Abstract:A kind of retrofitted bolt weld connection details and its corresponding design methods are proposed on the basis of the conventional RHS column joint with through diaphragm to meliorate structural robustness. With a view to material fracture and the path tracking after fracture, the numerical results indicate that the retrofitted bolt weld connection details can enhance the vertical deformation capacity of the beam column assemblies before the force transmission failure at the bottom of connection region, which is conductive to the development of catenary action by axial force in the beams. Therefore, the beam column assemblies can provide greater vertical carrying capacity and the connection details can be used in transforming structures against progressive collapse.