Issues on performance-based engineering for buildings and bridges

Structures including buildings and bridges deteriorate and may not function in a satisfactory way as expected with time. Increasing number of cases of lack of satisfactory performances prompted the profession to consider developing performance-based design guidelines replacing or at least providing alternatives to the current specification (code) based practices. However, before developing such guidelines, the civil engineering profession should reach consensus on the definition of performance and establish quantitative, measurable indices that will permit the measurement of current or the projection of expected future performances. Performance-based design concept depends on many inter-connected issues including areas of applications, definition of performance, tools for measuring performance, quantitative indices that need to be satisfied, and performance under uncertainty. It is also important to note that since all major building codes on concrete, steel, wood, and masonry are now based on the Load and Resistance Factor Design (LRFD) concept; the future performance-based design guidelines should reflect the thinking behind this same concept. It is also known that the performance-based design concept is relatively new for civil engineers, the area is evolving, and comprehensive basic research is in its infancy. The paper will outline some of the recent thoughts on developing performance-based design guidelines.