Discussion of 'Reliability Index for Serviceability Limit State of Building Foundations' by Yu Wang and Fred H. Kulhawy

摘要

The paper deals with an important and interesting topic. The authors came to a rather shocking conclusion, i.e., the reliability index for serviceability limit state (SLS) is higher than that for the ultimate limit state (ULS). Therefore, it is necessary to trace the calculation procedure and find the reason for this conclusion. The writer would like to share the following observations and comments:1. The authors assumed that the capacity, Q, determined for the ULS is smaller than the capacity for SLS. This assumption is contrary to the approach used elsewhere in the literature and needs clarification. ULS is by definition the "ultimate" capacity; therefore, SLS capacity can at most be equal to ULS. Of course, for the same load, the reliability index is higher for the higher capacity.