Eighteenth Canadian Geotechnical Colloquium: Limit States Design For Foundations. Part II. Development for the National Building Code of Canada: Discussion

Abstract

The following comments and observations deal only with the direct calibration of the limit states design (LSD) method by fitting with the traditional working stress design (WSD) method. However, it is observed by the author that the results of direct fitting calibration are quite similar to those obtained by calibrating the LSD method with reliability theory as discussed in the paper. In the WSD method a design is considered acceptable if Rn $ FSΣ Sni, while in the LSD method a design is acceptable if ΦRn $ ΣαiSni. In these expressions Rn is the nominal resistance and Sn is the nominal load. If it is assumed that the nominal loads are the same in both design methods then we have the following relationship which applies to all limit states, e.g., bearing capacity, sliding: