U.S. Pat. Nos. 6,386,295 and 6,942,430, which are incorporated here by reference, disclosed the use of vibratory and rotary drivers for the installation of pipe piling. Pipe piles, as used in the installation of structural foundations or geothermal piles, are segments of pipe that must be connected and driven together from the surface to reach the desired depth. Consequently, whether used in connection with vibratory or rotary drivers, the connection between pipe pile segments is vitally important to maximizing the driving power and reducing wear and tear in the pipe segment connection points. As the length of the column increases, weaknesses in the junctions between the pipe pile segments weaken the entire column, making it important to limit movement in the junctions.
Thus prior art methods that require the use of bolts through pipe pile and connectors increase the wear on the piles and the fasteners as some of the power from the drivers is transferred inefficiently through such joints. U.S. Pat. Nos. 6,386,295 and 6,942,430 disclosed pipe pile coupling mechanisms that may render the use of fasteners unnecessary, however, the force applied to the coupled joint through threading also created wear in the coupler and the pipe pile due to over threading or thread damage.
While it is generally acknowledged that installation of pipe piling is improved in stability and/or strength when installed with grout or similar material along the exterior of the column, prior art methods, including those disclosing push-out tips, are limited by the actual ability to push out the tip at the bottom of the column, or by difficulty in handling the grout during installation.
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