The advent of the digital computer made it necessary to reorganize the theory of structures into matrix form, and the first edition of this book was written for that purpose. It covered the analysis of all types of framed structures by the flexibility and stiffness methods, with emphasis on the latter approach. At that time, it was evident that the stiffness method was superior for digital computation, but for completeness both methods were extensively discussed. Now the flexibility method should play a less important
role and be characterized as a supplementary approach instead of a complementary method. The flexibility method cannot be discarded altogether, however, because it is often necessary to obtain stiffnesses through flexibility techniques.
This book was written as a text for college students on the subject of the analysis of framed structures by matrix methods. The preparation needed to study the subject is normally gained from the first portion of an undergraduate engineering program; specifically, the reader should be familiar with statics and mechanics of materials, as well as algebra and introductory calculus. A prior course in elementary structural analysis would naturally be beneficial, although it is not a prerequisite for the subject matter of the book. Elementary matrix algebra is used throughout the book, and the reader must be familiar with this subject. Since the topics needed from matrix algebra are of an elementary nature, the reader can acquire the necessary knowledge through self-study during a period of two or three weeks. A separate mathematics course in matrix algebra is not necessary, although some students will wish to take such a course in preparation for more advanced work. To assist those who need only an introduction to matrix algebra, without benefit of a formal course, the authors ha ve written a supplementary book on the subject.