|
Helical piers have been in use for more than 160
years. In 1838 a lighthouse was built upon
helical piers designed by an Irish engineer, Alexander Mitchell.
In 1863, Eugenius Birch
designed the Brighton West Pier in Brighton , England . These piers
are still in use 140 years
later. The original helical piers were installed at 10 feet per
hour using eight 20 foot long torque
bars and the force of 32 to 40 men. Sporadic use of helical piers
has been
documented throughout the 19th and early 20th centuries mainly for
supporting structures and
bridges over weak or wet soil. Hydraulic torque motors became available
in the
1960's, which allowed for easy and fast installation of helical
piers. Helical piers then
became the favored product for resisting tensile forces. Electric
utility companies began to use
helical piers for tie down anchors on transmission towers and for
guy wires on utility poles.
helical piers are ideal for applications where there is a need to
resist both tension and axial
compression forces. Some examples of structures having combination
forces are metal
buildings, canopies and monopole telecommunication tower foundations.
Current
uses for helical piers underpinning foundations include foundations
for commercial and residential
structures, foundation repair, light standards, retaining walls
tieback anchors, failed foundation restorations, pipeline and pumping
equipment supports, elevated walkways, bridge abutments, and
numerous uses in the electric utility industry. Many times helical
anchors are the best solution for your foundation repair project.
ECP
Torque Anchors™
ECP Helical
Torque Anchors™ are a part of the complete product line of
helical piers, steel piers
and foundation repair products manufactured by Earth Contact Products,
LLC, a family owned
company based in Olathe , Kansas . The company was built upon the
ECP Steel Pier™, a
fourth generation end bearing steel mini-pile designed and patented
by Don May .
Our 85,000 square foot state of the art manufacturing facility produces
all components
and steel assemblies. The only processes not done in our facility
are galvanization and hot
forge upsetting of couplings. Because of this we are able to custom
configure products to fit
engineered specific applications. Earth Contact Products uses only
certified welders and robotics for quality fabrication.
Torque
Anchor™ Components
The ECP Torque Anchor™ consists of a shaft fabricated from
either solid square steel bar or
tubular steel. Welded to the shaft are one or more helical plates.
The plates can vary in
diameter from 6” to 16” and have a thickness of 3/8”
or 1/2” depending upon the soil and the
application. Typically the plate diameters increase from the bottom
of the shaft upward
and are spaced a distance of three times the diameter of the plate
directly below, unless
specified otherwise by the engineer. The standard thickness for
all helical plates
diameters is 3/8 inch, except the 16” diameter which is manufactured
only in 1/2” thickness.
In high load applications plate thickness of 1/2” may be specified
for all plates. The pitch of the
helical plate is three inches, which means that the anchor advances
into the soil a distance of
three inches during one revolution of the shaft. The available lead
shaft lengths are 10”, 60”,
84” and 120”, however, other lengths may be specially
fabricated. Because Helical piers
are considered deep foundation elements; they are usually installed
into the soil to a depth
greater than just the length of the typical lead section. Extensions
of various lengths are
available and are supplied with couplings and hardware for attachment
to the lead or other
extensions allowing the Helical piers assembly to reach the desired
depth. Helical
plates may also be installed on the extensions where the length
of the lead is not sufficient to
allow for the proper interval between plates. The number of the
plates per Helical Torque Anchor™ is limited only by the capacity
of the shaft to transmit the torque required to advance the Helical
Torque Anchor™ into the soil.
Helical piers
may terminate with a pier cap that will be embedded into a concrete
foundation. In other applications such as tieback anchors, a transition
is made from the anchor
shaft to a continuously threaded rod. Various beams, wall plates,
etc. can be attached to the
threaded bar for wall support, and to restore or to simply stabilize
walls or other structure from
overturning forces. In foundation restoration repair and stabilization
applications, foundation
brackets are available that attach between the Helical Torque Anchor™
and the foundation beam or footing. Transferring the load from the
soil below the footing to the Helical piers
restores the structure.
ECP recommends that only a registered engineer design and oversee
the application of helical anchors when used in foundation repair
or new construction projects.
Configurations
of Typical ECP Torque Anchors™
|
