Steel Structure Inspection

In accordance with EN 1090-2 Section 5, all structural steel must bear CE marking and be traceable through mill certificates (EN 10204 Type 3.1). Steel grades (S235, S275, S355, S460) must match the project specification. Material properties must comply with EN 10025 for hot-rolled products. CTE DB SE-A establishes supplementary requirements for Spain.

1. Check that mill certificates (EN 10204 Type 3.1) are available for all steel elements

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

3. Confirm that steel grade markings on elements match the design (e.g. S355J2)

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

5. Ensure substitute materials are of equal or higher grade with engineer's approval

- Missing or incomplete mill certificates

- Steel grade not matching project specification

- Traceability lost during fabrication — unmarked offcuts reused

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

In accordance with 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. Hole tolerances per EN 1090-2 Table 11.

1. Check bolt class (8.8 or 10.9) matches design — verify head markings

2. Check 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 hole alignment — no excessive reaming or elongated holes

5. Ensure washers, nuts and bolts are from the same matched set

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

- Preloaded bolts not correctly tightened — slip under service loads

- Misaligned holes forced with drift pins causing element damage

- Washers missing on oversize or slotted holes

In accordance with EN 1090-2 Section 7 and EN ISO 5817, welds must achieve 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 that welding procedure specifications (WPS) are approved and available

2. Check that 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 and lack of fusion

4. Verify that 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

In accordance with EN 1090-2 Section 10 and EN ISO 12944, corrosion protection must match the corrosivity category (C1-C5, CX). Surface preparation must achieve the specified grade per EN ISO 8501-1 (typically Sa 2 1/2 for blast cleaning). The coating system (primer, intermediate, topcoat) must correspond to 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 2 1/2 is typical for structural steel

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

4. Inspect coating defects: holidays, runs, blisters or untreated areas

5. Verify site connections and welds are touch-up coated after erection

- Insufficient surface preparation — rust or mill scale beneath coating

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

- Site welds and bolted connections left uncoated

- Incorrect coating system for the corrosivity category