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334 Barry’s Advanced Construction of Buildings
150–250 mm
530 mm
225
mm
Lightweight concrete
filler block
Carbon steel strip
lattice reinforcement
cast into plank
Structural concrete topping
Plank
120
mm
Precast reinforced
concrete plank
up to 12.0 m
Solid block
for pipes
or ducts
Planks at 600 mm
centres bear on beam
Filler blocks
between planks
100 mm deep solid
blocks at bearing
Figure 5.57 Precast beam and filter block floor.
Precast beam and filler block floor
This floor system of precast reinforced concrete beams or planks to support precast
hollow concrete filler blocks is illustrated in Figure 5.57. For use with steel beams,
the floor beams are laid between supports such as steel shelf angles fixed to the web of the
beams or laid on the top flange of beams, and the filler blocks are then laid between
the floor beams. The reinforcement protruding from the top of the planks acts with the
concrete topping to form a continuous floor system spanning across the structural
beams. These small beams or planks and filler blocks can be positioned without the
need for heavy lifting equipment. This type of floor is most used in smaller-scale buildings
supporting the lighter imposed floor loads common in residential buildings, for
example.
Hollow clay block and concrete floor
This floor system, illustrated in Barry’s Introduction to Construction of Buildings, consists
of hollow clay blocks and in situ cast concrete reinforced as ribs between the blocks. This
floor has to be laid on temporary centring to provide support until the in situ concrete has
gained sufficient strength and is labour intensive.
Precast concrete T-beams
Precast concrete T-beam floors are mostly used for long-span floors and particularly roofs
of such buildings as stores, supermarkets, swimming pools and multi-storey car parks
where there is a need for wide-span floors and roofs, and the depth of the floor is no disadvantage.
The floor units are cast in the form of a double T, as illustrated in Figure 5.58.
The strength of these units is in the depth of the tail of the T, which supports and acts
with the comparatively thin top web. A structural reinforced concrete topping is cast on
top of the floor units.