The role and arrangement of reinforcement in non-composite floor slabs

Reinforcing steel plays an irreplaceable role in both composite and non-composite floor slabs. Depending on the nature, the reinforcement is arranged differently.

The role of reinforcement in non-composite floor slabs

In a non-composite floor slab, the steel deck acts only as a formwork, and the forces of the entire slab are designed according to a normal concrete floor slab. Then the floor slab is not only arranged with temperature reinforcement at the surface of the slab, but also with positive moment reinforcement at the bottom of the slab.

The bar reinforcement in non-composite slabs usually takes the form of a relatively light welded fabric, commonly supplemented by some bar reinforcement. The bar reinforcement is required to perform a number of functions:

  • Provide bending resistance at the supports of the slab in the fire condition (this reinforcement is usually ignored under normal’ load conditions).
  • Reduce and control cracking at the supports, which occurs because of flexural tension and differential shrinkage effects.
  • Distribute the effects of localised point loads and line loads.
  • Strengthen the edges of openings.

The arrangement of reinforcement in non-composite floor slabs

For non-composite floor slab, so when calculating, the arrangement of reinforcement is calculated in the same way as the ordinary concrete floor slab, because the rebar is arranged on steel form deck In the ribs, attention should be paid to the spacing of the ribs of steel form deck, and the stressed rebars should be arranged according to the spacing of the ribs.

Recommended tension laps and anchorage lengths for welded fabric and bars for design to BS 8110 are given in Table 4.3, and for design to BS EN 1992-1-1 in Table 4.4. Structural designers can make reference based on working conditions.

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In China, structural engineers calculate the specifications and layout of reinforcement bars based on different working conditions. Of course, they need to consider load, fire resistance, crack resistance, reinforcement of individual areas, etc.