A New Method for Design of the Semi-Rigid Steel Frame—The Integration of Joint Inverse Design and Structural Design

In the past few decades, semi-rigid connections have been studied extensively; several major international steel structure design specifications have incorporated this component into their own systems. However, there is still no appropriate way to integrate the semi-rigid joint design into the structural design more efficiently. The forward design method of introducing joint characteristics into the frame by predetermining joint details requires considerable effort to trial massive amounts of variables, which is undoubtedly a nightmare for those structures composed of thousands of members and joints. In this paper, a feasible method for the reversed design of semi-rigid steel frames has been developed. Being similar to the traditional one, the structural design is still divided into member design and joint design. In the member design phase, a joint is abstracted as a performance parameter and its details are no longer concerned. Then, in the joint design phase, the joint details can be reconstructed subject to the joint required performance by using the optimization algorithm. Throughout the process, engineers simply tune the desired properties of the joins rather than their construction geometry, which results in clearer tuning direction and improved solution efficiency. In addition, determining how to choose a good, required connection stiffness as the starting design is discussed and recommendations are given. Finally, two examples are solved to verify the effectiveness of the proposed method.