1. Department of Civil and Environmental Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA - 15213, USA
2. Department of Civil and Environmental Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA - 15213, USA, Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea,
3. Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA - 15261, USA