The herald and news. [volume] (Newberry S.C.) 1903-1937, 1904-06-28

per square inch.
On the sheets herewith submitted,
showing calculations, I have in
large figures given the actual stress
per square inch called upon by the
various girders to resist, and also the
factor OF safety.
As to Mr.. Wilson's Calculations.
AS stated to you verbally, it was
my intention to make also compare
tive sheets of Mr.. Wilson's calcula-
tions and my own, substituting only
! The sizes of members which |, by
examination of the shop detail draw
ings as we'll as by actual measure
ment OF the work in place. found to
be incorrectly assumed by Mr.. Will
sons calculations. But I consider this
not only unnecessary but to no pur-
pose, as it appears that not only are
the sizes used by Mr.. Wilson wrong.
but in his calculations he has ignored
important rules for the application
OF the loads and stresses and it is
very difficult to analvze his compu-
tations.
I shall therefore. for the sake OF
comparison. only show wherein Mr..
Wilson differs from actua. facts as
to the sectional area of the different
girders. From what source he has
obtained these sizes cannot determ-
inc. They correspond neither with
original or revised designs nor with
the show drawings or with actual
measurements of the work in place.
In this connection I beg to call at
tention TO the fact. that I in every
single instance found that actual
work in place is strictly in accord
ance with the shop detail drawings,
but that these have not been prepared
in accordance with the design furn-
ished the architect by the American
Bridge company. .
In the table attached I have thus
shown three different sets of sizes
for each of the main girders. 1t will
be seen that the sizes assumed and
used by Mr.. Wilson in his calcula-
tions are materially smaller than the
actual sizes taken from measurements
OF the work in place. which have. OF
course. used in my calculations.
Not Seriously Overloaded.
Those tables alone are sufficient to
disprove the correctness of Mr.. Will
sons calculations. and show that he.
by his own methods. would have OBJ
tanned very different results had he
used the, correct hange areas.
My calculations furthermore dis
prove. with no uncertainty, the state
ment that the girders are seriously
overloaded and show conclusively
that in no. case is the factor Of safety
less than 3.13, in some cases more
than 4: and in every instance. there
fore, are the stresses we'll within the
elastic limit.
AS regards the stone bearing
blocks under north end of girders
No. or CT, these are the only parts
of the supports of the dome which
warrant criticism. And yet they are
within safe limits under ordinary cir
cumstances. The reaction at north
end OF girders is 100000 pounds. This
should be considered as uniformly
distributed load, because the base of
the girder is so wide that it nearly
covers the clear span OF the stone, if
this be considered as a beam SPAN
ming the hues. The stiffness of the
girder base makes it even quite per-
missible to assume that the load
would act on the stone in sheer rath-
er than bending. But considering
the worst case that under the cir
cumstances could exist. that Of a
, oeam with total load applied as uni
| formly distributed, the calculations
show that the sound stone has fac
tor of safety of over 2 I-2.
The possibility of danger on the
| side whore the cracked Intel oecurS