Omaha daily bee., 1897-05-02

ton for the New York end of the bridge,
was awarded. However the old saw which
says, "a thing begun is half DONE seems
to apply with especial Appropriateness to the
building of great public works such as this,
and it is confidently asserted that the bridge
will be finished and opened to traffic within
q year after the opening of the twentieth
century.
bridge. may be called a bridge expert. At
any rate, several of the greatest engineering
triumplis of recent years. in bridge cohstruc-
ton were planned by him and he is to be
classed well up among the half dozen men
who are the leaders of American engineers
in this line of work. In this statement the
word American might just as well be re
placed by THE world" for il is a fact that
in the essential points of economy, llSht'
ness and up-to-date construction Americans
lead the world in building bridges. Besides
the great spans already built in this country
across the East river, the Niagara, the
Ohio and the Mississippi, American hrms
and American engineers have constructed
giant bridges in Mexico, Australia and sew
eral South American countries, lncluulhs
Peru, where is probably the highest bridge
in the world. In a number of these enter
prises. both at home and abroad, Mr.. Buck
has been the engineer, and 1t 10 safe 10 say
that there Is no man better fitted to speak
with authority on the subject than he. Wheh
asked recently to describe the constructor
of a great bridge from the engineers polht
of view, Mr.. Buck said:
AN ENGINEERING FEAT.
..Tbe building of an immense bridge must
be looked upon as an engineering feat rathe'
than as a settled business, such, for example,
us the erection of sky-scrapers' Ihe rta
son for this is very evident. In putting up
buildings, the conditions under when the
work must be done vary but little, ana new
problems once worked out are settled 1or
good and all. In bridge building. on the
other hand. one never has the same cohdi-
lions twice over, and the engineers TASK
becomes one of adaptability, while fresh ana
perplexing difficulties must be met ana over.
come at every hand. Still, the general plan
of procedure is in all eases much the same
10 begin with, in any given undertaking
there are certain fixed conditions anu TO-
quirements that cannot be departed from
The bridge Is to be between certain poIh'si
therefore. II must be of such and such q
length. II is to carry a certain III
amount OF traffic: to have so many tracks,
drives and pathways, That practlcally ae-
cides its width. 1t is to be cantileVer or
suspension, as seems most feasible under
the existing conditlons; that settles the gen
eral style OF construction.
'tNNith these conditions as the basis or his
calculation. the engineer sets to WORK 10
figure out his plans. Since the bridge is TO
TO. be SUSPENDED by huge caples, ne oec'u u
what is. 10 his mind. the DETECTION OF the
cables. or 'Yersedsine,' that Will give the
greatest frmness, durability and sustaining
power. The answer to this question mas It's
effect on the appearance OF the completed
structure. For example, In the rev East
river bridge the cable loop will fall away
from the overs more sharply than In the
Old Brooklyn bridge. The middle portion OF
the bridge must be 1876 feet above high
water, so the towers will have to 1886 feet
high TO get the proper detection. The next
point to settle is the carrying load OF the
cables. Having fixed upon a certain form
of steel construction for the platform of
the bridge, the weight per foot of the sus-
pended superstructure can easily be de-
termined. Then a certain live load Is as
from the best obtainable estimates,
and, with these two factors, the necessary
power OF the cables Is settled.
OF course, In making these estimate every
thing Is taken into account. such as the ef-
feet of the temperature ON the cables, and a
margin Is allowed. as In all these estimates.
'Havlng advanced TO this point, 1t is pos
sible to determine how much weight will
come on the towers, and this settles the in-
portant question of how much foundation
Is necessary. The size Of the anehorages
IL determined by the pull OF the cables, and
with anehorages and foundations completed
your bridge Is done"
although the rearing OF an immense bridge
pounds a simple matter under this modest