Book excerpt: This book is prepared according to the ACI Code 2019 for buildings and AASHTO LRFD Specifications for Bridges 2007. The units used throughout the presentation are the SI units, however, the expressions and examples are also given in US Customary units in the starting chapters to keep continuity with the traditional system of units. It is tried that the three main phases of structural design, namely load determination, design calculations and detailing are introduced to the beginner. This book is useful with the 2nd part of the same book. The comments on the previous editions of the book sent by colleagues, fellow engineers and students are incorporated in this edition. All persons who contributed in this regard are greatly acknowledged. Suggestions for further improvement of the presentation will be appreciated and will be incorporated in the future editions.