FATIGUE STRENGTH OF 3/4 INCH STUDS IN LIGHTWEIGHT CONCRETE

THIS REPORT PRESENTS THE RESULT OF FATIGUE TESTS OF COMPOSITE STRUCTURAL SPECIMENS CONSISTING OF LIGHTWEIGHT CONCRETE SLABS ATTACHED TO A STEEL BEAM WITH 3/4-INCH ROUND HEADED STUD SHEAR CONNECTORS. FOURTEEN PUSH-OUT SPECIMENS WERE TESTED TO OBTAIN DATA ON THE EFFECT OF STRESS RANGE AND MAXIMUM STRESS IN EACH RANGE. SLIPS BETWEEN THE CONCRETE SLABS AND THE STEEL SECTION WERE MEASURED DURING STATIC AND FATIGUE LOADING. THE RESULTS ARE PLOTTED AS S-N CURVES, AND COMPARED WITH THE RESULTS OF SIMILAR TESTS IN WHICH REGULAR CONCRETE SLABS WERE USED. A COMPARISON IS ALSO MADE BETWEEN THE ABOVE TESTS AND BEAM FATIGUE TESTS.THE FOLLOWING ARE THE MAJOR CONCLUSIONS WHICH ARE GIVEN' 1/ THE STRESS RANGE HAS A SIGNIFICANT EFFECT ON THE FATIGUE LIFE OF SHEAR STUDS, 2/ IN GENERAL FAILURE OCCURRED WHEN FRACTURES DEVELOPED AT THE HEAT AFFECTED BASE OF THE STUDS, AND 3/ SLIP RESULTS DO NOT SHOW ANY IMMEDIATE RELATION TO THE FATIGUE LIFE OF THE SPECIMENS. /BPR/