Abstract: A fastener assembly for use in a joint in a work-piece comprises a first fastener component for extending through a hole in the work-piece, a second fastener component and a resilient element. The first component has a first contact portion for engaging the work-piece. The second fastener component has a second contact portion for cooperating with the first fastener component to compressively load the work-piece thereby forming the joint. The resilient element is located between the first and second contact portions so that it is it is compressed under load. The resilient element has a first stiffness characteristic when subjected to loading less than a predefined amount and has a higher stiffness characteristic when subjected to loading more than the predefined amount.