| 摘要 |
A low cost, easy to install underpinning apparatus (14) for supporting below-grade structural footings such as foundations (10) or the like is provided which makes use of a power installed, load-bearing helix-type screw anchor (16) together with a connecting bracket assembly (b 19) secured to the foundation (10). The anchor (16) is screwed into the earth below the foundation (10), leaving the upright end of the anchor shaft (20) adjacent the foundation (10). The bracket assembly (18) advantageously includes a foundation-engaging plate (28) with a pair of spaced, outwardly extending wall portion (30, 32) rigidly secured thereto. An elongated, U-shaped bracket (36) together with a mating retainer (42) are releasably secured to the wall portions (30, 32) and serve to captively retain the upper end of the anchor shaft (20), with the U-bracket (36) having a top crosspiece wall (38) provided with a threaded opening (40) therethrough. A threaded, force-transmitting bolt (54) screwed into the bracket crosspiece (38) engages the uppermost butt end (22) of the anchor shaft (20) so that the anchor (16) becomes a load-bearing support for the foundation (10). Rotational torque is imparted to each screw anchor during installation as a force independent of a respective support and the foundation until a predetermined torque value is achieved. The rotational torque on the screw anchor is then relieved and the dead weight and any live load of the building structure carried by the bracket assembly is transferred to the screw anchor.
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