An overhead crane runway extension on W24×84 bridge girders — cyclically loaded per AWS D1.1 Cl. 1.4 due to continuous crane operation. The inspector evaluated 24 fillet welds on splice plates and rail clips. 22 accepted. Welds W11 and W18 rejected for visible surface porosity — two pores approximately 1/32″ diameter on the cap pass toe, violating the cyclic zero-tolerance rule (Cl. 6.9.8). After grinding and repair passes, all 24 welds accepted on re-inspection.
Frequently Asked Questions
Why does a crane runway get cyclically loaded inspection criteria?
A bridge crane traverses the full runway length repeatedly — girders experience load application and removal with every cycle plus dynamic impact loads from hoisting. AWS D1.1 classifies this as cyclic loading. Surface porosity that would not cause static failure can seed fatigue cracks under millions of load cycles.
What is a repair pass for a porosity rejection?
A corrective weld deposited after the rejectable condition is removed. Per AWS D1.1 Cl. 5.25, rejectable discontinuities must be removed by grinding or gouging before repair welding. After repair, the weld must be re-inspected to confirm acceptance.