A steel building fabricated in China is normally detailed and fabricated to Chinese practice. When the project follows AISC or AS 4100, the design intent may be identical but the supporting standards are not, and the differences land in the shop drawings, the material certificates, the weld procedures and the bolt supply.
This guide lists where those differences actually appear, so they can be written into the enquiry instead of being discovered during inspection.
The standards that shift together
| Subject | United States | Australia / New Zealand | China |
|---|---|---|---|
| Structural design | AISC 360, with ASCE 7 for loads | AS 4100, with AS/NZS 1170 for loads | GB 50017, with GB 50009 for loads |
| Material standard | ASTM A992, A36, A572, A500 | AS/NZS 3679.1, AS/NZS 1163 | GB/T 700, GB/T 1591 |
| Fabrication practice | AISC 303 | AS 4100 and project specification | GB 50205 |
| Welding | AWS D1.1 | AS/NZS 1554.1 | GB 50661 |
| Structural bolting | ASTM F3125 (A325 / A490) | AS/NZS 1252 | GB/T 1228 to 1231 |
| Coating | SSPC / project specification | AS/NZS 2312 and project specification | ISO 12944 or project specification |
Where the differences show up in fabrication
- Section shapes. US practice centres on W-shapes; Australian practice uses universal beams and columns; Chinese fabrication commonly uses hot-rolled H-sections in GB sizes or welded built-up sections. Substituting one family for another changes connection geometry.
- Bolts and holes. Bolt diameters, thread pitch and hole sizes differ between the ASTM, AS/NZS and GB systems, and anchor bolt templates have to match the foundation drawings exactly.
- Welding procedures and welder qualification. A procedure qualified to GB 50661 is not automatically acceptable under AWS D1.1 or AS/NZS 1554.1, and the qualification records have to travel with the job.
- Inspection scope. The required percentage of ultrasonic or magnetic particle testing, and who witnesses it, is set by the project standard or the inspection and test plan rather than by the fabricator.
- Units and detailing conventions. Imperial drawings, weld symbols and standard hole details have to be converted deliberately, not by habit.
- Tolerances. Member straightness, camber, hole position and frame plumbness acceptance criteria are not interchangeable between the three systems.
Material substitution is an engineering decision
A comparison table can suggest that two grades are similar, and that is all it can do. Strength, impact class, thickness limits, weldability and the reduction factors used in the original design all have to be checked by the engineer responsible for the project.
- State the grade and the impact class, and the thickness range they apply to.
- Ask whether mill certificates to the project standard are required, or whether an equivalence statement is acceptable.
- Record any approved substitution in the approved drawings, not in an email thread.
What to send with the enquiry
- The design code and its edition, plus the load code if it differs.
- The material standard and grade, with the impact class and thickness range.
- The welding code, and whether welder qualification records must be supplied.
- The bolting standard, and whether bolts are supplied with the structure.
- The inspection regime: which checks, what percentage, who witnesses them.
- The tolerance standard and the acceptance criteria for dimensional checks.
- The coating specification with corrosion category and dry film thickness.
- Whether shop drawings are produced by the fabricator and who approves them.
This guide describes general practice for steel structure projects. It is not a design, and it does not replace the specification or the engineer responsible for your project.