1. Associate Professor, Dept. of Civil Engineering, Univ. of Toronto, 35 St. George St., Toronto, Ont., Canada M5S 1A4 (corresponding author).
2. Professor and Canada Research Chair in Earthquake Engineering, Group for Research in Structural Engineering, École Polytechnique, Montreal, Canada H3C 3A7.
3. Postdoctoral Fellow, Dept. of Civil Engineering, Univ. of Toronto, 35 St. George St., Toronto, Ont., Canada M5S 1A4.
4. Research Engineer, Group for Research in Structural Engineering, École Polytechnique, Montreal, Canada H3C 3A7.