The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1853-08-02
NATIONAL SCIENTIFIC CONVENTION.
American Association for the
Advancement OF Science.

Second Day Morning sessisn.
ON rHs RAsisrANoE OF vERTicAL PLATES OF TuBU-
LAR BRIDGES, BY HERMANN HAUPT, SUP. PssS.
ChkTRAL RAILRoAD.
The great ossidsrstap in the oentrueton If bridges
N arrssgsDset Of paris thst With gissn ~saeas Of
material VII possess efci Mt power OF resft
asos. An fulnls the coalition of nsximan res-t
with given weight Of material when the ditribu
tkoao6 the wood 10 constant With esrnspent ~-gat
Wheeler formly Distributed or net there u c,u sc
% equilibrium. and gives mount Of weight Of n. sssl
o. aDted conform 20 his curve, II give the ski
mum Of reeisAsoe which the material is capable OF
posing but for oror AIRY hridges especially for rail osd
puy ps,ss here be Of the load
Il only ysrisbe but vsrv great IN proportion
weight 81 the fuusture; ard were an eq ihbium posi-
bic in position IL uls stable for
only bs sps Of the load 20 assshsr positicn vsud
Ut oDea ARturb II.
mt the, efore that the psiasple Of
applies Only sqntcucts or othof structures upon when
the losds constant aud hat 10 render
s~saos OF sustaining vsr, Ole load IL must silhsr b
nsd~ deep that The Va iaucns Of the If pres
Will Itver outi the arch. II must be cos-
bsss 9th resisting bile OF eHscasg or op-
Ps-ips Any tendency 20 chAres sf Egure
Aoss Of the Dridsss In general lilo traeons 81
tins species Of coa biz asious but the rsspse is
usually psed ION ihs truss the arah being asea
When wood used thi. of m ,tsral is not OBJ
ecoaAbe sxc~pt sof.r IL increases lily the
weight the structure; but ~hsn boB il ena yed it
becomes ss.eL,sy mpor tant that the d<triouie VI
The frsss Ieud he Understood tns str.in ali the
oiDensions correctly propo-uoned 20 the required re-
sistabee
aheany been tises to ,h~ pubic in the general
theory OF bridge coDss-ucuon and further
Of these primo PIES weuid lead TO radical change ths
OF BtIuc'sg brcgss surses and instead OF
lsirg IN arch - suxiiAr, To truss the arch GOULD
D. sde chief dspeodst and the trusI pop I'd 10
sctien If the variable Loo 6s and pevsat
change Of figures il the arsh during tner passage
tbe Dfids Wren al po.sd this IsAnser = given
qu.nity ef material will oppose ecaent resi-.
ell her 20 vibration fexurs or fracture.
IL tubular iroE b,iS-es which have recently attracted
much 2rtBi,np eifculty ia fosAd In desriaug tie
srah the horizontal kabies and in props
them eorIscy bot the mepsions Of the vsrtcsI ribs
and the beat Dsnss- Of stiff ming them, viii s,.oS
osy he Isgstude Of the weight but upon the mode
Of the 'pphe II the well ht supi sphed At
the Dicd ola tubular bridge its aetiea would tend
shoren she diagonal esdsg from the MIDDLE Of the
top eod c.b 10 the end of tbs bottom table, asd ~
from the middle Of the bottom table the end II the
top table. The strain upon the last diagonal would
Of the nate-sl but the oppssits diAg ,nL being
jeetec to ms,esvs forces ~ouli, t formed Inns Of
thin plate OF metal b. unable 70 op any efficient
resistance, and the bridge would probably fail in the
rec l. n OF This dsRosAL
Il becsAes Necessary therefore to provide for
ss, the ribs and THE usually efsted BY rive ting
to them vertically, p.eea Of ron at short intervals
BY these additions he sstrbation Of the strains il
chang ed thu the parts ilar to ta.t Of
trUsn the Pratt plan the vertical stifsners akny
the place VI tina paris ard ia. Uses Of short iros
Hecine The Opposite Of PANEL hs ing
Idilg seion to The ordinary diagonal reds The
taDce WI Oh such An arrangement capable Of opso.iag
II pcpSssd 70 dsslnne nom the fos wing Considers
A0Bss-
In the general theory bridge construction Il has
been d.Dobs rated that when the lead ia uuforIolv
disniou ed the vertical strain Increases uniformly from
zee middle " The ~ncs. The upsn Niagoasl
Of my panel gill - eDEts of the diAroasl 70
tbs length Of the vertical s,ss a.d also it. dstasoe
nom he middle Of the tru.s the maxyertieAl strata
Being Of eqnsl to the whole weight Of bicse
AID It's load with the mcaentuD doe to motioa ssd
v,brauon, when t1e strue.ur. ia not riria. IL has
hat ErA nal