Wheeling register. [volume] (Wheeling, W. Va.) 1878-1935, 1892-03-11
THE BIG BRIDGE ARCH
SHOWS NO SIGNS OF FURTHER SETTLE
MENT.
Another Set Of Levels Taken Yas.eriay-Ihe In
melso Strength Of ,he SUaciure-A Cor
responder, Answered.

The surmiSe Of those familiar with
the stone bridge arch, that further
slight settlement would be shown yes
terday, was not a well-iounded con-
lecture.
Engineers Hoge and White took an-
other set OF levels yesterday proceed
ing with the utmost care, and they were
gratfed TO find that there had been no
change in the arch in the twenty-iour
hours elapsing since the levels Of We'd
neSday were taken. This showed that
the arch had settled permanently into
place during Tuesday night and We'd
nesday morning, and that no further
change was 10 be looked for, from this
time on. During yesterday evening the
engineers worked up their data, aud
found that the average settlement Tor
the crown az the arch, after the With
drawal of the centres, was l.9Sh Inches.
The settlement Of the east key was 2.Ol6
inches. aud OF the west key, 1856
inches. The average Of the two is thus
.0l4 OF an inch short of TWO inches,
which, iu modern par.ance, breaks the
record for long stone arches, through
out the world.
Engineer White said, last night
II have made some interesting calcu-
lations concerning the arch. For in
stance. hud that change in the tenn
perature OF 100 degrees, the extreme OF
our climate. which runs from about
zero Ia winter % 100 degrees in the hot
test summer, will make a difference Of
Ia toll inches In the length 0f the
arch. In other words, the expansion
OF the stone will have the effect Of rails
ing the crown in summer, aEd depresS-
Ing 10 in winter. 7 suppose the
crown will rise nearly an
inch. ON hOr day i'm
midsummer. above its level to-day, with
the mercury az 20 Another interesting
calculation is iu regard 90 the pressure
upon tine arch stones. The pressure
upon the sides OF the sheeting and ring
stones of the arch is about $50 pounds
per square inch. or 1866 tons per square
foot. There are some stone 6X6 feet,
and they thus have 10 SuStaina pressure
of 1916 tons This is something ire
meudOus, and fully answers the
query sometimes heard among spec
tators, OF 'what makes the centre
stones stick up there. This tremen-
dous pressure would hold them. even il
they were not an integral part OF the
arch, and each q segment of circle.
Given a properly propOrtioned and
weighted arch. such as this, and the
stones iu the crown are just as secure
and tight as those lower down towards
the abutmeutS.
What weight is the bridge calcu-
lated % stand, in the shape Of what is
technically known as live iOad?'
Anything which can possibly pass
over it. Any moving weight which will
ever be upon the bridge will be insight
fcant. Live load is an important con
sideration i'm an iron or steel bridge,
but 10 does not figure i'm this case.
Trains Of loaded freight cars could be
run over 10 with perfect safety. Its
too massive TO ever be affected to any
appreciable degree by any weight
liable 10 be placed upon it,
when viii the timber centres be
taken away?'
AT once. All the sand was scraped
out OF the boxes yesterday, and the
work Of removing the timbers will COM
mence tomorrow. They will be clear
ed out as rapidly as possible