1. Research Fellow, Dept. of Civil and Structural Engineering, The Univ. of Sheffield, Sheffield S1 3JD, U.K.
2. Professor, Dept. of Civil and Structural Engineering, The Univ. of Sheffield, Sheffield S1 3JD, U.K.
3. Professor, School of Architectural Studies, The Univ. of Sheffield, Sheffield S10 2TN, U.K.