Performance-based design method is the emerging design procedure especially for reinforced concrete structures demanding a realistic assessment of the performance. This accurate assessment is critical especially for columns in bridges and tall buildings not only for designing new structures but also for decisions such as retrofit or replacement of the existing ones. The effects of the axial load and loading pattern are significant in the overall performance of reinforced concrete columns. Flexural strength capacity, failure pattern, and ductility and deformation of reinforced concrete columns are affected by not only the level but also the pattern of the applied axial load. The plastic hinge formation is different in the case of a variable axial load, requiring a modification of the existing plastic hinge models. The conventional analytical methods may underestimate or overestimate the flexural strength of a section for the same level of the axial load depending on the load history. Results of an extensive analytical and experimental research on the effects of the load pattern on the performance of reinforced concrete columns is addressed in this book.