Steel-framed buildings are frequently built with floor slabs using profiled metal decking.  These may be trapezoidal (eg Ribdeck, Multideck) or re-entrant (eg Holorib).

Trapezoidal decking	Re-entrant decking

In either case there were, until recently, considerable difficulties in achieving a secure restraint fixing into the top of such slabs.  It is not uncommon for the slab depth over the ribs to be in the order of 70mm.  This precludes the use of standard sockets, which are typically 75mm or more in length.  Similarly, ‘standard’  channel including the retaining anchors is frequently in excess of 70mm deep.  It is not possible to state that the anchor must always be in the ‘deep’ section between ribs, since this is subject to site conditions and cannot be relied on.  In addition, such slabs are only lightly reinforced, and there is a risk of sideways failure in the case of a cast-in socket near to the slab edge.
To overcome this problem, there are now purpose-made channel assemblies available, made specifically for use with decking slabs.  J&P’s system is called a ‘sled’ and Halfen’s is known as a ‘ski’. 

They both consist of normal channel section but with additional straps welded on.  When the top of the channel is flush with the top of the concrete, then the straps sit on the decking and are pinned to it.  This means that no top locations are needed  as is the case with sockets or standard channel.   

J&P sled	Halfen Ski

Both systems will take horizontal loads of up to 20 kN or more, depending on the configuration.  This is normally more than adequate for a cladding restraint fixing.  Both manufacturers will provide CAD and sketches for a given situation.