Republican news item. [volume] (Laport, Pa.) 1896-19??, 1906-07-19

STEEL CONCRETE BRIDGE, PLAIEWELI,
MICH.
when beautiful bridge is suggested
we take alarm at the cost and are apt
to decide otfhand that the older type
without its good appearance is well
enough
This is u phase of the subject that is
very pertinent, whether it should be de-
plored or not. 1t is only by reason Of
this careful consideration of cost that
our country is able to compete with
European countries in the construction
of bridges in foreign dependencies. 1t
has been said that any fool could build
bridge if he had money enough, but
it takes an engineer to do it econom-
ically.
This matter Of cost has compelled us
to limit the construction of stone arch
bridges to very small number and to
put in their place a metal truss of
straight lines and sharp angles. 1t is
not that we have failed to appreciate
the beauty of the curved arches, but
ury when we needed so many of them.
Thirty years ago our bridge builders
were crying the need OF reform as to
aesthetic design but had 10 offer us in
place of sham decorations only the
simplicity and harmonious construction
of Il well built truss suitably painted,
and there can be no doubt that great
In, hac Tho
sheet iron denominations which covered
up the outlines Of the truss and which
were what Ruskin would have called
Constructed decorations have been
abandoned, and the bridge is left to
depend for its beauty. on the noble lines
of strength and the general symmetry
Of its construction.
AS progress has been made in the
building of our roads so have we moved
forward in the design of our bridges.
For many centuries cement and broken
stone have been used to replace the eX-
penSive cut stone in arch construction,
but only recently have we succeeded in
surmountng Il difficulty long recognize
ed. Concrete is building material
generally accepted when it is to be sub
iected only TO compreSSive force. 1t
lacks sufficient strength If any pull or
tension is applied. This fact has SO
limited us in the use of concrete that
only in rare instances has il been eco
nomical to use it in bridge construc-
ton.
A feature that requires careful con-
4 - 4.
neering structure is The effect of the
changes in temperature upon the ma
terial used. The fact that steel and
concrete are affected in the same way
and to the same extent By heat first
suggested their use in combination
This idea has been Geyeloned now /"
such an extent that we are able to VS.,
the steel to resist III" tension IN Oal
structure and the concrete to take care
of the compression and to 50 design the
whole that there will hr Il sul.!gicu!
amount OF each material AMI yet 40
expensive waste. We have found the
stone arch too expensive ana the ,,ce!
truss lacking in beauty Combine the
two, ana the result is the s;ccl-conc"cte
arch having the requisites as to beauty
and comparing very fayorably rs to
cost.
When one is considering the construc-
ton of Il bridge several points should
be conSidcred
First That it shall answer the utl-
itarian purpose for which it is wanted.
Second.-it should be "A monument to
the progressive ideas of the community
and serve as an education and an in
spiratio to others.
Third.-It should be built for the fu-
ture as well as the present, and its per-
mauencc should be assured.
These can all he met by the use of
steel concrete
Revising the Digest.
Several changes In the digest OF our
Order were reported To the national
grange by the committee appointed n
year ago for this purpose. The sug-
gested changes are to be printed in
connection with the section or para
graphs cs which they form part and
then sent to each state master for his
consideration. At the next meeting Of
the national grange the committee Will
present It's final report