SHEAR BEHAVIOR OF NOVEL DEMOUNTABLE BOLTED SHEAR CONNECTOR FOR PREFABRICATED COMPOSITE BEAM

Bolted shear connectors offer alternatives to achieve steel-concrete composite action instead of conventional welded headed studs especially for prefabricated constructions and demountable composite structures. This paper firstly proposed a new type of demountable steel-concrete bolted shear connectors based on the double-nut friction-grip high strength bolted connector, which modify the upper nut into conical locking nut. This paper performed ten full scale push-out tests to study shear behaviors of the developed new type of connectors. Testing parameters included bolt configuration, strength, diameter of bolts and strength of infilled grout. Test results indicate that shear behaviors and slip capacity of the conventional bolted connectors are significantly improved when the bolted connector incorporating with conical locking nut. The influences of these studied parameters on shear behaviour of novel bolted shear connectors are revealed and discussed. The developed novel demountable connector exhibits an average 25% improvement in ultimate shear resistance over conventional bolted connectors. Moreover, the shear stiffness of the developed bolted connectors is about six times of the conventional bolted connector through eliminating the clearance between steel flange hole and bolt shank.