Computer assisted conceptual structural design of steel buildings

The design quality of a building is mostly determined during the conceptual design stage since the succeeding design tasks generally aim at satisfying the constraints imposed during this stage. Computers have been used extensively in structural design, but usually in applications that have focused on well-posed procedural problems. However, they have not been used effectively to handle an ill-structured problem such as the conceptual design of a building structure.; The ultimate goal of our research is to develop an intelligent consultant system (ICS) for the conceptual structural design of buildings. As an initial step towards this goal, this study focuses on the development of a design support system that can be employed to acquire the design control knowledge needed for a computer-based ICS. An interactive design system, BERT (Building Engineering and Reasoning Tool), has been developed for designing moment resisting steel frame structures. Both object-oriented symbolic and procedural programming paradigms are employed in the development of BERT. Given the loading conditions (earthquake loads, live loads and dead loads) and building configuration (such as number of stories and number of frames), BERT has the capability to design and "optimize" member sizes through reasoning about the behavior of the structure.; The methodology for "optimizing" member sizes is based on two basic criteria. The first is to satisfy the strength requirements at the local (member) level. The second is to satisfy interstory (flexural and shear) drift control requirements at the global level by considering the behavior of the structural system. The results based on the strength and interstory drift requirements are combined to provide the design information needed to evaluate the costs of material, fabrication and erection of a steel building structure.; A comparison between BERT's results and FEM results confirmed the validity of the design methodology implemented in BERT. The effectiveness of BERT is demonstrated by designing several alternatives for a 15-story steel frame building, evaluating their cost effectiveness, and comparing the design results of Bert with those of an expert engineer.