Any opinions, statements, or recommendations contained in this report are those of the authors and do not reflect the views of or imply endorsements by NIST or the U.S. Government. Additionally, neither NIST nor any of its employees make any warranty, expressed or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, product, or process included in this publication. NIST policy is to use the International System of Units (metric units) in all its publications. In this report, however, information is presented in U.S. Customary Units (inch-pound), as this is the preferred system of units in the U.S. earthquake engineering industry.