Floor deck, also known as fluted decking or roof decking, refers to corrugated steel panels that are used in buildings as the structural support for concrete floor slabs. Floor deck sheets are an important component in creating lightweight and fire-resistant floor systems in modern steel frame structures. The deck sheets act as a permanent formwork or mold for the concrete slab that is poured over them. They also provide shear bond with the concrete topping and act as horizontal bracing to the structural steel frame against lateral loads.
Floor decks are cold roll formed from steel coils into a ribbed profile which provides strength and stiffness to the deck. Roll forming is an efficient and cost-effective manufacturing process ideal for producing large volumes of deck sheets to custom lengths as per project requirements. The floor deck profiles can be trapezoidal, re-entrant or other shapes. The flutes or ribs run parallel to the length of the deck spanning between the supporting steel beams. The deck surface is embossed or imprinted to provide better bonding with the concrete.
How Does a Floor Deck Roll Forming Machine Work?
A floor deck roll forming machine progressively cold forms metal coils into the desired ribbed deck profiles as the strip material passes through a series of passes containing forming rollers. The key components and working of a floor deck roll forming machine are explained below:
Coil Loading Section
- Coiled steel strips of the required thickness and grade are loaded at the uncoiling station. Coils weighing up to 5 tons can be handled.
- The strip is passed through a straightening machine to remove coil set curvature and achieve a flat strip input for the roll former.
- Accumulators are used to maintain continuous line speed and productivity in case of coil changeover.
Roll Forming Section
- The leveled strip enters the roll form station where it passes through a series of forming stands.
- Each stand haspairs of shaped forming rollers that progressively cold work the strip into the final deck profile.
- The rollers bend and shape the strip in each pass incrementally forming the ribs and corrugations.
- Internal web stiffeners may also be formed between the intermediate stands to provide additional shear strength.
- Roll forming allows high production speeds up to 130 m/min with excellent profile precision and repeatability.
Cut-Off Press
- At the end of the production line, the continuously formed deck sheet is cut to length by a cut-off press as per specified floor dimensions.
- The press uses hydraulically powered blades for clean burr-free cuts. Servo or CNC control allows quick changeovers for varying sheet lengths.
Other Components
- Guide rollers precisely align the strip through the roll former stations.
- Adjustment tables with wedge screws assist in precision adjustment of roller gaps.
- PLC and HMI provide machine control, monitoring and diagnostics.
- Hydraulic powerpack drives the production line.
Therefore, with a floor deck roll forming machine, it is possible to mass produce floor decks of various profiles, thickness and strengths with high dimensional accuracy and speed for meeting large project demands.
What are the Functions and Benefits of Floor Decks?
Floor decks serve the following purposes in concrete floor systems:
Formwork Function
- Primary function of floor deck is to act as permanent formwork for the concrete slab poured over it.
- The steel deck replaces the need for conventional wooden shuttering.
- Speeds up construction and reduces labor. No time needed to remove formwork after curing.
- Provides uniform propping support during concrete pour.
Structural Strength
- Steel decking has high strength-to-weight ratio which allows longer spans.
- Acts like a beam and distributes loads from the slab to the supporting steel structure.
- Fluted profile provides moment of inertia and resists bending forces.
- Embossments ensure composite action between deck and concrete slab.
Shear Bond
- The deck surface embossments provide mechanical interlock with concrete topping.
- This prevents horizontal shear slippage between the deck and slab layers.
- The composite deck slab thus acts as a solid plate resisting loads.
Stiffness and Stability
- Deck ribs enhance rigidity and stiffness of the floor system.
- Acts as horizontal bracing and stabilizes the steel frame against sway.
- Minimizes vibrations under live loads like foot traffic and movable equipment.
Fire Resistance
- Steel floor decks contribute to fire resistance rating of floor-ceiling assemblies.
- Deck protects steel structure from fire damage on the underside.
- Concrete topping also provides protection from above.
Service Integration
- Deck flutes can accommodate electrical conduits, ducts and piping within floor depth. -allows efficient MEP services integration saving overall floor height.
Lightweight Construction
- Steel decking results in reduced slab dead weight than conventional concrete floors.
- This allows longer spans, smaller steel sections and foundations.
- Lowers overall building weight beneficial for high-rise structures.
Faster Construction
- Steel deck installation is quick and easy to handle due to lightweight panels.
- Eliminates time for formwork erection and removal as in site-cast slabs.
- Allows fast-track construction schedules to be met.
Economic Benefits
- Using floor decks is highly cost effective due to speed of construction.
- Requires less supporting steel tonnage due to composite interaction with concrete.
- Low life-cycle costs and reduced maintenance over long service life.
Therefore, floor decks offer optimum functional performance along with cost and construction efficiency which has led to their widespread adoption in concrete flooring systems worldwide.
What are the Different Types of Floor Deck Profiles?
There are several standard and proprietary profiles available for floor decks to suit varying project requirements:
Trapezoidal Profiles
- Most common and economical deck profile.
- Trapezoidal or dove-tail cross-section with wide top flanges.
- Flange width provides shear bond area and flute depth provides stiffness.
- Suitable for most floor loads and spans.
- Variations in depth and pitch available like 38mm, 50mm, 60mm, 75mm decks.
Re-entrant Profiles
- Have narrower but higher ribs than trapezoid decks.
- Higher steel usage but can support heavier loads over longer spans.
- Re-entrant shape gives higher moment of inertia and lateral stability.
- Common variants include 76mm, 102mm and 153mm re-entrant decks.
Cellular Decks
- Feature a flat pan section between angled ribs giving a cellular appearance. -Pan provides positive sheer bond while ribs carry bending forces.
- Allows easy integration of services within the floor depth.
- Increased usage of steel makes it more expensive.
Composite Decks
- Use a trapezoidal lower section combined with a re-entrant upper profile.
- Provides both high shear capacity as well as increased strength.
- Suitable for floors with heavier loading requirements.
Long Span Decks
- Designed for longer spans up to 5m without intermediate beams support.
- Have deeper ribs like 180-230mm for higher stiffness.
- Top flange is typically tapered.
- Permit more open and flexible interior spaces.
Non-composite Decks
- Simple fluted profile without shear bond embossments.
- Act as permanent shuttering for concrete but no composite interaction.
- More flexibility in design as no reliance on composite slab strength.
- Lowest cost option.
Acoustic Decks
- Contain small perforations in the pan section between embossed ribs.
- Perforations absorb sound and provide noise dampening.
- Useful where sound transmission through floors must be minimized.
Friction Grip Decks
- Mechanical profile allows positively anchoring the deck to supports.
- Interlocks with supports through button-punching or roll-forming.
- Eliminates need for welding or screw-fastening in many cases.
Composite Slim Floor Decks
- Have narrower ribs and flat pans well-suited for shallow slabs.
- Permits slim floor construction depth up to 20% thinner slabs.
- Useful where floor-to-floor height needs to be minimized.
Therefore, by selecting the appropriate profile and depth, floor decks can be designed to optimally suit varying project spans, loads, costs, construction needs and architectural requirements.
What Design Factors are Considered for Specifying Floor Decks?
The choice of optimal floor deck type and thickness depends on several inter-related design factors:
Dead and Live Loads
- Design deck strength to support combined self-weight and imposed loads.
- Higher loading requires deeper deck profiles and/or lower steel gauge (thickness).
Structural Span
- Longer spans demand greater deck stiffness to minimize deflections.
- For spans above 3m, deep re-entrant or long-span decks preferred.
Floor Vibration Control
- Heavier and stiffer decks reduce vibrations and floor motion.
- Important for sensitive equipment and comfort of occupants.
Composite Slab Interaction
- Profile type determines extent of shear bond developed with concrete.
- Important for achieving design composite strength.
Fire Resistance Rating
- Deeper decks and lower steel gauge provide increased fire protection.
- Important for structural fire safety and human life safety.
Acoustic Isolation Needs
- Perforated cellular or acoustic decks reduce airborne noise transmission.
- Useful for sound privacy between floors in buildings.
Depth Constraints
- Shallower deck profiles allow minimizing overall floor depth where height is limited.
- But may require heavier sections for strength or closer beam supports.
Service Integration
- Deck shape should allow routing electrical conduits and ductwork.
- Cellular decks provide cavities for MEP services.
Constructability and Handling
- Lightweight decks speed up installation. Narrower panels easier to handle.
- Friction grip decks avoid on-site fastening needs.
Cost Optimization
- Choosing the lightest deck to satisfy design criteria reduces material costs.
- Fast installation also compensates for higher deck cost.
By balancing these factors, floor decks can be effectively designed and specified to meet the technical and economic needs of a building project. Manufacturers provide design software tools and advice for this purpose.
What are the Design and Installation Considerations for Floor Decks?
Some key considerations for floor deck design and installation include:
Design for Shear Bond with Concrete
- Specify adequate deck profile embossment type and depth for shear transfer.
- 0.7mm and 1.0mm embossment depths are common.
- Ensure embossments cover up to 50% of deck area.
Design for Bending Strength
- Select deck depth and steel thickness to provide required strength.
- Re-entrant decks offer higher section modulus than trapezoidal.
- Ensure deck Rib bearing length adequate on supports.
Design Edge Details
- Reinforce deck edges to prevent longitudinal cracks in concrete.
- Use edge stiffeners or thicker steel sections at end laps and openings.
Fix Deck Elevations
- Set deck soffit levels precisely to ensure even finished slab surface after pour.
- Allow for deflections, camber and settlement.
Avoid Deck Damage
- Use plywood or other surface protection during storage and lifts.
- Prevent point loads when placing bundles to avoid denting.
Secure Deck to Structure
- Use mechanical fasteners or welds to securely anchor decks to steel framing.
- Avoid uplift forces due to wind during construction.
Install Safely
- Take precautions against fall hazards during installation at height.
- Use safety nets, temporary planks, and tie-offs for worker fall protection.
Place Reinforcement
- Install slab reinforcing bars and mesh over deck flats before concreting.
- Maintain cover to ensure durability and fire resistance.
Check Alignment
- Ensure deck sheets are properly aligned before permanently fixing.
- Misaligned deck could lead to concrete cracking under load.
Pour Concrete Carefully
- Avoid damaging deck surfaces during concrete pumping and placement.
- Prevent excessive point impact loads.
Allow Concrete to Cure
- Let concrete develop sufficient strength before allowing construction loads.
- Premature loading can over-stress deck before it compositely acts with concrete.
By following good practices in design, handling and installation, floor decks can be implemented successfully and safely to create robust concrete flooring systems in modern steel buildings.
What are the Different Materials Used for Manufacturing Floor Decks?
Floor decks are predominantly cold roll-formed from pre-painted galvanized steel coils. The key deck sheet materials include:
Hot-dip Galvanized Steel
- Low carbon steel hot-dip galvanized with zinc coating.
- Provides good corrosion resistance and long service life.
- Most economical material for floor decks.
- Available with regular galvanized coating up to Z275 or heavier coatings like Z600.
Prepainted Steel
- Bare galvanized steel with polyester paint coating.
- Enhances durability and aesthetics of deck underside.
- Useful in multi-story buildings where underside of deck is visible.
- Available in various color options.
Bonderized Steel
- Galvanized steel treated with a phosphate bonding process.
- Creates a passive layer for improved adhesion with concrete.
- Enhances the composite shear bond strength.
High Tensile Steel
- Higher strength steel alloys with yield strength up to 550 MPa.
- Provides increased load capacity from stronger material.
- Allows longer spans or lower steel gauge.
Stainless Steel
- Corrosion resistant steel alloys like 304, 316 grades.
- Used where decks are exposed to moisture or chemical attack.
- More expensive but very durable in aggressive environments.
Aluminum Alloy
- Aluminum sheets as light alternate material instead of steel.
- Good corrosion resistance without need for separate coating.
- Lower strength than steel but compensated by lighter weight.
Glass Fiber Reinforced Concrete
- Thin ultra-high performance concrete panels with glass fibers.
- Corrosion proof and high strength-to-weight ratio.
- New alternate product to steel decks gaining adoption.
Therefore, while galvanized steel remains the standard, floor deck manufacturers offer various material choices to suit different environmental conditions, strength needs and budget requirements.
What are the Testing and Quality Standards for Floor Decks?
High quality floor decks that conform to design specifications are essential for safety. Key standards for deck quality assurance include:
Steel Material Standards
- Base steel grades as per national standards like ASTM, EN, etc.
- Galvanized coating thickness standards such as AS 1397, EN 10346, ASTM A653, etc.
Roll Formed Sections Standards
- Deck profile dimensions and tolerances adherence.
- E.g. AS 2327.1, EN 1090-4, CAN/CSA S136, etc.
Deck Load Testing
- Testing underFactored Uniformly Distributed Loads per AS 2327.1.
- Proof load testing to 1.1 times design live load.
- Testing under concentrated loads.
Resistance Welding Tests
- Shear and tensile testing of welded connections.
- Ensures deck sidelaps and endlaps have adequate strength.
Concrete Interaction Tests
- Shear bond strength between deck and concrete topping.
- Tests composite interaction and mechanical interlock.
Product Certification
- Third party product conformity certification such as CE markings.
- ISO 9001 certification of manufacturer’s quality systems.
Code Compliance
- Designed and manufactured to conform to building standards like AS 3600, Eurocodes, etc.
Inspection and Documentation
- Raw material inspection, in-process inspection and compliance documentation.
Therefore, compliance with relevant standards through rigorous factory testing provides assurance of reliable field performance of load bearing floor decks.
What are the Common Problems and Repairs for Floor Decks?
Some key problems that may necessitate floor deck repairs include:
Corrosion Damage
- Due to water ingress or chemical exposure. Prevent with proper protective coatings.
- Minor corrosion can be cleaned and coated. Severe corrosion needs deck replacement.
Mechanical Damage
- Impact damage, scratches or cracks in deck during concreting work.
- Repair damaged sections by welding new steel plating.
Loose or Broken Embossments
- Shear knobs broken or concrete bonding failed.
- Need to restore shear transfer like gluing new shear studs.
Delamination and Concrete Spalling
- Moisture causing corrosion and concrete cover failure.
- May require partial or full slab removal for repair.
Deck Buckling or Sagging
- Indicates overload damage or impact from heavy objects.
- May require supplemental supports or strengthening plates welded below.
Insufficient Anchoring
- Deck lifting or inadequately secured to structure.
- Needs re-anchoring with additional fasteners and welds.
Fire Damage
- Heat exposure weakens deck strength and coating protection.
- Cool affected deck and coat with intumescent paint for patching.
Leaky Seams
- Gaps at sheets sidelaps allowing water leakage.
- Seal gaps using mastic sealant. Cover with flashing strips.
Excessive Deflection
- Deck overloaded beyond design limits and sagged.
- Strengthen deck by attaching steel plate or channels below.
Floor Vibration
- Insufficient deck stiffness causing unplanned vibrations.
- Stiffen deck by welding support angles or flat bars between ribs.
By identifying issues early and implementing suitable repairs, the problems in floor decks can be rectified to restore structural integrity and prevent further damages.
What are the Safety Precautions for Working with Floor Decks?
Key safety guidelines for working with floor decks include:
Use Fall Arrest Systems
- Install temporary guardrails or safety nets during deck installation at heights.
- Wear body harnesses and use tie-off points for fall arrest when working near unprotected edges.
Wear Cut-resistant Gloves
- Sharp deck edges present laceration hazards to hands.
- Wear proper gloves to avoid injuries when handling sheets.
Use Personal Protective Equipment
- Hard hats, safety shoes and glasses mandatory for all deck work.
- Additional PPE when using welding gear or concrete work.
Prevent Slips and Trips
- Ensure good housekeeping. Remove debris, tools and cords from walking paths.
- Take precautions when walking on deck sheets before concrete pour.
Practice Safe Material Handling
- Use mechanical lifting equipment for heavy or awkward loads.
- Get help when manually lifting long deck sheets to avoid injury.
Caution with Overhead Loads
- Stay clear when lifted loads are being maneuvered to prevent falling objects.
- Barricade below areas when work is ongoing above.
Eliminate Fire Hazards
- Avoid hot work like welding or flame cutting near flammable materials.
- Have fire extinguishers and water hoses standby during hot works.
Ventilate Work Areas
- Ensure adequate ventilation for indoor deck work and welding fumes extraction.
- Workers should wear respirators when ventilation is inadequate.
Guard Against Electrical Hazards
- Prevent contact with energized lines when installing deck sheets around electrical systems.
- Tools should be properly insulated and grounded.
Barricade Work Zones
- Cordon off areas where deck installation is in progress.
- Restrict and control access to authorized personnel only.
By following good safety practices and using the right protective gear, the risks of injuries and accidents while working with floor decks can be minimized for improved project safety.
What are the New Trends and Developments in Floor Deck Technology?
Some interesting new trends shaping floor deck technology include:
Advanced Profiles
- Innovative new deck shapes for enhanced strength, composite interaction, vibration control and span capabilities.
Lightweight Decks
- Use of high strength steels allows reducing deck thickness and weight.
- Improves structural efficiency.
Energy-efficient Decks
- New coatings offering thermal reflectivity to reduce heat gain through decks.
- Helps improve building energy performance.
Acoustic Control Decks
- Advanced profiles and perforations to curtail noise transmission through floors.
- Makes floor assemblies meet stringent sound insulation requirements.
Vibration Control Decks
- Deck features like folded return flanges to increase damping of vibrations.
- For sensitive equipment and human comfort.
Embedded Conduits
- Pre-fabricated deck panels integrating conduits for electrical and plumbing.
- Saves on-site installation time and labor.
Shear Studs Integration
- Decks with pre-welded shear studs for composite interaction with concrete.
- Eliminates on-site stud welding.
Fire Protection
- Innovative materials and coatings to enhance deck fire resistance.
- Helps achieve longer fire ratings for floor assemblies.
Sustainable Materials
- Use of recycled content steels to reduce environmental footprint.
- Coatings with low VOC and toxicity.
Automated Production
- Integration of Industry 4.0 technologies for smart and lean manufacturing.
- For improved precision, efficiency and quality control.
Therefore, advanced research and technologies will continue to drive innovation in floor deck products and expand their functionality frontiers.
Conclusion
In summary, floor decks are an integral component of modern steel-framed buildings. They serve the vital function of acting as permanent formwork to create lightweight composite concrete floor slabs. If designed and installed correctly, floor decks provide several benefits including structural strength, fire resistance, service integration, faster construction and cost savings.
Various factors need consideration when specifying suitable floor deck sections for a project based on requirements of strength, span, construction method, vibration control and life cycle costs. By selecting from the wide range of deck profiles and choosing appropriate materials, floor decks can be optimized for different application needs. Manufacturers offer design support services to assist with product selection.
High quality deck materials and rigorous compliance with building standards is crucial. Proper precautions need to be exercised during on-site handling and installation of floor decks to avoid damages. With responsible safety practices, potential hazards can be controlled to prevent accidents and injuries when working at heights.
Going forward, continuous technology improvements and innovative new deck products will expand the performance horizons and applications of floor decking. Their proven advantages will continue to drive widespread adoption in residential and commercial building construction worldwide.