Quality Assurance, Inspection, and Testing of Steel Construction
This domain separates quality control (QC) from quality assurance (QA). QC is the fabricator's and erector's own process control - their own inspectors, checks, and records, taken as a condition of doing the work. QA is the owner-side verification, sampling the contractor's results through independent observation and testing. AISC 360 Chapter N names the inspection tasks and the records that must exist; the special inspector typically performs the code-mandated portion.
What is actually inspected
- Bolted work: bolt grade and length, hole type and condition, washer placement, snug-tight condition, the tensioning method, calibration records, and match marks. For pretensioned and slip-critical joints, the RCSC inspection practice observes a sample of the bolts in each connection - commonly at least 10 percent, with a minimum of two per connection - rather than verifying every bolt.
- Welded work: WPS availability and adherence, welder qualification, fit-up and joint preparation, preheat, and visual inspection of all welds, with NDT where specified.
- Testing equipment: tension calibrators (Skidmore-Wilhelm) for wrench calibration; feeler gauges for DTIs; qualified NDT personnel and calibrated instruments.
Inspection is organized around hold points - stages where work may not proceed until the inspector has observed and accepted it, such as before welding a CJP groove joint or before final tensioning.
Traps: treating QA as a duplication of QC and therefore unnecessary; assuming a sample inspection proves every bolt or weld; confusing a calibrated torque wrench with a tension calibrator (torque is not tension); failing to record which bolts were sampled.
Rule of thumb: if it is not written down with a date, a location, and a piece mark, it did not happen - record the sample size and the acceptance basis for every inspection lot.