Fisher, J. W.

Tebedge, N.

English

Lehigh University: Lehigh Preserve

Lehigh University
Lehigh Preserve
Fritz Laboratory Reports Civil and Environmental Engineering
1972
Test of jumbo shape with surface seams
N. Tebedge
J. W. Fisher
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Recommended Citation
Tebedge, N. and Fisher, J. W., "Test of jumbo shape with surface seams" (1972). Fritz Laboratory Reports. Paper 1255.
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TEST OF JUMBO SHAPE
WITH SURFACE SEAMS
Negussie Tebedge
John W. Fisher
for
Bethlehem Steel Corporation
Bethlehem, Pennsylvania
FRITZ ENGINEERING
LABORATORY LJ8RARY
Fritz Engineering Laboratory
Department of Civil Engineering
Lehigh University
Bethlehem, Pennsylvania
December 1972
Fritz Engineering Laboratory Report 200.72.13.4
200.72.13.4
1. INTRODUCTION
Seams or laminations may result from rolling thick
plates or heavy shapes. These discontinuities are generally
oriented in the direction of rolling.
Fatigue and fracture studies of structural details have
shown that discontinuities are only detrimental when the discon-
tinuity lies in a plane perpendicular to the applied
stress.(1)(2)(3)(4) Fortunately, seams and lamination usually
are in planes parallel to the line of stress and do not affect a
member's behavior or performance.
To confirm this fact, a heavy rolled jumbo column sec-
tion was tested which had extensive surface seams. The objective
was to determine whether or not these seams changed shape or ex-
tended and influenced the capacity of the column. A stub column
test was selected for this investigation since it can be used to
measure the effectiveness of the member's resistance under fully
plastic load. Also, it can furnish experimental data that can be
used to make a column strength prediction. Based on a single stub
column test, it is possible to establish column strength curves
over the complete range of slenderness ratios used in practice.
1.
2.
200.72.13.4
2. TEST PROCEDURE AND RESULTS
Preparation of Test Specimen
A specimen with severe discontinuities in the form of
surface seams was used to carry out the experimental investiga-
tion. The selected specimen was a W14x730 rolled shape ("jumbo!!
shape) of ASTM A572 grade 50 modified steel. The seams on the
surface of the specimen are shown schematically in Fig. 1.
Several probe holes were drilled along the seams to
accurately check the depth of the seams and to provide a means
of detecting any crack growth or opening of the seams when the
specimen was subjected to high axial compressive force. The
locations of these probe holes and the seam depths at the re-
spective locations are given in Table 1. The seam widths are
about 0.001 in. near the flange surface and taper near their
extremities. Figure 2 shows photographs of the flange surfaces
after testing.
Tension Coupon Tests
A total of four 8-inch gage length tension coupon
tests were made following ASTM specifications (E370): two from
the flange and two from the web. Figure 3 is a schematic diagram
of the locations of the coupons with respect to the cross section.
The stress-strain curves for the flange and web are shown in
Fig. 4. The "dynamic" stress rate used for the tension tests
3.
200.72.13.4
was about 3.5 ksi/min. This rate was established while the
specimens were elastic and the same valve setting was maintained
throughout the test. It is readily apparent from Fig. 4 that
the material does not exhibit a yield plateau. An increase in
load was observed after the proportional limit was exceeded with
increasing strain. Table 2 summarizes the results of the coupon
tests. The proportional limit was defined by a measured offset
of 10 micro in./in. The static yield strength was defined by the
stress at 0.005 in./in. strain. The proportional limit varied
between 43.2 ksi to 46.0 ksi for the tension coupons. The re-
corded yield strength varied between 57.8 ksi and 59.6 ksi for
the web, and between 60.7 ksi to 61.0 ksi for the flange. It is
of interest to note that the specimens from the flange show a
higher yield strength level than. those taken from the web. This
is contrary to the case observed in most lighter rolled shapes.
Stub Column
The purpose of a stub column test is to determine the
average stress-strain curve for the entire cross section, includ-
ing the effects of residual stress and yield strength variation
over the cross section. The proportional limit, the elastic
modulus, and the tangent modulus are the most importa~t data
furnished by a stub column test.
In this test the effects of the seams on the overall
behavior of the column was of primary interest. The test was to
4.
200 72 13.4
provide data that could establish the applicability of crack
propagation observations on the significance of discontinuities
or seams on static strength.
The length of the column was selected such that it was
sufficiently long to retain the original residual stress in the
column but short enough to prevent premature failure by buckling
before the yield load of the section was reached. For the W14x730
shape, a length of 100 inches was selected. The cross sectional
measurements are compared with the nominal dimensions in Table 3 .
. The procedure used in testing the column is described in detail
in Ref. 5.
Figure 5 shows the stub column set-up and the instru-
mentation. The test wa~ performed in the 12-million pound capac-
ity testing machine at the National Bureau of Standards, Gaithers-
burg, Maryland. The average stress-strain curve obtained from
this test is shown in Fig. 6. Using an offset of 10 micro in. lin.
the proportional limit was estimated to be 28.0 ksi for the stub
column. The testing was terminated when the specimen was loaded
up to the capacity of the testing machine (12 million pounds).
At this load, the specimen was beyond the initiation of yield
and had exhibited substantial evidence of yielding by the flaking
of mill scale. The dashed line in Fig. 6 shows the stub column
behavior that was predicted from the tension tests. The weighted
yield strength level of the stub column is estimated as 60.4 ksi
which is significantly greater than the minimum specified value
of 50 ksi.
s.
200.72.13.4
It is readily apparent in Fig. 6 that the stub column
test is in good agreement with the prediction based on coupon
tests. The results are directly comparable to other stub column
tests where no seams were present. es ) The deviation from the
predicted curve reflects the influence of residual stresses.
The maximum compressive residual stress level was estimated from
the difference between the proportional limits of the tension
coupons and the stub column. This yielded an estimated maximum
compressive residual stress for this specimen of 16.5 ksi.
During the test each proble hole was examined for
growth or change in seam size or its shape as the applied load
was increased. There was no indication of any change in the
size or shape of the seams due to the applied load when observed
with a SOx hand microscope. This was true even though loads
between 8 million and 12 million pounds were applied to the
column for 30 to 45 minutes. A comparison of the conditions of
the seam at probe holes A and B is shown in Figs. 7 and 8. The
photographs show the specimen at the zero load level and at 12
million pounds. The seams were not changed by the high axial
force.
~ • SUMMARY AND CONCLUSIONS
A specimen with severe discontinuities in the form of
surface seams was experimentally investigated to determine the
influence of seams on the capacity of columns. The selected
specimen was a W14x730 rolled shape of ASTM As70 grade 50 modified
6.
200.72.13.4
steel. Standard tension coupons were tested to determine the
basic properties of the specimen and a stub column test was
performed to check the effects of the seams on the overall be-
havior of the column.
This test on a stub column with large seams in the
flange surface from the rolling process has confirmed that dis-
continuities that are in the direction of applied stress have no
effect on the strength and behavior of a structural member. This
is in agreement with other studies on structural members. For
example, the lack of penetration at partial penetration web-to-
flange welds have also been observed to have a negligible effect
on both beam and column behavior. These discontinuities are also
parallel to the applied stress. Comparable conditions have
existed in riveted and bolted built-up shapes.
TABLE 1
PROBE HOLE DIMENSIONS AND SEAM DEPTHS(*)
":l
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1'0
·I-'
v.J
·~
Probe Hole Hole Diam.(In)
A 3/4
B 3/4
C 3/4:
Seam Depth(In)
3/16
7/32
5/16
Hole Depth(In) Seam Width (In)
7/16 0.0009
15/32 0.0009
9/16 0.0006
(*) Refer to Fig. 1 for locations of probe holes.
200.72.13.4
TABLE 2
SUMMARY OF TENSION COUPON TESTS (ASTM)
FLANGE WEB
Fl F2 Wl W2
Area at Net
Section (in2) 2.315 2.303 2.293 2.290
Dynamic
O'yct 62.7 62.5 59.5 61.4
Proportional
Limit 43.2 45.0 46.0 43.6
Static
0' 60.7 61.0 57.8 59.6ys
Ultimate
Stress 89.4 90.3 92.9 87.8
Fracture
Stress 82.5 83.0 70.9 69.9
Percent
Elongation 18.0 18.8 22.8 20.6
Percent
Reduction 26.4 27.9 49.1 49.4
All stresses in ksi.
Refer to Fig. 3 for locations of specimens.
8.
200.72.13.4
TABLE 3
CROSS-SECTIONAL MEASUREMENTS
9.
._-.-.---~..... _.~... .- .. ..
. "r .-
Measured(in) I Nominal(in)
Depth 22.513 i 22.440I
i
Flange Width 17.777 I
17.889
Flange Thickness 4.881 I 4.910I
I
Web Thickness 3.175 I 3.069i
I
I
;
AREA(in2)
I
214.02 ! 214.65
!
Flange I
1_ 15" -I
Flange :II:
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·I--'
tJ'!
·
B
27"
Fig. 1 Schematic Layout of Seams and Probe Holes
I--'
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·
200.72.13.4
11.
Fig. 2a Flange I Surface
after Test Show-
ing Probe Hole A
and Flaking Mill
Scale
Fig. 2b Flange II Surface
after Test Show":
ing Probe Holes
Band C and
Flaking Mill Scale
200.72.13.4
-r-
WI W2
~ ~~
I I
I
FI F2 6 11 311.o/~ I
,-~
22.5 11
Fig. 3 Locations of Test Specimens ilin the
Cross Section of the.W14x730 Shape
7.911
12.
150
Flange (F2) !')o
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·
-...J
!')
·
Web (WI)
4 6
STRAIN x10- 3
APPLIED
LOAD, P
(kips)
100
50
o 2
2"\
G =all Iv. II1- y2
:+ ~ I---p
1_ 29~o".1 -I
a 10
Fig. 4 Tension Coupon Test Results
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·
200.72.13.4
Fig. 5 Test Set-up and Instrumentation
14.
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LN
·..p,
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·
N
o
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·
10'8
P
P
--- Stub Column Test
- -- Tension Test (Extrapolation)
4 6
STRA IN x10-3
Fig. 6 Stub Column Test Result
Unloading
---~P:cit~of :esting_MaChi:" - - - -
8
4
2
12
10
o L 2J EO =1.0 X 10-4
APPLIED
LOAD, P
(kips x 103 ) 6
200.72.13.4
16.
Prior to Loading
Fig. 7
At 12,000,000 lb.
Close-up of Probe Hole A
Prior to Loading
Fig. 8
At 12,000,000 lb.
Close-up of Probe Hole C
... 17 .
200.72.13.4
4. REFERENCES
1. Gurney, T. R.
FATIGUE OF WELDED STRUCTURES, Cambridge University Press,
Great Britain, 1968
2. Fisher, J. W., Frank, K. H., Hirt, M. A., and McNamee, B. M.,
EFFECT OF WELDMENTS ON THE FATIGUE STRENGTH OF STEEL BEAMS,
NCHRP Report 102, Highway Research Board, 1970
3. Fisher, J. W.,and Yen, B. T.
DESIGN, STRUCTURAL DETAILS, AND DISCONTINUITIES IN STEEL,
Proceedings, Specialty Conference on Safety and R'eliability'
of Metal Structures, ASCE, Pittsburgh, Pa., November 1972
4. Rolfe, S. T., and Egan, G. R.
DESIGNING TO PREVENT FRACTURE IN TALL BUILDINGS, State-of-Art
Report 6, Tech. Comm. 18, ASCE-IABSE International Conference
on Tall Buildings, August 1972, Preprints: Reports Vol. 11-18
5. Tall, L.
STUB COLUMN TEST PROCEDURE, Document C-282-61, Class C
Document, International Institute of Welding, Olso, June 1962;
Also CRC Tech. Memo No.3, "Column Research Council Guide",
2nd Ed., edited by B. G. Johnson, Wiley, 1966
6. Yu, C. K., and Tall, L.
SIGNIFICANCE AND APPLICATION OF STUB COLUMN TEST RESULTS,
Journal of the Structural Division, ASCE, Vol. 97, ST7,
July 1971
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Test of jumbo shape with surface seams

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