Investigation of aluminium bolted joint (HBJ) system behavior

Abstract

Joints transfer forces propped by members to other sections of space frame. It support and connect braces with other members which provide restraints to members. In general, joints behavior is ideally rigid or ideally pinned (flexible) in typical design and study of space frames; ideally rigid Joints cannot undergo rotation and ideally pinned joints cannot transfer moment. In reality, rigid joints have relative flexibility which makes them rotate and ideally pinned have means to transfer moments. Thus, real space frame both idealized models are not real and all joints present a semi-rigid behavior [1,2]. Thus, real joint in space frame is ”semi-rigid”. Several tests have plainly shown that joints behave nonlinear because of gradual yielding of joint parts such as; plates, angles, bolts. Space frame buildings use bolted joints. However, joint behavior is complex to analyze because of discontinuities in joints areas. Features which influence joints behavior includes; bolts positions and spacing, bolts pretension and material properties. Other features such as; joints parts and contact areas evolution, compression center positions and stiffeners presence can change joints behavior. Tests can predict joints behavior, as well as elaborated modeling and analytical approaches. Space frames joints work under axial force, shear force, and bending moment. However, for most joints, axial and shear deformations are usually small liken to bending deformation [2]. This work considers only joints rotational deformation because of bending action. The present paper includes design of Aluminum bolted joints and explores it behavior experimentally. Also it analyzes and models the moment-rotation behavior of these joints by using Finite Element Model and mathematical formulas. Which will finally help to integrate the moment-rotation curves efficiently into a Space frame analysis computer program.