Aerodynamic Derivative Identification Method of Parallel Twin-girder Bridges by Mixed Forced vibration Wind Tunnel Test ZhouQi ZhuLedong ZhouCheng GuoZhenshan 2017 This paper was reviewed and accepted by the APCWE-IX Programme Committee for Presentation at the 9th Asia-Pacific Conference on Wind Engineering, University of Auckland, Auckland, New Zealand, held from 3-7 December 2017.