| In recent years, the use of rectangular Hollow Structural Sections (HSS) as columns has become increasingly popular. In many instances rectangular HSS column members are replacing customary I-section members due to their superior column performance. In turn, welded longitudinal branch plates that have been a traditional and convenient method for the connection of brace members and other attachments to I-section columns are now similarly used for rectangular HSS columns. The current design method, consisting of welding a branch plate parallel to the axis of the column has not been thoroughly investigated, especially for the effects of connection flexibility, of branch plate inclination angle and of axial compression load in the column. This represents a known omission in current HSS column connection design knowledge and published design specifications.; Based on experimental testing of isolated connections, parametric non-linear Finite Element analysis and analytical yield line analysis, the strength and behaviour of longitudinal branch plate-to-rectangular HSS member connections have been determined. On the basis of this, design criteria are herein proposed. These recommendations have also been reported in technical literature and the recommendations are being incorporated into design specifications and guides for HSS connections.; A conventional longitudinal branch plate-to-rectangular HSS member connection tends to cause excessive distortion of the HSS connecting face. Such a connection therefore results in a low, deformation limit state, design resistance. In an effort to reduce this inherent flexibility of longitudinal branch plate connections, stiffening plates or structural tees can be welded to the HSS connecting face. Also, a “through” branch plate connection that extends through both walls of the rectangular HSS member can be used to increase the strength of a standard longitudinal branch plate connection. These “alternative” connections represent the next generation in rectangular HSS connection design. Once again, based on experimental testing of such connections, non-linear Finite Element analysis, and analytical yield line analysis, the strength and behaviour of “alternative” branch plate-to-rectangular HSS member connections have been determined and modelled, resulting in published recommendations.; This thesis develops comprehensive, rational, limit states design procedures and equations that encompass, and wherever possible consolidate the behaviour of, the multitude of branch plate-to-rectangular HSS member connection types that will now be available to designers. |
