TORQUE SHEAR TEST OF CYLINDRICAL FRICTION PILES

ALTHOUGH AXIAL LOAD TESTS ARE THE ONLY SURE METHOD FOR DETERMINING ULTIMATE BEARING CAPACITY OF INDIVIDUAL PILES, CONVENTONAL PROCEDURES ARE COSTLY AND INCONVENIENT. BECAUSE OF HIGH COSTS AND TIME, FEWER PILE LOAD TESTS ARE SPECIFIED THAN MIGHT BE USEFUL AND DESIRABLE. WHEN DEALING WITH FRICTION PILES IN VARIABLE SOIL CONDITIONS, ONE WONDERS WHETHER THE TEST LOAD-PILE LENGTH CAN BE APPLIED TO THE WHOLE JOB. THUS THE NATURAL TENDENCY IS TO DRIVE PILES "LONG" TO BE SURE OF SAFETY. HERE A SIMPLIFIED FIELD TORQUE SHEAR LOAD TEST IS PRESENTED. THE TEST DETERMINES REQUIRED PENETRATION DEPTH OF FRICTION PILES ON THE BASIS OF TORQUE SHEAR RESISTANCE MEASURED DURING CONSTRUCTION. /ASCE/