?is =mula has be5 d]iv$ f exp]im5ts made by ! mo/ reliable au?orities4 ,! con/ant1 #abej1 adopt$ = wood 9 ! foll[+ =mula1 is an av]age con/ant1 d]iv$ f ! table1 ( ^? woods m commonly us$4 ,n[ to r$uce ! =mula to ! mo/ conv5i5t %ape = use1 we sub/itute ! value ( s1 & we h #d x #abej bd ,w ------------1 ,l ,te,x3 ,w frac#d times #abej bd#b,l or #ejjj bd ,w --------4 ,l ,te,x3 ,w frac#ejjj bd#b,l ,b1 to r$uce ! load to ! prop] work+ /ra91 we mu/ divide ?is equival5t by #d1 ! factor ( safety1 & we %all h #ejjj bd ,w --------4 #d,l ,te,x3 ,w frac#ejjj bd#bd ,l ,let u apply ! =mula-- ,case ,i4 ,giv5 a span ( #ad feet1 a bread? ( #h in*es1 a dep? ( #ad in*es4 ,requir$ ! safe load4 #ejjj bd ,! =mula ,w -------- #d,l ,te,x3 ,w frac#ejjj bd#bd ,l becomes1 by sub/itution1 #ejjj x #h x #aif ,w -------------- #aa4fff lbs4 #d x #h ,te,x3 ,w frac#ejjj times #h times #aifd times #afh #aa1fff lbs4 ,case ,,ii4 ,giv5 ! safety load #ahjjj lbs4 ! bread? #i in*es1 ! l5g? #ad feet4 ,requir$ ! dep?4 ,f ! above =mula we h ------- _/ ,w ,x #d,l d _/ ------ _/ #ejjj b ,te,x3 d sqrtfracw times #d,l#ejjj b sub/itut+ ---------------- _/ #ahjjj x #afh x #d ------ d _/ --------------- _/ #bfh4h #af1 in*es ne>ly4 _/ #ejjj x #i _/ ,te,x3 d sqrtfrac#ahjj times #afh times #dejjj times #i sqrt#bfh4h #af ,case ,,iii4 ,giv5 ! safety load #bb1djj lbs4 ! dep? #ah in*es4 ! l5g? #ad feet4 ,requir$ ! bread?4 ,d]iv+ b f ! =ego+1 we h1 ,w x #d,l b ---------- #ejjj x d ,te,x3 b frac,w times #d,l#ejjj times d#b sub/itut+ #bbdjj x #d x #afh b --------------- #i4c in*es ne>ly4 #ejjj x #cbd ,te,x3 b frac#bbdjj times #d times #afhejjj times #cbd #i4c ,= a ca/ iron beam or gird]--,mr4 ,hodgk9son f\nd f num]\s c>efully conduct$ exp]im5ts t1 by arrang+ ! mat]ial 9 ! =m ( an inv]t$ ,t--?us creat+ a small top flange z well z ! l>g] bottom "o1 ! resi/ance 0 increas$1 p] unit ( section1 ov] t ( a rectangul> beam1 9 ! ratio ( #dj to #bc4 ,9 ?is beam ! areas ( ! top & bottom flanges are inv]sely proportional to ! p[] ( ! iron to resi/ compression & ext5sion4 ,mr4 ,hodgk9son's =mula = ! dim5sions ( 8 gird]1 is #bf ad ,w ------ ,l ,te,x3 ,w frac#bf ad,l ,! factor ( safety be+ #f = ca/ iron beams--! =mula = ! work+ load w be1 #bf ad ,w ------ #f ,l ,te,x3 ,w frac#bf ad#f ,l &1 to f9d area ( l[] flange1 we %all h #f ,,wl a ---- #bf d ,te,x3 a frac#f ,,wl#bf d ,! g5]al proportions ( 8 gird]s are z foll[s3 ,l5g?1 #af ,height1 #a ,area ,top ,flange1 #a4j ,area ,bottom ,flange1 #f4a ,9 ! above =mula = ca/ iron beams1 ,w weight 9 tons4 a area 9 squ>e in*es ( bottom flange4 d dep? 9 in*es4 h l5g? 9 in*es4 ,! web unit+ ! two flanges mu/ be made solid--z any op5+1 by caus+ irregul>ity 9 cool+1 w\ld s]i\sly affect ! /r5g? ( ! beam4 ,example4--,requir$ ! dim5sions ( a ,hodgk9son gird]--= a span ( #fj feet--) a load ( #aj tons 9 ! c5tre4 #f x #aj x #fj x #ab a ---------------- #cg in*es ne>ly4 #fj x #ab #bf x ------- #af ,te,x3 a frac#f times #aj times #fj times #abbf times frac#fj times #abaf #cg & ! area ( ! top flange w be1 #cg -- #f4af in*es-- #f ,te,x3 frac#cgf #f4af s t our dim5sions w be z foll[s3 ,l5g?1 #cj feet4 ,dep?1 #de in*es4 ,area ,top ,flange1 #f4af in*es4 ,area ,bottom ,flange1 #cg in*es4 ,illu/ration3 ,pl4 #a4 ,! ?ickness ( web is usually a little great] at ! bottom ?an at ! top1 & v>ies f #a_/ad to #a_/bd ( ! dep? ( ! gird]4 ,! bottom rib is usually made f six to eight times z wide z x is ?ick1 & ! top rib f ?ree to six times z wide z ?ick1 s t1 9 ! example above giv51 we c\ld h z dim5sions = ! p>ts ,top ,flange1 #d #a_/d x #a #a_/b in*es ne>ly4 ,bottom ,flange1 #f x #b #a_/b in*es ne>ly4 ,web1 #a #a_/b in*es ?ick4 ,! simple/ bridge1 consi/+ ( a s+le /ick1 to span op5+s ( #bj feet & "u1 is calculat$ accord+ to ! =mula ------ _/ #d,,wl d _/ ------ -- _/ #ejjj b ,te,x3 d sqrtfrac#d ,,wl#ejjj b ,example4--,! dep? ( a beam1 ( #ab feet span & #ab feet wide1 to support a load ( #bbdjj lbs4 w be ------ -------------------- _/ #d,,wl _/ #d ,x #bbdjj x #ab x #ab ------- d _/ ------ _/ ------------------- _/ #bae4jd #ae 94 ne>ly _/ #ejjj b _/ #ejjj x #ab _/ ,te,x3 d sqrtfrac#d ,,wl#ejjj b sqrtfrac#d times #bbdjj times #ab times #abejjj times #ab sqrt#bae4jd #ae ,! foll[+ ,table 0 calculat$ by ! above rule--& ! dim5sions alt]$ accord+ to ! actual practice ( ! writ]4 ,span4 ,bread?4 ,dep?4 #d #aj #ab #f #aj #ab #h #ab #ab #aj #ab #ac #ab #ab #ae #af #ab #ah #ah #ab #bj #bj #ab #bb ,^! dim5sions w give ample /r5g? & /iffness4 ,fig4 #a1 ,plate ,i4 gives an illu/ration ( ?is k9d ( bridge--9 :i* a1 a1 are ! bol/]s or wall plates1 %[n 9 section1 to :i* ! bridge beams are not*$ & bolt$4 ,fig4 #a1 ,a1 ,plate ,i1 %[s ! me?od ( diagonally brac+ ^! beams by planks1 dim5sions ( :i* 9 g5]al use are #f to #h by #b to #c in*es4 ,! track %\ld re/ on ties1 ab\t #f in*es by #h or #aj in*es--! same bolt conf9+ ! ends ( ! ties & diagonal braces :5 practicable4 ,^! ties %\ld be not*$ on ! /r+ pieces #b or #c in*es--)\t cutt+ ! /r+]s4 ,bel[ is a table giv+ g5]al dim5sions1 9 in*es1 ( ! sev]al p>ts ( a bridge ( ?is description4 ,span4 ,bol/]s4 ,/r+]s4 ,ties4 ,braces4 ,diamet] ( ,bolts4 #d #ab x #ab #aj x #ab #f x #h #b x #h #a in*4 #aj #ab x #ab #ab x #ac #f x #h #b x #h #a #af #ad x #ad #ab x #ah #f x #h #b x #h #a #bj #ad x #ad #ab x #bb #f x #h #b x #h #a ,ea* bolt mu/ h a wa%] "u ! head1 & also "u ! nut4 ,= a span ( f #ae to #cj feet1 we c use ! comb9ation %[n 9 ,plate ,,ii1 ,fig4 #c4 ,! piece ,a ,f mu/ h ! same dim5sions z a simple /r+ piece ( a l5g? ,a ,b--s t x may n yield betwe5 ,b & ei!r ( ! po9ts ,a or ,d4 ,! two braces ,d ,f & ,e ,f mu/ be /iff en\gh to support ! load com+ ^u !m4 ,suppose ! weight on a pair ( driv]s ( a ,locomotive to be #aj tons1 !n ea* side mu/ be> #e tons1 & ea* brace #b-a_/b tons #b-a_/b x #bbdj #efjj lbs4 ,n[1 to all[ = sudd5 or extra /ra9s1 call #hjjj lbs4 ! /ra9 to be support$ by ea* brace1 &1 accord+ly1 #h squ>e in*es ( sectional area w\ld be suffici5t = compression only2 b1 z ! brace is incl9$1 ! /ra9 is increas$4 ,let ! v]tical di/ance f ,a to ,d be #aj ft41 &1 call+ ! span #cj ft4--,a ,b w be #ae ft4--f :5ce ,d ,f mu/ be #ah ft41 !n we %all h ! proportion #aj 3 #ah 33 #hjjj 3 #addjj lbs4 :i* w\ld require an area ( ab\t #ae squ>e in*es ( section to resi/ compression1 or a piece #cx#e in*es4 ,n[1 z ?is /ick is m ?an #f or #h diamet]s 9 l5g?1 x w yield by b5d+--& consequ5tly its area mu/ be increas$4 ,! load1 :i* a piece ( wood act+ z a po/ or /rut w safely su/a91 is f\nd by ! =mula already giv54 #bbdj bd ,w -------- ,l ,te,x3 ,w frac#bbdj bd#c,l#b ,n[ sub/itut+ #c = b1 & #e = d1 we h #bbdj x #c x #abe #hdjjjj ,w -------------- ------ #beib lbs4 #cbd #cbd ,te,x3 ,wfrac#bbdj times #c times #abecbd;frac#hdjjjjcbdbeib :i* is n en\gh4 ,us+ #f = b & #h = d1 we h #bbdj x #f x #eab ,w -------------- #babch lbs4 #cbd ,te,x3 ,w frac#bbdj times #f times #eabcbd #babch :i* is some?+ l>g] ?an is actually requir$1 b x is no h>m to h an excess ( /r5g?4 ,n[ 9 _m cases ?is arrangem5t w\ld be objectionable1 z n af=d+ suffici5t head room on acc\nt ( ! braces--& we c z well use ! =m ( /ructure giv5 9 ,pl4 ,i4 ,fig4 #c1 s9ce x is evid5tly immat]ial :e!r ! po9t ,b be support$ on ,f or susp5d$ f x1 provid$ we c prev5t motion 9 ! feet ( ! braces1 :i* is done by not*+ !m into ! /r+] at t po9t4 ,?is ( c\rse creates a t5sional /ra9 along ! /r+]1 :i* is f\nd z foll[s3--,repres5t+ ! appli$ weight by ,f ,b1 ,pl4 ,,ii1 ,fig4 #b1 draw ,b ,d p>allel to ,f ,c1 also ,d ,h p>allel to ,a ,c--,d ,h is ! t5sion4 ,?is is ! graphical con/ruction1 & is ne> en\gh = practice4 ,geometrically we h ! two simil> triangles ,a ,f ,b & ,d ,f ,h1 :5ce ,a ,f 3 ,d ,f 33 ,a ,b 3 ,d ,h ,d ,f x ,a ,b & ,d ,h --------- ,a ,f ,te,x3 ,,dh frac,,df times ,,ab,,af ,?is /yle ( /ructure may be us$ up to #ej feet1 b x is n employ$ = spans exce$+ #cj feet 9 l5g?4 ,x is v cu/om>y to make ! braces 9 pairs s z to use small] scantl+1 & ga9 9 lat]al /iffness--! two pieces =m+ "o brace by be+ prop]ly block$ & bolt$ toge!r4 ,bel[ is giv5 a table ( dim5sions = ! v>i\s p>ts ( ?is /yle ( /ructure3 ,span4 ,rise4 ,bol/]4 ,/r+]4 ,braces4 ,rod4 ,no4 ,size4 #ae #f #ab x #ab #ab x #ab #b--e x #f #a-a_/h #bj #g #ad x #ad #ab x #ac #b--e x #h #a-c_/h #be #h #ad x #ad #ab x #ae #b--f x #h #a-a_/b #cj #aj #ad x #ad #ab x #ah #b--f x #i #a-e_/h ,s+le ,beams "u ea* rail firmly brac$ lat]ally1 & truss$ by an iron rod1 7or pref]ably by two iron rods17 & a po/ on ! "u side ( ! beam4 ,! deflection ( ! rod is usually tak5 at #ah ( ! span4 ,pl4 ,,ii41 ,fig4 #a1 repres5ts ?is /yle ( truss+ a beam--:i* is g5]ally us$ = spans ( f #ae to #cj ft4 ,bel[ is a table ( dim5sions = ?is truss ) s+le & d\ble rods2 if d\ble rods are us$ only half ! giv5 section w be necess>y = ea* "o ( ! pair4 ,span4 ,rise4 ,/r+]4 ,po/4 ,rod4 ,rods4 ,feet4 ,9 ,feet4 7s+le47 7d\ble47 #ae #a-g_/h #ab x #ab #f x #h #b-a_/h diam4 or #a-a_/b diam4 #bj #b-a_/b #ab x #ad #g x #h #b-a_/b #a-c_/d #be #c-a_/h #ab x #af #h x #h #b-c_/d #b #cj #c-c_/d #ac x #ah #i x #i #c #b-a_/h ,x is z well to t5on ! po/ into ! beam1 & also /rap x firmly ) iron plates--& ! end %\ld be %od ) iron to =m a saddle = ! rods to be> ^u4 ,n[ if we %\ld make a bridge1 on ! plan ( ,fig4 #c1 ,pl4 ,i41 #ge or #ajj feet1 or p]haps m1 9 l5g?1 ! braces ,a ,f & ,f ,c1 w\ld n only be v long b v l>ge & heavy1 & "o *ief requisite 9 a good bridge is1 to h all ! beams s proportion$ t !y w resi/ all ! /ra9s act+ ^u !m1 )\t be+ unnecess>ily l>ge4 ,x n[ becomes necess>y to h a diff]5t arrangem5t ( ! p>ts ( ! truss 9 ord] to obta9 increas$ l5g? ( span4 ,suppose we h a span1 ( #dj feet1 z repres5t$ 9 ,fig #b1 ,pl4 ,i4 ,n[ in/ead ( runn+ ! braces f ,a ,c until !y meet 9 a po9t1 z be=e we /op !m at a1 & c1 & place ! /ra9+ beam1 a c1 betwe5 !m to prev5t ^? po9ts f approa*+1 susp5d ! po9ts ,b & ,d f !m1 & />t ! braces ,b b & ,d b--&1 if ! truss 7 long]1 w\ld cont9ue on 9 ! same mann] z f> z ne$ful4 ,to prev5t !4 truss f alt]+ its =m1 z %[n by ! dott$ l9es ,a' b ,c'1 & ,a ,e ,c1 by any pass+ load1 we ins]t ! c\nt] braces m>k$ ,r4 ,! braces ,a a & ,c c1 mu/ support all ( ! weight ( ! bridge & its load )9 ! p>allelogram ,b a c ,d--& ! next set ( braces1 ,b b & ,d b1 su/a9 t "p ( ! load :i* comes ov] ! c5tre ( ! bridge4 ,consequ5tly ! braces mu/ increase 9 size f ! c5tre t[>ds ! abutm5ts4 ,! rods resi/ ! same pressure 9 am\nt z _! braces--b be+ v]tical1 d n ne$ ! increase1 giv5 to ! braces on acc\nt ( _! incl9ation--b increase simply ) ! /ra9 ^u !m1 f ! c5tre to ! ends ( ! truss4 ,!re are _m =ms ( small bridges diff]+ f ^? enum]at$1 9 v>i\s m9or details1 b suffici5t has be5 said to give ! read] a fair idea ( ! /ra9s ^u ! diff]5t p>ts1 & h[ to arrange & proportion ! mat]ials to resi/ !m4 ,,practical ,,rules ,,& ,,examples ,,9 ,,wood5 ,,bridge ,,build+4 ,9 any case t may arise1 we mu/ det]m9e approximately ! gross weight ( ! bridge & its load--z a basis1 & !n we c proce$ z foll[s--9 case ( a ,h[e1 ,pratt1 or ,ar* ,brace ,truss4 ,to f9d ! dim5sions ( ! ,l[] ,*ord4 ,! t5sion at ! c5tre ( ! ,l[] ,*ord is f\nd by divid+ ! product ( ! weight ( ! :ole bridge & load by ! span1 by sight times ! height--or lett+ ,tt5sion 9 lbs41 ,wweight ( bridge & load 9 lbs41 ,sspan 9 feet1 & hrise or height--we h ,w x ,s ,t ----- --4 #h h ,te,x3 ,t frac,w times ,s#h h ,9 ?is case we h tak5 ! rise at #a_/h ( ! span1 :i* is evid5tly ! be/ ratio betwe5 ^? dim5sions1 z x equalizes ! v]tical & horizontal =ces4 ,z to ! proportions ( ! bays or panels1 7or t portion ( ! truss b\nd$ by two adjac5t v]ticals1 z /ruts or ties1 & ! *ords17 ! ratio ( ! rise 7or ! v]tical di/ance betwe5 ! c5tre l9es ( ! two *ords17 & ! l5g? on ! *ord %\ld be su*1 t ! diagonal truss memb]s may make an angle ( ab\t #ej ) ! *ords2 z ! size ( ! timb]s is increas$ by decreas+ ! angle1 &1 if ! angle is increas$1 !re are m timb]s requir$4 ,mr4 ,g4,l4 ,vose1 9 8 admirable "w on ,r4,r4 ,con/ruction1 obs]ves v truly t ,! braces1 at ! end ( a long span1 may be ne>] ! v]tical ?an ^? ne> ! c5tre1 z !y h m "w to d4 ,if ! end panel be made twice z high z long1 & ! c5tre panel squ>e1 ! int]m$iates v>y+ z _! di/ance f ! end1 a good ar*itectural effect is produc$4 ,n[ x is necess>y = u to h "s data f :i* to det]m9e ! approximate weight ( ! bridge1 & also its load4 ,^! c be f\nd by comp>+ weights ( bridges 9 common use1 z obta9$ f reports4 ,9 a small bridge ( %ort span1 ! weight ( ! /ructure itself may be entirely neglect$1 because (4 ! v small proportion ! /ra9s caus$ by x be> to ^? due to ! load2--b1 9 long spans1 ! weight becomes a v important elem5t 9 ! calculations = /r5g? & safety--inasmu* z x may exce$ ! weight ( ! load4 ,9 all ,bridges ( #abj ft4 span1 ab\t #a_/c ( a ton1 p] foot run1 w be ! weight ( ea* truss = a s+le track1 includ+ floor timb]s--transv]se brac+1 c4 ,if ! bridge 7 load$ ) ,locomotives only1 ! greate/ load w\ld be1 on ! :ole bridge--#afj tons #a4cc tons p] ft4 run ( ! bridge or 4#fff tons p] ft4 run ( ea* truss4 ,n[ if we make ! rise ( ! bridge #ae ft41 & divide ! span into #ab panels ( #aj ft4 ea*1 we %all h = total weight ( bridge & load #bdj tons1 or = a s+le truss #aj tons to ea* panel4 ,l[] ,*ords4 ,n[ to f9d ! t5sion on ! ,l[] ,*ords1 ,w x ,s ,t ----- & supply+ values1 we h #h h ,te,x3 ,t frac,w times ,s#h h #bdj x #abj ,t --------- #bdj tons1 or #ecgfjj lbs41 #h x #ae ,te,x3 ,t frac#bdj times #abjh times #ae #bdj = ! two ,l[] ,*ords1 & #a_/b ( ?is1 or #bfhhjj lbs4 = "o *ord4 ,! ,t5sional ,/r5g? ( timb] = safety may be tak5 at #bjjj lbs4 p] squ>e in* ( section1 & h5ce ! area ( timb] requir$ to su/a9 ! above /ra9 w be #bfhhjj ------ #acd4d sq4 in*es4 #bjjj ,te,x3 frac#bfhhjjbjjj #acd4d ,b ?is *ord has also to su/a9 ! transv]se /ra9s aris+ f ! weights pass+ ov] x1 &1 z 9 ! case ( a ,locomotive1 ! weight ( #bj tons on #b pair ( driv]s1 7or #aj tons = "o truss17 may be conc5trat$ on ! middle po9t ( a panel--! *ord mu/ be s proportion$ z to safely be>1 z a horizontal beam1 ?is weight4 ,suppose we take ?ree /icks ( #h x #ab1 to =m ! *ord 7! great] dim5sion be+ ! dep?17 we %all h #c x #h x l#b #bhh squ>e in*es area ( section1 & all[+ = splic+ #gb squ>e in*es1 foot blocks1 #bd bolts1 #bd wa%]s1 #h we %all h aft] d$uct+ all[ances 7#bhh-abh7 #afj squ>e in*es area1 giv+ an excess ov] #acd4d1 ! area dem&$1 suffici5t to cov] all[ances = any accid5tal /ra94 ,upp] ,*ords4 ,! upp] *ords are compress$ z =cibly z ! l[] ones suff] t5sion--ow+ to ! action & reaction ( ! diagonals4 ,9 ?is case ! compression is #bfhhjj lbs41 & z #a squ>e in* ( section w safely be> #ajjj lbs41 we h = ! #bfhhjj area requir$1 ------ #bfh4h #ajjj ,te,x3 frac#bfhhjjajjj #bfh4h squ>e in*es1--?ree pieces #h x #aa w give #bfd squ>e in*es & ?is area w require no r$uction1 z ! :ole *ord presses toge!r :5 prop]ly fram$ & is n weak5$ by splic+4 ,s f>1 ! calculations made w\ld apply to ei!r ( ! ?ree ,bridges m5tion$1 z well z to a ,w>r5 ,truss4 ,b n[1 to obta9 ! dim5sions ( ! web memb]s1 s call$1 ( ! ,truss1 x is necess>y to decide ^u ! specific v>iety4 ,! =m ( ,bridge 9 m g5]al use 9 ! ,unit$ ,/ates is call$ ! ,h[e ,truss1 f its inv5tor1 & 9 spans ( #aej feet1 & "u1 is v reliable2 = spans exce$+ #aej ft4 x %\ld be /r5g!n$ ei!r by ,ar* ,braces or by ! addition ( ,ar*es1 z ! heavy /ra9s f ! weight ( bridge & load be>+ on ! feet ( ! braces ne> ! abutm5ts1 t5d to cripple & di/ort ! truss by sagg+1 al?\gh ! ,baltimore ,bridge ,co4 h built a ,wood5 ,h[e ,bridge ( two ,trusses ( #cjj ft4 span1 #cj ft4 rise1 & #bf ft4 wide1 )\t any ar*1 b x has a wr\ght iron l[] *ord1 & is only proportion$ = a mov+ load ( #ajjj lbs4 p] ft4 run4 ,vide ,vose on ,r4,r4 con/ruction4 ,9 ord] to ensure uni=mity 9 /r5g? 9 ! *ords--b "o jo9t %\ld be all[$ 9 a panel--& t %\ld come at ! c5tre ( ! panel l5g?--b 9 long spans ?is _c always be done4 ,web ,memb]s4 ,we w n[ proce$ to calculate ! web memb]s ( a ,h[e ,truss ( ! =ego+ dim5sions1 :5 subject$ to ! /ra9s above m5tion$4 ,braces4 ,! end braces mu/ evid5tly support ! :ole weight ( ! bridge & load1 :i* = "o end ( "o truss w be #acddjj lbs41 & z ^! braces are 9 pairs1--#fgbjj lbs4 w be ! /ra9 v]tically on ! /ick--b z ?is /ick is a diagonal--^: v]tical is #ae ft41 & horizontal #aj ft41 we %all h = its l5g? #ah ft4 9 r\nd numb]s1 :5ce ! /ra9 along ! diagonal w be f\nd f ! proportion #ae 3 #ah 33 #fgbjj 3 #hjfdj lbs41 :5ce we h an area ( #hj in*es requir$ = compression1 or a /ick ( #h x #aj4 ,n[1 to asc]ta9 if ?is is /iff en\gh = flexure1 we w sub/itute ^! values 9 ! equation #bbdj bd ,w --------1 & we h ,l ,te,x3 ,w frac#bbdj times bd#c,l#b #bbdj x #h x #ajjj ,w ---------------1 or r$uc+1 ,w#eecjh lbs4 #cbd ,te,x3 ,w frac#bbdj times #h times #ajjjcbd #eecjh ,n[1 ^! proportions w give ample /r5g? = bo? flexure & compression1 = if we block ! two /icks compos+ ! end brace toge!r1 & firmly connect !m by bolts1 we %all h a built beam #bbdj x #bd x #ajjj ( #bd x #aj--:5ce ,w ---------------- #afeibe lbs41 #cbd ,te,x3 ,w frac#bbdj times #bd times #ajjjcbd #afeibe & z #acddjj lbs4 0 all t ! conditions dem&1 we really h an excess ( /r5g?4 ,! next set ( braces supports ! weight ( ! rectangle includ$ betwe5 ! upp] ends ( ! braces & ! two *ords1 & ! dim5sions ( ! /icks are calculat$ 9 ! same mann]4 ,we f9d1 z we approa* ! c5tre ( ! bridge1 t ! /ra9s on ! braces become less1 & consequ5tly _! scantl+ %\ld be r$uc$1 b 9 ord9>y practice ?is is seldom done4 ,rods4 ,! next ?+ is to asc]ta9 ! dim5sions ( ! v>i\s tie rods4 ,x is evid5t t ! same weight comes ^u ! fir/ set ( rods1 z on ! fir/ set ( braces--:i* w give = ! rods at "o end ( "o truss1 #acddjj lbs42 & z !re are two ( ^! rods1 ea* w su/a9 a /ra9 ( #fgbjj lbs4--&1 at #ae1jjj lbs4 p] squ>e in*1 w h an area ( #d4dh sq4 in*es1 &1 by ,vose's ,tables1 mu/ h a diamet] ( #b-a_/b in*es4 ,! sizes ( ! rods 9 ea* set w decrease t[>ds ! c5tre ( ! bridge z ! weight becomes less4 ,illu/ration3 ,pl4 ,,ii4 ) ,fig4 #a41 ,fig4 #b41 ,fig4 #c41 ,fig4 #d4 ,c\nt]braces4 ,n[1 z to ! necessity ( ,c\nt]brac+1 !re are v>i\s op9ions4 ,! object ( x is to /iff5 ! truss & *eck vibrations4 ,if a load be plac$ ov] any panel po9t1 x causes t portion ( ! truss to s9k1 & produces an elevation ( ! correspond+ panel po9t at ! o!r end ( ! truss--?us produc+ a di/ortion1 :i* *ange ( =m is resi/$ by prop] c\nt]braces4 ,! /ra9 to :i* ?is timb] is subject$ is caus$ by ! mov+ load on "o panel only--& requires only scantl+ ( ! size ( ! middle braces4 ,^! c\nt]braces %\ld n be p9n$ or bolt$ to ! braces :]e ! cross--z _! action is !reby entirely alt]$--b x is well to s conf9e !m z to prev5t v]tical or lat]al motion4 ,%oes4 ,=m]ly x 0 ! cu/om to foot ! braces & c\nt]s on h>d wood blocks on "o side ( ! *ord1 ! v]tical rods pass+ ?r\gh & screw+ aga9/ a block on ! o!r side--?us ! :ole /ra9 t5d$ to cru% ! *ord across its fibres4 ,?is is n[ rem$i$ by ! use ( ca/ iron blocks1 be>+ on "o side ( ! *ord1 b hav+ tubes ext5d+ ?r\gh to ! o!r side1 :]e ! wa%] plate = ! bolts fits firmly on _! ends1 =m+ a complete protection1 z all ! cru%+ /ra9 is receiv$ on ! block itself4 ,wid?4 ,x n[ becomes necess>y to det]m9e ^u ! wid? betwe5 ! two trusses4 ,= a s+le track bridge = a railroad1 #ad ft4 is ! usual wid? adopt$1 & = a highway bridge1 f #ab to #af ft4 ,:5 a d\ble track is requir$1 ?ree trusses are usually employ$1 ) a wid? = ea* roadway ( #ad ft4 = railroads4 ,bol/]s4 ,l>ge timb]s #ab x #ab1 or !reab\ts1 are laid on ! bridge seats ( ! abutm5ts to support ! ends ( ! trusses1 "o ( ^! %\ld be directly "u ea* ( ! extreme panel po9ts4 ,a panel po9t is ! int]section ( ! c5tre l9e ( a brace produc$1 ) ! c5tre l9e ( a *ord4 ,! rise ( a truss is ! v]tical di/ance betwe5 ! c5tre l9es ( ! upp] & l[] *ords4 ,camb]4 ,7 a bridge to be fram$ ) its *ords p]fectly horizontal1 x w\ld be f\nd to fall bel[ ! horizontal l9e on be+ plac$ 9 its prop] position1 ow+ to ! clos+ up ( ! jo9ts 9 ! upp] p>ts ( ! /ructure1 & op5+ ( jo9ts 9 ! l[] p>ts1 z well z to ! compression ( ! p>ts4 ,to obviate ?is defect1 x is usual to curve ! *ords slightly 9 a v]tical direction1 by elongat+ ! upp] *ord1 s t ! bays or panels are no long] rectangul> b ( a trapezoidal =m--&1 z a consequ5ce1 ! incl9$ web memb]s are slightly l5g!n$1 & ! v]ticals become radii ( ! curve4 ,! am\nt ( deviation f a horizontal l9e is call$ ! ,camb]4 ,a table ( ,camb]s = diff]5t spans w be f\nd fur!r on1 z also a table ( multipli]s1 by :i* to multiply ! camb] 9 ord] to f9d ! elongation ( ! upp] *ord4 ,"p ( ! ,camb] table is tak5 f ,trautw9e's ,eng9e]'s ,pocket-,book1 7:i* %\ld be ! insep>able companion ( e eng9e]17 & "p 0 calculat$ = ?is pamphlet1 accord+ to ,trautw9e's rules4 ,! table ( multipli]s is ,trautw9e's4 ,diagonal ,brac+4 ,9 ord] to /iff5 a bridge1 x %\ld h ! two ,trusses brac$ toge!r at ! ,l[] ,*ords always1 at ! ,upp] ,*ords :5 practicable--& 9 case ( a deck bridge1 :]e ! roadway is support$ on ! upp] *ords1 x is z well to h rods = v]tical diagonal braces1 _! planes be+ p]p5dicul> to ! axis ( ! bridge4 ,! m usual =m is simil> to ! web memb]s ( ! ,h[e ,truss--! rods f #c_/d to #a 9 diamet]1 & ! braces ( #f x #g scantl+1 foot$ on wood5 blocks1 usually4 ,x is m usual to h ! tie rods ( ! horizontal diagonal brac+1 & ! braces !mselves1 meet 9 a po9t ab\t midway ( a ,truss panel on ! c5tre l9e1 ne>ly1 ( ! *ord4 ,?is w g5]ally give a half panel ( diagonal brac+ ne> ea* end ( ! truss--& x is v usual to h ! diagonals foot at _! int]section !re aga9/ a cross timb] int]pos$ betwe5 ! trusses1 :ile ! tie rod prev5ts any spread+4 ,floor ,timb]s4 ,! g5]al dim5sions ( ! transv]se floor beams1 :5 ab\t #c feet ap>t1 f c5tre te c5tre1 are #h x #ad1 ! l>ge/ dim5sion be+ ! dep?4 ,! /r+]s %\ld be not*$ to ! floor beams ab\t #a or #b1 & %\ld be ab\t #aj or #ab x #ad4 ,! cross ties %\ld be #ah to #bd ap>t1 f c5tre to c5tre1 & be #c-a_/b x #f4 ,l>ge1 heavy bridges require no fa/5+ to connect !m ) _! seats1 b light bridges %\ld be fa/5$1 z ! spr+ on ! sudd5 removal ( a load1 7z :5 ! la/ c> ( a tra9 has pass$17 may move x f its prop] position4 ,splices4 ,z ! upp] & l[] *ords h to be made 9 sev]al l5g?s1 securely fa/5$ to ea* o!r1 &1 9 ord] to weak5 ! built beam z little z possible1 x is necess>y to adopt "s =m ( splic+ :]eby ! greate/ am\nt ( t5sional /r5g? may be reta9$ 9 ! *ord ) ! lea/ am\nt ( cutt+1 & yet h a secure jo9t4 ,su* a splice is %[n 9 ,pl4 ,,ii1 ,fig4 #d1 & bel[ is a table f ,vose's ,h&-book1 giv+ reliable dim5sions4 ,span4 ,a ,c ,b ,b ,c ,d ,feet4 ,feet4 ,in*es4 ,feet4 #ej #a4jj #a-a_/b #a4ej #ajj #a4be #b #b4jj #aej #a4ge #b-a_/b #b4be #bjj #b4jj #c #b4ge ,?is mann] ( splic+ requires ! back ( ! splice block to be let into ! *ord /ick1 aga9/ :i* x lies1 ab\t #c_/d ( an in*4 ,to %[ h[ ! v>i\s ,eng9e]s diff]1 z to _! e/imates ( ! sizes ( ! sev]al p>ts ( bridges1 ,i subjo9 two ,tables--"o by ,pr(4 ,g4,l4 ,vose1 a well kn[n ,eng9e]1 & "o by ,jno4 ,c4 ,trautw9e1 an ,eng9e] ( note also--& ,i w\ld premise t a bridge built accord+ to ei!r w\ld be amply /rong4 ,,table ,,= ,,dim5sion+ ,a ,,h[e ,,truss ,,bridge4 ,g4,l4 ,,vose4 ,end ,c5tre ,c5tre ,span4 ,rise4 ,panel4 ,*ords4 ,braces4 ,braces4 ,end ,rods4 ,rods4 #ej #aj #g #b--h x #aj #g x #g #e x #e #a--a-a_/h #b--a #ge #ab #i #b--h x #aj #h x #h #e x #e #b--a-a_/b #b--a #ajj #ae #aa #b--h x #aj #h x #i #f x #f #b--a-c_/d #b--a #aej #bj #ac #d--h x #ab #aj x #aj #f x #g #c--b #c--a #bjj #be #ae #d--h x #af #ab x #ab #g x #g #e--b #e--a ,,table ,,= ,,dim5sion+ ,a ,,h[e ,,truss ,,bridge4 ,,jno4 ,c4 ,,trautw9e1 ,c4,e4 ,an ,upp] ,a ,l[] ,an ,end ,a ,c5tre ,end ,c5tre ,cle> ,no4 ,*ord4 ,*ord4 ,brace4 ,brace4,c\nt]4 ,rod4 ,rod4 ,span ,rise ( ---------------------------------------- ------------------------- 9 9 ,pan- ,no ,no ,no4 ,no ,no ,no4 ,no4 feet4feetels4,pcs,size4,pcs,size4,pcs4,s ize,pcs,size,pcs,size,rods,size4 ,rods,size4 ---------------------------------------- ------------------------------ #be #f #h #c #dx#e #c #dx#aj #b #dx#f #b #ex#e #a #dx#e #b #a-e_/af #b #g_/h #ej #i #i #c #fx#g #c #fx#aj #b #fx#g #b #ex#f #a #ex#f #b #a-e_/h #b #a-a_/af #ge #ab #aj #c #fx#i #c #fx#aa #b #fx#h #b #fx#f #a #fx#f #b #a-g_/h #b #a-c_/af #ajj #ae #aa #c #fx#aj #c #fx#ab #b #hx#i #b #fx#h #a #fx#h #b #b-c_/af #b #a-e_/af #abe #ah #ab #d #fx#aj #d #fx#ac #b #hx#aj #b #fx#i #a #fx#i #b #b-e_/h #b #a-c_/h #aej #ba #ac #d #hx#aj #d #hx#ad #c #ix#aj #c #fx#i #b #fx#i #c #b-c_/h #c #a-c_/af #age #bd #ad #d #ajx#ab #d #ajx#ae #c #ix#aa #c #hx#h #b #hx#h #c #b-e_/h #c #a-a_/d #bjj #bg #ae #d #abx#ab #d #abx#af #c #ix#ab #c #hx#aj #b #hx#aj #c #b-g_/h #c #a-c_/h ,bo? ( ^! tables 7 calculat$ = a s+le ,railroad track1 & w\ld answ] equally well = a d\ble ,highway ,bridge4 ,9 ! bridge accord+ to ,trautw9e's ,table1 ea* l[] *ord is suppos$ to h a piece ( plank1 half z ?ick z "o ( ! *ord pieces1 & z long z ?ree panels1 firmly bolt$ on ea* ( its sides1 9 ! middle ( its l5g?4 99 99 99 99 99 ,,pratt',s ,,bridge4 ,?is is opposite 9 arrangem5t ( p>ts to a ,h[e ,bridge1 z ! diagonals are rods1 & su/a9 t5sion1 & ! v]ticals are po/s1 & suff] compression3 ,example4--,span #ajj feet4 ,rise #ab ,panel #aj ,weight p] l9eal ft4 #cjjj lbs4 ,! t5sion on ! l[]1 or compression on ! upp] *ord1 w be #cjjjjj x #ajj ------------ #ccccccc lbs4 #if ,te,x3 frac#cjjjjj times #ajjif #ccccccc ,! dim5sions ( ! *ord & splic+ w\ld be f\nd 9 ! same mann] z = a ,h[e ,truss4 ,susp5sion ,rods4 ,fig4 #a1 ,pl4 ,,iii41 repres5ts an elevation ( a ,pratt ,bridge4 ,n[1 x is evid5t t ! fir/ sets ( rods mu/ support ! weight ( ! :ole bridge & its load1 :i* we h f\nd to be #cjjjjj lbs4 ,ea* truss w h to su/a9 #aej1jjj lbs41 & ea* end set ( rods #ge1jjj lbs4 ,n[1 if !re are two rods 9 ea* set1--ea* rod w h to be> a /ra9 ( #cgejj lbs41 & ?is w h an increase due to its incl9ation1 s t ! /ra9 on x mu/ be f\nd by ! foll[+ proportion3 ,height 3 diagonal 33 ,w 3 ,w' or #ab 3 #ae4h 33 #cgejj 3 #dicge lbs4 ,ref]r+ to ! ,table = bolts1 we f9d t #b-a_/h gives a /r5g? a little 9 excess1 & w be ! prop] size4 ,! next set ( rods be> ! weight ( ! :ole load1 less t due to ! two end panels1 & s on4 ,fig4 #b1 ,pl4 ,,iii1 %[s ! mann] ( apply+ ! rods4 ,! bevel block %\ld be s fitt$ to ! *ord t x w n h a cru%+ action4 ,c\nt]s4 ,top & bottom *ords are always us$ 9 ?is bridge1 & consequ5tly ! c\nt] rods h only to su/a9 ! movable load on "o panel4 ,! weight ( ! mov+ load _c be m ?an #bjjj lbs4 p] l9eal foot :i*1 = a panel ( #aj ft41 gives #bjjjj lbs41 or #aj1jjj lbs4 = ea* set1 & if we h two rods 9 a set1 ! /ra9 on ea* rod w be #ejjj lbs41 increas+ ?is = incl9ation1 we %all h1 #ab 3 #ae4h 33 #ejjj 3 #fehe lbs41 requir+ a rod ( #c_/d ( an in* diamet]4 ,! po/s 9 ?is bridge correspond to ! braces ( ! ,h[e ,truss1 b be+ v]tical1 are n s l>ge4 ,subjo9$ are two ,tables1 "o by ,pr(4 ,g4,l4 ,vose1 & "o by ,mr4 ,trautw9e1 giv+ pr9cipal dim5sions = bridges ( diff]5t spans ( ! ,pratt type ( ,truss4 ,,table ,,( ,,dim5sions ,,( ,a ,,pratt ,,truss4 ,,pr(4 ,g4 ,l4 ,,vose4 ,end ,c5tre ,end ,c5tre ,c\nt] ,span4 ,rise4 ,*ords4 ,po/4 ,po/4 ,rod4 ,rod4 ,rod4 #ej #aj #b--hx#aj #e x #e #d x #d #b--a-c_/h #b--a #a--a-a_/b #ge #ab #b--hx#aj #f x #f #e x #e #b--a-e_/h #b--a #a--a-a_/b #ajj #ae #c--hx#aj #g x #g #f x #f #b--a-c_/d #b--a #b--a-a_/h #abe #ah #c--hx#aj #h x #h #f x #f #c--a-g_/h #c--a #b--a-a_/c #aej #ba #d--hx#ab #i x #i #f x #f #c--b-a_/h #c--a #h--a-a_/h #bjj #bd #d--hx#af #aj x #aj #f x #f #e--a-g_/h #e--a #c--a-a_/h ,,table ,,( ,,dim5sions ,,( ,a ,,pratt',s ,,truss4 ,upp] ,l[] ,ma9 ,brace ,rods4 ,c\nt] ,cle> ,no4 ,*ord4 ,*ord4 ,rods4 ,po/s4 ,span ,rise ( ---------------------------------------- --------- ---------- 9 9 ,pan-,no4 ,no4 ,no4 ,size ,no4,size4,num ,no4 ,size,no4,size4 feet4feetels4,pcs,size4,pcs,size4,ctr,c5 tre,end ,end4b] ,size4 ,end ,end4,ctr,c5tre ---------------------------------------- --------------------------------- #be #f #h #c #dx#e #c #dx#aj #b #a #b #a-c_/h #a #a-g_/af #c #dx#e #c #dx#d #ej #i #i #c #fx#g #c #fx#aj #b #a-c_/af #b #a-a_/h #a #a-e_/h #c #fx#f #c #fx#e #ge #ab #aj #c #fx#i #c #fx#aa #b #a-e_/af #b #b-a_/b #a #a-g_/h #c #fx#g #c #fx#e #ajj #ae #aa #c #fx#aj #c #fx#ab #b #a-g_/af #b #b-g_/h #a #b #c #fx#i #c #fx#g #abe #ah #ab #d #fx#aj #d #fx#ac #b #a-a_/b #b #b-c_/h #a #b-a_/h #d #fx#i #d #fx#g #aej #ba #ac #d #hx#aj #d #hx#ad #c #a-e_/af #c #b-a_/b #b #a-e_/h #d #hx#h #d #hx#g #age #bd #ad #d #ajx#ab #d #ajx#ae #c #a-e_/h #c #b-c_/d #b #a-aa_/af #d #ajx#aj #d #ajx#h #bjj #bg #ae #d #abx#ab #d #abx#af #c #a-a_/b #c #c-a_/h #b #a-ac_/af #d #abx#aj #d #ajx#h ,?is table is p>tly giv5 9 ,trautw9e's ,eng9e]'s ,pocket ,book1 & p>tly made up f directions !re9 giv54 ,,table ,,( ,,dim5sions ,,= ,,small ,,s+le ,,track ,,pratt ,,trusses4 ,at c5tre ,at end ,c5tre ,end ,cle> ,*ords ,c5tre ,end ( truss1 ( truss1 ,c\nt]1 ,c\nt]1 ,span1 ea*1 ,po/1 ,po/s1 ,diam4 ( ,diam4 ( ,diamet]1 ,diamet]1 ,ft4 ,ins4 ,ins4 ,ins4 ,rods4 ,rods4 ,ins4 ,ins4 #cj #i x #aa #d x #i #g x #i #a #a-e_/h #a-c_/h #a #dj #aj x #ab #d x #aj #h x #aj #a-a_/h #a-g_/h #a-e_/h #a #ej #aj x #ad #e x #aj #i x #aj #a-a_/d #b-a_/h #a-c_/d #a #fj #ab x #ae #e x #ab #i x #ab #a-c_/h #b-c_/h #b #a #gj #ab x #ag #f x #ab #aa x #ab #a-a_/b #b-a_/b #b-a_/h #a ,?is bridge possesses an advantage ov] ! ,h[e ,truss1 = ! panel diagonals c be tight5$ up by screws1 s t e "p ( ! truss c be =c$ to p]=m its "w4 ,9 ,h[e's bridge ! adju/m5ts mu/ be made by w$g+ ! braces & c\nt]s4 ,bel[ are giv5 ! dim5sions ( a ,h[e bridge on ! ,v]mont ,c5tral ,r4,r41 at ,s\? ,royalton1 7s+le track1 deck47 ,no4 ( ,upp] ,l[] ,span4 ,rise4 ,panels4 ,*ord4 ,*ord4 ,braces4 ,c\nt]s4 #aej #bj #ab #d--f-a_/b x #ac #d--f-a_/b x #ac #b--h x #i #a--h x #i ,rods4 ,transv]se ,brac+4 ,braces4 ,rods4 #c--a-a_/d #f x #h #g_/h ,! bridge ov] ! ,:ite ,riv]1 on ! ,passumpsic ,r4,r41 is a ,h[e ,truss1 /r5g!n$ by an ar*4 ,! v]ticals are ( wood1 & ! diagonals foot on /eps =m$ by enl>g+ ! ends ( ! v]ticals4 ,! c\nt]s are 9 two l5g?s1 & are adju/$ by w$ges at ! po9ts :]e !y int]sect ! braces4 ,! bridge is 9 two spans1 & has a d\ble track1 & consequ5tly ?ree trusses4 ,!re are two timb] ar*es to ea* truss1 & ! truss is support$ on !m by connect+ !m to ! v]ticals by %ort cross pieces not*$ into ! po/s1 & re/+ on ! upp] surface ( ! ar*es4 ,x is a v /iff bridge1 & simil> to ! "o at ,bell[s ,falls1 bo? hav+ _! axis oblique to ! *annel ( ! /ream !y cross4 ,! timb]s c\ld h>dly be procur$ n[1 except at great exp5se4 ,no4 ( ,upp] ,l[] ,span ,pan- ,rods ,*ord ,*ord ,braces ,c\nt]s ,uprights ,ar*es els #ahb #ad #ba #b--h x#af #b--h x#ag1 #a--ba x#h #a--h x#aj #ba x#aa #b--h x#i #a--e x#af #b--d x#ag1 #a--e x#ag1 ,diagonals #f x #h1 ,rods #g_/h4 ,floor timb]s susp5d$ bo? f ar*es & truss1 #i x #ac2 /r+]s #aj x #ad4 ,9 ! ,*e%ire ,bridge1 ! braces are only #bjx#h1 & ! span is only #age feet1 ! numb] ( ,panels be+ #ad1 z 9 ! ,w4,r4 ,bridge--! o!r dim5sions are ! same4 ,bel[ are giv5 ! dim5sions ( a ,h[e ,truss ( #ajh ft4 span1 weight to be borne on upp] *ord4 ,no4 ( ,upp] ,l[] ,e4 ,floor ,rise ,camb] ,pan- ,*ord ,*ord ,braces ,c\nt]s ,rods ,timb]s ,ft4 ,ins4 els ,ins4 ,ins4 ,ins4 ,ins4 ,ins4 ,ins4 #ac-a_/b #c #ab #h--c x#ab #h--c x#ab #b--h x#aj #a--g x#aj #b--b-a_/h #i x#af ,z plank is us$ = ! *ords1 ! pieces mu/ be bolt$ ?or\ghly ) #e_/h bolts4 ,a =m ( bridge t has be5 us$ to "s ext5t on ! ,baltimore & ,ohio ,railroad1 by ,mr4 ,latrobe1 is ! ,ar* ,brace ,truss4 ,9 ?is =m ( ,truss ! braces lead directly f ! abutm5ts to ! head ( ea* v]tical2 ?us ! load is transf]r$ at once to ! abutm5ts1 )\t pass+ ?r\gh a s]ies ( web memb]s4 ,! c\nt]brac+ is effect$ by means ( a light lattice1--& is appli$ to bo? sides ( ! *ords1 & ! int]sections ( ! diagonals are fa/5$ :ile ! bridge is /ra9$ by a load--?us prev5t+ recoil--s t ! effect ( a mov+ load is to light5 ! /ra9 on ! lattice--)\t o!rwise affect+ ! ,truss4 ,illu/ration3 ,pl4 ,,iii4 ) ,fig4 #a41 ,fig4 #b41 ,fig4 #c41 ,fig4 #d41 ,fig4 #e4 ,!re are two models ( ?is /yle ( bridge1 to my k2 "o built by ,pr(4 ,g4,l4 ,vose1 on a scale ( #a_/b an in* to ! foot1 & repres5t+ a span ( #aej feet1 :i* support$ #b1ejj lbs4 at ! c5tre1 & a movable load ( #aej lbs41 prov+ itself to be /rong & rigid en\gh = any ?+4 ,! o!r1 on a scale ( #a in* to ! foot1 & repres5t+ a span ( #gf feet1 0 built by ! ,class ( '#gc1 ( ! ,?ay] ,eng9e]+ ,s*ool1 "u ! writ]'s direction1 & ?\gh be>+ v heavy weights1 has nev] be5 ?or\ghly te/$--x has1 h[ev]1 be5 subject$ to ! sudd5 %ock ( #ajdj lbs4 fall+ #bj in*es1 )\t injury1 sev]al times4 ,subjo9$ are ! dim5sions ( ! models m5tion$4 ,,dim5sions ,,( ,a ,,model ,,( ,,an ,,ar* ,,brace ,,truss4 ,g4,l4 ,,vose4 ,l5g?1 #g feet4 ,height1 #a foot4 ,wid?1 #a foot4 ,*ords1 #d--a_/d x #a_/b in*4 ,braces #d--a_/d x #a_/h ,lattice1 #a_/d x #a_/af ,?is repres5t$ a span ( #aej ft1 a rise ( #bj feet1 & a panel ( #ae ft4 ,weight1 p] runn+ foot ( bridge & load1 0 tak5 at #cjjj lbs4 ,! me?od ( calculat+ ! dim5sions ( ?is truss1 f ! =ego+ data1 is z foll[s4 ,! half numb] ( panels is #e1 & ! l5g?s ( ! correspond+ diagonals 7neglect+ fractions7 are --------- _/#bj #ae #be feet4 ,te,x3 root#bjb #aeb #be _/ --------- _/#bj #cj #cg ,te,x3 root#bjb #cjb #cg _/ --------- _/#bj #de #di ,te,x3 root#bjb #deb #di _/ --------- _/#bj #fj #fd ,te,x3 root#bjb #fjb #fd _/ --------- _/#bj #ge #gh ,te,x3 root#bjb #geb #gh _/ ,! weight ^u ea* set ( braces is t due to "o panel1 or #cjjj x #ae #dejjj lbs41 half ( ?is1 or #bbejj lbs41 is ! weight = "o truss only--&1 z !re is a brace "u ea* ( ! #d *ord /icks1 we divide by #d1 & h #efbe lbs4 p] /ick ( ! brace2--n[1 correct+ = incl9ation1 we %all h #bj 3 #be 33 #efbe 3 #gjca lbs4 #bj 3 #cg 33 #efbe 3 #ajdjf lbs4 #bj 3 #di 33 #efbe 3 #acgha lbs4 #bj 3 #fd 33 #efbe 3 #ahjjj lbs4 #bj 3 #gh 33 #efbe 3 #baicg lbs4 ,! weights f\ud %[ ! compressional /ra9s on ! sev]al braces2--&1 7 ! pieces to be proportion$ = compression only1 _! ,scantl+ w\ld be q small--b on acc\nt ( _! ela/icity1 !y require l>g] dim5sions4 ,^! braces %\ld n be fa/5$ to ! v]ticals1--b %\ld be conf9$ bo? lat]ally & v]tically1 :]e !y pass !m4 ,! l5g? ( beam1 = :i* we h to gu>d aga9s flexure1 is ! l5g? betwe5 v]ticals 9 any panel4 ,9 panel ,no4 #a1 x w be #be feet1 #b1 #ah #c1 #ag #d1 #af #e1 #af ,n[1 us+ ! =mula #bbdj b d --------- ,w1 ,l ,te,x3 frac#bbdj bd#c,l#b ,w we %all h1 9 r\nd numb]s1 ! foll[+ dim5sions3 ,= ! #a/ panel1 #be feet long1 #h x #aj #b;d #cg #h x #aj #c;d #di #h x #aj #d? #fd #h x #aj #e? #gh #h x #aj ,= ! lattice "w1 a d\ble c\rse on ea* side ( ea* truss1 9 long spans2 & a s+le c\rse1 9 %ort] spans1 ( #c x #f1 or #b x #i plank1 bolt$ at int]sections1 is suffici5t4 ,,g5]al ,,table ,,( ,,dim5sions ,,= ,,ar* ,,brace ,,truss4 ,g4,l4 ,,vose4 ,span4 ,rise4 ,*ords4 ,ties4 ,braces4 ,lattice4 #ej #aj #b--h x #aj #a--h x #aj #b--f x #f #ge #ab #b--h x #aj #a--h x #aj #b--f x #f #b x #i #ajj #ae #c--h x #aj #b--h x #aj #c--f x #f or #aej #bj #d--h x l#b #c--h x #aj #d--f x #h #c x #f #bjj #be #d--h x #af #c--h x #aj #d--f x #i ,! ar* braces mu/ all foot on an iron ?ru/ block1 ( :i* a view is giv5 9 ,fig4 #d1 ,pl4 ,,iii2 & ! c5tre ( pressure ( ! braces mu/ be directly ov] a bol/]1 to prev5t crippl+4 ,! sev]al /icks =m+ a brace mu/ be block$ toge!r at int]vals1 & ,:5 !y are splic$1--a butt jo9t ,%\ld be us$--& x %\ld come 9 ! c5tre ( a panel4 ,bel[ are giv5 ! dim5sions ( ! ,?ay] ,eng9e]+ ,s*ool model4 ,height ,ins4 #ab ,no4 ,panels #h ,*ords ,ins4 #b--a x #a_/b ,po/s ,ins4 #a--b_/c x #e_/f ,braces ,ins4 #b--a_/b x #a_/b ,lattice ,ins4 #a_/d x #a_/b ,wid? ,ins4 #ac ,!re are sev]al o!r =ms ( ,bridge1 ! mo/ notable among :i* are ! ,:ipple1 ,mc,callum's1 ,po/'s1 ,t[ne's1 ,haupt's1 & ,burr's4 ,b en\gh has be5 said to give ! /ud5t an idea ( ! g5]al arrangem5t ( ! diff]5t p>ts ( a ,truss1 & to enable him to det]m9e ! /ra9s to :i* ! v>i\s memb]s are subject$4 ,no?+ w be said 9 reg>d to ,wood5 ,ar*es1 z our space is too limit$4 ,pile ,bridg+4 ,a bridge ( ?is description is useful 9 cross+ m>%es1 or 9 %all[ wat]4 ,fig4 #e1 ,pl4 ,,iii1 gives a good example ( ?is k9d ( bridge1 "u #bj feet 9 height4 ,if on a curve1 !re mu/ be extra brac+ on ! convex side4 ,tre/le ,"w4 ,?is is a comb9ation ( po/s1 caps1 & braces2 & is us$ = bo? tempor>y & p]man5t works4 ,plate ,,iv1 ,figs4 #a1 #b1 #c & #d1 give "s ( ! be/ v>ieties 9 use4 ,figs4 #a & #b1 may be us$ up to #ae feet 9 height2 ,fig4 #d1 up to #bj feet2 & ,fig4 #c1 to #cj ft4 ,! di/ance ap>t ( ! v>i\s b5ts %\ld n exce$ #aj or #ab ft41 unless brac+ is introduc$ betwe5 !m1 & ! b5ts %\ld always be rais$ above ! gr\nd a few feet on a solid masonry f\ndation4 ,want ( space =bids any m5tion ( abutm5ts & pi]s1 :i* really come m prop]ly "u ! head ( masonry4 ,iron ,bridg+ is gradually work+ its way into favor1 & ,w probably ev5tually sup]s$e wood5 trusses2--b 9 _m cases wood is ! only mat]ial at h&--& !re=e "s k ( ,wood5 ,bridg+ is desirable4 ,x is int5d$ to foll[ ?is pamphlet ) a portfolio ( %eets conta9+ work+ draw+s ( sev]al k9ds ( ,wood5 ,bridges1 tak5 f actual measurem5ts ( "s ( ! be/ specim5s ( ! diff]5t /yles ( ,truss 9 use4 99 99 99 99 99 ,,practical ,,notes4 ,:5 putt+ a truss toge!r 9 its prop] position1 on ! abutm5ts1 'false works' mu/ fir/ be erect$ to support ! p>ts until !y are s jo9$ toge!r z to =m a complete self-su/a9+ truss4 ,! bottom *ords are fir/ laid z level z possible on ! false works1 !n ! top *ords are rais$ on tempor>y supports1 su/a9$ by ^? ( ! l[] *ord1 & are plac$ a few in*es high] at fir/ ?an _! prop] position1 9 ord] t ! web memb]s may be slipp$ into place4 ,:5 ?is is done ! top *ords are gradually l[]$ into place4 ,! screws are !n gradually tight5$1 7beg9n+ at ! c5tre & work+ t[>ds bo? ends17 to br+ ! surfaces ( ! jo9ts into prop] contact1 & by ?is me?od1 ! camb] =ms itself1 & lifts ! l[] *ords cle> ( ! false works1 leav+ ! truss re/+ only ^u its prop] supports4 ,! subjo9$ ,table w be f\nd useful 9 e/imat+ ! /ra9s on a truss :5 proportion+ a bridge = any mov+ load4 ,table ( weights p] runn+ foot ( a bridge1 7ei!r ( wood or iron17 includ+ weights ( floor1 lat]al brac+1 c41 complete1 = a s+le track4 ,cle> ,weight ( ,span4 ,bridge4 ,tons4 lbs4 #be 4#bff #eif #cj 4#bha #fbi #dj 4#cac #gja #ej 4#cdc #gfh #fj 4#cgd #hch #gj 4#djd #ije #hj 4#dcd #igb #ij 4#dfd #ajci #ajj 4#did #aajf #abj 4#eed #abda #adj 4#fad #acge #aej 4#fdc #addj #afj 4#fgc #aejg #agj 4#gjc #aege #ahj 4#gcc #afdb #bjj 4#gib #aggd #bbe 4#hfg #aidb #bej 4#idj #baje #bge #a4jac #bbfi #cjj #a4jhg #bdce ,! weight ( a s+le track railway bridge may be tak5 z equal to t ( a d\ble track highway bridge1--& ! trusses t w be l>ge en\gh = "o w be l>ge en\gh = ! o!r4 ,! greate/ load t a highway bridge c be subject$ to is #abj lbs4 to ! squ>e foot ( surface4 ,,table ,,( ,,camb]s ,,= ,,bridge ,,trusses4 ,span4 ,camb]4 ,span4 ,camb]4 ,span4 ,camb]4 ,span4 ,camb]4 feet4 ,in*es4 ,feet4 ,in*es4 ,feet4 ,in*es4 ,feet4 ,in*es4 #be #j4h #ge #b4e #age #e4h #bge #i4b #cj #a4j #ajj #c4c #bjj #f4g #cjj #aj4j #ej #a4g #abj #d4j #bbe #g4e #cbe #aj4h #fj #b4j #aej #e4j #bej #h4c #cej #aa4g ,,trautw9e',s ,,table ,,= ,,f9d+ ,,increase ,,9 ,,l5g? ,,( ,,upp] ,,*ord ,,beyond ,,! ,,l[] ,,*ord ,,on ,,acc\nt ,,( ,,! ,,camb]4 ,multiply ,multiply ,dep? ( ,camb] ,dep? ( ,camb] ,truss4 by ,truss4 by #a-d span #b4jj #a-ab span 4#fff #a-e #a4fj #a-ac 4#fad #a-f #a4cc #a-ad 4#ega #a-g #a4ae #a-ae 4#ecc #a-h #a4jj #a-af 4#ejj #a-i 4#hhh #a-ag 4#dgj #a-aj 4#hjj #a-ah 4#ddd #a-aa 4#gbg #a-bj 4#djj ,,table ,,( ,,am]ican ,,woods4 ,weight p] ,resi/ance 9 lbs4 p] ,k9d4 cubic foot squ>e in*4 ,value ( s4 9 p\nds4 ,ext5sion ,compression4 ,:ite ,p9e4 #bf #ab1jjj #fjjj #abbi ,yell[ ,p9e4 #ca #ab1jjj #fjjj #aahe ,pit* ,p9e4 #df #ab1jjj #fjjj #agbg ,r$ ,p9e4 #ce #ab1jjj #fjjj #aebg ,virg9ia ,p9e4 #cg #ab1jjj #fjjj #adef ,spruce4 #dh #ab1jjj #fjjj #ajcf ,tam>ack4 #bf #ab1jjj #fjjj #ijg ,canada ,balsam4 #cd #ab1jjj #fjjj #aabc ,:ite ,oak4 #dh #ae1jjj #gejj #agdc ,r$ ,oak4 #da #ae1jjj #gfjj #afhg ,bir*4 #dd #ae1jjj #gjjj #aibh ,a%4 #ch #af1jjj #hajj #agie ,hickory4 #ea #ae1jjj #gbjj #babi ,elm4 #de #af1jjj #hjaa #aigj ,! above table is compil$ f a mu* full] "o 9 ,vose's ,treatise on ,r4,r4 ,con/ruction4 ,,table ,,( ,,bolts ,,& ,,nuts ,,calculat$ ,,= ,a ,,work+ ,,/ra9 ,,( #ae1jjj ,,lbs4 ,,p] ,,squ>e ,,in* ,,( ,,section4 ,diamet]4 ,area4 ,/r5g? 9 ,weight p] ,?ick's ,no4 ?r's ,in*es4 ,sq4 in*es4 ,p\nds ,foot4 ,squ>e nut4 ( nut4 p] in*4 #a_/b 4#aifce #bidj #j4ff #a-a_/d 9 #c_/d 9 #ab #e_/h 4#cjfhj #dfjb #a4jc #a-c_/h #c_/d #aj #c_/d 4#ddagi #ffcj #a4di #a-a_/b #g_/h #aj #g_/h 4#fjacb #ijai #b4jc #a-c_/d #a #i #a 4#ghedj #aagge #b4fe #b #a #h #a-a_/h 4#iidjb #adiaj #c4cf #b #a-a_/h #g #a-a_/d #a4bbgb #ahdje #d4ag #b-a_/d #a-a_/d #g #a-c_/h #a4dhdi #bbbfj #e4jb #b-a_/b #a-c_/h #f #a-a_/b #a4gfga #beeje #e4ig #b-c_/d #a-a_/b #f #a-e_/h #b4jgci #cajie #g4ja #b-g_/h #a-e_/h #e #a-c_/d #b4djec #cfjge #h4ac #c #a-c_/d #e #a-g_/h #b4gfab #dadae #i4cc #c-a_/d #a-g_/h #d-a_/b #b #c4adaf #dgacj #aj4fb #c-a_/b #b #d-a_/b #b-a_/h #c4eaff #ecaij #ab4jj #c-c_/d #b-a_/h #d #b-a_/d #c4igfa #eifdj #ac4dj #d #b-a_/d #d #b-c_/h #d4dcja #ffdej #ae4jj #d-a_/h #b-c_/h #d #b-a_/b #d4ijhg #gcfbj #af4gj #d-a_/d #b-a_/b #c-a_/b #b-e_/h #e4daai #haagh #ah4bj #d-a_/b #b-e_/h #c-a_/b #b-c_/d #e4icif #hijid #bj4jj #d-c_/d #b-c_/d #c-a_/b #b-g_/h #f4diah #igcgg #ba4ij #e #b-g_/h #c #c #g4jfhf #ajfjbi #bc4hj #e-a_/d #c #c #c-a_/d #h4bieh #abddcg #bg4ij #e-c_/d #c-a_/d #c #c-a_/b #i4fbaa #addcaf #cb4dj #f #c-a_/b #b-a_/b ,,table ,,( ,,safe ,,work+ ,,load ,,9 ,,lbs41 ,,= ,,holl[ ,,ca/-,,iron ,,columns4 ,g4,l4 ,vose4 ,outside ,l5g? or height 9 ,feet ,metal ,diamet] ,?ickness 9 in*es4 #f #h #aj #ab #ae #ah #bj 9 in*es4 #c #afjjj #adjjj #acjjj #aajjj #ijjj #gjjj #fjjj #c_/h #d #cjjjj #bijjj #bfjjj #bdjjj #bbjjj #ahjjj #afjjj #a_/b #e #ejjjj #cgjjj #dejjj #dbjjj #cijjj #cgjjj #cajjj #e_/h #f #eijjj #egjjj #eejjj #ebjjj #dijjj #ddjjj #dajjj #c_/d #g #ajajjj #iijjj #ifjjj #ibjjj #hhjjj #hajjj #gfjjj #ac_/af #h #acajjj #abijjj #abfjjj #abbjjj #aahjjj #ajijjj #ajejjj #g_/h #i #afijjj #afgjjj #afdjjj #afjjjj #aefjjj #adfjjj #adajjj #a #aj #bajjjj #bjjjjj #bjjjjj #bjjjjj #aijjjj #ahjjjj #ahjjjj #a-a_/h #aa #bejjjj #bejjjj #bdjjjj #bdjjjj #bdjjjj #bcjjjj #bbjjjj #a-a_/d #ab #cjjjjj #cjjjjj #bijjjj #bijjjj #bijjjj #bgjjjj #bgjjjj #a-a_/b #ad #dejjjj #dcjjjj #dajjjj #chjjjj #cgjjjj #cejjjj #ccjjjj #a-c_/d #af #ebjjjj #ejjjjj #dhjjjj #dfjjjj #ddjjjj #dbjjjj #djjjjj #b #ah #fejjjj #fcjjjj #fajjjj #eijjjj #efjjjj #ebjjjj #dgjjjj #b-a_/b #bj #hjjjjj #gfjjjj #gdjjjj #fijjji #fejjjj #eijjjj #edjjjj #c ,illu/ration3 ,pl4 ,,iv4 ) ,fig4 #a41 ,fig4 #b41 ,fig4 #c41 ,fig4 #d4 ,transcrib]'s ,notes3 ,,disclaim]3 ,?is docum5t %\ld ,,n be us$ to eng9e] any bridge projects6 ,_m typesett+ errors 7 f\nd1 & x is possible t !re are fur!r errors 9 ! in=mation t 7 n caught4 ,=mulas h be5 provid$ bo? z ,,ascii & ,te,x foll[+ 9 brackets4 ,bold head+s are h&l$ ) equal signs be=e & aft] ! bold text4 ,italicis$ text uses ! /&>d und]l9es be=e & aft] ! text4 ,fractions are express$ 9 ! =mat3 #b-a_/d means two & "o qu>t]4 ,! page numb]s li/$ bel[ are project page numb]s4 7,! orig9al book us$ ,roman num]als to numb] ! pages47 ,note t ! book uses ! long ton equal to #b1bdj p\nds4 ,,corrections ,,made3 #a4 ,page #h--! =mula = d mu/ use a cube root1 :i* is h[ x is %[n "h1 b ! '#c' to indicate a cube root is n f\nd 9 ! orig9al docum5t4 #b4 ,page #h--typo 9 ^w 'secti5'--*ang$ to 'section'4 #c4 ,page #aj--,value = work+ comp4 /r5g? ( ca/ iron 9 ! table _h a typo 7#be1v#jj74 ,s9ce o!r values use r\nd numb]s1 x is assum$ ! value %\ld be #be1jjj4 #d4 ,page #aj--,two o!r typos4 ,*ang$ '! !' to '!'1 & 9 table head+1 orig9al ^w 0 'detrution'1 *ang$ to correct spell+ ( 'detrusion'4 #e4 ,page #ab--;*ang$ 'woood5' to 'wood5'4 #f4 ,page #ac--;,example ,,ii--,9 ! calculations1 ! int]m$iate value 9 ! book 0 pr9t$ z ! squ>e root ( #fg4b4 ,! left "p is correct1 b r$uces to ! squ>e root ( #bfh4h1 & t is #af4cie4 ,s ,i h correct$ ! int]m$iate value4 #g4 ,page #ac--;,because ! orig9al page scan cut (f ! text on ! "r edge1 ,i h made assumptions on :at text 0 miss+4 ,because ! scans came f an outside s\rce1 ,i c\ld n get ! miss+ in=mation1 :i* 0 ! words at ! end ( ,example ,,ii1 & words 9 ! la/ p>agraph ( ! page4 #h4 ,page #ad--,?ree typos f\nd3 'dim5si5s' = 'dim5sions'1 'betng' = 'be+'1 & 'ars' = 'are'4 #i4 ,page #ag--;a value 9 a =mula 0 pr9t$ z #fjjj1 b 9 ! context ( ! o!r in=mation1 p>ticul>ly ! example imm$iately foll[+1 ! value 0 believ$ to be incorrect1 & 0 *ang$ to #ejjj4 #aj4 ,page #bc--,! value ( #chh sq4 in*es at ! top ( ! page 9 ! book is incorrect2 #c x #h x #ab #bhh1 s has be5 correct$4 #aa4 ,page #bd--,rods section1 num]ical value appe>$ to be #ae4jjj 9 ! book1 b f context1 mu/ be #ae1jjj in/ead4 #ab4 ,page #bh--,typos3 *ang$ ',trautw9e's ,edg9e]'s ,pocket-,bood' to ,trautw9e's ,eng9e]'s ,pocket-,book'2 correct$ 'af' to 'z'1 'bracas' to 'braces'4 #ac4 ,page #cj--;,app>5t typo 9 ! table at ! bottom ( page4 ,value = ,c5t] ,brace size = #bjj' span 0 %[n z '#h x #a'1 believ$ f context ( table to be '#h x #aj'4 #ad4 ,page #cc--table ( dim5sions ( a ,pratt ,truss1 la/ column1 r[ />t+ ) #aej1 ! orig9al says #h--a-a_/h1 ?is is believ$ to be1 & has be5 *ang$ to1 #c--a-a_/h4 #ae4 ,page #cg--,! five =mulas ) squ>e roots 7 incorrectly pr9t$ 9 ! book1 multiply+ ! t]ms inside ! squ>e root in/ead ( add+ !m1 :i* is obvi\sly incorrect p] ! ,py?agorean !orem ( "r triangles4 #af4 ,page #ch3 ,! fif? ratio 9 ! gr\p ( five ne> ! top ( ! page mu/ />t ) #bj1 n #aj z 9 ! book #ag4 ,page #ch--,! equation = ,w z pr9t$ on ?is page is n consi/5t ) t f\nd on pages #ah to #bd1 s has be5 correct$ f 'bd#b' to 'bd#c'4 #ah4 ,page #ci--;ar* brace truss table head+ typo-*ang$ ',,foe' to ',,='4