Statically Indeterminate Members

Abstract

The problems encountered in all the preceding chapters dealt with members subjected to force systems known as statically determinate force systems. The reason for this name is the fact that in all of these problems, the force system (including applied as well as known and unknown reactive forces, torques, and moments) could be fully ascertained by satisfying the applicable equations of equilibrium. In most practical situations, however, members are subjected to force systems that cannot be completely defined by satisfying only the conditions of equilibrium. For these members the equations of equilibrium lead to systems of equations in which the number of unknown quantities exceeds the number of equations. Thus the system of equations is not solvable unless supplemented, according to the principle of consistent deformations, by additional equations that are based upon member deformations. Such members are said to be subjected to statically indeterminate force systems.