To settle definitely the much
discussed and much mooted question of the strength of
the various types of construction (and there have been
many many changes of "fixed" tests with special slabs,
by different concerns) we employed Robt. W. Hunt & Co.
Inspection and testing Engineers of international
reputation to test and report to us the load bearing
strength of a stock slab of each of our different
forms. Below will be found extracts from their report
on the PASCHALL sidewalk installation.
"The following is a report of our
'Transverse Tests' in your Paschall Standard
Interlocking Vault Light Construction and made with
your glass No. 43-A."
Construction
"The specimens tested were
17½ inch wide by 54 inches, 78 inches and 102 inches
long, respectively. In the 17½ width there were three
rows of No. 43-A glass."
"The longitudinal reinforcement,
partially imbedded in concrete, consisted of four I
beams 1½ high with a web thickness of 1/8 inch
and a width across the flanges of 7/16 inch. These I
beams were spaced 4¼ inches to 4½ inches
center to center. The transverse reinforcement
consisted of flat bars 1 inch by ¼ inch, not
imbedded, and carried between the adjacent glasses
and directly underneath them, engaging shoulders on
the same. They were spaced 4¼ inches center
to center."
Conduct of Tests
"The specimens were successfully
placed on supports 8 feet, 6 feet, and 4 feet, c. to c.,
respectively. The loads were applied on the 1/3 points
of the span and under increasing loads the deflections
at the center of the span were measured. The observed
loads and the deflections were carefully plotted."
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Summary of Tests
"In the following
is given a summary of the deflections under the calculated
uniformly distributed loads."
Slab No.
Span in Feet | 43-A
4 feet |
43-A
6 feet | 43-A
8 feet |
|---|
Calculated Distribution
Load Lbs. per Square Foot |
Deflection at Center of Span Inches |
|---|
| 0 | .00 |
.00 | .00 |
| 100 | .01 |
.07 | .21 |
| 150 | .02 |
.13 | .38 |
| 200 | .03 |
.19 | .56 |
| 250 | .04 |
.25 | .76 |
| 300 | .05 |
.30 | .99 |
| 350 | .06 |
.36 | 1.18 |
| 400 | .08 |
.42 | 1.45 |
| 450 | .09 |
.48 | 1.75 |
| 500 | .10 |
.53 | 2.22 |
| 550 | .11 |
.59 |
| 600 | .12 |
.66 |
| 700 | .15 |
.82 |
| 800 | .16 |
1.04 |
| 900 | .19 |
1.46 |
| 1000 | .22 |
2.46 |
| 1200 | .26 |
| 1400 | .32 |
| 1600 | .39 |
| 1800 | .48 |
| 2000 | .64 |
| 2200 | .85 |
| Maximum distributed load sustained |
2370 | 1015 | 525 |
|---|
| Deflections under maximum load |
1.30 | 2.94 |
2.50 |
|---|
| (Signed) Robert W. Hunt & Co. |
Note that in all tests the supports
were under the ends of the slab. If the support had been on
all four sides the load could probably have been increased
by 50%.
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