11. Foundation(Base) rebar arrangement
1) Foundation(base) work
In foundation work, the lean concrete underneath the footing concrete, is very
Without it, constuction site, on which a building will be raised up, it would not be
clean and stable disturbing construction work.
Be sure to make lean concrete working mat having at least 50mm of thickness.
If F.L. of lean concrete is not fit, there are difficulty in fix S.L.
2) The height of spacer
Bar spacer is used to maintain the arranged bar balanced.
When arranging the bars or flooring, stones and bricks can not be used to support
You have to prepare spacer in advance because there are high possibility of unbalance
when using stones or bricks to level the ground.
(in case of spacer height lean concrete top is 60mm)
< Cover thickness of rebar >
part to not contact land
part to contact land
over 80mm of cover thickness in
over 50mm of cover thickness than pile
head on base concrete
The reason that the top of piles is embedded into foundation is that , in case of an
earthquake , the pile causes bending fracture.
Especially , when the ground is unstable , there should be specified directions on
the drawings.(in case pile cover bending moment & compresssion or cover tension
PC Steel wire
2 times of
HOOP D13@150 4
Hole closure PC or PHC PILE
3) Independent Foundation(Single Footing)
Usually in double footing and floating foundation , remained bar length is bent up and
down to splice them together as depicted below.
However, the remaining parts of the bar can be cut off to reinforce the foundation.
<In case of securing splice length> <In case of not securing splice length>
when securing In case of below
splice length splice length
4) Foundation(base) pillar tie hoop
The main purpose of the tie hoop is to restrain the transverse load in order to relieve
vertical load into pillar.
Even though foundation concrete has capacity to support the loads from the pillars, tie
hoops help main bars be fixed at which they should be and it is important job.
<Before reinforcement> <After reinforcement>
main bar tie hoop should be
pillar @300 distance per
the drawing regulation,
bottom tie hoop
lean concrete spacer
The tie hoops at the bottom hold the bars of the pillar in lean concrete and marking
on the mould form is compared with drawing to ascertain the center of the pillars.
pillar location marking
The outer pillar must check main bar line.
5) Foundation(base) upper-support(Wooma) rebar
- Foundation thickness : below T=1,000mm for HD16, over T=1,000mm for HD19
space should be @1000-@1500