Dynamics of Civil Structures, Volume 2: Proceedings of the 39th IMAC, A Conference and Exposition on Structural Dynamics, 2021, the second volume of nine from the Conference brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of the Dynamics of Civil Structures, including papers on: Structural Vibration Humans & Structures Innovative Measurement for Structural Applications Smart Structures and Automation Modal Identification of Structural Systems Bridges and Novel Vibration Analysis Sensors and Control.