Deep Metal Deck, Shallow Foor Construction.

Deep metal decks are normally used to create shallow floors e.g. Slimflor® and Slimdek® construction. The deep metal deck extends the span capability up to 9m; however, the deck and/or support beams may require propping during concreting.

An additional tensile reinforcement bar is provided within the  ribs of the deep decking to improve the load carrying capacity and fire resistance of the floor slab.

Although there are several variants internationally, Slimflor® construction in the UK comprises a universal column with a plate welded to the underside supporting the deep metal decking. Shear studs are shop-welded to the top flange of the beam to form a connection between the steel beam and concrete slab. Slimdek® construction is a technologically advanced solution comprising a rolled asymmetric beam (ASB) which supports the deep metal decking directly. Shear connection is achieved through the bond developed between the steel beam and concrete encasure. These features reduce material and fabrication content. Partial concrete encasement of the steel beam provides up to 1 hour inherent fire resistance.

The range of deep metal deck profiles (Fig. 2.25(b)) is more limited than for shallow decks, and those available carry similar attributes and  advantages. Some additional advantages of Slimflor ® and Slimdek® construction are:

• The shallow composite slab achieves excellent load capacity, diaphragm action and robustness
• There are fewer frame components to erect, saving construction time
• The shallow floor construction allows more floors for a given building height or
reduces the cost of cladding and vertical services, lift shafts, etc.
• It provides up to 1 hour inherent fire resistance and up to 2 hours using passive fire protection to the beam soffit only
• Large openings for vertical services can be formed in the floor slab without the need for secondary framing
• Services can be integrated between the decking ribs passing through web- openings in the beam
• ASBs achieve composite action without the need for shear studs
• Rectangular hollow section edge beams provide good torsional resistance and maintain the shallow floor depth
• Floor slabs can be used for fabric energy storage forming part of an environmentally sustainable building solution.

Figure 2.27 illustrates a typical beam layout at the building perimeter.

Slimdek® floor arrangement
Fig. 2.27 Slimdek® floor arrangement

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