What is the difference between a composite deck and a form deck?

Composite Deck:

• Function: Composite decks are designed to work in tandem with concrete to form a composite floor system. The steel deck and the concrete act together as one unit, combining their strengths.
• Design: The steel deck in a composite system usually has embossments or ribs that interlock with the concrete, enhancing the structural bond between the two materials. This helps to increase the overall strength and stiffness of the floor.
• Load-bearing: Composite decks contribute to both the construction phase (before the concrete hardens) and the final phase (after the concrete is set). The steel deck supports the weight of the wet concrete, and once it cures, the concrete and steel deck share the load-bearing responsibility.
• Typical Application: Used in multi-story buildings, office buildings, and commercial construction where the strength of a composite floor system is required.

Form Deck:

• Function: Form decks are designed primarily as a permanent formwork to support wet concrete during construction. Unlike composite decks, form decks do not act as a structural element once the concrete hardens.
• Design: The steel deck acts as a mold for the concrete but does not provide additional structural strength once the concrete is cured. It typically has a simpler rib pattern and lacks the embossments that composite decks use to bond with the concrete.
• Load-bearing: During construction, the steel form deck supports the weight of the wet concrete and any temporary construction loads. Once the concrete cures, the form deck no longer plays a significant role in load-bearing.
• Typical Application: Used in applications like concrete slabs where only temporary support is needed during the curing process, such as in parking garages or flat roofs.

Summary:

• Composite Deck: Works with concrete to create a strong, integrated floor system that supports both the construction phase and the building’s long-term structural loads.
• Form Deck: Provides temporary support for wet concrete during construction but does not contribute to the long-term structural performance of the building.