CYLINUIPICAL SUFAIR SPECIMEN FOR
(NAM,' CCN1TCL HST (A GLUE
113CNIDS I IAMINATUD TIMULPS
ti)
e0
November 1962
No. 2259
CY)
C/)
11111111Iiiiiinui
iiIiiimmumw
FOREST PRODUCTS LABORATORY
UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE
MADISON 5, WISCONSIN
In Cooperation with the University of Wisconsin
CYLINDRICAL SHEAR SPECIMEN FOR QUALITY CONTROL TEST
ON GLUE BONDS IN LAMINATED TIMBERS!
By
M. L. SELBO, Chemical Engineer
2
Forest Products Laboratory, — Forest Service
U.S. Department of Agriculture
Synopsis
The quality of the glue joints in laminated beams can be evaluated by removing
round plugs (with their axes perpendicular to the glue lines) from noncritical
areas of the beams, such as the end trims, and testing them in shear. A
standard block shear tool was modified to facilitate testing glue joints in
round plugs, and comparison of results from such plugs and standard shear
blocks are presented. Pros and cons of the test are discussed.
Introduction
A cylindrical specimen and a method to test it were developed at the. Forest
Products Laboratory to meet a need that sometimes occurs for making tests
on glue joints of structural laminated wood members in service. This test
also offers considerable promise as a method for quality control in production.
Because of improper exposure during erection, severe drying conditions
after enclosure of the building, or other causes, checking and joint separation
1
—Presented at the Symposium on Timber--A Tested Material for the Engineer,
Fourth Pacific Area National Meeting, American Society for Testing and
Materials, October 3, 1962, at Los Angeles, Calif.
—Maintained at Madison, Wis., in cooperation with the University of Wisconsin.
Report No. 2259
sometimes develop on the surfaces of laminated timbers. When joints separate
an appreciable amount at the surface, the quality of the glue bond in other
parts of the timber is always questioned, and a need for some means to determine this has been evident for some time. It should be kept in mind, however,
that surface checking in the wood is no indication of weak glue joints but
rather the contrary; careful examination, often by use of a magnifying lens,
is required to distinguish between joint separation and failure or checking in
the wood.
As a possible solution to this problem, the Forest Products Laboratory has
developed a test by which a check on the quality of the glue bond in various
parts of a laminated member can be made without impairing the structural
quality of the member. For quality control, the specimens could also be taken
from the end trimmings that usually are removed in squaring up the ends of
the members. Cylindrical shear specimens of various types have been used
previously,1, 4 but none of them appeared applicable to this particular problem.
Description of Test
The method is a modification of theglue block shear test (ASTM D 905-49).5The major difference is that the specimens used are cylindrical, about 1 inch 6
in diameter, and with the glue joints perpendicular to the axis of the cylinder.
The shear tool used in most of the development work was a modified glue block
shear tool (figs. 1 and 2). The movable and stationary members that apply
the shearing force have cylindrical holes of about the same diameter as the
specimens. These holes coincide with each other when the movable shearing
member is in the correct position for insertion of the specimen. Figure 2
shows a specimen in the shear tool ready for testing. The plane of the glue
joint must coincide with the interface between the stationary and the movable
shearing members. This was accomplished by making a fine pencil line on
3 Twiss, S. B. and Clougherty, L. B. A Disk Shear Test for Adhesives.
ASTM Bull. Sept. 1958, p. 57.
lithude, M. J. A Survey of Methods for Making Shear Tests of Wood. Thesis
submitted in partial fulfillment of the requirements for the Degree of Mas ter of Science (Civil Engineer), University of Wisconsin, 1950.
...American Society for Testing and Materials. Test for . Strength Properties
of Adhesives in Shear by Compression Loading. ASTM D 905-49.
.-A
6 n earlier description of the method was published in the February 1962
issue of the Forest Products Journal (Vol. XII, No. 2). Some important
modifications in the method have been made, however, since the earlier publication.
Report No. 2259
_
OOP
•
the periphery of the specimen, parallel to the glue joint and at a distance from
the joint equal to the thickness of the frontal shearing member. When the specimen was inserted for testing, this pencil line coincided with the frontal face
of the front shearing meinber. A small block of steel of exactly the same thickness as the frontal shearing member, and with a hole through it of the same
diameter as that of the specimens, was used for marking the distance from the
glue line equal to that of the thickness of the shearing member on the specimens.
The direction of the shearing force must be parallel with the grain direction
of the adjoining laminations.
,Cylindrical Plug Cutter
Various types of plug cutters were considered, and three types were tried.
The one that produced the plug having practically no cutter marks or torn
grain is shown in figure 3. This cutter is available commercially in sufficient
length to produce about a 2-inch plug. To produce plugs about 4 to 5 inches
long, this cutter was cut at the base of the half cylinder, and a cylinder or
barrel extension was welded to it (fig. 4).
The inside diameter of the plug cutter measured 1.015 inches. A number of
plugs that were cut from laminated Douglas-fir and southern pine at approximately 12 percent moisture content were measured for length of diameter
along and across the grain. This was repeated on plugs cut from materials
that were at about 6 percent moisture .content. The results are shown in
table 1 The plugs averaged from 0.001 to 0.002 inch less in diameter than
the cutter except for those cut from the pine at 6 percent moisture content,
which averaged the same as the cutter. The ranges were from 1.013 to 1.015
inches for the individual pine specimens and from 1.012 to 1.014 inches for
the Douglas-fir specimens.
The plugs were cut with a drill press, and various cutter speeds and feed rates
were tried. When the cutter turned at 295 revolutions per minute and with
axial feed rate in the range of 0.004 to 0.020 inch per revolution (equivalent
to a cutting speed of about 80 feet per minute), the smoothest plugs were obtained.
Reasonably smooth plugs were also obtained at 475, 715, and 870 revolutions
per minute with feed rates of 0.004 to 0.020 inch per revolution. Slight burning developed on dense wood at 870 revolutions per minute, and at 1,335 revolutions per minute both burning and rough plugs resulted when dense wood
Report No. 2259
was involved. The smoothness of cut will vary somewhat, depending on the type
of grain involved, and a few trials may be required to obtain the smoothest cut.
No portable equipment was developed, but this would be needed for taking plugs
from laminated members in service.
Comparisons of Shear Results from
Shear Blocks and Round Plugs
Two Douglas -fir boards and two southern yellow pine boards 1 by 6 by 24 inches
in size at about 12 percent moisture content were laminated with phenolresorcinol adhesive, using a 2 -minute assembly period. Similar boards were
glued using 45- and 90-minute assembly periods. The entire procedure was
repeated with casein glue on the two species. The extremely long assembly
period (particularly for casein glue) was used to obtain borderline or inferior
glue-joint quality. Both types of adhesives were cured at about 80° F. for an
overnight period. The laminated boards were allowed to condition for 1 week
at 65 percent relative humidity and 80 F. Equal numbers of shear blocks and
round plugs were then cut from the glued assemblies in such a way that each
plug was cut next to a shear block, both across and along the grain, thus
affording both end and side matching.
A universal testing machine (fig. 5) was used for both the block and cylindrical.
plug shear tests. The rate of loading was 0.015 inch per minute.
The results are shown in tables 2 to 5 inclusive and indicate that the shear
strength obtained with the round plug is somewhat lower than that obtained
with the standard glue-shear block. The averages for 20 specimens ranged
from 0.85 to 1.00 in the plug-to-shear block strength ratios. In slightly more
than half of the results, the standard deviation showed greater variations in
the data obtained with the plugs than, in the data obtained with the shear blocks.
The average estimated wood failures were generally in reasonably good agreemenu between the two types of specimens, particularly with the resorcinolglued material.
The causes for the generally lower shear strengths that were obtained using
the plugs were not investigated in detail. It is possible, however, that less
pure shear develops at the glue line with the cylindrical plug than with the
shear block because of the slight tolerance required in order to be able to insert the plug. Because of this tolerance, together with the compression of
the wood under the shearing members, the axis of the specimen and the axes
of the cylindrical holes into which the specimen is inserted may be at a slight
angle with each other at the time of failure. A couple about the glue joint,
Report No. 2259
-4-
consequently, will occur that exerts a certain amount of tension perpendicular
to the joint. Since wood is weaker in tension perpendicular to the grain than
in shear, this couple action could contribute to the lower shear values obtained with the cylindrical specimen.
A couple action develops with the shear block also, but might be less pronounced than that associated with the cylindrical plug specimen. The thickness of the movable shearing member was about 1-5/32 inches and the thickness of the stationary member was about 31/32 inch. The use of thicker
shearing members than these would result in less disalinement between the
axis of the specimen and the axes of the holes into which the specimen is inserted.
In an attempt to reduce the couple action and to simplify the alinement of the
glue line at the interface of the two shearing members, the shear tool was
modified as shown in figures 6 and 7. (Figure 8 is a line drawing of the tool.)
By means of the locking device shown on the front of the shear tool the specimen can be held securely in position, thus keeping the axis of the specimen
more nearly in alinement with the axis of the holes.
A group of plugs were tested in the modified shear tool and a group of shear
blocks, end-matched and side-matched to the plugs, were also tested. The
diameter of these plugs were about 1.003 inch, slightly shorter than for those
used in the previous tests. The results of the shear tests are shown in table
6.
Again, the average shear strength was somewhat higher when the standard
block test was used; the difference between the means was significant at
the 2.5 percent level, but not at the 1 percent level. The ratio of the average
plug strength to average shear block strength was 0.92, which was also the
grand average ratio for all tests made before the final modification was made
on the shear tool. It is believed, nevertheless, that the locking device is a
definite improvement on the shear tool, particularly when the plugs do not fit
too snugly (in the final tests, table 6, the diameter of the plugs was about
0.010 less than in the previous tests).
The opening in the top of the fixed shearing member greatly facilitates the
positioning of the glue line at the interface of the two shearing members, and
appears to be a definite improvement in the ease and speed with which the test
can be carried out.
The difference in the height of shearing area between the two types of specimens could cause or contribute to the lower shear strength developed by the
Report No. 2259
-5-
cylindrical plug. Johnson and Larson 1 found a reduction in shear strength of
about 10 percent in Douglas-fir when the height of the shearing area was
reduced from 1.5 to 1 inch.
Lower shear strength values are apparently obtained with a 1-inch-diameter
cylindrical specimen than with the standard glue shear block. This does not,
however, make the cylindrical specimen unsuitable for evaluation of glue
joint quality. For such an evaluation, the amount of wood failure developed
is equally important. In general, no consistent differences were found in the
amounts of wood failure developed by the two test methods.
Discussion of Test
A larger shearing area would be expected to give less variability between
individual test results, but it would also require that heavier tools be used
for cutting the plugs than were used in these experiments. In some laminated
members or places in laminated members, furthermore, a plug that is larger
than 1 inch in diameter would be detrimental. Hence, it was thought, a 1-inch
plug was a suitable choice.
The suggestion has been made that shear blocks could be cut from the cylindrical plugs. It is doubtful if this would provide a more accurate evaluation
of the glue joints, and it would, of course, reduce the shear area and multiply
the work of preparing the test specimens. An outstanding advantage of the
cylindrical specimen is the speed with which it can be prepared.
A torsion test on the plugs has also been suggested. This may have possibilities, but experience and data would have to be accumulated before the test
would be applicable for assaying glue joints.
Probably many variables or factors might have an effect on the shear strength
in a cylindrical plug, such as the angle between grain direction and the glue
line. Investigations of the effect of such factors would have been interesting
but not necessarily essential to prove the usefulness of this test method.
Furthermore, time was not available for an exhaustive study of the various
factors that might have affected the results.
7
—Johnson, R. E. , and Larson, W. C. The Effect of Length of Shear Area on
the Shear Strength of Wood. Thesis submitted in partial fulfillment of the
requirements for the Degree of Bachelor of Science (Civil Engineer),
University of Wisconsin, 1950.
Report No. 2259
-6-
S
•
The plug cutter that was used was entirely adequate to produce samples for
evaluating the test method. To obtain plugs from deep members, a much
longer tool than this cutter would be needed. It has been reported that another
laboratory is well underway in the development of such a plug cutter, so no
work was done along these lines except that the available cutter was extended
to about 4 or 5 inches in length.
It has also been reported that accelerated soaking-drying tests on increment
cores from laminated members have been carried out by another laboratory,
hence it was decided to limit this investigation to evaluation of the joints by
shear tests.
Conclusions
The test that was developed--shearing of glue joints in cylindrical plugs-appears sufficiently promising to be used, where it becomes necessary, to
make tests on glue joints of laminated members in service. It also a.ppelrs
to have possibilities as a rapid test method for use in quality control.
When the test is properly carried out and high wood failures and shear strength
are obtained, there should be reasonable assurance that the joints are of good
quality.
A portable drill could probably be modified to operate a plug cutter under
field conditions, but no work was done to explore this phase of sample cutting.
Report No. 2259
-7-
2.-20
Table 1.--Measurements of diameter arallel to and across the grain of
Dou g las-fir and southern ine .lugs cut with 1-inch.lu g
cutter at two different moisture content levels
12 percent moisture content
Plug
No.
•
6 percent moisture content
. Diameter :
Diameter
perpendicular : parallel :
to grain
: to grain :
1P-
2P
•
Plug
No.
•
Diameter
: Diameter
perpendicular • parallel
• to grain
to grain
In.
In.
In.
•
In.
1.014
•
1.015
1P
1.014
•
1.014
1.014
•
1.014
2P
1.013
•
1.015
3P
1.014
:
1.015
4P
1.015
•
1.015
5P
1.013
•
1.014
1.014
•:
1.015
•
1.014
•
1.014
3P
1.014
1.014
4P
1.014
1.014
•
•
5P
1.014
1.014
•
1.014
1.014
Average:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
10-
1.012
1.013
2F
1.013
1.013
3F
1.014
1.013
•
1F
1.014
2F
1.013
1.013
41?
1.013
5F
1.013
1.014
3F
•
•
4F
1.014
5F
1.014
•
•
Average: :
1.013
P indicates southern pine and F indicates Douglas-fir
1
Report No. 2259
1.014
•
1.014
'0
Cu
4)
5
,4
i)
0
1 .-4
114
p.
u
03
W
Co
to
cd
a)
.i.)
0
r4
4J 0
00
0 no
"O
••
•
0
•rI
W
co
›,
O
P4
az
u)
cd PO to
.4.) 1.4
Co a) to
0 ca
mi
14 a)
'
13
to •ri
w
w 0 )4
Co
4 A w
44
co
"0 44
44 W •4
4+b
CC,
Ca 0 CU
Co
4.►
Co
ar
14
•o
o
u)
Co o
14 a W
r
4
CO 0
a
Co
04
•• ••
W
0 un un un
CO r- 04 VD
0InIn 0
•r-1 0 N-4
4J
CC)
r-4
Cn
43
44
14
Cd
a
O
4
C/3
4.,
H 00
al 0
W (1)
.0 P
tn 4-)
O
M.
•
04
•• ••
0
w
cd PO
0 0 •--1
4-)cp
Co
44
04
•• - • . • ••
4.)
6;4
1,4 00
CO 0
w w
4
,4
tI 4.)
N•
CO
ng
("4
41
tri
o .-0+
4.1
44
CO
N.
qo
N.. 0 N.
CO 4J
to
Report No. 2259
u1 Ul CD ul
C) CD un CD
r-4 01 1-4
r4 C,1
rA Ul r4 QD
C)
0 VD VD vO
01 r4 rA OD
A A A
^ rarl'
r-4
CD Ch CD Ch
e-4
•• •• •• ••
In In
in 0
0)
CO CO 0,1 0
A w
•
•
•• •• ••
,4
H
r- r,
r1
.1 c4 m0 0
r.4 r4 00 01
A .
r-I r-I
00
H
rA
H
rl r-4 ra H
In In in 0 in
CA CD
0)0)0
r4
H
4-4
H
•• •• •• •• •• •• •• •• ••
•• •• •• •• ••
0)
M
c4
CD
H•
Ch Ch CM OD
ft
r-I
•'
••
•
•
••
•••
•• •• ••
r,
r...4 04
0.4 cm .4 mD
C) CV ul CD
4 cm q) 4
r4 Ch CD r♦
A
w
A
A
4-4
•• •• ••
•• •• •• ••
OD OD r4 CD
r-1 en C.4 .4
OD C4 CM r4
r^I HH 0
4 cm 4 4
C)ACD
CD H
A A dus
0)
•• •• •• ••
CA CA CD cm
CD CM CD CD
H
.•
•
U1 Ul .1
Ul CD CD CDcm U1
cr, cm Ch
CD In U1 C) ul C) CD
••
•
•• 414 •• •• •• •• •• •• •• •• •• •• •• s.
N CD Tn 03
•• ••
C4 r,
0►
In
••
••
.•
C) 01 C) 0
c) M VO C4
C4 CD
CDwCDA
. a
1.4 r-4 r-I ra
oo en en r-
••
•• •• •• •• •• do.
•• ••
r, el rl 01
CD P,
• •
••
en T., T, CD
as s..0 0 .4
0 0 C4 r...1
. . . .
•
•• ••
0
H
E'4
CD
r4
In
CT,
0
1'
••
If) In 0 0
C) Ch
0) 0)00`
In Lr1 0 0 0 ,r)
CD cm CD CD CD Ch
0)00)
r4 ra 1.4
H
rA
rA r.4 r4 r.4
000'0'
••
••
N
N
O
A A
H r4 H 1-4 1-4 H H H r4 H
rd r"I
0 .11 0
00 00 qp
•• •• e•
• •
qp
in In 0 0
In In 111 In
•
•
.0 •• •
CA H Ch H Ul n 4 cm cm
VD mD CO , c0
ch eq 4 00 CA 00 04 r4
00 04 1.4 r4
CM r4 Ch r4
n0)01-4
A A A
•
•
•
0)
•• •• •• •• •• •• •• •• •• r4 Itt) c.1
C4 '1') ,t CA
01 0 01 0
I, In 01 00
%AD CM r4
03 C) 1".• 00
H
H
.-4
r4
••
CD 0 111 In
Ch MD
0)0)
CM CM 00 CO
010' ,0 01
••
••
is ••
•• •• •• •• •• •• •• •• •• •• •• •• ••
•• •• •• •• •• •• ••• ••
In CD C) CD
•• •• 06 •• •• •• •• •• •• •• •• ••
••
0 r, 0 el
ol VI MOON'
C)
nnnn
0 -t 04 C4 04 CA
00 CD 1/40 m0 N C4 P., 0' H NI
,4 C4 CD H00n
CD CA C4 Ch C4 CM CD CD rq',AAA
A A A
••
•• •• •• •• •• ••
CO
r•4
0
O
r•4
r-4
•• ••
••
•• ••
••
4.)
0
w
In c) un .1
0)
CA CM
0)0)0)
ul CD Lon CD
O ul C, CD
CD Ch Ch CD 00 CD 0) 0'
H
In C)
CD In Ul 0
CD Cm cm cm 00 ch Ch 00
r-4
W
04
•• •• ••
14
as 00
0
w w
)4
v-4
••• •
••
•• •• •• •• ••
w
$4
rl
(7,
••
••
c.TA
Co
r-
CM OD 01 1..4
OD QD
C4
r4
r,
W
04
W
14
W
00
0
•
•4
Co
•• •• •• •• •• ••
0i4
. ••
•• •• •• •• ••
4
r-4
C) U1 Ul CD
,t
•• •• •• •• •• •• •• ••
In C4 In .1
qD ,t rA VD
CD
CD Ch r4A
.
r-4 r-1
cm c)
0 0'0)0.
4. 0
MD r4
••
••
••
C4 r..4
r,
,-4 qD 0' -
01 h, 01 Ul
Ch H Ch CM
00 CD CO in
••
• OH 0)U0)0)0)
•uO
bt
H
•
,4
M
14
4J
0
4-)
44 1.4
044 w
O
0
C.)
••
r-4 4.)
o
•1-1
•• •• ••
• 4,)
1.4
r-1
. ••
4.1
4.1
34 60
••
CA
H
1.4N
w in 0 in 0
a) .0
c:n 0
r•-•
U
O 0r-4
•e4 o
w
co
44
134
• •
CO
• •
C, Ch op
CD 0 W1 CD .1 Ul CD Ul
04
%.0
CA
en
U1 C) U1 Ul
1/40
a)
04
to.
CO 0
W la)
).4
CJ)
4.1 '4•4 0
Co I r-I
C.)
O
tIj
1-4 .1.)
$ 0,J
0
OC1
••
1,. p. 1... 00
.0 .0 .0 r4
ON
in In Ul CD
W
4.1
00
00 Co
4J a
b c0
U
k
Co
•• •• •• ••
•• •• •• ••
0
Co 14
Po
0
O a.)
'-4
.0
0 r-I
0 .4-I
••
4 ,t 04
In CD r-4
A A A A
I-.
H
r-I
r-4 r-4
4-1
124
O
••
••
.
4:1
43
.. .c: • •
4.)
Po 00
r4
14
.
4-1 3 al
4.4
co
0
.0
0
'0
14 a)
ca
W)
4 a
to
co
C '0
C)
1.4
0.1
Cli
cn
104
Ii .•
Co
•• •• ••
'0)
4.)
w
Co
0
)4
4i
W
cd "O 0
0
O
r-1
. .
CD VI CD CD
VI •-.1 r.... in
Co
0w
4J14
0
.1-1
01
0
os
$.
0 v..4
0 •rl
CO
(4-1
.4
4.)
ID 00
00
JD
e
4.1
xI
af
4.)
CO
41
• •
00
00
4J
0
Co
li 0
to.
••
••
••
r".. r, Ns 1, 1". 11, 0 0 0 en en NM NM
QD .1 QD
C4 4 r,
C4 C4 4 OD 03 CD C4 C4
rA C4 r4 CM
C4 ,4 C4 CD .t0NN 4 00 C4
A A A
It 11.1
A
A A A
A A A A
H r4 r-4 H H H
r4 r4 r4 H H rA ra
F-41
••
•• •• ••
0 0
en r,
H CD H 04
A A w A
H r4 H r4
•
9
w00 01In
r.
0 ul
14 r4
..0
H
W
> ,--4
HIH
4
ro
r
C
o
.4•1 0
4. 1
ca
0
o 41,
41
v-s
CU
6;41 Pcv•
••
•
••
,4
P4
4.1
0a)
44
4-1
44
U)
•• O• ••
r41
Ed) "0
••
••
••
••
••
••
4 el 01 0
4 mD Ch 4
CD CD r4 ch
ft
ft
"
r4
r4 r-4 r4
• ••
'V a)
1-)
00
• •
CD C) In mD
r4
CD CD CD ul
CD CD U1 CD
4 op ul mD
CD CD CD CD
ul CD CD CD
r. op ei ,t
ft
a)$4
4-)co
a0 0
.1-1 0 .1-1
o 4.)
cp on
N e4 el MD
4 Ch ch .0
mD r,
00
• •• •• ••
0
O\
ul el r4
a)
04
44
•• ••
U)
CD
4.1 co
1.4
k
M $-4
r-4 0
.0
ul C) CD ul
w
0
np 00
00
0a)
$4 .,4
4)
0
r-4
4.1
a)
a)
4.)
••
••
. •
••
•P
cyl u1 00
CM QD MD r4
01 CA r4 0
w "
r-1 v•4 r-1 N
op
c4 40c4,
r• 4 r4 4
••
••
••
••
MencOcq
cm 4 mD Ch
00
111
w
r-4
o u1 o ul
N
4 01 01 MD
CD CD ul CD
mD cm ul 0'
N r, Ch r,
w
a)
0
••
Ts to
•
•r♦
0 a)
0).
4.1
0111
•
••
•
••
• ••
4)
4•1i4
0El V
0 r.-1
•4.1,1 0 .14td
4-1
0
a)
••
•/
0 0
1 0) .r4
CU
0 w
00
0
bn
U)
k
•• •• ••
0 ulul
,o op
qp
000ul
ul
1, 0 ,0
ul cp ul ul
N CP ul
rA
•• ••
• • •• ••
••
•• • •
cnenr•
encnor.
rn
CD rn CD rn
N.
N. 00 elf•-•00
ul 01 C11 VD
Cp cm el C4
el 00 C4 4
00 4 ,JD co
CD CD ,t CD
Ch .1 00 U1
r, ch r, r,
CD ul Ch MD
CD 00 00 mD
CD 00 rn Ch
,4 r4 r-1 e4
C4 r.4 1-4 v-4
r4
C9 r• C4 rA 1-4 ,-1
v--4 M v-4 r..1
• .•
•• •• .0 •• •• •• ••
••
•• •
CD
00
CD CD CD
CD ul ul CD
$ P. r, 00
CD Ch .1 O- r4
cp ul
03 '0
q)
ui
r4
•• •io •• •• •• •• ••
Oa 00 •• •• •• 00 •• ••
•• •• •• •• •• •• ••
4
ul
00
vp
r,
c> ul ul
c) c) ul ul
ch 00 r, M0 CD 00 00 00
Cl
r.4
• ••
••
• • •• •• •• •• •• •• •• •• •• ••
•• •• •• •• •• •• •• ••
••
P1
••
.0
'0
,4
a) (1)
ED
C4 ,ID C4 C)
4. MD cm 4
0, 00 0.. Ch
04
v-4 v-4 r-4 r-1
•• •• •• • •
0. •• 60
k
od
a)
g
4.1 o cts
0 id u)
.0
P
CO 4 .1 ca
to
00 4)
0 co
••-1 0
U) a, I-4
•
•
El) 041
.0 C/1 4-4
U)
v4
•
U)
41
a)
04 • • • • .4 ar• •-• 4-0
•I
0)
0)
14
4.)
0
a)
4.)
Et
14 Ei
El)
44 /4 0
041 r-1
at
U) 4-)
0
C)
El)
a)
1 4 U) U)
k Or
0
o
..
ni
E0
cd
c.)
.
El
H
..
r-4
•
r.-4 r-4 r-4 •- 4
r.-4 N r-4 r -1
r...
rA
ft ft .
•6 •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• a)
1:14
•••
1
Et 0 (1)
a)
CO
0 i4
.6/ •ri .0
N y-4 r-I r-I
.
0
po
A
0,
0
1 00
I 0
r4
›N $
I
4) I1
V1 l
a)
0
134
4-1
•
04)
14
0)
RS
44
•••••
••
14
••
I
ma
0
H
•
154
•,1 0 •rd
1.4
Report No. 2259
uJ
VD
0"
00
00r-10100
.
A " . A
ft
.
Fa
CD
••••
.1.,g
N
.
.
4
v.4
r4 r4 r4 r-4
,4 r•4 ,4 ,4
••
•• •• •• •• •• •• •• 60 •• •• •• •• 00 04. •• •• ••
••
••
••
• •
••
• • •• ••
•
N
u1
•• •• •• •• •• •• •• ••
•• ••
*r4
•
U)
••
•• ••
O
co
CD
w w w w
w n n w
r-I r-4 r-1 r• 1-4 r-I 1-4 r4
e•
w w w w
v-4 N r-1
r•4
00
ww
.
4% w
.
r•I v- 4 v-4 v- 4
N-
'0
U,
r•4
VD 0,
00
0
••
ul CD U1 ul CD CD
0U,0
I, CM
N
/0 ft ft
,4 r-1 r-1 v-1
•• •• •••• •• •• .•• •• •• •• •• •• •• •• •• •• 410 •• •• ••
ul cp
W CD ul ul ul CD ul CD ul U, 0U,0
CA 0 01 00 ul .11
o
U 04 CA 0% oo
v-4
a)
cc;
4.)
ca
•• •• •• ••
Cf)
••
•• •• ••
4.)
0
.0 14
01 CD 01 CD
aNN07,
011,01,0
,4 OD r4 N op N N04 r, N O r4 00 ul NVD 4 MD 00 m0 03
r-4 r-4 11-1
'04 v-I4
401010
0
0,44 ∎ul
r••• 0"..°
•
r, ol op ul
r, r• 00 4
'0 MD qp
cm ul 00 c4
U)
a)
1.4
0
,4 r• r4 r-I
,t
$
H
(/)
H
u1 ul ul CD
CD c) ul ul
Cp u1 ul ul
CD CD CD CD
u1000
CD CD
ch ch ch CD 00 CD 00 ch qD CD
00 CD 01 010'0'
CD CD co, ch 01 0000
r4
r-4
r.-4
ri r-4
v-i
••
•• •• •• •• •• ••
14 0
C0 0
aJ 0)
V% 1,0 w00.
.• ••
•
.0
14
u1 4.)
•
.
•• •• •• •• •• •• •• •• ••
000...0..U1
•• ••
P4
4-)
14 00
CE1 0
(1) 0)
1J
a)
4,,o
P., 0
C0',000.4
" " .. et
r4 r 4 ,4 ,..4
01010..0."
v. " v. "
r4 ,4 r4 r4
,-1
(14
4-1
o •r4
U)
.6
r, CD T, CD
C) CD
01 P.. CD 01
0 1-00
CD 01 CD CD
CD C0 MD 00 .401VDN In 41/40M NN n000
CD
Ch
0
I
mD
..0.0 •• •• •• •• •• •• •• •• •• •• •• •• ••
••
FG
..
cn
••
.0 ••
r,
N
t.4
4- 1.4
N
r-4 r-4 r-4 r4
el mD 00 e4
0' 1-4 VD 4
cm 03 4 y0
0
cp ul on c)
CD CD CD ul 0)
CD CD ul C)
U1 U1 CD CD
ul CD U1 CD
U 4 r, N- 0' 00 oD ul r, r, N- N- N- .0 op .0 00 ,t 01 op ,4
4.1
a) 0
a)
0
o 4.)
c4 c4 ol mD
op C4 01 c)
C4 C4 C4 op
r4 4 Ch ch r4 4 4 1-4 4. r-4 4 .0
op
.0
1....CDin4. 11%
Ul 0.. 4 Cm
. In •6 ft C). r,. ul
. ft
. . . .
4
Z
C)
4-4
4.)
u3
0
04
44
••
•• ••
ft
r.4
••
00
00
a
•
00
ct5
W
4 (1)
00
111
0'
" w w
r-4 r•4 r•4
4 .1 .1 P.
w n n w
v--4 v-4 r•1 1-4
••
4
• •
4.1
op
0
o
r-4 1-4
0)
CO
td
•• •• •. •• .• •• ••
••
r, CD CD el
N 00 VD
0O1-••O
r-4
f y
0" 0 C ) C l
•• •• •• .• •• •• .• •• •• •• •• •• •• •••• ••
or--Mel
,4 cm
rn ocno
.04 r, CD
c) mp
op CD rl
0000,1-4
Or40,0
r ". 0000,4.w
r-1 r-4
N v-4 C4
r-4"
v--1"
0001
C.1 01 0"
CM
CD rA
0N0,N.0
r-4
r-I
vi 4
ON
14
w
r-4
••
.
••
$.4
0
tO
0
n-41-4
0
r
14
0
C)
1 •,-4 0 •,-1
$4
g
I
W
••
••
4.1
00
000
"0 co
a) "0
1.4 0
rit
CO
-o
o 0c
'0 .n
/4 W
td 0 a)
0) r."4 U)
C.)
14
'0 0
0 r•4
-1-4 0 •r4
x
tO
4.1
0)
$4 "0
01
a
0
4J rA
cd U
••
••
O
00
P4
,1)
W
1-4
41
••
4
C13
••
U) 4.4
0 0
0 U
01
C.)
U)
c.)
0
r4
an
(0
(1)
X
•
.
CD ul P• 01
CD
e4 '.0
,t 00
CO 0 r-4 01 01
p, u, 00
,tAe4A,tAA
ul
•
cn.
C14
Report No. 2259
A A A A
r4 rA rA
•• •• • •
un
en VD CD Cm
CO r •4 00
e•-•1
q 4 .1 04
A A A A
r•
•
••
•
'-0
O
"-I
CO
C.)
.
•• •• •• •• n • •• •• •• ••
•• •• •• •• •• •• •• •• •• •• n • •• •• •11 nn
til
In (41
0, 0, 0 0,
WI 111 0 0 0
OCOOO CO 1/10 0ON
ON ON 0' 0
0 a, 0 a, a, m r-4
0 0 111 (11
0 0 0,
r4
r4 r4
rA
••
••
▪ 0 rn CD
00 co un
C.4 ul
CO
1/40
0 ra r-4 1-4
••
•.11/
••
••
••
••
Cr, 000
Ir.• en M rn
1•••• r....• M cf.)
C., cvi t•-. r--
q mD cp
CD
01 CD 00 4 4 ri o1 4)
Cm
CO r'.0 f.... VD
00 Ch
00 1/40
cq 4 co
q0
r,dr.
r, 00
. A A
01 m0 ul.n
m0.
A A
A A A ..,
r4 r4 r4 r4
r4 r4 r4 r4
r4 rA e4 r4
•
• 4.
• n • n •• •
•
14
0 ul CD
cm 0
•• 0
r•-4
r-4
••
• Lin un CD
CD C) CD un "
•• •• •• ••
r4
•
411,
0)
1.4
C)
0 In N r-4
•..0 1/40 C`.1
C`1 CD 4 0,
• 00 f`•• CNI
. on el ,t
• CV ••-.0- C71.
r-4 v-I r•4
•
r4
Ul 111 0 U1
,r) 0 0 I.r)
01 01 0 ON Ch CD CM
rA
••
CD un cp ul
00
0,
111 00 01
01 r4 CO r4
111 r4 N 04
ON 01 '0 01
00 r-4 00 I-4 r-I C,1 ....t CNI
• r-I r-4 r4
r•4 r.4 r•4 r•4
r4 1.4 r4 ,4
w A 4%
•
• n •• •• •
0 0 0 tn
CM CD Ch CM
1.4
•n A
n ••
•• nn
ul ul ul
Ch 00 Ch Ch
O
•4
▪
1.4 00
I
C0
•
•
•• ••
•• ••
•
••
•• ••
r- r- CD
0 01 0 on 0 r, r1
,t 01 4 10 ch mD cp rA 4 CD V)
0 01 C1
A A A A
r4 r4
rAl
r4
•• ••
••
•• ••
CV ,0 CnI
CNI In 0 In
01
• CD
VD 00 04
0010 4
rA r4 r4 rA
r4 r4 r4 r4
r4 r4 rA r4
A A h A
AI% A
A A A
ul
▪
0
00
A
••
,0
n.0
0
4
NC•1
0.
r4
A A A A
•• • n •• •
•.
4
Ch
•
CD
«0
4•)
.•
••
ul CD 0 0
Cm CD 0 CD
r4 r4 r4
114
•• ••
cv
rA
0
r•4
• r-4
00
ft
r4
•• •• •• ••
• co co ,t
•• ••
••
mD
•a,0,0 omoa,
00'0a,
rA
rA
rA
•• •• •• ••
••••
• • • •
CD
w . et
r4 r4 r4 r4
W
P41
ccS
4.4
g 0
•r4 0 ,-I
cc)
to
44
c=3
Olt
.• •• •• •• ••
u
0
•• •• ••
CA
• •
mD 00
0r,1 00
r, u, 00
1.4 rA r4 rA
1.4 rA rA r4
••
o.
r4
•• ••
.•
4)
pC 14
CA dJ
r•4
01 C) 0/
4
CO
••
•• ••
I
•
ta
C
0
0
••
CD CD un un
un ul CD CD
CD '41 CD CD
•
••
..
r•4
r4 rA r4 r• • n ••
W
1.4
$.4
,C,
•• •• •• •• •• •• ••
v.) o
a)
• 0r-1
o
U 0r40r-Ia, 0
C)
0
00
,0
P4
U1
•• .
a)
r-4
•r-I C4 0
14•0
cd 0 a)
a I-4 .0
E
0
•• •
(1)
4.)
r-
r• r4 r4 C4
0
01
1..4
1-4
4J
44
0
4.1
0 4-4 0
••
▪
4-1
V)
••
.
op r. CD
A A A A
rA r4 rA rA
OA r4 r4
r4
r
,40
4 03
A A A
••
••
•• •• ••
•
••
0 C') 0 0
-...t (11 0 0
4C, 1--• 1... ON
..... • ..
r•4 r.4 r-4 r-.1
0 el I,
rl h ce.)
CM - Ch 00
•• •• ••
r,
ch
04
r4 ,t l
A A A A
.0
4.1
14 00
0 0
01 W
4 .14
(0
(1)
r-I
0
c.)
r4
cn
o
e4 ,0 r• rA
-or • ul
I--AAA
A
••
00 0000, mo,00
0,0,00,
r4 r•4
1,1 r-4
0
(1)
0
on O
D r-04CD
r
A A AA
r-)
w..♦ cm
4 q
••
••n
••
••
••
•r4
• .1 00 00
y
U)
U)
4
••
••
4J
cu
••
•• ••
0
••
r4 rA r4 r4
U
V •4
4J (1)
0 4
IJ
•
0)
4-41.4
"O 0
0 1-4
W0
u) C
jJ ,4
rA
•
cf)
4 A a)
0
•
•
0 0
01 0)
••
0, 00 a, a, O
oe a, co r4
0
r4
un 0 CD CD CD CD CD un
CI
0
C) 0 r1 C.) 01 0 r-4 r-4
r•4 r-4 r•-1
/4
•r4
4-1 O ,13
co 4.4
r4
••••
• •• ••
•• ▪
r-4
O
r4
0 0 0 41
CO a,
$11 0 0 III
v1OuOu1
11100,1"1
ON 0 ets
rA
VICDO Irl
00 0, 0, 0,
•• e• •• ••
(1)
04
CO
CI)
c:14
•• • •
.61
OV
co
CO
r4 r4 r4
.C4
• • nn n • •• •• ••
0
••
••
4J
0
(0 a)
'0
$.4 a)
cc, 4.4
0 44
,n
'0
0
1.4
U) •14 W
41 44 CD
CO I 14
Cl.) U3 .0
4.3 (c1
44
•4.4
r4 r4 r4
rA r-1r4 r4
r4 r-1 r4 rA
r4 r4
-I
14
44
•-c)
r4
01
g
U)
4
CO
U)
I w
N
4.1
•!4
W
. IR A A
CA.
O 43)
rA
• ICJ
P4
ro
cd
FA rA
rA
,c)
'0
14
W
'0
0
a/
4-4
U)
co
•• •• •• ••
CO
4
ri)
•• •• •• •• •• •• ••
.• ••
•• •• •• ••
▪
r, Cm 00 u1
ON un op 4 CD Ch un
CD ,t 01 CD co p, un un r-4
,4 Ul .1 C1
01
00 r4
r-4 00 01
01 rn on op
03 rA
rr.4 1/40
00rl 0A TV
01 ,0u1
eq,Dm0 01 CO mD r, unAonACO
A A A
A
A
A
A
A A
a
••
••
• • • •
CO
4J
cd
0(0
• . • • .. • •
• •
CA.
4J
r-1
r-4
r-4
.-•
4-i
rd 00
O 0
O a)
1-1
•
4 4.)
C.) •,-4
r,
CD C) CD CD
0000
r-4
CD CD un CD
CD un un un
CD CD CD CD
CD cm
ul uncm
CDCD CD
CD CD CD CD
cm cm cm cm Ch Ch CD
o
9-4
r-41
.-4 r-1 r-4 r-I
a)
00 1I u)
01 41••
iv
c
rA
W
W
I 4.1
•
••
•• •• • •
cn0--0 0
r4 1/40 00 CD
V1 01 rA U1
••
0
0
00 r-4
CO C4
T.4
h A A A
rA r4 r4 rA
••
"4
00
rl
Co
'0
a)
4.)
0
4)
4-1)4
0 IJ 0
(1)
C) .1 Ul Ul
CD U1 .1 CD
.1 .1
41000
CD CD
U
on e••• oi, oo 0
• O 0 r4
o a, co (:),
c)41, CD
0 ONo,
a l's, a,r--
r4
4-1CI
41)
tg) 1 U)
44
CLI
O
41
••-,4
• • •• •• • •6
•• •• .. •• •• •• .• •• • • •• •• 06
••
04
O0
o4
$4
•0
.$4
1/40
00
CD CD U1 U1
a 0 00 el
1.4
nn
•• •• •• •• •• ••
• •
•• ••
.
4,
4
• •
4-;
bt)
00 00 00 01
NCO 01 r,
oo C4 C4 C,
C4 VD 04 03
C4 04 C4 VD
ch
0'
O 0
r4 r.4 r4 4
4 r-i cr., 0,
r4 cm 4 r4
II)
.4 rA .4 r4
%SD
Ch CM ,T r4
to v1
O a)u
U)
• to,,
Ul .1. N./. r4
U1 qD VD C4
41 00 1/4,0 41
P. VD VD 00
41r-4
•.
A h h
$4
h h h h
A h I, h
A
A
IN h A
h
t-1 r4 H r4
4...
r-4 r-4 r.4 r-I
I-4 r-4 '
.4 '.4
r4 r-1 r-4 4-4
r-4 r-4 r4 r4
r4
0 •• . at
•• • '0•• •.
••
•• •• •• •• .. •• •• •• el. •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• n • •• •
n •
A
•
C)
4.1 CO
•• •• ••
P
01
• •
••
••
••
•• ••
• •
• •
•
A
•• ••
••
r,
1,...
A A A
r4
A
A
0)
(1)
4J
O 4-1
41
k
0
40
1:1 0
a)0 .1 Ul CD
41 0 CD
041
.1
Ul .1 .1 Ul
Ul CD .1 CD
41 41 41 41
..Sd
C)
W
0
r4
03 Ch 00 Ch
Ch 00 Ch C.,
Ch CN CM CM
Ch Ch 00 CM
1:5
Ch Ch Cr, 00
C)
44 0 44
$4
"r) a)
O
4.1
0
a)
O )4 CO
r4
0)
44
114
0 0 rd
4
4.1
00
••
• nn •
••
•• •• •• •• ••
••
••
••
• • ••
••
•
••
•11
O
4-1
.M
(1)
a)
.0 00
...
el
CD P, CD C)
C)
CD
CD
P
n
u 0a
rn
01
Tn
CD
CD C) C) ("I
4 0 0
..4. ri C4 01
C4 qD 04 C)
00 41 00 CD
CD CD 00 o
0
04 %0 1 r4
CI5
0 a)
0!
4) Ul 4 Ul
01 r. 04 01
Ul 4 01 I.,
in
VD r,
41 OD 41 03
C,
r.4
A
4
NA h
•
)
A
h h A h
0• h h h
.
.0 0) 4
r-4
r4
r4
r4
r4
P
4
r4
rA
r4
r4
'.4 r4 r4 r4
r-4 r4 r4 r4
,4 '.4 r4 r4
r4
0 4
to
•• •• •• •• •• ••
•
••
•• •• n •• •• •• ••
•• •• •• •• •• o• •• •• e• •• •
•• •• •• •• •• •• ••
td a 0)
a
1
V
a) U)
a)
a)
4J
4 ao to
4...
14
0
to 14 0
!I no 0
a)
00 ul Ul
41 .1 CD C) 41 0 C)
al in
r-4
41 C) .1 C) 41 04,
C)
00
4-4
U
01 0 CO 01
CO os 00 0
a, 0% 00
ceci.
cy, r, a, 0, co c!), a, ch
01
a)
44 0
O
a)
4-)
0
a)
•-• 4.)
OD
0
44
0
00
O
41
•-•4
›,
1.1
•• .n • •• •• ••
•• •• o• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• •• e• •• •• •• •• '0 IJ u
"4
P4
.a•1J
ta co 4.1
0
14
00
•:4
el
en cV CO
I's CO in c4
1-.1-.. ,-.4 eV
00 1/40 V1 C:0
el CV CO ell
CV
't) V 0
CU
a co 0
oN 0. ..d .-4
.0 r-4 1/440 ..d. r-1 1/40 01 ON
1/40 r-4 ON ∎D
01 0, ,c) 4
en
O 14 a)
U3
1 a) a)
0. CV r1/41 1/40. 1/40
.1 41% 0., 411CV 411 00 411
Ul
el es. ....t 4
4 41 el 4
0 0 )4
U1
ft . . .
1
4
$.4
IR
h
A
A
h h A A
n•• h •• ••
h h A A
.
4-1 0 a)
14
I 01 4.1
r4
r4 r• r• r4
r4 r4 r4 r4
r4 r4 r4 r4
r-I r4 r4 r4
'.4 r4 r4 r• r-4
,4
0
C)
00
.-4
A A A
1
•
••
•• ••
••
•• ••
4
U) .0 44
44
O a) •,1
o 0 91
to • aa)
461
a)
w
O
O
4.1
..-1
O 0 14
a) )4,0
4-)
a) 4J
4.) 4-)
OS 0 0
a) 0
U) a)
U)
>
r0
4.4 a) to
O 4-1 a)
ul
U)
11
4.4 .1•1
.-4
$-4
0
U) r.4 0
QS
L4 0
0 C.)
44 )4 14
0 4-4 0
Ca
4.1 co
O 0 )4
O0
to
r4
••4 to 0
ot
rood
• 4
ao
in
-.t
1
U)
•• •• o. •• •• •• ••
1 •0
1 CU
4J
a)
1 4,
k
0
. I 5 n o; 0
a))
U
6.. I p 0 r-.4
•
..4 o -.4
$.4
o
4.)
0
a)
r-4
0)
44
A.)
.1:1
i4
to
4)
X
CI)
•
••
•• ••••
43•• .* •• .. o•
.1.4
00
tt 0
0.
a) a)
4
)4
0) 4-4
P4
0)
•• •• ••
IV
43
14 00
00
4) al
a)
0
14
a)
11,
g vo H
0
44 0 44
1-4
60
1-4
.0
O
C!)
Report No. 2259
4.1
Ca
in 1.--. ts. 1,6
q
• •
J
••••
••
I's 0 en
en 0
c..,
ui
,ID
00'4
A A A A
r4 '
.4 ,4 C4
r...
$-4
Le)
.4. ,․)
en ON
•• •• •• •• •• •• •• •• •• •• •• •• •• •• •
.
r-4
••
••
op
nn
•• ••
g
.5
•0 ••
tr, IA Ul Ul
co r, 00 CM
▪
CD U1 CD CD
CM 00 00 03
••
41 CD .1 Ul
MD CD CM Ch
r-11
• •• •• •• •• •••• ••
r4 r4 C4 41
00 -. r4 Ch
4 CM 4 r4 r4 r4 4 M
OD OD MO CD
41 rq 00 r4
. . . A
r4 •.4 r-4 CV
.
C., .4 VD 41
r4 t0r4 r4
T., r4 r. Ch
.A 00 .
A A
r-4 04 r4 C4
••
1,4 C4 r4 r-.4
CD CD CD .1
CD 03 CM CA
r-4
•• •• .• ••
•
U1 .1 .1 CD
Ch ON OD Ch
OD
•• •• •• •• ••• .
r4 CN Ch CD
C) 41 04 Co
Ch 01 01 Ch Ch r4 0' 00
00 4 r4 0 cD cm r, en
..
A
A 01 h
A . . .
r4 r4 CV r-.1
C4 r-1 r-4 CV
••
•
Co
Co
CD
ON •-.4
••
•• •. •.••
•• •. •• ••
CV
in
s
it)
• •
en
01
CV
el
C)
Co
0
a'.
•
0
••.
..
. ..
4
4.)4
0
II) 0000 0 .1 in in in V.1 0 .1 41 In 00 0000
C.)
OCA000
01000001
O1/4C710101
01010101
00010100
14
r4
r4
.03 0
4)
U)
44
04
k4
•• .• •• •• ••
.i.)
O
a)14 O0
4
0 0
V/
4) 0.1
4 )4
.0 a1 Lrl 0
h A A It
r4 r4 r4 04
h A •• h
r4 r4 r4 rqr4 r4 ,. C4
•• •• ••
Al
.. •• •• •.0
.4. •.
II
a)
a) i 4.)
C)
•• •• •• •• •• •• •• •• •• •• •• ..
n• h A IN
r4 r4 r4 r4
h. .0 .0 0
N.
00.
0
Ul CD .1 C)
41 00 41CDI/1
Ln
cor.r...1.
en en en 0
r. tn ts1 0
.0An0AN-h .0h
r4
m 0'
•. •. •• •• .. •• .• ••
U)
U)
14
410041
CD U1
01 1,6 ON 00
••
•• •• •• •• • n
as,
00
4.)
•4
.0 N
U) 4.1
•••
•• .. ..
0 .1 Ul CD
0 ON ON 00
,-4
01 00
0 r,r. r... r,.0
r, r, 1 • .. el
..n 1/400.0
c v o 0 .0 -4.CO cnI kr) aN
•.n •• .
a)
$.4
g ll 0
0 r4
-r40".4
4.)
0
u)
44
43
•• ••
••
4,
tn.
".4
a)
04
41 C> .1 CD
ON 01 CT 01
.0
i4
4.i
00
O
▪
•• •• •• •• •• •• •• •• •• ••
Z
0
H
E4
.1-4
•
U)
0t4
•• •• .. •• •• ••
el en en en
cs1 r, re) 0,)
r4 Ch r4 O
..
A h
A
CV 6-4 CV H
r41
•• .. •• •• •• •• •• •• •• •• .• .. •• •• .. ••
r, 0 0 r...
cv 0 cv e4
CD CD CD r4
h h h h
CV e1/41 CV CNI
r-. 0 1.... 0
,t ,.1* eg o0
Co Ch CD Ch
A •• h ••
r-4 r-I CV r-4
00
1,.
`
04 VD 4
r4 CM 01 r-4
h A A
en
el
art
CV r-1 CV CV
Is. Ce1 0 0
C'l
h. 0 0
01 r4 C.,
CD
A h •• h
CV eV P-4 cV
r-4
0,
..
a)
b0 CO
c0.1'
'4'
$.4 CD
(I) I,
> C•I
<4
a)
••
1/40
Lti
r4
• ••
0
0
Cd
ni
)4
0
0
O
CO
0
H
'1
Table .--Results of shear tests on standard lue shear blocks and on
cylindrical plus using modified shear tool
Cylindrical plug
Shear block
Shear strength :
Estimated
wood failure
: Shear strength :
Estimated
wood failure
P.s.i.
Percent
P.s.i.
Percent
1,527
1,640
1,700
1,513
1,414
95
95
80
95
100
1,316
1,595
1,532
1,639
1,101
95
100
95
95
100
1,607
1,460
1,467
1,660
1,367
1,740
95
100
100
100
95
75
1,620
1,323
1,715
1,487
1,633
1,335
90
100
95
100
1,280
1,860
1,860
1,813
1,727
1,853
90
100
90
95
100
100
1,539
1,722
1,835
1,785
1,532
1,614
100
95
95
100
95
100
1,840
1,793
1,787
1,820
1,853
1,780
90
95
90
80
100
90
1,861
1,601
1,633
1,658
1,690
1,677
85
95
60
85
95
95
1,600
1,820
1,800
1,793
1,660
1,593
80.
90
70
100
95
95
1,759
1,734
1,462
1,608
1,405
1,171
80
85
80
95
100
95
1,370
1,100
1,327
1,473
1,113
1,733
90
95
100
95
100
90
1,297
1,070
962
1,000
1,120
1,772
100
100
75
95
95
95
1,513
1,380
1,800
1,947
90
85
95
. 95
1,272
1,082
1,411
1,810
95
95
90
95
Average:
1,625
93
1,497
93
.:
STANDARD DEVIATION
216.5
253.1
AVERAGE RATIO--PLUGS:SHEAR BLOCKS 0.92
Report No. 2259
100
95
Figure 1. --Front view of shear tool for testing cylindrical specimens.
The two cylindrical holes must coincide before specimen can be
inserted.
Figure Z. --Shear tool with cylindrical specimen inserted for testing.
A broken specimen and a plug cutter are shown at the base of the
tool.
Figure 3. --Cutter for making 1-inch cylindrical plugs
about 2 inches long.
Figure 4. --Cutter after extension was added so plugs
4 to 5 inches in length could be cut.
Figure 6. --Modified shear tool for testing glue joints in
cylindrical plugs. A device for holding the specimen
securely in place during test is shown in front of the
tool.
Figure 7. --Modified shear tool with plug-holding device
in place and specimen ready for testing.
Figure 8. --Modified glue-block shear tool for shear testing glue joints in
cylindrical specimens.
SUBJECT LISTS OF PUBLICATIONS ISSUED BY THE
FOREST PRODUCTS LABORATORY
The following are obtainable free on request from the Director, Forest
Products Laboratory, Madison 5, Wisconsin.
List of publications on
Box and Crate Construction
and Packaging Data
List of publications on
Chemistry of Wood and
Derived Products
List of publications on
Fungus Defects in Forest
Products and Decay in Trees
List of publications on
Glue, Glued Products,
and Veneer
List of publications on
Growth, Structure, and
Identification of Wood
List of publications on
Mechanical Properties and
Structural Uses of Wood
and Wood Products
Partial list of publications for
Architects, Builders,
Engineers, and Retail
Lumbermen
List of publications on
Fire Protection
List of publications 'on
Logging, Milling, and
Utilization of Timber
Products
List of publications on
Pulp and Paper
List of publications on
Seasoning of Wood
List of publications on
Structural Sandwich,
Plastic Laminates, and
Wood-Base Aircraft
Components
List of publications on
Wood Finishing
List of publications on
Wood Preservation
Partial list of publications for
Furniture Manufacturers,
Woodworkers and Teachers
of Woodshop Practice
Note: Since Forest Products Laboratory publications are so varied in subject, no single list is issued. Instead a list is made up for each
Laboratory division. Twice a year, December 31 and June 30, a
list is made up showing new reports for the previous 6 months.
This is the only item sent regularly to the Laboratory's mailing list.
Anyone who has asked for and received the proper subject lists and
who has had his name placed on the mailing list can keep up to date
on Forest Products Laboratory publications. Each subject list
carries descriptions of all other subject lists.