ABSTRACT
This chapter examines the stress and the strain that occur in a structure when external forces are applied, and see how structural safety can be achieved by limiting these stresses. Normal or axial stresses are produced by forces that tend to make an object lengthen or shorten. Shear stresses are produced by forces that tend to make certain parts of the object slide over other parts. If this sliding is prevented, the shear stresses produce angular distortions within the object. If normal stresses are produced, the body will change its dimensions by lengthening in tension or shortening in compression. The change in dimension, expressed as a fraction of the original unstressed dimension, is called the strain. Materials differ greatly in their ability to resist tensile stress. A structural member that carries an axial tensile stress is called a tie. A structural member that carries an axial compressive stress is called a strut or a column.
