Behaviour of Steel

End-plate connections have become more popular in steel building constructions due to their economy, simplicity of fabrication, and good structural performance. The end-plate connections have been presented with three typologies: header, flush and extended end-plate connections. From which five observations can be made: -The most studied are the extended and double end-plate connections.-Most models use four bolts and no stiffeners.-3D FE is mostly used for bolts, although truss, beams and plane stress elements have been used. The nut is less commonly modelled, however, when it is modelled, a3D FE is used. The extended and the flush end-plate 6-bolts unstiffened connections are usually analyzed. There are several analysis conducted using ABAQUS/Standard software. Both materials and geometry non-linearity were considered. This element helps avoid shear locking phenomenon (comparing with element C3D8R), which will significantly affect the initial stiffness of the connection. Since the solid elements have no rotational degree of freedom, the number of elements through the thickness of each component plate plays a critical role. For the regions where the hexahedra formulation was not possible to be used the wedge approach was used with an element designated by C3D6 which is a 6-node linear triangular prism and constant pressure element. To reduce the number of contact planes and the complexity of the model, the bolt nut forms an integral component with the bolt shank rather than as an individual part. Different mesh sizes have been examined to determine a reasonable mesh that provides both reliable results with less computational time. The results show that, if the mesh is too coarse, a convergence problem will occur as the contact element was used between the column flange and the endplate surface. However, if the mesh is too fine, the computational time will be excessive. The finite element mesh adopted for all joint components with the smallest and largest element sizes being 5 mm and 50 mm, respectively. The fine mesh is thus created at the region around the bolts and studs to achieve reliable results. The finite element mesh of each specimen contains a lot of elements. The material behaviour used for the joint is represented by the bilinear plus nonlinear stress-strain curve and the plasticity behaviour in the connection was represented by the isotropic work hardening assumption.