My bolt supplier said they can substitute ASTM F1554 Grade 55 anchor bolts for the F1554 Grade 36 anchor bolts that are specified on my project. Is this correct?

ASTM F1554 does specifically state in Section 6.4 that the manufacturing company can substitute weldable F1554 Grade 55 material in place of F1554 Grade 36 material at the option of the manufacturing company. So technically your supplier is correct that they can substitute F1554 Grade 55 for F1554 Grade 36 at any time, as long as it is weldable material. Due to a combination of factors (the specification is worded “may be furnished at the supplier’s option”, F1554 Grade 55 material has a higher tensile/yield, and is typically, but not always, weldable material) a fastener supplier/manufacture may make the decision to substitute F1554 Grade 55 with little or no notification/permission from the purchasing company. The vast majority of the time this substitution will likely not matter, however Portland Bolt has been contacted by engineers for specific projects with seismic concerns were substituting F1554 Grade 55 (or any other higher strength material) in place of F1554 Grade 36 may compromise the structural integrity of the design. In fact, we have recently seen many of these projects with comments written into the project specifications specifically prohibiting substituting anything for the F1554 Grade 36 anchor bolts.

Technically, by specifying F1554 Grade 36, an engineer is essentially allowing F1554 Grade 55 material to be used on their project, but the engineer may not be fully aware of this clause in the specification and may be expecting the properties of F1554 Grade 36. It is Portland Bolt’s stance to always notify the customer when making this substitution of F1554 Grade 55 for F1554 Grade 36 and encourage them to clear it with the Engineer of Record. Substituting grades or configurations of product without an engineer’s approval can expose both us and our customer to a tremendous amount of liability.

Also, F1554 grade 55 is inherently a more expensive material and your supplier could be passing their higher material costs onto you, just so they don’t have to inventory both grade 36 and grade 55 steel. Portland Bolt has committed ourselves to stocking a full line of steel round bar for both F1554 Grade 36 and F1554 Grade 55 to meet the needs of our customers. Our 140,000 square foot facility is filled with a comprehensive steel inventory in 12 different grades ranging from 1/2” – 4” diameter.

4. Classification

4.1 The anchor bolts are furnished in three grades denoting minimum yield strength and two classes denoting thread class as follows:

Grade Tensile Strength, ksi (MPa) Description Yield Strength, min, ksi (MPa) Size Range, in. (mm)
36A 58 - 80 (400 - 558) 36 (248) 14 - 4 (6.4 - 102)
55 75 - 95 (517 - 655) 55 (380) 14 - 4 (6.4 - 102)
105 125 - 150 (862 - 1034) 105 (724) 14 - 3 (6.4 - 76.2)
1A anchor bolts with Class 1A threads
2A anchor bolts with Class 2A threads
A When Grade 36 is specified, a weldable Grade 55 may be furnished at the supplier's option.

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