This book is prepared and arranged as a textbook for undergraduant and graduate students who may have different backgrounds in their academic and working careers in the field of structural engineering. Both of the basic concepts (or principles) of structural dynamic and the practical seismic design of RC bridges are emphasized throughout the textbook. The contents of the book are divided into: Chapter 1 includes the fundamentals of earthquake engineering and seismic design. Chapter 2 includes the features of seismic damages of bridges during recent earthquakes. Chapter 3 focuses on the seismic design philosophy of bridges. Chapter 4 includes the seismic codes and philosophy of design. Chapter 5 summarizes experimental and theoretical studies. Chapter 6 includes the ductility requirements of RC bridges. I am deeply grateful for ALMIGHTY ALLAH for giving me the power and ability to complete this work. I am presenting the work for the spirit of my parents, my wife and my beloved sons and daughter; Mohamed Rehab and Abdelrahman. I deeply wish that the readers enjoy and find it useful. Khairy Hassan Abdelkareem Professor of Concrete Structures Assiut University, Egypt