To meet the social and economic needs for safe and efficient transportation systems, more and more long suspension bridges have been built throughout the world using new design concepts and new structural systems.Nevertheless.the global environment is being largely changed by human beings activities, and these long suspension bridges are surrounded by harsher environment than ever before.modern structural health monitoring of long suspension bridges aims at providing a new way to ensure that bridge structures function properly throughout their long service lives and to prevent them from failing catastrophically during extreme events such as strong winds and earthquakes[1,2].