Evening star., 1922-02-06
FINDS ELEMENTARY RULES
OF ENGINEERING SLICHTED
CONTINUED From First Page.)

heads of the audience would have re-
suited.
In figure the double lines indicate
the six roof trusses, while the single
lines indicate the steel I-beams or
girders connecting with the trusses.
Four of the trusses connected at one
end Of each to the main truss. No. IL.
One truss. No. 16, extended from the
east wall to column No. 5. The main
truss, No. IL, was at right angles to
the other trusses, and it's north end
rested upon the curved wall on the
Columbia road side of the building.
Its south end was supported on the
upper end of a column (No. y, at the
level of the ceiling. This column, un-
like column No. 8, did not extend to
the roof, but stopped at the level of
the suspended ceiling, which was
about six or seven feet below the
roof. ...-,
Supported by Vertical Strut.
The three roof girders meeting at
the point over column No. 2 were
supported by a vertical strut, con-
which strut stood upon the bottom
chord of truss No. II. directly over
the top of column No. 2. 1t should hs
observed that there is no steel me m..
ber extending west from the end OF
this strut. This strut was supported
dollhouse" fashion, not being rigid
ly connected at its base and not con-
nected directly to. the column below,
contrary to accepted practice. See
figure s.
Truss No. IL is the one which ap-
pears in the various photographs of
the interior taken since the collapse.
1t is altogether, but has q bad break
in it's upper or compression fange.
This break is evidently due to tension
developed by tremendous side pull
which probably came with the general
collapse, rather than being tie cause
of the collapse.
Figure is a sketch to larger scale.
of the top Of column No. 3 and shows
the relative positions of the four roof
members connecting at this column.
Perhaps it is well here to call atten-
tion to the fact that all of these con-
neCti0nS were made with loose hitting
bolts instead of rivets: 1t may be
permissible to make steel connections
spans, but good practice dictates the
use of field driven rivets in the con-
nections for work of this character.
Where bolts are used the number
should always be greater than would
suffice for rivets, which is not the
case here.
Figure is an elevation or side view
Of a part of the connection shown in
plan in figure 3 This shows that
the twelve-inch / beam "B-41 was!
connected in a most flimsy fashion to
it's support. which was a short section
oh I've
an inch thick, standing on angle
brackets, connected to the column.
The upper fiange of this channel was
not fastened to the column in any
way, so that a very slight movement
of beam Bal" would certainly cause
the web of the channel to fold over.
bending near its bottom fange. and
this is just what did shappen to this
channel support. as shown by dotted
lines on figure 3.
ing beams and the angle strut above
column No. 9. The west end Of beam
Bill" was connected by bent
plate bolted to the 10-inch. channel.
Figure D shows a side view of this
connection to the west end of Bal to
the 10-inch channel. This connection
was made by six bolts through. the
bent plate and the web of the chan
mel, and this connection is still in-
tact in the wreckage.
Only Three Belts Garry Load.
Figure shows the connection of
this same 1o-inch channel to the ver-
tidal S-inch by 4-inch angle. by
means of three bolts Notwithstand-
ing-the fact that the load from Bal
was delivered to this channel by six
bolts and that the channel was also
called upon to carry in addition a
considerable area of the roof. only
three bolts were provided to. trans
nit all of this load to the supporting
angle. During the collapse this
channel was torn away from the an
gle support and one bolt head was
pulled clear through the thin steel
web of the channel.
Referring back to figure 1 it will
be noted that in case any force tend
ed to disturb the equilibrium of the
point of support over column No. 2.
and cause a movement Of B-41, there
was no member extending, westward
ly to resist such force, but the slight
est movement of Bal would tend to
upset the light angle strut, which
rested so insecurely on top Of the
truss below. : -
Figure Z, drawn to scale, shows the
relative positions and the Embraced
condition above the balcony of col
umn No. 2. and also of the angle
strut above it. When first erected
there was. no member in the plane
Of the ceiling between columns No. 2
and No 3, but this critical defect was
discovered. doubtless because column
No 2 would not stand alone and had
to be held. even temporarily. Conse-
auently the ten-inch ] beam strut was
provided at the ceiling level as shown.
This was not rigidly connected to the
truss, but simply connected by two
bolts to the f1ange of the truss
through a flat plate.
Splice Plates Ineffective.
Columns No. . and 3 were each
spliced, above the balcony level to
similar columns which extended from
the foundations up and through the
balcony framing. These columns
were more slender for their lengths
than good practice warrants. The
connections between the upper, and
lower columns was entirely made.
auate to develop the bending strength
of these columns and when subjected
to forces tending to move their top
iateraIly they simply broke away
from the ineffective splice plates, just
above the balcony.
Figure g shows the manner in
which the main truss was connected
to the top" of column No. O. sketch
(a) of figure s. shows the top OF
column 2 as looked down upon, when
it was in position. The four lug
angles on this column were pre-
sumably set level and flush with the
top of the column section. which was
cut SQUARE to the column axis. How
ever, it is practically impossible to
riyet sfour lug angles onto q column
in perfect alignment and one or more
will be found a little too high or
iittle too low or slightly out of