Abstract
Studs are primarily used as shear connectors in composite structures. The load carrying capacities of studs are determined with push-out tests. The test results are scattered about, even in the same batch of tests; in an extreme case, the minimum capacity is smaller than one half of the maximum. In the case of the same stud and the same concrete, the standard deviation of the material strength is very small, so it is not thougth that the scatter is caused by materials. And the scatter is to be caused by the uncertainty of the collapse mechanism. In this paper, three collapse modes, which are crush of concrete, pull out of stud, and ductile fracture of stud, are delt with. Three Fuzzy sets which express the collapse strengths of these three modes are made up. With these Fuzzy sets, the load carrying capacities are discussed.
