1. College of Shipbuilding Engineering Harbin Engineering University Harbin 150001, P. R. China
2. Department of Civil and Structural Engineering University of Sheffield , Sheffield S1 3JD, UK
3. School of Water Resources and Electric Power Qinghai University , Xining 810016, P. R. China
4. Department of Civil and Earth Resources Engineering Kyoto University , Kyoto 615-8540, Japan
5. School of Engineering and Mathematical Sciences City University London , London EC1V OHB, UK