Distortion failures are readily identified by the inherent change in size and/or shape. They are serious because they can lead to other types of failure or may even cause complete collapse of structures, such as bridges, ladders, beams, and columns. Distortion failures may be classified in different ways. One way is to consider them either as dimensional distortion (growth or shrinkage) or as shape distortion (such as bending, twisting, or buckling). They may also be classified as being either temporary or permanent in nature. This chapter discusses the nature, causes, and effects of all of these types of failures as well as the methods to manage them.

Depending on the operating environment and the nature of the applied loading, a structure can fail by a number of different modes, including brittle fracture, ductile fracture, plastic collapse, fatigue, creep, corrosion, and buckling. These failure modes can be broken down into the categories of fracture, fatigue, environmental cracking, and high-temperature creep. This article discusses each of these categories, as well as the benefits of a fitness-for-service approach.