What is mesh for?
It might be obvious to some of us, but for others who might be new to the industry, might not know the answer. When installing metal floor deck, mesh reinforcement provides an essential part of the slab design.
The composite steel deck profile provides the tensile reinforcement in the bottom of the slab, but the composite slab cannot perform as designed without the inclusion of mesh reinforcement (or fibres, which are not covered by this article).
There are several reasons why mesh reinforcement is required in a composite slab. Primarily, these are:
- To control cracking within the slab – note, it will not avoid cracking simply control the amount and size of cracks
- To aid with the effective distribution of loadings, this is particularly important where high concentrated loads (i.e. wheel point loads, wall line loads etc.) are applied to the slab
- To contribute to the fire resistance of the completed slab.
The amount of mesh required within the slab depends on numerous aspects of the design criteria and specification of the slab. For example, the profile type, slab depth, spans, temporary propping, fire rating and loadings will all have an effect on the amount of mesh reinforcement required in the slab.
As a rule, the minimum mesh required is 0.2% of the concrete area above the deck (see table 5.1a from SMD’s TGN below) but this will increase based on the design criteria aspects mentioned above.
Table from SMD’s TGN showing the mesh percentage rules for BS and EC.
For advanced guidance on calculating the minimum reinforcement percentages required refer to the relevant design standard and SMD’s TGN (refer section 5.1 – Reinforcement) or run a design using SMD Elements Design Software or SMD Elements Span Check App – Available on Google Play and Apple Stores.