1. School of Civil, Environmental and Architectural Engineering Korea Univ. 145, Anam‐ro, Seongbuk‐gu Seoul 02841 Republic of Korea
2. Dep. of Construction and Disaster Prevention Engineering Daejeon Univ. Daejeon 34520 Republic of Korea
3. Dep. of Civil and Environmental Engineering Univ. of California at Berkeley Berkeley CA 94720‐1710 USA