*Posted on behalf of a Hilti customer
What is the difference between Allowable Stress design (ASD) and Limit States Design (LSD)?
Dear customer,
thank you for your question. Under the Allowable Stress Design Method, the allowable load, or resistance, is based on the application of a safety factor to the mean result of laboratory testing to failure, regardless of the controlling failure mode observed in the tests. The safety factor is intended to account for reasonably expected variations in loading. The Limit States Design Method for anchor design has been incorporated into several codes such as CSA A23.3 Annex D. The method assigns specific strength reduction factors to each of several possible failure modes, provides predictions for the strength associated with each failure mode, and compares the controlling strength with factored loads. The Limit States Design Method is a more accurate estimate of anchor resistance as compared to the ASD approach. I hope I have answered your question. If there is anything else, please let me know.
Best Regards
Aidan