BantrelStructural
Structural
- Nov 5, 2002
- 25
I am looking for some back up literature on pre-tensioned anchor rods to fill in a few gaps in the information that I have been able to find todate:
1. I have seen recommendations in the past not to pre-tension rods with yield strength below 60-70 Ksi. I basically understand that there are concerns with pre-tensioning mild steel rods, but would like to see more specific information on these concerns.
2. I have also seen a range of pre-tension values, some expressed as a percentage of ultimate and others as a percentage of yield. Are there any good guidelines on what range of values should be considered?
I can see where questions 1 and 2 might be somewhat related as the relationship between yield and ultimate changes as the grade of steel increases (at least for ASTM F1554 specified materials).
These questions relate to bolts that are unbonded full length between the bottom nut/washer/plate and the equipment base plate, so the creeping failure of concrete/grout bond with the anchor is not a factor.
1. I have seen recommendations in the past not to pre-tension rods with yield strength below 60-70 Ksi. I basically understand that there are concerns with pre-tensioning mild steel rods, but would like to see more specific information on these concerns.
2. I have also seen a range of pre-tension values, some expressed as a percentage of ultimate and others as a percentage of yield. Are there any good guidelines on what range of values should be considered?
I can see where questions 1 and 2 might be somewhat related as the relationship between yield and ultimate changes as the grade of steel increases (at least for ASTM F1554 specified materials).
These questions relate to bolts that are unbonded full length between the bottom nut/washer/plate and the equipment base plate, so the creeping failure of concrete/grout bond with the anchor is not a factor.
