, 1880-02-15

stable OF FRED Rooms, EaSt " aluut FLA, "ao
burned tonight, and four horses perisnea IN
Meyers was damaged. Loss estimated at
S2,5oo; fully insured.
WHY THE TAY BRIDGE FELL.
Glaring Errors In Its Construction,
scamped Work, and Neglected Pre-
cautions.
Edinb,sry Scotsman. Jan g.
At the general meeting Of the twenty-thlrd
session of the Institution of Engineers ana
Ship-Builders in Scotland last night Mr. st.
John Y. Day, c. E., F. R. S. E., read paper
on "The proposed bridges for carrying
the North British Railway across the
Firth Of Forth, with some remarks on
the structure and cause ct me ,at iall
bridge was due to Tie pressure Of the train
upon it when the gale had reached point Of
high intensity. Nor could he give any credit
to Sir 7. Bouch's, theory that the oyerbal~
t seemed to him that the cause was in the
pillars. The structure OF these columns was
singularly at fault They had to carry the
permanent .'dead load, Of the bridge and ID
legs or struts forming the boundaries
| Of the elongated hexagon was straight
throughout its entire length, the outer leg
Or two feet in the eighty-two feet columns
Then these legs OF struts carried at their top
a triangular box girder, and the main glrder
rested midway between them. 1t, would
therefore be seen that the single outer col
umns Of the three at each side of the hex
agon had the same load to carry as the. two
| inner legs carried together. One.half, there
fore, Of The s.dead " and ''liye" loads Of that
partof the bridge was carried by the two
outer endward columns Of the hexagonal
number Of colums-these, furthermore,
being vertical-to carry it. A more errone-
Gus disposition Of the load itwonld be dildcult
to produce, for the two outer raking columns
had twice the work of carrying the girder to
do Of each Of the four inner ones. It was
true that the outer columns were, eighteen
inches in diameter as compared to the
inner ones, which were sixteen inches, but,
favorable position to resist; the downward
stress Of the load. Had the load been placed
on the four intermediate columns, and the
two outer ones been used for shoring-up the
structure against lasera @ wind ,,1 pressure 1ne
ment Of stability; but, the original design
having been departed from, 1t became l1npos-
sible, with the loorage over which the braced
proper distribution Of the load, for in CON
could produce sufficient width OF pier-head
for carrying. the highest girders when
founded on the ashl caps OF the dimensions
with which the submerged portions Of the
piers were finished. 1t is not to be forgotten,
either, that the triangular box-girders on
which the main gfrders rested were not tied
together. and that If they had been connected
with other ,cross..girdeTs so as to form
columns, the stability Of the bridge would
have been enhanced. He noticed in examin-
ing the columns that provision had been
made for the Introduction OF three ties OF
deep iron girders at tab0ut equal Intervals IN
the hight Of the columns, which would
have added to the stability Of the structure.
These girders were Shown In stu in model
in the Dundee Museum, and they might vel!
structure.
With regard to thosepters which carried
the girders on either side of the highest por-
ton, there also was a glaring oversight III the
use Of material to the best purpose; Inc SIX
ing the upper ten-feet lengths. Of the two
outer columns, which were inclined inwards
until their heads came in line with the heads
Of the two other columns, and stralght
be gIden Fesa S npoS M sonG be- Morse
than this arrangement of these outer
struts to resist the pressure Of the
wind, that being further ag gravated by
the absence OF any direct crosS-tles at
AA1V thA64Cs LAC HC<A1AIok PoAIAoa ~ ~AAoN
umns, The bracing Of the columns was de-
fective, and the holes in the fanges Of the
columns were much too large Tor Il me Dolls
Another source Of weakness was the 1nsunl-
which The iron columns we're attached to the |
pier-heatls, as they only extended through |
the first two courses Of ashlaI. Ihey were
told that these cast-iron tubular Legs
was was next t'o to imp impossible that such a
cast-iron tube with hard concrete core |
would resist the stress Of contraction to Whlch |
it would be exposed. t appeared to MN,
IRON an Of e Gers
ly be doubt but thata number OF these tunes
were burst II so, then during the last
twelve months the iron superstrncture 0t the
bsidge must have been in rickety condltlon,
he eaie S occurred. occur ed The filling Of such col
umns with concrete for the avoWed PURPOSE
Of protecting them from rust without the use
Of paint had been q fatal mistake. 49,
Then care did net seem t3 e. haye fS;enesa nes9
Of the metal Of which the legs OF the PIERS
were formed, while it was clear that they
had been cast on their sides instead OF their
ends under the pressure OF nlgn g;S;t,! S9+uma an
that it was not even probable, therefore,
that all the columns we're sound: lie IS IN
clined to the opinion that it was the northern
end Of the bridge which first gave e. WY; :
girders were iointed together in sets OF
ffours, that ai tie aS middle joint they, we're
boIted down to = pier-head, az and d. that lat
the northern end simply rested without an
attachment on box-girder at the end M 0f the
northern section Of The structure. With
strong wind blowing he had obseryed the
floor Of suspension bridges lifted, and IN
view Of that with gale acting on the west
them, with a leverage from the fixed middle
joint Of 49o feet it was reasonable to Suppose
that the lifting effect thereof on tl!e uhaer
side Of the floor of the girder would SO re-
duce the insulent weight thereof on Its rest
ing points that the friction by which u re-
sisted lateral movement was thereby muca
aednced re- and facility aftoIdefa ior tufnins ~
Old Men In New York.
Ns4p York Times. |
Many of the most responsible places In firms
and corporations arc held by men OF ~ o. mere tnste-
abouts, and they eyince no dtspos,non 70 fg.1te,