Abstract
Experimental study on high strength bolted friction joints with oversized and slotted holes were executed. From this investigation it became clear that the slip coefficient decreased up to about 10% in case using d+6mm oversized holes compared with standard holes and might decrease to about 15% in case of slotted holes. This phenomenon can be evaluated using the rate of the slip strength to the yield strength of the joints based on effective sectional area. The slip coefficients have little defference between bolt size and steel grade, and it increases with lapse of time a little in case of using rust + blust treatment on joint surface. As for the relaxation, it tends to increase in the order of standard holes, oversized holes, slotted holes.
