- Reinforcing Bar
- Reinforcing Mesh
- Mining Products
- Fencing Products
Specify the Sheet Direction
The most important requirement for structural safety of a slab is that the
correct reinforcement is placed in the direction of the span which controls the
In slabs supported on beams or walls, the controlling span is the SHORTER
span – this is true whether the slab is supported on three sides or on all
In slabs supported by columns, such as flat-slab floors and flat-plate floors,
it is the LONGER of the two spans which control the strength. Because the
reinforcement for these is complicated, well prepared detail drawings must be
However for minor structures, the reinforcement details are often not well
documented and steel fixers must be given additional instructions on the
All drawings should indicate the direction in which to place the longitudinal
wires of fabric, and also illustrate how fabric sheets are to be lapped.
Rectangular fabrics such a RL718 and RL818 require particular care when
Where suspended slabs have a span less than 6 metres, it is unusual that
fabric would need to be lapped at the end of a sheet.
If end laps are required, the actual length of the overhang should be allowed
for and specified, and a clear statement made on the drawings whether or not
the overhang is included in the lap unless the following rules are observed:
1. Full width sheets are overlapped by the distance between the two outermost
2. When cut sheets are lapped, the outermost two wires are also overlapped,
and the length of the overhang is neglected.
Specify the Fabric Position
The next factor to be considered is to locate the fabric in the right position.
Fabric in the bottom of a slab must be supported on bar chairs from the
Continuous bar chairs, such as the ARC “Goanna” chair, are the most suitable
here because they can be set out on the forms before the fabric is placed and
the weight of the fabric is evenly spread over many legs. Thus, there is no
need to place chairs under the steel that fixers are standing on.
Top reinforcement must be supported on high bar chairs, on high “Goannas”
or on “Deckchairs”.
These laps are based on AS3600 and on AS2870.1. The wires should be tied
together to prevent slippage. For tying, the orientation of the sheets is not
critical. That is, the lapped wires may be in the same layer or separated by the
wires at right angles.
Additional strips or finger mesh must be used when it is critical that the
effective depth be maintained.