Structural Comparisons • Centre Technique

Acier Léger Formé à Froid vs Charpente Lourde : Le Comparatif

Dans quels cas privilégier les profilés LGSF ou les profilés laminés à chaud pour votre projet ?

Auteur : İdris YAĞMAHAN (Architecte) Revue technique par : Celalettin YAĞMAHAN (Ingénieur Principal Structure) Temps de lecture : 9 min de lecture Mis à jour : 2026-02-28
Conception Certifiée Eurocodes 3 & 8
Contrôle Qualité Usine EN 1090-2
Empotage Conteneur 40ft HC en Colis Plat
Assemblage 100% Boulonné (Zéro Soudure)

⚡ Synthèse Rapide / Résumé Exécutif

Choosing between Light Gauge Steel (LGSF / CFS per EN 1993-1-3) and Heavy Hot-Rolled Structural Steel (S355JR per EN 1993-1-1) depends fundamentally on building geometry, clear span requirements, and payload types. Light gauge steel utilizes thin cold-formed galvanized profiles (0.8mm to 2.5mm, S350GD) to create dense, lightweight load-bearing wall panels and roof trusses—ideal for residential villas, multi-family housing, modular units, and commercial offices up to 4 storeys (spans up to 12m). Heavy structural steel utilizes hot-rolled I-beams (IPE, HEA, HEB) and welded plate girders (6mm to 30mm+) to achieve expansive unobstructed clear spans (18m to 60m+), high eave heights (6m to 20m), and heavy overhead crane support for industrial warehouses and factories.

Points Clés & Avantages Économiques

  • ✔ Clear Span Threshold: LGS is economical for spans up to 12m; Heavy Structural Steel is required for spans of 18m to 60m+
  • ✔ Weight Comparison: LGS superstructures weigh 20–35 kg/m²; Heavy Structural Steel portal frames weigh 30–65 kg/m²
  • ✔ Foundation Savings: LGS reduces concrete foundation volume and excavation costs by 25–35% due to ultra-low dead weight
  • ✔ Crane Integration: Only Heavy Hot-Rolled Steel can support 5t to 32t dynamic overhead traveling bridge cranes
  • ✔ Residential Dominance: LGS provides superior acoustic and thermal wall multi-layer cavity assemblies for modern housing
  • ✔ Hybrid Synergy: SerBuild frequently engineers Hybrid buildings (Heavy portal columns for clear spans + LGS interior infill walls)

1. Material Properties & Structural Behavior Comparison

Both systems utilize structural steel, but their manufacturing metallurgy and load transfer mechanics differ fundamentally:

  • Cold-Formed Light Gauge Steel (LGSF / CFS): Produced by roll-forming galvanized coil (EN 10346 S350GD+Z275) at ambient temperatures into C, U, and Z sections (0.8mm–2.5mm thick). Loads are distributed across a dense network of closely spaced wall studs (every 400mm–600mm) and engineered lattice trusses.
  • Hot-Rolled Heavy Structural Steel: Hot-rolled at ~1,100°C into solid thick-walled I-sections (IPE, HEA, HEB per EN 10025-2 S355JR) or welded from heavy structural plate. Loads are concentrated onto discrete, widely spaced portal columns and heavy rafters spaced at 6.0m to 8.0m bay intervals.
  • Seismic Ductility: LGS structures absorb seismic energy through screw connection deformation and strap bracing, exhibiting high damping ratios. Heavy steel frames absorb seismic energy through plastic hinge formation at rafter-column joints (Eurocode 8 MRF systems).

2. Technical Parameter Matrix: LGSF vs Heavy Structural Steel

The matrix below compares the engineering and financial metrics of both framing technologies (2026 benchmarks):

📊 Tableau Détaillé des Coûts & Spécifications (€ / m²)

Engineering Metric Light Gauge Steel (LGSF / CFS) Hot-Rolled Heavy Structural Steel Hybrid Steel Solution
Steel Grade & Standard S350GD+Z275 (EN 10346, Cold-formed) S355JR / S355J2 (EN 10025, Hot-rolled) S355JR Primary + S350GD Secondary
Steel Thickness Range 0.8 mm – 2.5 mm 6.0 mm – 40.0 mm+ Combined (0.9mm to 25mm)
Superstructure Framing Cost €95 – €180 / m² €65 – €130 / m² €85 – €150 / m²
Superstructure Dead Weight 20 – 35 kg / m² 30 – 65 kg / m² 28 – 48 kg / m²
Maximum Economical Clear Span 8 – 12 meters (Truss: 15m) 18 – 60+ meters (Clear portal) 24 – 36 meters
Storey Height Capability 1 to 4 Storeys (Load-bearing) 1 to 15+ Storeys (Moment frame) 1 to 6 Storeys
Crane Runway Capability Light Jib Crane (≤ 1.0t) only Heavy Bridge Cranes (5t – 32t+) Heavy Cranes in frame bay only
On-Site Assembly Method Self-drilling screws & rivet fasteners Grade 8.8 / 10.9 high-strength bolts Bolted frame + screwed infill

🔍 Matrice Comparative d'Ingénierie

Building Archetype Optimal Structural System Primary Engineering Rationale Estimated Cost Saving
Residential Villa / Modern House (150–350 m²) Light Gauge Steel (LGSF) Passivhaus thermal walls, fast dry construction, flexible floor plan 15% – 25% vs Concrete
Logistics & Storage Warehouse (1,000–10,000 m²) Heavy Structural Steel Wide unobstructed clear spans (24–36m), high eave clearance (7–12m) 20% – 30% vs Precast Concrete
Manufacturing Facility with 10t Crane Heavy Structural Steel Heavy column corbels, dynamic fatigue resistance per EN 1993-6 Mandatory (Only Heavy Steel qualifies)
Commercial Office with Storage Hall Hybrid Steel System Heavy steel clear-span hall + LGS multi-office mezzanine block 12% – 18% vs pure heavy frame
Modular Portable Buildings / Camp Housing Light Gauge Steel (LGSF) Compact flat-pack shipping, fast containerized assembly, light weight 25% – 35% vs container conversions

📋 Déroulement du Projet Étape par Étape

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1. Clear Span Assessment

Determine whether unobstructed spans over 15m are required for operations.

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2. Building Use Classification

Classify into Residential/Modular (LGS advantage) vs Industrial/Logistics (Heavy steel advantage).

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3. Crane & Heavy Equipment Audit

Check if bridge cranes, heavy storage racks, or dynamic machines are planned.

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4. Foundation & Geotechnical Review

Calculate if poor soil bearing capacity favors lightweight LGS construction.

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5. Consider Hybrid System

Evaluate if combining heavy perimeter portals with internal LGS wall cassettes offers maximum ROI.

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6. Structural Sizing by SerBuild

Receive side-by-side engineering models and comparative budget proposals.

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Foire Aux Questions (FAQ)

Réponses détaillées sur l'ingénierie Eurocode, la fabrication, l'exportation et le montage.

LGS is not economical for large open industrial warehouses requiring 20m+ clear spans without interior columns. For warehouses, heavy hot-rolled steel portal frames are far more cost-effective and provide completely unobstructed floor space.

A Hybrid system is often the most economical: heavy hot-rolled steel beams and columns form the main wide-span structural grid, while lightweight LGS wall panels and floor joists form the interior acoustic and thermal partitions.

LGS profiles feature continuous hot-dip zinc galvanizing (Z275 = 275 g/m² zinc) offering 50+ years of indoor corrosion resistance. Heavy structural steel is shot-blasted to Sa 2.5 and coated with 2-coat epoxy/polyurethane paint or hot-dip galvanized per ISO 1461.

Yes. LGS is exceptionally safe in earthquakes because seismic inertial force is directly proportional to building mass. An LGS house is ~70% lighter than masonry and concrete, resulting in dramatically reduced seismic lateral forces.

Yes. LGS floor joists easily support corrugated metal decking with 50mm–80mm lightweight concrete screeds (or fiber-cement dry screed boards), providing a solid, quiet floor with excellent acoustic dampening.

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Étape 5 : Coordonnées & Téléversement de Plans / CAD

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