Tension members are generally made of steel rods, rolled steel shapes and cables and are generally used as hangers, cross braces and truss members. Analysis One of the paradoxes of designing structures is that the stresses in each component must be known to correctly proportion the component. Thus, the member can not be designed unless the structure is analyzed to obtain stress, but the stresses can not be obtained without knowing the member geometry except in the special case of statically determinant structures. The designer must, therefore, make some assumptions about how the structure will behave, analyze the structure, calculate the stresses and check to be sure that the assumptions hold. Before the ubiquitous dominance of the computer, engineers developed a number of approximate methods for estimating the distribution of moments and shear in an indeterminant structure.
Any structural member occupies three dimensional space.
The stresses experienced by a member that experiences some loading will vary with location along the member. While the maximum moment or shear is an important quantity the designer cannot neglect the moments and shears at other locations. One very common method for displaying the variation of the shear and moment is using shear and moment diagrams. The process of designing a structural member involves arranging the dimensions and materials such that the member has sufficient strength at each location along the member. As an example, assume that a deck is being added to a restaurant.