Steel Structure Inspection

Per EN 1090-2 Section 5, all structural steel must have CE marking and be traceable to mill certificates (EN 10204 Type 3.1). Steel grades (S235, S275, S355, S460) must match the design specification. Material properties must conform to EN 10025 for hot-rolled products.

1. Verify mill certificates (EN 10204 Type 3.1) are available for all steel members

2. Check CE marking and declaration of performance for each delivery

3. Confirm steel grade markings on members match design (e.g., S355J2)

4. Verify material traceability — each piece traceable to its certificate

5. Check that substituted materials have equal or higher grade with engineer approval

- Missing or incomplete mill certificates

- Steel grade does not match design specification

- Traceability lost during fabrication — unmarked offcuts reused

- Incorrect steel sub-grade for service temperature (e.g., J0 used where J2 required)

Per EN 1090-2 Section 8, bolted connections must use the correct bolt class (8.8 or 10.9 for structural use per EN ISO 898-1). Preloaded bolts in slip-resistant connections must be tightened per EN 1090-2 Table 20 using calibrated torque, combined, or direct tension methods. Bolt hole tolerances per EN 1090-2 Table 11.

1. Verify bolt class (8.8 or 10.9) matches design — check head markings

2. Check bolt tightening method for preloaded connections (torque, combined, or DTI)

3. Verify torque values with calibrated torque wrench per EN 1090-2 Table 20

4. Inspect bolt hole alignment — no excessive reaming or elongated holes

5. Check that washers, nuts, and bolts are from the same set (matched assemblies)

- Wrong bolt class installed (e.g., 4.6 instead of 8.8)

- Preloaded bolts not properly tightened — slip under service loads

- Bolt holes misaligned, forced with drift pins causing member damage

- Missing washers on oversize or slotted holes

Per EN 1090-2 Section 7 and EN ISO 5817, welds must meet the specified quality level — typically B (stringent) or C (intermediate) for structural connections. Welding procedures must be qualified per EN ISO 15614-1. Welders must hold valid certificates per EN ISO 9606-1.

1. Verify welding procedure specifications (WPS) are approved and available

2. Check welder qualification certificates (EN ISO 9606-1) are valid and cover the joint type

3. Visually inspect welds per EN ISO 5817 — check for undercut, porosity, cracks, incomplete fusion

4. Verify NDT (non-destructive testing) has been performed per inspection plan — UT, MT, or PT as specified

5. Check weld dimensions (throat thickness, leg length) against design using weld gauges

- Welds not meeting quality level B or C per EN ISO 5817

- Lack of fusion or incomplete penetration in full-penetration butt welds

- Lamellar tearing in thick plates with through-thickness loading

- Welding without approved procedure or by unqualified welder

Per EN 1090-2 Section 10 and EN ISO 12944, corrosion protection must suit the corrosivity category (C1–C5, CX). Surface preparation must meet the specified grade per EN ISO 8501-1 (typically Sa 2½ for blast cleaning). Coating system (primer, intermediate, topcoat) must match the durability requirement (low, medium, high, very high).

1. Verify corrosivity category matches the environment (e.g., C3 for urban, C5 for marine/industrial)

2. Check surface preparation grade — Sa 2½ is typical for structural steel

3. Measure dry film thickness (DFT) of each coat — must meet specification per EN ISO 12944-5

4. Inspect for coating defects: holidays, runs, sags, blistering, or missed areas

5. Check that field connections and welds are touch-up coated after erection

- Insufficient surface preparation — rust or mill scale under coating

- Coating too thin or too thick (both cause premature failure)

- Field welds and bolt connections left uncoated

- Wrong coating system for the corrosivity category