Structural Steel Inspection Checklist: Standard Safety and Quality Controls
Rigorous job site quality control verifies that erected structural steel complies with engineering plans and AISC/AWS specifications. Performing systematic field inspections prevents structural defects, ensures worker safety, and prepares frames for sign-off.
1. Column Alignment and Plumbness Checks
Plumbness Tolerances: AISC code requires individual column shafts to be plumb within 1:500 relative to height, with maximum total offset caps applied based on story height. Transit levels or lasers measure deviations before final bracing verification.
Base Plate Contact and Grouting: Verify levelling nuts or shims support base plates properly before applying high-strength non-shrink grout. Inspect full grout coverage underneath plates to eliminate load-bearing voids.
2. High-Strength Bolt Tensioning Verification
Structural bolting requires verifying bolt grade (ASTM A325 or A490) and executing approved tensioning methods:
- Turn-of-Nut Method: Confirm bolts are brought to snug-tight status before applying specified fractional turns based on bolt length and diameter.
- Direct Tension Indicators (DTIs): Inspect squish washers using feeler gauges to verify required gap closure.
- Calibrated Wrench or TC Bolts: Check calibrated torque wrench logs or confirm splines snapped off tension-control bolts.
3. Weld Testing and Quality Assurance
Visual Inspection (VT): Inspectors evaluate fillet and groove welds for proper profile size, undercut limits, complete joint penetration, and absence of surface porosity or cracking.
Non-Destructive Testing (NDT): Critical full-penetration moment connections undergo Ultrasonic Testing (UT) or Radiographic Testing (RT) to inspect internal weld integrity, while Magnetic Particle (MT) testing checks surface boundaries.
Summary
Standardizing alignment checks, bolt tension verifications, and weld NDT testing keeps structural steel erection safe, code-compliant, and built to last.