In comparing the allowable (ASD) values for HY-270 in ungrouted CMU from the 2022 Technical Guide to the LRFD values for HY-270 in uncracked, ungrouted CMU from the Masonry Anchor Design Guide, it appears that the experimental loading values give a more favorable result vs. the design equations from AC58 since LRFD loading will be higher but ASD allowable values tend to be higher. Are the AC58 equations overly conservative for this application and can HILTI translate the experimental testing for ASD to LRFD values?
Hi Jason,
There are some differences between the ASD methodology and the LRFD methodology. When using the LRFD method, there are additional reduction factors that may need to be applied to account for several possible failure modes included edge distance and anchor spacing requirements. Additional information regarding the use of the LRFD method with masonry can be in the Hilti’s Masonry Anchor Design Guide.
If you have additional questions, please email hnatechnicalservices@hilti.com.
Regards,
Ashley