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Test Results.
SUMMARY OF HOLDING STRENGTH TEST RESULTS
Saddle Clips
Saddle Clips with Spring Clip
G-Clips Grating Fasteners
SADDLE CLIPS:
Test results are as follows:
Saddle Clips, Galvanized
These models fail independent of the method
used to attach them to the structural member. This is due to
the saddle clip (essentially a metal strip formed in a single
plane into a new shape) having no real beam strength. As a result,
just as a simple pressure can form it, so a pressure can re-form
it into another shape. And this is exactly what occurs when
the grating to structural member is stressed. Saddle clips deform
into a u-shape, and the grating is allowed to move upward, slipping
past the clip wings, which point upward. The grating almost
never can return to the installed position, since spring action
in the u-shape causes the shape to spread after the grating
rises, and as a result, the grating is help up, above the fastener
new shape.
Failure occurs at various forces from as
little as 200 pounds force to as much as 750 pounds. At no time
during these tests was there failure of the threaded fastener
holding the saddle clip to the structural member. Saddle clips
always fail by deforming into the new u-shape.
Saddle Clips, Stainless
Steel
These models also fail by turning into a
new u-shape. Such reforming occurs at as little as 500 pounds
force, and held to as much as 700 pounds force.
Methods of attaching Saddle Clips:
1. Welded studs are very secure. Properly
applied, welded studs hold 3 to 4 times the ability of the saddle
clip to maintain original shape. Approximately 15% fail during
initial (wrong) application technique.
2. Shot studs, using powder-driven techniques,
are a little less secure, since they are susceptible to failure
if an sideways force occurs. This causes the shot stud, at rest
in the hole it originally caused, to deform in its hole, and
loosen. It can subsequently be pulled free of its attachment
at a much smaller lifting force than before the sideways force
was applied. Properly applied, welded studs hold 2 to 3 times
the force which saddle clips can withstand.
3. Drilled and tapped combination fasteners,
(called Tec screws) are a very secure method and their holding
power greatly exceeds that of the saddle clip. 4. Holes drilled
through the structural member, which allow the saddle clip to
be bolted to the member, are very secure. Their holding power
greatly exceeds that of the saddle clip.
SUMMARY
OF TEST RESULTS: MECHANICAL FASTENERS
Test results are as follows:
Model (a) Mechanical Fastener [Saddle Clip]
This unit consists of a saddle clip, threaded
bolt, and lower unit that contains a spring-loaded unit that
connects to the grating underside (on its one end) and has a
flat portion that rests on the underside of the beam (its other
end). Lower unit is a lever arm in which the clamping action
achieved by the threaded member is reduced by the lever length.
Tests show that the unit lower body deforms
at forces of 250 pounds. No unit of this model has survived
forces above 400 pounds force in our tests. Catastrophic deformation
occurs, which renders the fastener incapable of further use.
Model (b) Mechanical Fastener [Saddle Clip]
This unit consists of a saddle clip, threaded
bolt, and lower unit that contains a stair-step effect that
connects to the grating underside and rests under the beam surface.
Lower unit is also a lever arm, in which the clamping action
achieved by the threaded member is reduced by the lever length.
Tests show that the unit saddle clip
deforms at from 400 to 600 pounds force. No unit of this model
has survived forces above 600 pounds force in our tests. Catastrophic
deformation occurs, which renders the fastener incapable of
further use.
G-Clips Grating Fasteners
This unit consists of a squared, saucer shaped
top assembly which is folded on four sides, and depressed in
the middle. It has a considerable amount of beam structure in
its shape, and greatly increased holding power over saddle clips.
The top is joined by a threaded fastener to the lower unit.
Lower unit consists of a shaped member which has no lever arm.
It concentrates clamping force into the holding face. Any force
developed in the tightening action, which is directly on the
same center line as the face of contact between the unit and
the beam underside, is therefore converted directly into clamping
force.
Tests show the galvanized carbon steel model
GG- I A withstands a minimum loading of 550 pounds of force
with no tendency to new shape. Test specimens have been tested
to 950 pounds before loosening. No failure occurs. Unit is further
tightened, and retains its ability to hold the grating in place.
Tests show the stainless steel XSSGG-IA model withstands a minimum
loading of 700 pounds of force while retaining its original
shape.. Test specimens have been tested to I 100 pounds before
loosening. No failure occurs. Unit is further tightened, and
retains its ability to hold the grating in place.
It has been found that both G-Clip models
tend to respond well to cyclic stresses as is seen during these
tests. After cycles of loosening, further tightening, and retesting,
the test specimens tend to achieve higher pressures before loosening.
In this way, they actually increase their holding power during
use, due to work-hardening. Catastrophic failure tends to occur
by fracture of the cap screw.
No G-Clip test specimens have failed
due to the top or the lower unit fracture.
See Certified
Test Results Letter
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