Can an F1554 Grade 55 anchor bolt be substituted for an F1554 Grade 36 anchor bolt?
Yes. According to ASTM F1554-15 when Grade 36 is specified, a weldable Grade 55 may be furnished at the supplier’s option.
F1554 Grade 36 vs. F1554 Grade 55
F1554 is the ASTM specification for fasteners that have an intended use for anchoring structural supports to concrete foundations. The specification is available in three strength grades: Grade 36, Grade 55, and Grade 105. The number designation for each grade is an indication of the grade’s minimum yield strength measured in ksi. F1554 Grade 36 is a low carbon, mild steel anchor bolt, whereas F1554 Grade 55 is a high strength, low alloy anchor bolt. Grade 36 has a carbon equivalence which allows it to be weldable. Grade 55 must meet the requirements of supplement S1 of the ASTM F1554 specification in order to be certified as weldable. Therefore, F1554 Grade 55 must meet supplementary requirement S1 and be weldable in order to be substituted for F1554 Grade 36. F1554 grade 55 anchor bolts that do not meet these weldability requirements cannot be substituted for F1554 grade 36.
Substitution Allowance
ASTM states in section 6.4 of F1554-15, “…At the manufacturer’s option, a weldable Grade 55 may be supplied when Grade 36 is specified.” This means the supplier, at their discretion, can choose to substitute a weldable Grade 55 for Grade 36. We would encourage our customers to confirm the substitution with the Engineer of Record.
Portland Bolt will often choose to implement this type of substitution in instances when it will save the customer time and/or money, however, we will only do this with the customer’s approval. This allowance is useful for Portland Bolt when asked to supply heavy hex Grade 36 bolts because we stock “blanks” that are already headed with a Heavy Hex head in F1554 Grade 55. Since the “blanks” meets S1 (weldable) we are allowed to provide Grade 55 instead of Grade 36 to meet the configuration requirement. We may also choose to substitute a weldable Grade 55 bent anchor bolt for a Grade 36 bent anchor bolt since we stock a variety of sizes.
Please note that this substitution of weldable Grade 55 for Grade 36 is the only substitution of a higher strength bolt for a lower strength bolt that ASTM allows within the context of their fastener specifications. Except for this instance, Portland Bolt estimators will never suggest you substitute one grade of fastener for another grade or suggest you substitute one type of bolt for another type of bolt without first consulting with the Engineer of Record. If you are using fastener suppliers who offer these types of substations, we suggest reconsidering the vendors from whom you choose to buy fasteners. Allowing these types of substitutions based on a recommendation from your fastener supplier may expose both you and your company to a tremendous amount of liability. For more on this topic, read Liability Issues Regarding the Substitution of Fasteners.
Copper content for anchor rods: it says “when specified”. Does that mean its up to me when I buy anchor rods to specify the specific copper content?
@Sam- It means that it isn’t a requirement unless the steel is ordered that way from the mill. If your needs require some copper, make sure to let us know and we can check our inventory. I did look a moment ago at several of our G36 and G55 mill test reports, and they all had above 0.20% copper.
What is the cost difference between the two grades?
@Marcus- The price difference will ultimately depend of the specifics of your need, but generally speaking it will be negligible. We’d expect a less than 5% difference unless there are extenuating circumstances.