Earth screw socket anchor for power line is governed by simple geotechnical engineering principles. In excavations,Earth screw socket anchor for power line is controlled primarily by the bearing resistance on each helical plate.A Earth screw socket anchor for power line is an extendable deep foundation system with helical bearing plates welded to a central steel shaft. The load is transferred from the shaft to the soil through these bearing plates.
Torque correlation method: The Torque Correlation Method is an empirical method that distinguishes the relationship between helical pile capacity and installation torque and has been widely used since the 1960's. The process of a helical plate shearing through the soil or weathered bedrock in a circular motion is equivalent to a plate penetrometer test. The method gained notoriety based on the study performed by Hoyt and Clemence (1989). Their study analyzed 91 helical pile load tests at 24 different sites within various soil types ranging from sand, silt and clay soils. They demonstrated the direct correlation of the installation torque of a Earth screw socket anchor for power line to its ultimate capacity in compression or tension. The common denominator discovered from the study was a parameter referred to as the torque correlation factor, Kt.
The equation is:
Pu = Kt T
Pu is the ultimate capacity of the helical pile or anchor [lb (kN)].
Kt is the empirical torque factor of the central shaft of the pile [ft-1 (m-1)].
T is the final installation torque [ft-lb (m-kN)].
It's important to point out that the tests analyzed by Hoyt and Clemence (1989) were in tension. It was shown in sub-sequential studies that the tension capacity of Earth screw socket anchor for power line was 16 to 33 percent less than the measured compression capacity. The difference is attributed to the fact that the lead helical plate is bearing on relatively undisturbed soil in compression applications. In tension applications, the leading and trailing helical plates are bearing on soil affected by the installation of the helical plates. It has become common practice to use the same torque correlation factor for a helical pile of the same size for tension and compression and ignore the slight increase in compression capacity. This creates a more conservative compression capacity for helical piles when compared to the Individual Bearing Method. Also unlike the Individual Bearing Method, the number of helical plates on a pile is completely independent of the piles capacity based on the Torque Correlation Method.
.A Earth screw socket anchor for power line is an extendable deep foundation system with helical bearing plates welded to a central steel shaft. The load is transferred from the shaft to the soil through these bearing plates.