Preface

Recent damaging earthquakes and other natural disasters have provided powerful reminders of how vulnerable we all are to the forces of nature.Consequently，one of the principal current challenges in structural engineering concerns the development of innovative concepts to better protect structures along with their occupants and contents from damaging effects of destructive environmental forces.

In recent years，many innovative concepts of structural protection have been advanced，one of which is passive energy dissipation（PED）.The basic role of PED devices，when incorporated into a structure，is to absorb or consume a portion of the input energy，thereby reducing energy dissipation demand on primary structural members，thus minimizing possible structural damage.

In this book，the author，Dr.Chen Yong qi，presents several case studies using PED devices in retrofitting existing structures in China and USA.The principal devices used in these studies are viscous fluid dampers（VFD）and tuned mass dampers（TMD）.These case studies provide both theoretical basis and effective application of this relatively new technology to seismic strengthening of existing structures.This book thus offers invaluable information regarding the application of these devices to existing buildings and bridges.

Tsu T.Soong

SUNY Distinguished Professor emeritus

State University of New York at Buffalo

June，2018