On the theory and calculation of continuous bridges

Mansfield Merriman

Description

ON THE THEORY AND CALCULATION BRIDGESCONTINUOUS MANSFIELD MERRIMAN, C.E., Ph.D., INSTRUCTOR I SHEFFIELD SCIEN NEW YORK: D. VAN NOSTRAND, PUBLISHER, 23MURRAY AND 27 WARREN STREET. i o / x+R^w ^ 2 Mc= R w+ -f + a (Z, x) I, (i I, x) 9w x-R In a whose issimple girder length each of whose reactions is R or w I the-J- shear and moment for section x willany be -w I (% x) wx* w , When the number of isspans large, the for the shear andmomentexpressions as above deduced become and in- long volve much arithmetical computation. We able toare, however, fortunately 16 them under a much form.place simpler First be written thusthey may R RS= w + w -f tox(R : I, 2 2 3) M= -R ll wl w/ R is4- the)Now(Rl l +R, 2 3 shear in at athe pointspan 3 infinitely near to the 3 let this be calledsupport ; S . Also the enclosed in in 3 quantity [ ] the second is the moment ofequation exterior forces with reference to thethe 3 let this be called M . Then thepoint ; 3 becomeequations toxS=S 3 M=M S x+%wx*3 5 Therefore the internal shear and mo- ment at section can beany immediately ofwithout the determin-found, necessity the ice know thereactions,ing provided shear and the moment thefor preceding This due tosupport. method, Clapeyron, of the moment at the in-supportsusing stead of the reactions greatly simplifies 17 numerical of a continu-the computations ous truss.

Sujets

• Girder
• Bridges

Informations

• Publié par: les_archives_du_savoir
• Nombre de lectures: 3
• Langue: English
• Poids de l'ouvrage: 10 Mo

Extrait

ON THE
THEORY AND CALCULATION
BRIDGESCONTINUOUS
MANSFIELD MERRIMAN, C.E., Ph.D.,
INSTRUCTOR I SHEFFIELD
SCIEN
NEW YORK:
D. VAN NOSTRAND, PUBLISHER,
23MURRAY AND 27 WARREN STREET.
i o /<7
I o 7 b.PREFACE,
are divided into threeThe following pages
The first of intro-chapters. presents by way
ofsome of theduction principleselementary
ideasand the fundamentalcontinuous girders,
The sec-to the calculation of strains.relating
toond the of flexure astheory appliedgives
the continuous of constant cross section,trjiss^
formula toand exhibits it in (I) (VI), ready
case and thefor toapplication any particular ;
an of the ofthird example computationgives
strains in a continuous truss of five unequal
with some useful hints theconcerningspans,
of such bridges.practical building
indicates theThe of flexuretheory that, by
instead ofuse of continuous single span
a in material of from tobridges, saving twenty
cent, be effected. lt is in-fforty per may easy
to that this will bedeed say advantage entirely
swallowed the effect of of tem-up by changes
increased labor of or addi-erection,perature,
notional cost of but amountworkmanship, by
such be esti-of canreasoning disadvantages
indicates amated. Theory large saving,whether or not it can be realized, bemay only
determined trial. Other nations have builtby
and are continuous and theirbuilding bridges,
has not shown that theexperience yet system
is inferior to that of The inter-single spans.
nowest Americanprevailing among engineers
in the recentand the fact that at somesubject,
let have been offered for abridge tings plans
continuous seem to that theindicatestructure,
will also be tried here.system
This little book then be of val-may perhaps
ue to as well as to studentsbridge engineers,
in general.
M. M.
New 1876.Haven, Conn., July 10,