TABLE OF CONTENTS Statics, as the name implies, is concerned with the study of bodies at rest or, in other words, in equilibrium, under the action of a force system. Actually, a moving body is in equilibrium if the forces acting on it are producing neither acceleration nor deceleration. However, in structural engineering, structural members are generally at rest and therefore in a state of statical equilibrium.
In this chapter we shall discuss those principles of statics that are essential to structural and stress analysis; an elementary knowledge of vectors is assumed.
The definition of a force is derived from Newton's First Law of Motion which states that a body will remain in its state of rest or in its state of uniform motion in a straight line unless compelled by an external force to change that state. Force is therefore associated with a change in motion, i.e. it causes acceleration or deceleration.
The basic unit of force in structural and stress analysis is the Newton (N) which is roughly a tenth of the weight of this book. This is a rather small unit for most of the loads in structural engineering so a more convenient unit, the kilonewton (kN) is often used.
All bodies possess mass which is usually measured in kilograms (kg). The mass of a body is a measure of the quantity of matter in the body and, for a particular body, is invariable. This means that a steel beam,...
