FOUNDATION PIER SYSTEM
Tube: 3 7/8" OD x 3 1/8" ID DOM. Minimum Tensile Strength
80,000 psi / Minimum Yield Strength 70,000 psi
Angle Bracket: ASTM A-36 Hot Rolled Steel. Minimum Tensile Strength
58,000 psi / Minimum Yield Strength 36,000 psi
Bracket Support Straps, Bracket Plate & Bracket Top Cap: ASTM A-36
Hot Rolled Steel. Minimum Tensile Strength 58,000 psi / Minimum Yield Strength
36,000 psi
Weld: E71Tl Minimum Tensile Strength 71,000 psi
Threaded Rod: Grade 7 Zinc Plated. Minimum Tensile Strength 133,000
psi / Minimum Yield Strength 115,000 psi
STORK - Twin City Testing Corporation
Project Number: 3618 199-8207.a
Date: November 5, 1999
Patzig Testing Laboratories
3922 Delaware Avenue
Des Moines, Iowa 50313-2597
Prepared by:
Brian S. Escherich
Job Manager Mechanical/Metallurgical Dept.
Phone: (515) 266-5101
Reviewed by:
Timothy B. Cox,
P.E. Product Service Manager Mechanical/Metallurgical Dept.
The test results contained in this report pertain only to the samples
submitted for testing and not necessarily to all similar products.
As a mutual protection to clients, the public and ourselves, all
Maxim Technologies, Inc reports are submitted as the confidential information
of clients, and authorization for publication of statements. Conclusions
or extractions from or regarding our reports is reserved pending our prior
written approval.
Introduction:
This report presents the results of load tests perforrned on house supports.
This work was requested by Mike Johnson. The samples were received on November
1, 1999 with the work conducted on November 3, 1999.
Sample Description:
A total of 2 samples were received. Each sample was described as a pier
bracket for 3" tube. Major design details consist of 0.5-inch X 8 X
8-inch angle iron as the bracket and 0.75-inch thick top plate with a l.0-inch
thick cap plate. Threaded rod to hold cap to top plate was 3/4-10 grade
7 with 3/4 inch 2N nuts.
Testing Procedure:
Each sample was attached to a fixture inverted from its normal position.
A three inch diameter solid round bar was used to apply the load directly
to the cap at a rate of approximately 12,000 to 24,000 lbs./minute with
inspections and data recorded at 20,000, 30,000 and finally at the point
when the samples would no longer accept additional loads. Deflection readings
were taken from a dial indicator measuring the relative travel between the
ram and the crosshead. (Some of the deflection may have been movement of
the fixture rather than the sample)
Testing Results:
Note: The bolt stretch for sample B = 0.49" RIGHT and 0.47"
LEFT. The bolt stretch was not monitored for sample A. There was no residual
deformation to either bracket at the conclusion of testing.
Disposition of Samples: Samples were returned to Mike Johnson at completion
of testing.
G:\WPDATA\AUTO99\199-XXXX\199-8207.abse
Pier Tube With Coupler Part No. FP3T
Friction Collar Part No. FP3FC
Tube: 3" OD x .129 Wall High Strength / Low Alloy Hot Rolled Electric
Weld. Minimum Tensile Strength 80,000 psi / Minimum Yield Strength 70,000
psi
Coupler: 2.75" OD x .134 Wall DOM Mechanical Steel Tubing. Minimum
Tensile Strength 80,000 psi / Minimum Yield Strength 70,000 psi
Friction Collar: 3.25" OD x .438 Wall DOM Mechanical Steel Tubing
x 3.125" long. Minimum Tensile Strength 80,000 psi / Minimum Yield
Strength 70,000 psi
Project Number: 3618 199-8240
Date: December 23, 1999
Prepared by:
Brian S. Escherich
Job Manager Mechanical/Metallurgical Dept.
Phone: (515) 266-5101
Reviewed by:
Timothy B. Cox,
P.E. Product Service Manager Mechanical/Metallurgical Dept.
The test results contained in this report pertain only to the samples
submitted for testing and not necessarily to all similar products.
As a mutual protection to clients, the public and ourselves, all
Maxim Technologies, Inc reports are submitted as the confidential information
of clients, and authorization for publication of statements. Conclusions
or extractions from or regarding our reports is reserved pending our prior
written approval.
Introduction:
This report presents the results of load tests performed on three inch
outside diameter tube. This work was requested by Mike Johnson. The samples
were received and tested on December 21, 1999.
Sample Description:
A total of 3 specimens were received. Each specimen was described as
a 3 inch O.D. tube with a nominal wall thickness of 0.120 inches by 3 feet
long. Each 3 foot long section of tube had a coupler welded to the inside
to fit to the inside of the adjoining pipe.
Testing Procedure:
Each specimen was placed vertically between two loading plates and loaded
in compression at a rate of approximately 24,000 lbs./minute until the specimens
would no longer accept additional loads.
Test Results:
Note - The columns would no longer accept additional load when buckling
started. The tests were performed with a friction collar over the coupler
at the base.
Disposition of Samples: Samples were returned to Mike Johnson at completion
of testing.
G:\WPDATA\AUTO99\l99-XXXX\199-8240bse
FOUNDATION PIER SYSTEM TECHNICAL SUPPORT DATA
Foundation Engineering by Peck, Hanson and Thomburn states the following
under the heading "Action of Piles Under Loads":
A point-bearing pile surrounded by soil is sometimes erroneously regarded
as a structural member that transfers its load like a column from the top
of the pile to the bottom where it is delivered to the underlying rock or
soil. This concept leads to the conclusion that the stresses in the pile
should not exceed those that would be considered tolerable in a column of
the same dimensions and materials. However, experience has amply demonstrated
that structural failures of driven piles are so rare that the eventuality
need seldom be considered in design. During load tests on piles, if structural
failure of the pile itself occurs, it usually takes place at or above the
ground surface where the projecting part of the pile is not surrounded by
soil. Furthermore, both experience and theory have demonstrated that there
is no danger that a point-bearing pile may buckle on account of inadequate
lateral support, provided it is surrounded by even the very softest soils.
These observations lead to the conclusion that the capacity of a point-bearing
pile depends almost entirely on the capacity of the material upon which
the point finds its bearings, and on the degree to which the point of the
pile has a satisfactory seat on the bearing material. It is obvious that
the ultimate bearing capacity of the pile increases with increasing bearing
area, whence it may be concluded that the capacity of piles with large point
diameters is greater than that of piles with small point diameters. On the
other hand, if the bearing stratum is at considerable depth or is overlain
by moderately resistant material, it may not be possible to drive a large-diameter
pile to a firm seat on the bearing stratum, whereas a more slender pile
that displaces less soil may successfully reach the firm material and may
have a higher capacity.
Thixotrophy
The Foundation Pier System carrying ability increases with time because
of the concept of THIXOTROPHY, which is defined as "particles attempting
to reoccupy the space from which they were removed." Simply stated,
the soil that is displaced by driving the pier tubes into the soil wants
to reoccupy the space that is now taken up by the tubes. The soil grabs
the pier tube wall which greatly increases the carrying ability because
of this frictional support.
Even in very short periods of time THIXOTROPHY will affect the pier capacity.
A pier started and driven at a given pressure that is left to sit overnight
may require 50% to 100% more pressure to begin driving again the very next
day. The additional pressure varies greatly due to varying soil types and
conditions. While this frictional support is not used in support load calculations,
it adds another significant safety factor to the system.
Foundation Pier System Corrosion Information
The United States Department of Commerce/National Bureau of Standards
book entitled NBS PAPERS ON UNDERGROUND CORROSION OF STEEL PILINGS states
the following in part:
Background
Data obtained by the National Bureau of Standards on the corrosion performance
of steel piles driven into the ground in a wide variety of soil environments
show that the strength and useful life of steel piles are not significantly
affected by corrosion. These findings are in sharp contrast to those of
earlier corrosion studies in which iron and steel specimens, such as pipe,
that are buried under "disturbed" soil conditions exhibit varying
amounts of corrosion.
Summary
Steel pilings which have been in service in various underground structures
for periods ranging between 7 and 40 years were inspected by pulling piles
at 8 locations and making excavations to expose pile sections at 11 locations.
The conditions at the sites varied widely, as indicated by the soil types
which ranged from well-drained sands to impervious clays, soil resistivities
which ranged from 300 ohm-cm to 50,200 ohm-cm, soil pH which ranged from
2.3 to 8.6.
The data indicate that the type and amount of corrosion observed on the
steel pilings driven into undisturbed natural soil, regardless of the soil
characteristics and properties, is not sufficient to significantly affect
the strength or useful life of pilings as load-bearing structures.
Moderate corrosion occurred on several piles exposed to fill soils which
were above the water table level or in the water table zone. At these levels
the pile sections are accessible if the need for protection should be deemed
necessary.
It was observed that soil environments which are severely corrosive to
iron and steel buried under disturbed conditions in excavated trenches were
not corrosive to steel pilings driven in the undisturbed soil. The difference
in corrosion is attributed to the differences in oxygen concentration. The
data indicate that undisturbed soils are so deficient in oxygen at levels
a few feet below the ground line or below the water table zone, that steel
pilings are not appreciably affected by corrosion, regardless of the soil
types or the soil properties. Properties of soils such as type, drainage,
resistivity, pH or chemical composition are of no practical value in determining
the corrosiveness of soils toward steel pilings driven underground. This
is contrary to everything previously published on specimens exposed in disturbed
soils and do not apply to steel pilings which are driven in undisturbed
soils.
FOUNDATION PIER SYSTEM
The National Association of Engineers (N.A.C.E.) publications titled
"Corrosion Basics" makes these statements pertaining to corrosion
and coatings:
NACE page213
An obvious method of controlling corrosion is that of interposing a barrier
between the threatened metal surface and the corrosive medium, i.e. some
kind of coating. Since corrosion always requires the presence of an electrolyte
(moisture) in contact with the metal, if a metal could be coated with a
material which was absolutely waterproof and absolutely free from holes,
all attack would be stopped. The coating, it should be noted, would not
only need these two properties when it was applied, but the two properties
would have to be permanent-the coating would have to remain perfect in both
respects.
NACE page 216
An important difference with steel piling is that a few pits or even
holes have little effect on its structural strength. Consequently, much
more corrosion can be tolerated than with pipelines. Piling is almost always
bare, vertical, and hence subject to the same kinds of cells that attach
oil well casings. Bonding often may be a problem because individual piles
may not be interconnected electrically, a condition that makes both investigation
and protection a problem.
NACE page 216
Galvanized steel is not normally installed underground. The thin zinc
coating is quickly dissipated by galvanic action with any exposed steel.
NACE page238
As soon as a pore or bare spot appears, the corrosion of the bare metal
is accelerated.
NACE page 266
A coating may fail as a result of a large number of potentially adverse
conditions. Some of these can be defined as mechanical, as when abrasion
or impact removes the coating.
The above information shows clearly that coatings on steel piers does
not effectively increase its life expectancy. It may in fact, due to abrading
that can occur in coatings of steel drive piers, actually decrease its life
expectancy. Please refer to the N.A.C.E. and N.B.S. publications for additional
information.
Foundation Pier System
Materials
Angle Bracket: 8" x 8"x1/2" ASTM A-36 Hot Rolled
Length: 10 inches
Tensile Strength: 58,000psi
Yield Strength: 36,000 psi
Bracket Plate: 5 1/2" x 9 1/2"x 3/4" ASTM A-36 Hot Rolled
Tensile Strength: 58,000psi
Yield Strength: 36,000 psi
Bracket Tube: 3 7/8" OD x 3 1/8" ID DOM Tubing
Length: 10 inches
Wall Thickness: 3/8"
Tensile Strength: 80,000psi
Yield Strength: 70,000 psi
Bracket Supports: 2" x 8" x 3/8" ASTM A-36 Hot Rolled
Weld: E71Tl - Tensile Strength: 71,000 psi
Bracket Cap: 4" x 8 1/2" x 1" ASTM A-36 Hot Rolled
Tensile Strength: 58,000psi
Yield Strength: 36,000 psi
Threaded Rod:
3/4" x 12" Long - Grade 7
Tensile Strength: 133,000 psi min.
Yield Strength: 115,000 psi min.
Pier Tube: 3" OD x .120 Wall - Hot Rolled Electric Weld
High Strength - Low Alloy
Tensile Strength: 80,000 psi
Yield Strength: 70,000 psi
Coupler: 2.75" OD x .134 Wall x 6" Long DOM Tubing
Tensile Strength: 80,000 psi
Yield Strength: 70,000 psi
Hydraulic lift:
22" Stroke Hydraulic Cylinder
Working Pressure rating of 3,500 psi
Ultimate cylinder lift capacity: 33,000
3000 psi reading on guage means 3000 pounds of force on each square inch
of the cylinder piston.
The cylinder piston is 3.5 inches in diameter. The square inch area of
the piston is determined by the formula 3.1416 x the square of the radius
of the piston.
3.1416 x 1.75 x 1.75 = 9.62 sq. in.
The total force exerted on the cylinder piston:
300 x 9.62 = 28,860 pounds
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