1. Research Engineer, Offshore Division, ExxonMobil Upstream Research Co., URC/GW3/745, P.O. Box 2189, Houston TX 77252-2189 (corresponding author). E-mail: adam.j.rinehart@exxonmobil.com
2. Associate Professor, Dept. of Civil Engineering, Texas A&M Univ., MS 3136 TAMU, College Station, TX 77843-3136. E-mail:keating@civilmail.tamu.edu