Extending Performance-Based Design Methods by Applying Structural Engineering Design Patterns

Performance-based design methods are powerful tools for designing structures that are safe, reliable, and predictable in an environment with rare but potentially catastrophic hazards, such as earthquakes. The design methods used today are made for the just-built state of the structure, and place relatively little emphasis on other stages in the structure's life cycle. Current design methods need extensions that specifically consider performance across the entire life cycle of the structure, for example for the construction stage or the stage of post-earthquake repairs. Such considerations are challenging during the early stages of design because the precision necessary for analyzing structural performance during, for example, construction and post-earthquake repair stages is typically unavailable until too late after design decisions are made. Therefore, the task of extending performance-based design requires an analysis of design information, analysis methods, and decision making. Those needs are fulfilled in this thesis by investigating structural engineering analysis and decision making methods using the design pattern method, and by defining the qualities and types of design information. Patterns describe procedures and practices for solving recurring problems in a general way, which allows comparison and understanding of the tradeoffs involved in their use. The definition of structural engineering design information categories reveals what information is needed to perform certain types of analysis for construction and repair, and how to communicate it at the appropriate level of detail. This description explains the different types of information needed for conceptual design and for construction. The discussion of analysis and decision methods using patterns identifies unnecessarily premature decisions in existing structural design methods, and locations where mechanics models alone are insufficient for understanding structural performance. The pattern definitions also allow concise expression of design intent within structural engineering problem solving methods. The modifications to performance-based design methods, developed through examples using the pattern framework and presented in this thesis, incorporate performance considerations for all phases of the structure life cycle. These recommendations include: considering additional analysis patterns during design, using decision patterns that account for performance in all life cycle phases, and implementing set-based design methods for evaluating multiple design options.