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More contactsTruss Steel Floor Deck Specification
Truss steel floor deck (full name: rebar truss steel floor deck) is an integrated structural component composed of a cold-formed galvanized steel base plate and a factory-welded steel bar truss. It is widely applied in prefabricated steel structure buildings, combining the advantages of fast construction, high bearing capacity, and good composite performance with concrete.
Material Specification-Steel Base Plate
Material Grade:Chinese standard: Q235B, Q345B ;American standard: ASTM A653 Grade 33/37 ;European standard: S235JR, S355JR
Thickness Range : 0.6–1.5 mm (common specification: 0.8–1.2 mm)
Coating Type: Hot-dip galvanizing (coating weight: 80–275 g/m²) Galvalume coating (Zn-Al alloy, 150–200 g/m²)
Density :7850 kg/m³ (theoretical value for carbon steel)
Rebar Truss Components
The truss is welded by chord bars (main stress-bearing bars) and web bars (connecting bars), with the following material requirements:
Chord bar grade: HRB400 (Chinese standard), Grade 60 (American standard), B500B (European standard)
Web bar grade: HPB300 (Chinese standard), Grade 40 (American standard), B400A (European standard)
Welding standard: The weld joint strength shall not be lower than the strength of the base metal; no weld defects, such as porosity or cracks, are allowed.
Bearing Capacity
Bending performance: Under construction load (1.5 kN/m²), the maximum deflection ≤ L/250 (L = span of the deck)
Shear capacity: The shear resistance at the support meets the requirements of GB 50017 (Chinese standard) or AISC 360 (American standard)
Composite performance: Bond strength between deck and concrete ≥ 0.2 MPa; no separation or sliding occurs under service load
Installation Requirements
Lap joint: The lap length between adjacent decks ≥ 50 mm; lap length on steel beam ≥ 80 mm
Fixing method: Use self-drilling screws (diameter ≥ 5.5 mm) or spot welding; fastener spacing ≤ 300 mm along the steel beam
Temporary support: For decks with span > 4 m, temporary supports shall be set during concrete pouring to control deflection
Concrete pouring: The concrete strength grade shall not be lower than C30; the pouring thickness shall match the truss height (generally 10–20 mm higher than the truss top chord)
Specification
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Parameter
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Specification Range
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Notes
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Overall Height
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70–200 mm (common: 100 mm, 120 mm, 150 mm)
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Determines the bending stiffness of the deck
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Nominal Width
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600 mm, 900 mm, 1200 mm
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Effective width is 500–1100 mm (considering lap joint margin)
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Length
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Customized (3–18 m)
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Subject to transportation limits; maximum length is generally ≤12 m for road transportation
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Truss Spacing
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150 mm, 200 mm, 250 mm
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Smaller spacing means higher bearing capacity
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The fire resistance limit of the truss steel floor deck system depends on the concrete thickness and protective measures:
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Concrete Slab Thickness
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Fire Resistance Limit
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Applicable Scenario
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≥ 100 mm
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≥ 1.0 h
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General industrial buildings
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≥ 120 mm
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≥ 1.5 h
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Multi-story office buildings
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≥ 150 mm + fireproof coating
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≥ 2.0 h
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High-rise buildings, fire-protection zones
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