Abstract
Failure analyses of cracked splice plates made from ASTM A514 quenched and tempered steel revealed that the steel was inadequately tempered, resulting in an excessively hardened, brittle defective steel. Consequently, this steel was also susceptible to stress corrosion cracking/hydrogen stress cracking (SCC/HSC). The I-275 twin bridges contained large quantities of A514 steel that needed testing to identify any remaining defective steel. A test plan was developed that incorporated hardness testing to discriminate between acceptable and the defective A514 steels. The plan incorporated the use of the ultrasonic contact impedance and impact hardness test methods. Field hardness testing was conducted over a 10-week period beginning in October 2008. During the testing, two additional cracked splice plates were discovered that contained defective A514 steel. The hardness test methods were successfully used to identify 14 defective A514 steel plates on the two bridges.