FieldVerify
Structural
- Aug 24, 2011
- 4
A recent project specified ASTM A325 Type 3 bolts. The Contractor came back and stated that he can get SAE J429 Grade 8 bolts for a 1/8th the cost and he can pass on the cost savings to the project for other work.
The question is, can a SAE J429 Grade 8 replace a ASTM A325 bolt in a long-life exterior application in a cold climate? The A325 is a weathering steel and the J429 is an alloy. The J429 yield strength is 130,000psi vs. 92,000psi for the A325 and the tensile strength of the J429 is 150,000psi vs. 120,000 psi for the A325. Other than the J429 having a smaller bolt head which can be rectified with a structural washer in this application, are there other issues that make the J429 unacceptable for this? Is the J429 susceptible to long term deflection/elongation that A325 is not? Is there any standard guidance for the choice between the two, I didn't find anything in AISC.
The question is, can a SAE J429 Grade 8 replace a ASTM A325 bolt in a long-life exterior application in a cold climate? The A325 is a weathering steel and the J429 is an alloy. The J429 yield strength is 130,000psi vs. 92,000psi for the A325 and the tensile strength of the J429 is 150,000psi vs. 120,000 psi for the A325. Other than the J429 having a smaller bolt head which can be rectified with a structural washer in this application, are there other issues that make the J429 unacceptable for this? Is the J429 susceptible to long term deflection/elongation that A325 is not? Is there any standard guidance for the choice between the two, I didn't find anything in AISC.
