Multi-Storey Steel Buildings
Multi-storey steel buildings from one fabricator: thick-web H and box columns, cruciform columns, steel floor beams, composite decking and stairs for commercial and industrial frames, with embedded parts and anchor bolts shipped ahead of the steel. Fabricated to designs prepared to AISC 360 or EN 1993, as your project specifies, and executed under EN 1090-2 EXC2.
What This System Includes
The component families we fabricate in-house for this product line. Send a BOQ and we quote against these directly.
Heavy H-Section Columns · Box / Rectangular Columns · Cruciform Columns · Circular Columns …
Profiled Steel Decking · Truss Floor Decks · Steel Gratings · Welded Steel Stairs
Technical Specifications
| Item | Specification |
|---|---|
| Design basis | AISC 360 / EN 1993-1-1, as the project specifies |
| Execution class | EN 1090-2 EXC2 (certificate 2787-CPR-01627) |
| Steel grades | S355 / S460 to EN 10025, ASTM A36 / A992, with EN 10204 type 3.1 mill certificates traced to heat number |
| Composite floors | EN 1994-1-1 / AISC 360 Chapter I; decking and headed shear studs detailed with the floor beams |
| Welding | AWS D1.1 / EN ISO 9606 qualified procedures and welders; full-penetration welds where the design requires them |
| NDT | 100% UT or MT on critical full-penetration welds to ISO 11666 / AWS D1.1, technicians to ISO 9712 or ASNT Level II |
| Site bolting | HSFG assemblies to EN 14399 / ASTM F3125, tightened by torque or turn-of-nut method with 100% torque audit records |
| Corrosion protection | ISO 12944, system selected per site environment (C3–CX); fire protection to the rating in the design |
| Documentation | MTRs, WPS/PQR, welder certificates, NDT and DFT reports with every shipment |
Project-specific tolerances, section sizes and load tables are issued with the quotation once your design basis is received.
Advantages vs Engineering Considerations
| Advantages | Engineering Considerations |
|---|---|
| Multi-storey frames with the floor systemColumns, floor beams, profiled decking, shear studs and stairs are detailed together, so the floor build-up and connections arrive as one package for a commercial park, plant building or hotel frame. | Floor systems such as decking and composite slabs add wet trades and curing time compared with a single-storey frame. |
| Heavy sections welded and testedBox columns and thick-flange H sections are welded on CNC lines with full-penetration welds where the design requires them, ultrasonically tested and reported before painting. | Vibration and deflection limits of long floor spans often govern member sizes more than strength. |
| Embedded parts ahead of the frameCast-in plates, anchor bolts and shear studs ship as an early consignment with setting templates, so foundations are poured to the steel geometry before the columns arrive. | Fire protection to the steel frame is usually required by local code and must be priced in. |
| Dual certificationAISC certified and CE marked to EN 1090-2 EXC2 under certificate 2787-CPR-01627; documentation is issued in the format your inspector expects. | Column grids are fixed at design stage; re-planning large openings later needs transfer structures. |
Certifications & Compliance
Every shipment leaves with the documents an auditor asks for. Scroll the row and open any certificate at full size.
China Steel Structure Manufacturing Grade I
AISC Certification
CE Marking – EN 1090-2 (CPR 01627)
OTC Document of Validity
International Welder Certification
Enterprise Qualifications Portfolio
DG Packaging Certificate
Labor & Scaffolding Contracting
Explosion-Proof Certificate
Industrial Pipeline Installation GC1
Power Facility License
Have drawings or a BOQ ready? Send them through the form and our engineers reply with a preliminary assessment.
Related Projects
Steel structures we fabricated and shipped for the same kind of building.
SynJect. Scale. Precision. Certainty.
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SynJect ENGINEERING
From Microns to Megastructures — 12 Rigorous Stages Certified to AISC & EN 1090
Detailed Engineering & Shop Drawing Development
Utilizing advanced BIM platforms such as Tekla Structures, detailed 3D modeling and shop drawings are executed strictly in compliance with AISC 360 or Eurocode 3 (EN 1993). Connection designs are rigorously verified, with manufacturing drawings generated to ISO 2768-m tolerance standards. 100% clash detection with primary architectural and MEP systems is performed to ensure zero structural conflicts during field erection.
Nesting & Material Optimization
Intelligent nesting layouts are performed using advanced software like FastCAM/SigmaNEST in accordance with EN 10029 / ASTM A6 dimensional standards. Accounting for cutting kerf (2mm-5mm depending on plate thickness) and thermal contraction allowances, raw material utilization exceeds 92%. Offcuts are digitally barcode-tracked to ensure 100% mill test report (MTR) traceability.
Raw Material Incoming Inspection
All structural steel (Q355B/C/D, ASTM A572 Gr.50, S355JR/J2) must be accompanied by EN 10204 3.1 Mill Test Reports (MTR). Incoming quality control conducts 100% dimensional and visual inspections under ASTM A6 / EN 10029, verifying thickness tolerances (Class A/B) and internal lamination integrity via Ultrasonic Testing (UT) to ASTM A435. Chemical composition and mechanical properties are spot-verified by accredited 3rd-party labs.
CNC Cutting & Edge Preparation
Plate profiling and component cutting are executed via CNC oxy-fuel, high-definition plasma, and multi-kW fiber laser equipment. Cut surface quality strictly complies with EN ISO 9013 for perpendicularity and surface roughness (Range 3/4 tolerance). Multi-axis CNC beveling machines execute weld prep bevel angles within ±2.5° and root face dimensions within ±1.0 mm.
Primary Structural Welding
Welding is performed exclusively by AWS D1.1 or EN ISO 9606 certified welders using qualified Welding Procedure Specifications (WPS) supported by Procedure Qualification Records (PQR) per AWS D1.1 / ISO 15614. Submerged Arc Welding (SAW) and Flux-Cored Arc Welding (FCAW) dominate Complete Joint Penetration (CJP) and fillet welds. Heat input is strictly controlled, achieving weld quality levels conforming to ISO 5817 Quality Level B or AWS D1.1 standards.
Weld Distortion Straightening
Post-weld angular distortion, camber, and sweep are rectified using automated hydraulic flange straighteners and controlled thermal flame straightening. Heating temperatures for High-Strength Low-Alloy (HSLA) steels are strictly maintained between 600-650 Celsius (air-cooled, zero water quenching) to prevent microstructural degradation. Post-straightening straightness tolerances meet ±3 mm, conforming to EN 1090-2 Execution Class 2 (EXC2) and AISC COSP standards.
Non-Destructive Testing (NDT)
NDT protocols are operated by ISO 9712 / ASNT Level II certified NDT personnel. 100% of critical Complete Joint Penetration (CJP) welds undergo Ultrasonic Testing (UT per ISO 17640 / ASTM E164) or Magnetic Particle Testing (MT per ISO 17638 / ASTM E709). Radiographic Testing (RT) is applied as requested for heavy sections. Weld acceptance conforms strictly to ISO 11666 Acceptance Level 1 or AWS D1.1 criteria.
Trial Assembly & Shop Alignment
Complex geometries, long-span trusses, and heavy framing undergo 1:1 physical trial assembly or high-precision 3D laser scanning virtual assembly per EN 1090-2 / AISC requirements. Bolt hole alignment is verified (≥95% free-pass rate for high-strength bolts), and critical dimensions (span, camber, 3D spatial alignment) are verified within tight tolerance limits (±2.0 mm) to eliminate site fitting risks.
Surface Preparation & Protective Coating
Structural members undergo automated shot blasting to achieve SSPC-SP10 / NACE No. 2 / ISO 8501-1 Sa 2.5 cleanliness, with a surface profile (anchor depth) of 45-75 microns. High-performance protective coatings are applied using airless spray technology in compliance with ISO 12944 (C3 to CX corrosive environments), featuring Zinc-Rich Epoxy Primers, Epoxy Micaceous Iron Oxide Intermediate coats, and Polyurethane/Fluorocarbon Topcoats. Dry Film Thickness (DFT) is verified adhering strictly to the 90/10 rule.
Final Quality Inspection & Certification
Final Quality Control (FQC) performs a comprehensive audit, inspecting paint aesthetics (zero runs, pinholes, sagging), critical geometry, bolt hole pitches, and component mark traceability. A complete Manufacturing Data Report (MDR) comprising MTRs, NDT records, coating inspection logs, and Certificates of Conformance is compiled to support CE Marking (DoP under EN 1090) and AISC final acceptance.
Export Packaging & Logistics Protection
Protective packaging is engineered for containerized (40HQ/OT/FR) and breakbulk ocean freight under heavy maritime transit conditions. Structural members are bundled on heavy-duty steel skids with high-tensile steel strapping. Machined connections are wrapped with VCI anti-corrosion film, EPE foam padding, and heavy rubber cushions. All timber packing complies fully with ISPM 15 phytosanitary standards and IMO Cargo Stowage and Securing (CSS) rules.
Global Field Erection & Site Management
We deliver international site erection supervision and turnkey EPCM construction services adhering to OSHA 1926 safety protocols, AISC COSP, and EN 1090-2 erection standards. Field teams, led by multilingual HSE and QA/QC engineers, utilize high-precision total stations to maintain structural plumbness within H/1000 (25mm max). High-Strength Structural Bolting is executed via calibrated Wrench or Turn-of-Nut methods with 100% torque audit documentation.
Frequently Asked Questions
Do you fabricate structural steel framing for a multi-storey commercial building?
Yes. Send the structural drawings or a BOQ with column and beam sections, floor decking type and stair scope. We detail the connections, fabricate the frame and quote the floor system with it.
How is column verticality controlled when the frame is erected?
Column plumbness is measured with total stations to H/1000, not exceeding 25 mm; high-strength bolts are tightened by the torque or turn-of-nut method with 100% torque audit records. The same records are handed over with the as-built drawings.
Can you supply the floor decking and stairs with the frame?
Yes. Profiled decking, truss floor decks, gratings and welded stairs are quoted with the floor beams so shear studs, edge trims and stair connections are in the same package — see the Floor & Access Systems sub-system.
Which design code do you fabricate to?
Whichever your design specifies. We work to AISC 360 or Eurocode 3 (EN 1993) for design intent, and execute to EN 1090-2 EXC2 under certificate 2787-CPR-01627. State the code in your enquiry and the quotation is issued against it.
Can you issue calculations our building authority will accept?
Yes. We provide English structural calculation reports with load combinations and 3D models. Where local regulations require a licensed local engineer to stamp the drawings, we supply the calculation package for their review.
What is a realistic lead time?
For a typical single-building scope the standard cycle is 40 to 50 days: 1–2 weeks from contract to 3D models and shop drawings for your approval, then 4–5 weeks for procurement, CNC fabrication, welding, coating and loading. Drawing approval is the part you control.
Do you supply the enclosure as well as the frame?
Yes. Roof and wall cladding, insulation, waterproofing, doors, windows, ventilation and drainage are quoted as one package — see Enclosure & Cladding Systems . Single-source supply removes the interface risk between frame and envelope.
How do we verify your certificates?
Ask us for the certificate together with its Document of validity — they are issued as an inseparable pair. We send both with the welding annex on request. Details are published on our certificates page .
Send Us Your Drawings or BOQ
Tell us the footprint, span, crane capacity and local loads — our engineering team reviews every request and replies with a preliminary assessment.
- Reviewed by our engineering team
- AISC certified · CE marked EN 1090-2 (EXC2)
- Mutual NDA available on request
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