For the Hilti HY 200 V3 epoxy, each size of anchor lists a maximum installation torque for threaded rods. For example, a 5/8" threaded rod shows a maximum installation torque of 60 ft-lb. What nut friction factor is this based on? Is it the same as ACI 355.4-19 which uses 0.2 for normal threaded rods without lubricants or friction-reducing coatings, or a different value?
What I specifically want to know, is does the installation torque needs to be reduced if a lubricant is used? I read in another ask Hilti article (https://ask.hilti.com/question/the-effect-of-over-torquing-a-chemical-anchor/muwleo) that over-torquing an epoxy anchor can cause micro-fractures and overstrain the epoxy and result in a reduced load. Do I need to take this into account with a lubricant which reduces the nut factor? And if so, what nut factor was used for the maximum installation torque in the MPII?
Hi Chad,
The maximum installation torque was found through testing. Additionally, Hilti does not have any testing if a lubricant is used with the nuts. However, it will be up to the engineer of record on the project to determine if a lubricant is suitable to be used for a specific application. If you would like to discuss your application further, please reach out to us at hnatechnicalservices@hilti.com or give us a call at 877-749-6337.
Regards,
Ashley