Section 1
REBAR ARRANGEMENT &
CONSTRUCTION CARRYOUT
1. Understanding of Drawing
1) Examination of drawing
When construction contract is completed, the contents of the drawings are surveyed
and checked before construction work.
Although it is a rule to survey the drawings right from the 1st page, it is common to
check the scale and the number of floors of the building and then plan, elevation,
exterior appearance, lines and windows of the building .
Not only orientation, precautions and specifications, but front elevation, rear side
elevation, right side elevation, left side elevation, partial development, partial section,
and detail section, etc should be also looked over to be reminded in the construction
site.
As construction work progresses , present work should be checked and compared
with instructions on the drawings , and an entire understanding of drawings should be
preceded before the next step.
Plan, structural plan, foundation, section, etc are checked if there is any suspicious
portion because all the drawings are not made by only 1 person.
There is also necessity of discussion when there is any question or changes in the
work.
In order to make smooth and steady progress of the work, a lot of time and repeated
practice are required.
In case of small scale of construction , it is progressed from the ground to the upper
floor in general , however there is no determined rule.
As construction work is not a simple one but rather complicated, it is difficult or
impossible to explain all of the construction methods satisfactorily in written or spoken
words alone.
Clear understanding of basic knowledge is quite helpful.
Plan of reinforcement should be drawn before reinforcement , however , when the
scale of construction is large , plan of reinforcement is given in advance or shop
reinforcement are also available .
Although the trend has been to increase the usage of shop reinforcement for the
smooth progress in the crowded city , field reinforcement is explained in this book due
to the necessity of prompt applications in the field and its convenience.
Every reinforcement has its own rule , however it could be changed when necessary
under the permission of supervisor.
For example , hooks at the tip of stirrup could be changed from Figure 1 to Figure 2.
Figure 1
Figure 2
2)What is drawing?
Drawings are used in every industrial field with the development of industries.
Although their types and applications are different, there are agreed rules that are
called IPC(International Graphic Code), accepted by everyone in each field.
Specified rules and standards with reference to symbols, numbers, lines and letters are
adapted to drawings to help everyone understand what they mean.
When one begins to construct a building, one should carefully consider the
implications of drawings.
In this book, plan of reinforcement is briefed to help the workers understand them
more easily.
Drawings of construction work are grouped roughly as civil engineering and
architecture.
Although there are some differences, all the contents could be understood since they
are all in accordance with IPC mentioned above.
3) Classification of drawing
① Shop Drawing
Drawings that suggest overall dimensions of each member with symbols, numbers
and lines for the construction work
② Detailed Drawing
Detailed drawings that describe shapes , types and dimensions of each element for
the bar-fabrication
③ Understanding of Drawing
Drawings are in their own sequence beginning with the title and contents on the 1st
page.
Structure drawing of Rebar is for this case.
There are several types of drawings which include machinery, electricity,
sanitation, fire protection, communication, etc according to the type of work and
there are details as follows.
A) Construction
i. Building layout
ii. Elevation
iii. Plane figure
iv. Cross Section
v. Part Detailed drawing
B) Structure
i. Drawing of column center
ii. Plane figure of structure
iii. Drawing of stairway and slab rebar arrangement
iv. List of pillar , beam and retaining walls
v. Detailed drawing of rahmen rebar arrangement
C) In general, the order of drawing is in a sequence mentioned above, and all the
drawings are in scale.
④ Scale (All the units in "mm")
Among several types of rulers used in drawings, scale is indispensable.
There are many types of scale. Among them 300mm scale is frequently used.
It has carved line in the middle of each side, colored red, blue and black to
distinguish its scale.
Scale in red
,
Scale in blue
,
Scale in black
Blue
Red
,
Black
Other different scales are available like
,
4) Usage of symbol
① General symbol
Description
Symbol
Length
L
Indication
Rebar indication
Area
A
Volume
V
Part cross section
Symbol
Distance of Rebar
Diameter of Rebar
High density
No. of Rebar
No. of cross section
No. of drawing
(Civil engineering, Architecture, Structure)
Radius
R
No. of cross section
No. of drawing
Part detailed
drawing
(Civil engineering, Architecture, Structure)
Main entrance
Level
indication(Plane)
Sub entrance
Scale
S 1/200
Finish
▽
Level indication
(elevation, cross
section)
No of layer &
Member
Structural plane
▼
EL. 0.0000
EL. 0.0000
Serial No. of Member
Symbol per part of structure
No. per layer
② Drawing Symbol
Symbol
Description
Symbol
Description
B
Bottom
T
Top
N.F.
Near Face
F.F.
Far Face
E.F.
Each Face
E.W.
Each way
B.O.F
Bottom of Foundation
T.O.C
Top of Concrete
T.O.F
Top of Foundation
E.J.
Expansion Joint
Ab
Size of a rebar(㎠)
C.J.
Construction Joint
fck
Strength of Concrete(kgf/㎠)
fy
Resistance strength of rebar(kgf/㎠)
fcu(t)
Compression strength of concrete per
date(kgf/㎠)
fe
Available resistance power of
ground(tonf/㎡)
D(db)
Nominal diameter of deformed
rebar(mm)
Fp
Available resistance power per
pile(tonf/㎡)
CL
Center Line
&
And
H
Height
@
Distance
THK.
Thickness
W
Width
CONC.
Concrete
TYP.
Typical
N.T.S
Not to Scale
ST’L
Steel
EL.
Elevation Level
FL.
Floor Level
2. Characteristic of Rebar
Throughout the reinforcement work, reinforcing bar strongly bonds to mixed concrete
and this makes floor, wall and other members very strong.
In other words, reinforcement is a bar that is embedded in the mixed concrete to make
a member strong.
Bar and concrete have low thermal expansion coefficients, 1×10-5 , and therefore
have little thermal deformation or failure, cooperatively strengthening members.
1) Production process of rebar
① Ingot : made from melted iron ore and pig iron
② Billet : made from hot-rolled ingot
③ Reinforcing bar : manufactured per type by hot-roll process from the
purchased billet
Type
Deformed
Rebar
Symbol
Resistance Point (kgf/mm2)
Classification
SD 30A
over 30
Green(D:General type)
SD 30B
30 ~ 40
White(D:General type)
SD 35
35 ~ 45
Red(HD:Density type)
SD 40
40 ~ 52
Yellow(HD:Density type)
SD 50
50 ~ 64
Black(HD:Density type)
p.s.) KS Symbol of Deformed Rebar : indicate as SD300, SD350, SD400, SD500
④ In SD400, S is steel, D is Deformed Bar, 40 indicates that resistance point is over
40kgf/mm2(=400N/mm2=4,000kgf/cm2).
2) Classification of rebar
① Regular bars : The length of one strip is 8,000mm by KS(Korean Standard).
Each bundle has almost same weight. (basis of 1-2 ton)
② Irregular bars : Irregular bars that are made of leftovers or nonuniform bars.
③ Reinforcing bars that are mainly used in the construction site are SD40 high
strength steel and SD30A mild steel, Each bar is colored yellow(HD) and green(D)
respectively in order to identify them.
Mild steel usually used as processed goods such as hoop , stirrup , etc.
Type
Deformed
Bar
Symbol
Classification
SD 30A
Green(D)
SD 40
Yellow(HD)
SD 50
Black
p.s.) SD:Steel Deformed
3) Type & Weight of rebar
▶If the worker in the construction site prepare the bars more than needed, there
might be rust on the surface of the rebar.
To prevent oxidation of the bar, it is advised to prepare moderate amount of the
bars.
▶When you need to pile the bars near the construction site, they should be classified
and piled on the big gravels to make the ventilation easy.
And also cover the stocked bars to avoid humidity.
▶There are usually two types of deformed steel used in the construction work.
① SD30A(mild bar) - normal strength bar, has green-colored end
② SD 40(high tension bar) - high strength bar, has yellow-colored end
※Size, Weight of Deformed Bar(8m)
(KS D3504)
Content
Type
1tonf
2tonf
nominal diameter
Per each
Per meter
Q’ty per
Q’ty per
(D)mm
(kgf)
(kgf)
1tonf
(kgf)
2tonf
(kgf)
HD10
210
420
9.53
4.48
0. 56
941
1,882
HD13
120
240
12.7
7.96
0.995
955
1,910
HD16
75
150
15.9
12.48
1.56
936
1,872
HD19
56
112
19.1
18
2.25
1,008
2,016
HD22
41
82
22.2
24.32
3.04
997
1,994
HD25
32
64
25.4
31.84
3.98
1,019
2,038
HD29
25
50
28.6
40.32
5.04
1,008
2,016
HD32
20
40
31.8
49.84
6.23
997
1,994
4) Weight limit of rebar
Size of Rebar
Less Than D10
Weight limit
1 each
- 0.8%
1 ton
7.0%
D10 ~ D16
6.0%
5.0%
D16 ~ D29
5.0%
4.0%
More Than D29
4.0%
3.5%
Remark
Sampling of test piece and
calculation of weight limit
should be in accordance with
KS D3504
3. Calculation for unit weight of Rebar
1) Unit weight
① Unit weight is the weight of bar per 1m.
※ FYI, the basic value in drawing and the length of rebar is “mm”.
When calculating unit weight, you must convert into “m” from “mm”.
② Unit weight per rebar type
Rebar Size
Unit Weight
Rebar Size
Unit Weight
HD10
0.56 f/m
HD25
3.98 f/m
HD13
0.995 f/m
HD29
5.04 f/m
HD16
1.56 f/m
HD32
6.23 f/m
HD19
2.25 f/m
HD35
7.51 f/m
HD22
3.04 f/m
HD38
8.95 f/m
③ Basic unit conversion
1ton = 1,000kgf
1kgf = 1,000gf
1m = 100cm
1cm = 10mm
2) Calculation of length(L) in model
①
②
③
4. Criterion of Rebar arrangement
1) Rebar coating
▶It means the shortest distance to the surface of concrete to cover rebar surface.
Rebar coating thickness of each part must be considered in the period of plan after
considering durability, refractory, safety in structure endurance & errors in
construction carry-out.
▶There are examples of coating case as ground criterion for all construction without
segmenting the case of ground and also the case of foundation regularly.
※ By the effect of CO2, humidity, acid gas, there will be going on of neutralization
step by step from the surface of concrete.
If the coating is small, its speed to arrive rebar will be faster .
If so, the rust will expand, the adhesion of concrete coating will drop, white
phenomenon will exist, senility of structure body will facilitate.
(Unit:mm)
Rebar Size
Classification
Minimum
coating/thickness Remark
Concrete pouring under water
Foundation
All rebar
100
Concrete burying under ground forever
after land pouring concrete adjoined
Foundation
All rebar
80
Concrete part to expose to outdoor
air and to adjoin land directly
Wall, pillar
over HD29
Beam (outside exposure
below HD25
beam)
Slab(foundation slab) below HD16
50
40
over HD35
40
below HD35
20
Beam, Pillar
Tiehoop
Stirrup
Spiral rebar
40
Shell, Member
All rebar
20
Slab, Wall, Under
Flooring
Concrete part not to adjoin land and
outdoor air
60
※ Note : “direct exposure to the air of outdoor” means the case of direct exposure of
climate change and humidity change.
< Independent
foundation >
< Pile
foundation >
Coating
thickness 80
< Pillar >
Coating
thickness 80
Coating
thickness 50
Cushion
Hoop
Coating
thickness 40
Lean Concrete
Lean Concrete
< Beam >
< Wall & Slab >
Coating
thickness 20
Wall
Stirrup
Coating
thickness
Slab
Coating
thickness
In Shear wall, the
arrangement of rebar
should be to the inside
of vertical rebar.
※Regarding wall, horizontal rebar should be arranged to the outside of vertical rebar.
※Regarding outside wall in underground which compressed by the land, more
arranged rebar should be arranged to the outside after comparing the arrangement
quantity between vertical rebar and horizontal rebar.
2) Rebar distance
Classification
Net Distance
Distance
Over 1.5 times of nominal diameter
Deformed
rebar
Over 1.25 times of max. size of thick aggregate.
Net distance
Over high value in 25mm
3) Type of tying
Regarding the working of tying , there are folded tying(lap splice) , compressed
tying(welded splice) , mechanical spiral tying(mechanical splice).
But compressed tying(welded splice) , mechanical spiral tying(mechanical splice)
have to be effected over 125% of resistance strength(fy) in plan criterion.
① Folded tying (lap splice)
It is tying method to fold the fixed length from end part to new tying part by using
regular rope currently.
※ Folded tying(lap splice)
Concrete
Strength
(kgf/Cm2)
Rebar
Type
210
SD30
(fy=3,000
)
240
270
210
SD40
(fy=4,000
)
240
270
The value in ( ) is the case of upper part rebar.
Rebar
Size
Tying length of deformed rebar to be
extended
A Class Tying
A Class Tying
Under D19
31.5d (41.0d)
41.0d (53.3d)
Over D22
39.3d (51.1d)
51.1d (66.4d)
Under D19
29.4d (38.2d)
38.2d (49.7d)
Over D22
36.8d (47.8d)
47.8d (62.2d)
Under D19
27.8d (36.1d)
36.1d (47.0d)
Over D22
34.7d (45.1d)
45.1d (58.6d)
Under HD19
42.0d (54.6d)
54.6d (71.0d)
Over HD22
52.4d (68.1d)
68.1d (88.5d)
Under HD19
39.2d (51.0d)
51.0d (66.2d)
Over HD22
49.1d (63.8d)
63.8d (83.0d)
Under HD19
37.0d (48.1d)
48.1d (62.5d)
Over HD22
46.3d (60.2d)
60.2d (78.2d)
Tying length
of deformed
rebar to be
compressed
21.6d
28.8d
1. The length of folded tying of rebars which have different diameter must over high value between the fixed
length of high diameter rebar and the folded tying length of low diameter rebar .
2. The tying position must be placed to low stress / to compressed stress of concrete.
3. By the criterion of concrete structure plan , it is mentioned that it is available for folded tying in case of
D29~D35 rebar.
However, you have to check in advance the problem such as the net distance of rebar is not secured and
also the tying length will be exaggerated if you apply folded tying of thick rebar.
Generally, there are more advantageous case by using mechanical tying instead of folded tying in case of
over D29 rebar.
A class tying : must be zigzag(rotation) tying arrangement and arranged rebar quantity is over 2 times of
required rebar quantity which defined in total block of tying part and also under 50% of rebar tying
quantity within required folded length.
B class tying : it is available for the tying of anti-earthquake plan and generally it is applicable to all
construction site.
Regarding SD500 , you must apply 1.25times of B class tying.
※ Regarding beam main bar tying , you must apply B class tying if you don't
mention tying position specially.
But, you can apply A class tying if you want to tying the compressed part of
concrete. (the compressed part of concrete : upper part main bar places near center
part of span, lower part main bar places near pillar)
※ The tying length of wall vertical length is available around 40db of under HD19
especially.
Example of folded tying(lab splice)
Vertical
rebar
Tying Length of Tension bar(Ls)
Slab upper
part
Slab upper part
Fixed length of Tension bar
Tying Length of Tension bar(Ls)
ⓐ Folded tying of vertical rebar in case the distance of rebar arrangement is different
Wall
S : Distance of Rebar
Ls : Tying length of Tension bar
ⓑ Folded tying of horizontal rebar
Tying Length of Tension bar(Ls)
Example) Length of folded tying to be extended
of vertical & horizontal rebar
Diameter
Length
② Compressed tying(welded splice)
It is the tying method to compress through heat-treatment end to end by using
machinery.
As shown in figure(A) , place 2 bars 3mm away , heat up both of the ends by using
mechanical equipment and add pressure to weld splice them figure(B), usually
available for all bars.
③ Mechanical spiral tying(mechanical splice).
As the mechanical splice method , it is rebar tying method to connect the spiral
part with nut & coupling by cutting screw by expanding the end of rebar over the
regular size.
(A) Connect Nut
(C) Move Coupler
(B) Connect Coupler
(D) Move Nut
4) Fixing and tying
① In order to effect the adequate resistance strength of rebar, it is essential to obtain
the enough adhesion strength with concrete.
The more you increase the net distance & coating thickness of rebar, the larger of
adhesion strength.
② Fixing length is the buried length in concrete to effect the adequate resistance
strength of rebar and fix the length with the criterion of max. stress point of
appropriate rebar.
③ The fixing and tying length of rebar is changing by the strength of material and
type of rebar arrangement , etc.
i. It will be lengthen by using HD(high density) rebar.(SD40 is 1.33times of
SD30A)
ii. It will be shorten by using HD concrete.(inverse proportion from square root of
concrete strength)
iii. It will be shorten if net distance and coating thickness of rebar increase.
iv. It will be shorten by the restriction effect if it is surrounded by stirrup and tie
hoop.
④ Caution : If the fixing and tying length of rebar will be shorten , the resistance
strength of rebar will be reduced as long as the shortened length.
Also, in case the heavy binding of splice part of rebar needlessly sometimes,
binding has only the role to prevent the movement of rebar when pouring concrete
and also no relation to adhesion strength of rebar. (the tensile of a D25 rebar is
5.04 4.0=20.16tonf)
⑤ If the position of extended rebar for the tying of poured concrete is wrong, it is
available for bending of splice with the angle of under
if error is trivial but you
need to take additional action to increase the section of additional material if error
is over that angle.
⑥ In case slab or wall rebar will be cutted by temporary exit such as material pick-up
exit, etc, you must extend the rebar which is over the length of splice to both ends
of exit.
If width of exit is narrow or the length of rebar extended is shorten , the length of
splice will be shorten when pouring exit concrete later.
⑦ Calculation of bar length
What should be added to original length : splice length, fixed length
Splice length : extra length to lap the bars
Splice length
Fixed length
Fixed length : developed length when the bar is fixed
⑧ Method to calculate fixed length
90°Standard hook
Fixed length of
rebar which has
standard hook
fixed length of tension bar
- In case of fixing to neighbor beam -
fixed length of
tension bar
- In case of fixing to end pillar -
⑨ Tension bar and compression bar
tension bar : The main usage is tension bar because rebar is reinforced material
to reinforce the tension of weak point of concrete.
compression bar : the rebar to be arranged in addition to increase the resistance
strength in concrete material and it is mainly applicable to the pillar of high
building to cover the compression.
⑩ Refer to the diagram (#22 page) for tying & fixing per rebar diameter
Compression
Tension
5) Form of fixed beam
※ When arranging beam, the marked on drawing as bending bar is mainly Japanese
method of rebar arrangement.
Our standard will be cut-bar instead of bending bar(Japanese method) .
① The length to
extend to reverse
side from max.
Stress point of
fixed length.
Hook should
place over the
center of pillar.
Fixed length
St
eff ress
(
we ect par
igh the t to
t)
Return point
beam
Return point is must not 1/4
point.
(return point of upper bar is
different from return point of
lower bar)
※① is fixed length of tension upper bar.
In case of fixing with standard hook, fixed length of rebar which has standard
hook will be applied.
If not, fixed length of tension bar will be applied.
is generally fixed length of lower compression bar and it is available of
fixation if it is extended to pillar over 15cm without hook.
6) Example of fixed length per rebar diameter
① Fixed length of tensile rebar
Fixed length of tensile rebar in slab(SD 400)
Str
en
gth
Rebar
(unit:mm)
24N/
240kgf/
27N/
270kgf/
30N/
300kgf/
35N/
350kgf/
40N/
400kgf/
300
300
300
300
300
400
380
360
330
310
540
510
490
450
420
730
680
650
600
560
Remark
※When using SD500 rebar(fy=500N/㎟=5,000kgf/㎠), apply 1.25 times
Fixed length of tensile rebar in foundation, pillar, beam, wall(SD400)
th
ng
re
St
Rebar
27N/
270kgf/
24N/
240kgf/
General bar
Upper bar General bar
30N/
300kgf/
Upper bar General bar
(unit:mm)
35N/
350kgf/
Upper bar General bar
40N/
400kgf/
Upper bar General bar
Upper bar
HD10
400
510
370
490
360
460
330
430
310
400
HD13
510
670
490
630
460
600
430
550
400
520
HD16
630
820
600
770
570
730
520
680
490
640
HD19
750
970
710
920
670
870
620
810
580
760
HD22
1080
1410
1020
1330
970
1260
900
1170
840
1090
HD25
1230
1600
1160
1510
1100
1430
1020
1320
950
1240
HD29
1430
1850
1350
1750
1280
1660
1180
1540
1110
1440
HD32
1570
2050
1480
1930
1410
1830
1300
1690
1220
1590
※When using SD500 rebar(fy=500N/㎟=5,000kgf/㎠), apply 1.25 times
② Fixed length of compression bar
Fixed length of compression bar(SD400)
Str
en
gt
Rebar h
HD10
(unit:mm)
24N/
240kgf/
27N/
270kgf/
30N/
300kgf/
35N/
350kgf/
40N/
400kgf/
50N/
500kgf/
210
200
200
200
200
200
HD13
270
260
240
230
210
210
HD16
340
300
300
280
260
260
HD19
400
370
360
330
310
310
HD22
460
430
410
380
360
360
HD25
520
490
460
430
400
400
HD29
600
570
540
500
470
470
HD32
670
630
600
550
520
520
※When using SD500 rebar(fy=500N/㎟=5,000kgf/㎠), apply 1.25 times
7) Example of splice length per rebar diameter
1) Classification of tension splice
ㆍA class tying : must be zigzag(rotation) tying arrangement and arranged rebar
quantity is over 2 times of required rebar quantity which defined in total block of
tying part and also under 50% of rebar tying quantity within required folded
length.
ㆍB class tying : it is available for the tying of anti-earthquake plan and generally it
is applicable to all construction site.
Actual arranged rebar requirement
Required rebar Q’ty
Max. splice % within folded splice length
50%
50%
2
2
2) Upper bar : horizontal rebar without concrete harded over 300mm under splice part
and fixed length
3) The rebar with folded splice without contacting directly each other in bending
material must not depart over little value between 150mm or 1/5 of folded splice
length.
① A class splice length of tension rebar
Splice length of slab(SD400)
Str
en
gth
Rebar
HD10
(unit:mm)
24N/
240kgf/
27N/
270kgf/
30N/
300kgf/
35N/
350kgf/
40N/
400kgf/
300
300
300
300
300
HD13
400
380
360
330
310
HD16
540
510
490
450
420
HD19
730
680
650
600
560
Remark
※When using SD500 rebar(fy=500N/㎟=5,000kgf/㎠), apply 1.25 times
A class splice length of foundation, pillar, beam, wall(SD400)
St
ren
gth
Rebar
27N/
270kgf/
24N/
240kgf/
General bar
Upper bar General bar
30N/
300kgf/
Upper bar General bar
(unit:mm)
35N/
350kgf/
Upper bar General bar
40N/
400kgf/
Upper bar General bar
Upper bar
HD10
400
510
370
490
360
460
330
430
310
400
HD13
510
670
490
630
460
600
430
550
400
520
HD16
630
820
600
770
570
730
520
680
490
640
HD19
750
970
710
920
670
870
620
810
580
760
HD22
1080
1410
1020
1330
970
1260
900
1170
840
1090
HD25
1230
1600
1160
1510
1100
1430
1020
1320
950
1240
HD29
1430
1850
1350
1750
1280
1660
1180
1540
1110
1440
HD32
1570
2050
1480
1930
1410
1830
1300
1690
1220
1590
※When using SD500 rebar(fy=500N/㎟=5,000kgf/㎠), apply 1.25 times
② B class splice length of tension rebar
It is available for the tying of anti-earthquake plan and generally it is applicable
to all construction sites.
B class splice length of slab(SD400)
Str
en
gt
Rebar h
HD10
(unit:mm)
24N/
240kgf/
27N/
270kgf/
30N/
300kgf/
35N/
350kgf/
40N/
400kgf/
390
390
390
390
390
HD13
520
490
470
430
410
HD16
700
660
630
580
550
HD19
940
890
840
780
730
※When using SD500 rebar(fy=500N/㎟=5,000kgf/㎠), apply 1.25 times
Remark
B class splice length of foundation, pillar, beam, wall(SD400)
(unit:mm)
St
ren
gth
Rebar
General bar
HD10
510
670
490
630
460
600
430
550
400
520
HD13
670
870
630
820
600
780
550
720
520
670
HD16
820
1070
770
1000
730
950
680
880
640
830
HD19
970
1260
920
1190
870
1130
810
1050
760
980
HD22
1410
1830
1330
1720
1260
1640
1170
1510
1090
1420
HD25
1600
2080
1510
1960
1430
1860
1320
1720
1240
1610
HD29
1850
2410
1750
2270
1660
2150
1540
2000
1440
1870
2050 SD500
1930
1830
1690 1.25
2650 rebar(fy=500N/㎟=5,000kgf/㎠),
2510
2380 apply
2200
HD32 using
※When
times1590
2060
27N/
270kgf/
24N/
240kgf/
Upper bar General bar
30N/
300kgf/
Upper bar General bar
35N/
350kgf/
Upper bar General bar
40N/
400kgf/
Upper bar General bar
Upper bar
③ Splice length of compression rebar
Strength
Rebar
fck = 21N/
SD400 (fy=400N/
= 70N/ (210kgf/
=4,000kgf/
)
- 700kgf/ )
SD500 (fy=500N/
HD10
300
410
HD13
380
540
HD16
470
660
HD19
550
780
HD22
640
910
HD25
720
1030
HD29
840
1190
HD32
930
1320
=5,000kgf/
)
④ Fixed length of tension bar which has standard hook fy=400N/㎟(4,000kgf/㎠)
(diameter)
fixed length of tension bar
destroyed section of concrete
min
(diameter)
tension
tension
3db HD10 ~ HD25
4db HD29 ~ HD35
5db over HD38
or
Str
en
gt
Rebar h
24N/
240kgf/
27N/
270kgf/
30N/
300kgf/
35N/
350kgf/
40N/
400kgf/
50N/
500kgf/
HD10
210
200
200
200
200
200
HD13
270
260
240
230
210
210
HD16
340
300
300
280
260
260
HD19
400
370
360
330
310
310
HD22
460
430
410
380
360
360
HD25
520
490
460
430
400
400
HD29
600
570
540
500
470
470
HD32
670
630
600
550
520
520
※ When using SD500 rebar(fy=500N/㎟=5,000kgf/㎠), apply 1.25 times.
⑤ Fixed length and splice length of binded rebars.
Increase the fixed length and splice length of binded rebars as follows.
a) 3pcs binded rebars : increase 20%
b) 4pcs binded rebars : increase 33%
The splice of each rebar must not duplicated
5. Criterion of Rebar bend-processing
1) Bending of main bar and leftover length
(unit:mm)
fixed roller
center pole
fixed roller center pole
(over 12d)
Drawing
(4d or over 60mm)
Rebar size
Rebar
diameter
HD10
9.53
HD13
12.7
HD16
Roller min. radius
Condition
A
Leftover length
Condition
B
Condition
C
30
120
60
40
160
60
15.9
50
190
70
HD19
19.1
60
HD22
22.2
HD25
25.4
HD29
28.6
HD32
31.8
3d
3d
4d
70
12d
230
270
4d
80
90
80
310
110
120
350
120
130
390
130
2) Bending of stirrup, hoop and leftover length
fixed roller
center pole
(unit:mm)
fixed roller center pole
Drawing
Roller min. radius
Condition
A
Leftover length
Rebar size
Rebar
diameter
HD10
9.53
HD13
12.7
HD16
15.9
35
100
HD19
19.1
60
120
HD22
22.2
HD25
25.4
20
2d
3d
3) Rebar processing form
Rebar’s hook(one-side, both-sides)
one-side
both-sides
Condition
30
70
80
6d
12d
B
Condition
C
60
60
80
80
6d
or
60mm
100
120
280
140
320
160
U type
Closed type
Transformational
closed type
4) Slope dimension of rebar processing(hunch)
100
140
120
370
520
430
640
910
740
910
1290
1050
110
160
130
380
540
440
650
920
750
920
1300
1060
120
170
140
390
550
450
660
930
760
930
1320
1070
130
180
150
400
570
460
670
950
770
940
1330
1090
140
200
160
410
580
470
680
960
790
950
1340
1100
150
210
170
420
590
490
690
980
800
960
1360
1110
160
230
190
430
610
500
700
990
810
970
1370
1120
170
240
200
440
620
510
710
1000
820
980
1390
1130
180
260
210
450
640
520
720
1020
830
990
1400
1140
190
270
220
460
650
530
730
1030
840
1000
1410
1150
200
280
230
470
670
540
740
1050
850
1010
1430
1170
210
300
240
480
680
550
750
1060
870
1020
1440
1180
220
310
250
490
690
570
760
1080
880
1030
1460
1190
230
330
270
500
710
580
770
1090
890
1040
1470
1200
240
340
280
510
720
590
780
1100
900
1050
1490
1210
250
350
290
520
740
600
790
1120
910
1060
1500
1220
260
370
300
530
750
610
800
1130
920
1070
1510
1240
270
380
310
540
760
620
810
1150
940
1080
1530
1250
280
400
320
550
780
640
820
1160
950
1090
1540
1260
290
410
340
560
790
650
830
1170
960
1100
1560
1270
300
420
350
570
810
660
840
1190
970
1110
1570
1280
310
440
360
580
820
670
850
1200
980
1120
1580
1290
320
450
370
590
830
680
860
1220
990
1130
1600
1300
330
470
380
600
850
690
870
1230
1000
1140
1610
1320
340
480
390
610
860
700
880
1240
1020
1150
1630
1330
350
500
400
620
880
720
890
1260
1030
360
510
420
630
890
730
900
1270
1040
6. Tying method of Rebar
When tying the bars, the hook is used in Korea and Japan.
While in other countries, the wrench is used.
Tying the bars requires many times of practice.
All the places that two bars meet are recommended to tie.
However, it is usually accepted to skip all other crossing point in case of light-loaded
bars.
There are several types of binding the bars such as cross tie, Saddle tie with twist,
wall tie and double string tie, etc.
1) Cross tie
Ties to fix the stirrup onto beam ties to prevent hoop from slipping down
2) Double string tie
Same procedure when you use hook to tie the bars mostly used in Asian countries
applicable to many construction sites such as wall, slab, etc.
You must tie different tying each bars.
3) Saddle tie with twist
Ties the bars in high beam or wall to fix them firmly
or to avoid twisting off
4) Wall tie
- The same procedures as saddle tie with twist and tie
it as the method of right picture
- Ties the bars that extend from the wall to keep the
required positions and distances between them
5) References
① Every crossing point of the bars at the bottom span should be tied, and wound
more than 3 times.
② When tying the bars at the top span, tie the bar changing the tying direction(one
time to left and next to the right)
③ When tying the bars in a slab, you may skip every other, but it is better to wind the
hoop before tying the bars.
④ It is advised to wind the hoop 3 times at the important crossing point.
※ There are several kinds of ties, and in construction works, #20 tie is normally used
in folded state.
7. Bar support , Spacer
① Bar support is usually to hold the location of placed bars, and spacer maintains the
cover depth of a member as intended.
② In addition, they also prevent dispersions of located bars due to high impacts and
undesirable vibrations.
Especially in reinforced concrete, cover depth, which is one of the important
factors for durability, should be seriously considered.
③ Undoubtedly, bar support and spacer should be strong or even stronger enough to
to support the bar and endure high impacts
④ When metal is used to reinforcement, spacer must have special rust protection on
the portions nearest the face of the concrete by attaching pvc cap.
Part
Type
Area : 4m2 - 8EA
16m2 - 20EA
Bar Space - around 1.5m
(Closer than 1.5m at the end)
Foundation
Foundation
Beam
Remark
By calculation if Mat
thickness is over 1,500
Install to top span,
bottom span, sides
At the 1st tie hoop in the top span
In the middle of pillar in the middle
span
less than 1.0m of pillar width 2EA
More than 1.0m of pillar width 3EA
Pillar
Steel Reinforcement
Wall
Basement
Outside Wall
Q’ty & Layout
&
Concrete material
At the first tie hoop in the top span
1.5m from the top in the mid span
Transverse spacing 1.5m
Within 1.5m at the end
Beam
Bar Space - around 1.5m
(Closer than 1.5m at the end)
Slab
Bar 1pc(1.3/m2) per width by long,
each 1m at the top & bottom bar
At the top and the
bottom except side
beam
Also on the sides in the
side beam
8. Conventional processing work tools
Once the construction work is initiated, reinforcement needs to be manufactured,
several different tools are used depending on the type of work.
1) Types of conventional tools.
① Bending die : die to bend the bar on
② Bender : bends the bars
③ Hammer : adds force to cut the bar
④ Lower cutting blade
⑤ Upper cutting blade
⑥ Mat plate to fix the cutbar
⑦ Various types of bar bender and bar cutter are available(see Chapter.3)
2) Preparation before reinforcement of rebar work
① Fabricate the bar bending die (The height should be about 850mm).
② Prepare the power cable to connect the bending machine and binding machine
③ Prepare chalk or other writing instrument to mark the dimension.
④ Prepare the tools and bending die.
<Bending Table>
Bending Pin
Bending Plate
<Manual Bender> Prepare per rebar size
<Mat>
<Low cutting blade>
<Manual Cutter>
<Hammer>
<Upper cutting blade>
3) Tools needed if assembling does
a. Measuring tape ~ measures the dimension
b. Hook ~ a tool to tie the bar(usually used in Korea and Japan).
Wrench is used in Europe and South-East Asia
c. Conventional shearing machine ~ cuts a bundle of binding wires to bind the bars in
a beam, a pillar(divide to half) or a slab(divide to 3parts)
d. Plumb ~ using to assemble the pillar bar vertically
e. Bar-tying hook ~ ties #8 wire
<Measuring tape>
<Inch Ruler>
<Plumb>
<Bar-tying hook>
※ Tools mentioned above are rather old type ones, and newly developed tools are in
the construction site now.
9. Point of conventional processing work
1) Marking the bending point (example : D10~D13 stirrup , hoop)
Mark the bending point on the bending die. Be sure to nail the bending panel on the
bending die to fix it firmly.
Nail
Processed
dimension
Bar backstopper pin
Working point
Keep the 1.5d of tolerance from the working point
(in case of D10, keep the 15mm of tolerance)
2) Determining the location of the manual bender
Be careful
Make space +20mm width from the
bending start pin.
The space of working point must over 20mm
than using rebar.
The position of bender must have space of
20mm from working point to bender using to
head of handle. (install within eye shot)
3) Processing
Bend the bar a little more than intended angle.
Make sure that there is 20mm of distance between the tip of bender and bending
point.
The distance between these two points should be neither too far nor too close for high
bending accuracy.
With your left hand, gently push the bender outward to bend the bar, while you grab
the bar with your right hand to fix it firmly.
4) Posture and position of foot
It is recommended that bending
direction should be from right to left.
The left hand that pushes outward to
bend the bar should be at the level of
your belt.
Your right foot just turns the direction,
while your left foot moves quickly to
bending direction(Weight shift along
bending direction)
5) Currently using machinery
General Bender TYB-D35
Mobile Cutter TYC-D29A
10. Calculation of the quantity of Rebar material
1) Extra of rebar
① In case of deformed bar, extra is 3% in general when including fixed & splice
length of rebar, however, it is proportional to bar size.
16mm or larger : more than 5% extra
3% of 100ton is 100×0.03 = 3ton
② Rebar calculation included extra 3-8% after calculating fixing & splice.
Therefore, those works will prevent from the reason of illegal construction
practices with correct quantity & regular position carryout of construction by
calculating bar-list with shop drawing.
③ If rebar will be processed in rebar processing factory , basically extra is as follows.
In construction work 3%, in engineering work 6%, support work 3~4%.
You have to consider the economical efficiency and construction carryout
efficiency in site after analyzing in advance about extra percentage per rebar size
by the criterion per construction carryout area.
2) Base plate(Footing)
<Example : 1>
<Example-1>
In 2000×2000 foundation, shown as above, requirement of bar includes 20pcs HD22
bars of 1,840mm (80(cover depth)×2(both ends) = 160mm is extracted from
2,000(original length of foundation), 2pcs D19 assist bars of 2,601mm(1,840)×1,414
2 ), diagonal direction) and 4pcs short diagonal bars(2 bars in each diagonal
direction) of 2,318mm(1,640(200mm is extracted from main bar length 1,840mm)×
(
1,414 ( 2 ).
① HD22 1,840mm×20(foundation) = 36,800mm
Weight = 36.8m(36,800mm)×3.04(unit weight) = 111.872kgf
② HD19 2,600mm(long bar)×2 = 5,200mm
Weight = 5.20m(5,200mm)×2.25(unit weight) = 11.700kgf
HD19 2,310mm(short bar)×4 = 9,240mm
Weight = 9.24mm(9,240mm)×2.25(unit weight) = 20.79kgf
ⓐ Actual requirement of bar is ① HD22 = 111.872kgf
② HD19 = (11.700kgf+20.79kgf) = 32.49kgf
※ LOSS(left bar strip) : The original length of bar before cutoff is usually 8,000mm.
In case of ①above, 4pcs 1,840mm bars are produced and 640mm of bar strip is
left.
5 bars are needed for foundation, hence 640×5 = 3,200mm of bar strip is left. Its
net weight is 3.20m(3,200mm)×3.04(unit weight) = 9.72kg.
ⓑ Actual requirement of bar is 8m×3.04(unit weight)×5 bars = 121.6kg
<Example : 2>
① What is the weight of D10 8m bar?
0.56kg×8m = 4.48kg
② How many D13 bars(8m criterion) in 2ton?
2,000kg÷(0.995kgX8m) = 251EA(standard is 240EA)
③ Arrangement in foundation (base plate F)
( All the unit in drawing should be in 'mm')
HD16 rebar 200mm space
HD19 rebar 300mm space
HD13 reinforcement bar 3EA
HD16 = 2,000-(80(cover depth)×2(both ends)) = 1,840 (cutoff dimension)
HD19 = 3,000-(80(cover depth)×2(both ends)) = 2,840 (cutoff dimension)
₂
₂
HD13 = 1840 +2840 = 1840×1840+2840×2840 = 3,383 (cutoff dimension)
₂
₂
(Note. x = x×x, 10 = 10×10 = 100)
Here, multiply unit weight and number, then net weight of bar is
HD16 = 1.84m(1,840mm)×1.56kg = 2.87kg
2,840 ÷ @200 = 14.2 → 14 ⇒ 14+1 = 15EA
2.87kg×15 = 43.05kg
HD19 = 2.84m×2.25kg = 6.39kg
1,840 ÷ @300 = 6.13 → 6 ⇒ 6+1 = 7EA
6.40kg×7 = 43.73kg
HD13 = 3.38m(3,380mm)×0.995kg = 3.36kg
Weight = 3.36kg×assist bar(3+3) = 20.16kg
※Among 6 assist bars, two(2) of them in 3,380mm and the other(4) in 12,320mm
(4x3,080mm : 300mm shorter)
Net weight is 43.05+44.73+21.60 = 109.38kg and add 5% extra, hence 114.84kg is
required.
3) Base(footing) and pillar
As various footing types like continues footing, single footing and mat footing, there
are many shapes of footing, that is, triangle, right triangle, square, rectangle, pentagon,
circle, multi-layer plate, etc.
In this book triangle shape footing and single reinforcement footing are dealt with.
In case of footing shown left cover
depth, the type of bar and the size of
HD22@200
bar should be considered.
In addition, the reinforcement at
footing-pillar junction should be
included here.
HD19-6EA
Before bar cutoff, the size of C1,
HD22@200
the area of main reinforcement, the
size of hoop and the spacing of
F1 plane
stirrup are all considered consulting
the bar list.
cover50
Calculation :
cover80
Footing shown left is in contact
with soil, hence cover depth is
80mm at each end(80×2 = 160 at
both ends).
Section
160mm is extracted from footing
length 2,000mm, and this(1,840mm)
is divided with spacing 200mm.
D10@300
D10@300
upper part, lower part @150
HD22-8EA
Then 10 reinforcement(at every 9
spacing +1 at the end) is required
here.
Now reinforcement is in two
directions and therefore we need 20
reinforcements.
4) Pillar
Similar to footing, there are many shapes of pillar, that is, triangle, right triangle,
square, rectangle, pentagon. circle, etc.
The worker is recommended to earn a lot of working experience.
① Calculation of pillar
In calculation, tie hoop, stirrup, main bars
in column and the others should be
included here.
D10@300
D10@300
upper part, lower part
@150
First extract cover depth from hoop size
(400mm), and cover depth in the basement
and above the ground should be different.
HD22-8EA
Net length cover depth 400 - (40+40) =
320 (dimension)×4(4sides) ⇒ 1,280 +
100mm of hook then, cutoff length is
1,380mm.
Since net length of hook is 100mm, only
100mm of extra length is added here.
If the bar size is D10, one end is hooked
in circular, so 2 times of bar diameter
(20mm) is extracted here, As 5 hooks are
needed and hook length is 100mm at each
end(200mm in total), 80mm is extracted
from 100mm.
Then this 80mm is added to produce
200mm of hook length.
5) Calculation of main rebar
If you will carry-out with 8,000mm rebar including both fixed length(anchor) from
total length of 1 span , you just add the splice length from rebar diameter to use.
Example) Total length 62,000mm + both fixed length(anchor) 1,000mm = Gross Total
63,000mm. When using HD19 rebar, splice length is 19×40d = 760mm. Rebar
8,000mm - splice length 760mm = 7,240mm. Gross Total 63,000mm ÷ 7,240mm =
8.7 piece (long bar 8piece & rest 5,080mm) Above splice length is 5,080mm
including anchor.
You can calculate it as above , but you have to carry-out the splice position as soon as
closely by calculating several methods if spice position is not fit well.
<Sample of processing>
END
long bar processing
end top-bar center top-bar in span
end top-bar center top-bar in span
CENTER
splice rebar
long bar
outside end
outside end
6) Calculation of top rebar
Please refer to the method in construction site as follows because it is very difficult to
explain in theory.
If 1 span is 8,000mm, 4,000mm will be center part and add 40times(40d) + rebar
thickness is the length of top rebar in center part & end.
You cut as 4,000mm +760mm = 4,760mm.
※ When assembling current processing status , center part is from beam to upper part
rebar splice position and end is lower part rebar splice position if splice rebar 2 pcs
4,580mm + long bar processed 1pc as upper part rebar and splice rebar 1pc
4,580mm + long bar processed 2pcs as lower part rebar will be used.
And so, you assemble it mutually crossed and upper part is 2 bar from 3 bar from
splice position.
7) Calculation of hoop
① If pillar size is width 400mm length 500mm, actual processing size is 320mm,
420mm except cover 40mm each(both 80mm).
② When processing hook by hand, it will be included 40mm from total length.
When using Taeyeon's bending machine, it will be included 50mm from total
length .
coating
thickness 40
process size
③ Cut size : (420×2)+(320×2)+50 = 1,530mm
※ Example of hoop usage : To avoid wrong bending of main bar and to restrict inner
concrete , you maintain the space and no problem to assemble with 135°hoop at
one side.
8) Calculation of stirrup
① If beam size is length 500mm , actual processing size is 420mm , 420mm except
cover 40mm each(both 80mm). If beam size is width 300mm , actual processing
size is 220mm , 220mm except cover 40mm each(both 80mm).
② Including hoop 50mm , you can use Taeyeon's bending machine.
END
CENTER
Process size
③ Cut size : (420×2)+(220+50(hook)=1,100mm
※ Example of stirrup usage : To surround tension & compression bar and to restrict
inner concrete , you maintain the space and bend with over 135°as stirrup end
length.
Taeyeon bending machine will be processed 90°or 135°with free by
manufacturing of special tool & electric circuit.
9) Fact of processing
According to rebar thickness and to bending angle , 2 times of rebar thickness will be
used because of bending by circle of bending part than the length per actual straight line.
<Tolerance of rebar process size>
Item
Symbol
stirrup, tie hoop
A, B
5
below HD25
A, B
15
over HD29
A, B
20
-
20
Drawing
main
bar
length after processing
Tolerance( )
10) Changed size if it bent 1 angle per specification
When bending 1 angle, rebar D10 will be increased by 2cm each.
When bending 1 angle, rebar D13 will be increased by 2cm each.
When bending 1 angle, rebar D16 will be increased by 3cm each.
When bending 1 angle, rebar D22~25 will be increased by 5~6cm each.
Because bending part will be bent like R type, rebar will be less used per rebar
diameter.
Regarding processed rebar, it will be less used also by measuring with outside
diameter size.
If actual cut size is D10,
(42×2)+(32+8(hook)) = 124cm
Note) Process size must be outside diameter size of processed rebar.
11) Tolerance of processed size
Item
stirrup, tie hoop, spiral rebar
processed size
others
Tolerance( )
5
under D25 of deformed bar
15
D19~D41 of deformed bar
20
total length after processing
20
11. Foundation(Base) rebar arrangement
1) Foundation(base) work
In foundation work, the lean concrete underneath the footing concrete, is very
important.
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
them.
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
foundation rebar
lean concrete
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
properly only)
6-D13(circular arrangement)
PC Steel wire
2 times of
pile diameter
Fillup CON’C
HOOP D13@150×4
(foundation CON’C)
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>
when securing
splice length
<In case of not securing splice length>
In case of below
splice length
standard
hook
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>
slab
<After reinforcement>
main bar
pillar
tie hoop should be
@300 distance per
the drawing regulation,
tying
footing
lean concrete
MAT
bottom tie hoop
spacer
pillar
※ 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.
<Foundation plate>
pillar location
marking
eccentric
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
12. Pillar rebar arrangement
1) Indication of pillar(C)
Main bar drawing - It indicates the length of span by the criterion of pillar and wall,
etc. and indicates the position of pillar & wall.
<Example>
C - pillar
BC1 - #1 underground pillar
1C1 - #1 first-story pillar
500×500 - actual size of concrete
8-HD19 - 8pcs of HD19mm rebar
D10 @250 - install per 250mm of HOOP distance
D10 @250 - install per 250mm of DIA HOOP distance
※ Be careful of this point if there are rebar quantity's differences according to pillar
assembly x0, x1 or y0,y1 direction.
2) Indication of floor
2SL(upper concrete)
2FL(upper part’s closing condition)
Height of floor
1) GL - GROUND LEVEL
2) FL - FLOOR LEVEL
(ground level per floor)
3) SL - SLAB LEVEL
(upper part of structure per floor)
3) Sequence of pillar assembling
< Stand the same to diagonal direction if each side is even. >
< Stand the same to all directions if each side is odd. >
< Stand the same to one direction if each side is even & odd. >
4) Tying method of pillar
① Even the tiny little requirement for the construction should be taken into
consideration.
Keep the pillar reinforcements vertically and splice the bars 3 times.
Upper and lower parts of the reinforcements should be cross-tied.
② When tying the corner of tie hoop, it is better to wind the tying wires changing
directions up and down to let it not to be hung down.
It is also recommended that worker wind the tying wires at least one time in
advance to hold the main bar to its original position.
main bar
tie bar
③ Tie bar for assisting pillar should be at every distance to install tie hoop .
Diamond type
General type
④ Bind the tie hoops clockwise(as shown below) and spacing at the top and bottom
levels of vertical reinforcement should be within
of hoop spacing beginning at
50mm from the bottom of the floor.
5) Position of pillar tying
① In pillar bar slice, follow the instructions on drawings in order to splice them
adequately, that is, if not, the length of reinforcement is not fit for column with the
reason that usual 8,000mm bar is cut into two 4,000mm bars to splice.
good location of splice
available location of splice
bad location of splice
[Note]
It is desirable that reinforcing bar should be in a variety of sizes, but 8m bar is usually
available in the market.
In other words, if you need a bar other than 8m in size, you should give a customerorder for it, which does not go well with economical strategy.
Reinforcing bars from D10~D16 do not have much problem in using them as
reinforcement for slabs or bearing walls. We have some advantages here.
Bar loss and the frequency of splice will be decreased if using bars of 8m ~ 12m
length by mixing.
② Splice of pillar and pillar
over 75
under 75
max. 150
Dowel rebar
splice
fixing
max. slope
max. 150
splice/
fixed length of tension bar
slope rebar splice
using dowel rebar
6) Cross assembling of pillar and beam(only for outer pillar)
① Don't fill up tie hoop to assemble beam the crossed part of pillar & beam.
In this case , there are difficulty in carrying out the construction but you must fill
up tie hoop of outside.
Especially, you should prevent from the protruded main bar by filling up tie hoop
on outer pillar and edge pillar.
pillar
pillar
tie hoop
beam
from current
rebar arrangement
carry-out
of construction
② In case over 600mm of pillar size , you should fill up support tie hoop by shop
drawing.
You should get rid of support tie hoop in order to worker's entrance to pillar tube
to connect #8 wire for working of pillar outer appearance.
After this, the worker should not forget to bind the assist wire before he gets out.
※ In case the splice length for pillar splice is shorter than required, be sure to destroy
the concrete to maintain splice length but it is impossible possibility to execute
actually.
Therefore, you should check the availability of welding splice, compressed splice,
mechanical splice.
7) Correction of pillar
① Bend the bar gently at a very low level
② Pillar correction angle should not exceed
of overall angle
③ Heat should not be added to correct the main bar because it makes the strength of
rebar, just destroy the part that needs correction and bend it
of overall angle.
④ Destroy the part that needs correction and modify it.
These are 2 cases of correction depending on correction angle.
ⓐ When the correction grade is low
If corrected angle is about
,
insert the bar into pillar after bending.
Bending after concrete work.
ⓑ When the correction grade is higher than
, change the bending angle to
and cover the pillar as thin as possible.
Increase to minimum pillar thickness
Pillar rebar protruded to outside.
8) Detailed drawing of pillar and beam rahmen(arrangement)
① Don't apply compression splice length except pure compression material.
Regarding bending material , apply B class splice for tying near max. stress point
and apply A class splice for the rest block.
fixed length
A class tension splice
2nd floor HO
main
head
A class tension splice
The fixation of upper bar calculates fixed length from the main
bar bend area of pillar’s upper part, not from the inside of pillar
1st floor HO
space
When the beam is arranged, the bottom bar should be all tied,
and the stirrup upper binding supported by spacer should be
tied 2,3 times tightly.
tension splice
(over B class splice length)
tension splice
② Apply to anti-earthquake
slab rebar
In case all plane of
pillar have beam
Lo
max. size of pillar section
max.
max.
beam lower
part bar
In case some plane of pillar has beam
(ground outside pillar)
So
8db(main bar)
Lc/6
24db(hoop bar)
45
1/2(min size of pillar section)
30
13. Beam rebar arrangement
1) Principle of beam rebar arrangement
① Calculate the size and depth of beams according to the drawing and arrange them
in a suggested order, that is, exterior beams and big beams(G) & deep beams first
and then binding small beams(B beams) later.
② Supervisor has to check if the bar used at the top span meets the requirement on
the drawing.
Shorter bar than required might be used to save cost when the span is longer than
8,000mm, the bar standard.
③ The bar might deflect from undesirable vibration when placing concrete if the
double reinforcement or top end bar are tied with tying wires.
To prevent this, 3 pieces of stirrups are used to tie the bars at the top and as many
pieces to place double-leg bar & top bar on the bottom bar.
<The height will be changed by th rebar size>
Stirrup:end support(S.T.)
Center support(S.T.)
④ Cap tie bar should carry out 1 by 1 at least.
※ The 1st stirrup should be arranged with the space 50mm from the perimeter of
side pillar.
1st stirrup
arrangement beside
of big beam main bar
1st stirrup
arrangement beside
of pillar’s main bar
big beam
@/2 or under 50mm from side pillar
@/2 or under 100mm from side big beam
※ The splice for upper part rebar of beam's end and lower part rebar of beam's center
apply tension splice length.
<Main bar arrangement>
0.3L1 OR 0.3L2
0.3L1 OR 0.3L2
middle/
big value
middle/
big value
12db
Ldh
min 15㎝
0.125L1
0.125L1
min 15㎝ or continuance
min 15㎝ or continuance
0.125L1
0.125L2
L1
L2
<Distance of stirrup>
S2
S1
S3
50
50
end
0.25L1
center
0.5L1
L1
S4
50
end
0.25L1
end
0.25L2
center
0.5L2
L2
※ Apply the above except the case of marking separately on beam chart.
※ S1-S4 : stirrup distance
2) Types of stirrup
<a> Open type
- beam without cap tie bar
- beam to be arranged by front end without twisting
- beam without anti-earthquake plan
<b> Closed type
① slab on both sides
② slab on one-side
③ no slab on both sides
over 45cm
splice against total
distance of member
over 30cm
- beam with front end and twist
- in case of anti-earthquake plan
3) Position of beam tying(splice)
※ Splice location : diagonal line
① Calculation of bender
When bent bars are used to reinforce beams, bending point of the bar is usually
calculated as
distance from the center of the pillar.
However, it is formal to divide it into 4 parts from the end of beam reinforcement
to the other end.
wall girder
pillar
② An example for processing
Anchorage(fixed) bars are classified as the top bars and the bottom bars, when the
former have tensile loads and the later have compression loads.
Therefore, the top bars and bottom bars set fixed splice length with same method
because it has difficulty in working separately for processing and
assembling.(criterion of concrete structure plan)
In a real construction, 40d is used for both of them for convenience sake.
③ Cover depth of beams
ⓐ Stirrup with spacer should be tied several times.
ⓑ Pay attention when arranging reinforcements in order to have enough cover depth.
X beam
spacer
cover
thickness 40
Y beam
height 40
Y beam
X beam
Tension fixation
4) Bending position of bender (classification of tension & compression)
Tension
fixation
A class tension splice
bent bar
A class tension splice
(Top floor)
penetration
of bent bar
top bar
bent bar
(General floor)
※ Using the bent bars in beams is Japanese style, while cutoff bar is now in common.
5) Beam rebar arrangement(CUT TYPE)
① In case of beam
0.3L or 0.3L1
big value
0.3L or 0.3L1
big value
② In case of girder
0.3L or 0.3L1
standard hook
fixed length
big value
0.3L or 0.3L1
big value
Note
1) * : apply general bars splice length(A class splice) as standard splice length &
fixed length of rebar(22page 6)) for above size
2) ** : fixed as standard hook form about center part bottom bar's 25%
3) splice length according to splice position of rebar arrangement
- tying on upper part rebar(beam)
tying except upper part rebar(beam)
- tying on lower part rebar(beam)
tying except lower part rebar(beam)
block : apply A class tension rebar splice
block : apply B class tension rebar splice
block : apply A class tension rebar splice
block : apply B class tension rebar splice
6) Beam rebar arrangement by using stepped pulley
The types of step are classified as planar step, elevated step, step in material
according to their shapes.
In each case, arrangement is in vertical or in horizontal.
If the worker has no choice but to bend the bar, bend it at low grade.
When the mid span of a beam has steps as shown below left, the bar might be
necessarily bent, which is quite undesirable.
The load tends to straightly pass through.
If pulled out, the bar does not straighten as it looks.
Far from straightening, it will break or fracture.
Needless to say, it is recommended that the worker cut the bars and arrange them
separately, as depicted below.
breakable due to the tension
tension fixed
length
Wrong method
Correct method
tension fixed length
7) Hunch beam
① Bend the bars at the bottom in a hunch former and anchor them onto the pillar.
② Bend a half of the bars at the bottom to let the anchorage length penetrate the pillar
and anchor near the hunch point.
③ One size bigger stirrup should be used at the hunch point.
S.T. one size bigger stirrup
stirrup
8) Pillar-holding rebar (Butterfly stitching rebar/Stirrup closing rebar)
① As few drawing gives direction on pillar-holding rebar, it is common to use it at
every third stirrup.
If not, all junctions of pillar-holding rebar should be confined per every stirrup.
<butterfly stitching rebar>
processing
(current)
(revised)
Better if one end hooked 135°
9) Symbol of beam
·Continuous end of beam
·Center of beam
·Exterior of beam
·Interior of beam
·Outside of beam
center top bar :
HD22-2
end stirrup:arrange 200mm distance-D10
lower part bar :
upper part : HD22-3
HD22-3
end top bar : HD22-2
center stirrup-arrange 250mm distance-D10
support bar : HD13-2EA
END(end)
EXT(exterior) CENT(center)
400×500(stirrup process size : 320×420)
tension splice
(B class splice)
stirrup : arrange 200mm distance-D10
upper part bar : HD22-3EA
support bar : HD22-3EA
lower part bar : HD22-3EA
END(end)
CENT(center)
300×500(stirrup process size : 220×420)
10) Detailed drawing of beam rahmen(arrangement)
horizontal rebar : HD10@200(arrange 200mm distance-D10)
vertical rebar : HD10@200(arrange 200mm distance-D10)
END(end)
CENT(center)
400×500(stirrup process size : 320×420)
tension splice
hoop : arrange 250mm distance-D10
support big bar : arrange 250mm distance-D10
400×400(hoop process size : 320×320)
main bar : 10-HD19
tension splice
(B class splice)
Each floor bottom structure plane figure symbol & beam chart symbol
※ You should check pillar size & rebar Q’ty per each floor, and also arrange after
checking rebar Q’ty & drawing of outer pillar’s front and side.
14. Caution if beam assembling does
1) Lean concrete working mat beneath the underground beam helps to ease the
arrangement of bars.
If gravel or brick is used to support underground beam, the reinforcement in the
beams might deflect to break the top of stirrup.
Furthermore, it might disturb the arrangement of reinforcement at the bottom of
beam and so cover condition of vertical & horizontal is not fit.
Stirrup as criterion must tie without breakage 2 times, 3 times when tying upper
part.
100mm from pillar rebar
breakable of stirrup tying
spacer
all bottom bars should be tied
2) When placing the concrete, it is usual to place concrete again after curing, and
repeat the same procedure.
During this procedure, protruded bars may become damaged or underground beam
and floor slab may not fit very well because of shrinkage.
Also, it will be not cleaned well because of dust if you will do concrete job with
arrangement of ground slab without neighbor ground cleaning completely.
3) In the author's view, it is recommended that, after completing lean concrete
working mat, the worker build up the fence around the reinforcement zone, in
which the bars are arranged, to cast in concrete at the same time.
It would be quite efficient since 2 cast-in procedures can be reduced to 1 procedure
and it also saves time and cost considering input of material & carpenter.
4) Regarding beam rebar arrangement by using stepped pulley , you must be
processed separately because the continuity of rebar arrangement is different for
lower part rebar , and pay attention to the difficulty in entering of G bar & G bar
when assembling B(small beam) lower part rebar.
15. Tying position(splice location) of
underground tie beam
<Tying position in case footing slab
get forced from weight of top>
<Tying position in case footing slab
get forced from the soil >
<Tying position in case footing slab get not
forced from the soil>
<Arrangement method in case footing beam get
forced from the soil>
tension
fixation
pillar
mainbar
tension fixation
<Arrangement method in case footing slab get
forced from the soil>
Example : actual fixed length of D22 is 770mm
if pillar size is 500mm, actual anchorage length is 370mm
p.s.) Fixed splice length and standard hook(anchor) length refers to concrete structure
plan’s criterion
16. Calculation of beam rebar
Bent bar that is placed above(up) and below(down) of beam is Main-Bend, and bent
bar that is placed on both sides of beam is Side-Bend.
Main-Bend
※ Hunch angle should not exceed 45°(bent angle is "bent angle")
Side-Bend
Calculation of all 2 types of bent bar is the same except the way of extracting pure
height of main bar from stirrup height(thickness).
Either span of
,
from one end can be accepted depending on their uses.
1) Calculation of up-down bend(Main-Bend) in the beam
Provided that the height of beam is 500mm , the length of span is 8,000mm and the
size of pillar is 500mm , then the steel requirement is as follows.
100 cover
beam height
inner length
left
up·down cover
ST height
right
up·down cover
① 8,000mm-(500mm-40mm-40mm)-(500mm-40mm-40mm)=7,160mm
7,160mm÷4=1,790mm Hence, the value of ① is 1,790mm
② 1,790mm×2=3,580mm(value of ②) are extracted hunch length from inner length
③ Extract cover depth from 500mm(beam height : 420mm) and multiply this by 1.4,
and again extract 20mm(D10 diameter), [500mm - (40mm×2)]×1.4 - 20mm =
568mm, and then we have 568mm.
※ Calculation of hunch
Hunch = the height of stirrup×1.4 - 20(bar diameter of top and bottom stirrup×2)
④ fixed length is 40d in usual, hence provided that used bar is HD19,19mm×40d=760mm
The length of anchor ⑥ is 760mm- pillar fixation 400mm=360mm
⑤ 400mm + ① 1,790mm = 2,190mm
⑥ 400mm is the rest value except cover 100mm from width of pillar.
The length indication when spreading above calculation is as follows.
※ Total length 9,806mm for 8,000mm bar, the splice length is 2,566mm.
(example) 9,806mm-8,000mm=1,806mm, Total length is 1,806mm+760mm(splice
length)=2,566mm
2) Calculation of side bend in the both sides of beam
100 cover
beam height
280(ST height)
actual height
END
CENTER
inner length
ST height
left
right(up·down distance)
① 8,000mm - (420mm - 70mm - 70mm) - (420mm - 70mm - 70mm) = 7,440mm,
side-bend height
that is, 8,000mm - (280mm×2) = 7,440mm, and then 7,440mm×
② Center point is
, and then 7,440mm×
= 2,232mm.
= 2,976mm.
③ Hunch length is calculated from hunch height multiply 1.4.
280mm×1.4 = 392mm, hence hunch length is 392mm.
④ Fixed length is 40d in usual, hence provided that used bar is HD19, 19mm×40d =
760mm is fixed length , 760mm - 400mm(pillar fixed) = 360mm(anchor value⑥)
value① 2,232mm + 400mm = 2,632mm(actual distance of end upper part)
⑤ Cover depth(100mm) is extracted from pillar size(500mm)
500mm - 100mm = 400mm
If the bent bar mentioned so far is straightened in a line, it is like shown below.
total
length
※ Total length required is 9,744mm and provided that the standard bar length is
8,000mm, we need to splice here and the splice length is 2,504mm.
example)
9,744mm - 8,000mm = 1,744mm
1,744mm + 760mm(splice length) = 2,504mm(total length)
※ To summarize, Main-Bend's return bend point is
lx point, Side-Bend is
point, you can find the bending to exterior side(to center part).
lx
17. Slab rebar arrangement
1) Slab rebar arrangement
Slab type classification
2-way slab rebar arrangement method
(ly < 2lx Type)
1-way slab rebar arrangement method
(ly < 2lx Type)
main block
main block
Slab main bar arrangement type classification
Bent bar type
- Union type of outer beam and slab
0.3L or 0.3L1
big value
0.3L or 0.3L1
big value
90°standard
hook
apply A class splice of tension bar if upper part bar tying on
location (apply B class splice of tension bar on the rest location)
- Union type of outer wall and slab
0.3L or 0.3L1
big value
0.3L or 0.3L1
big value
wall
apply A class splice of tension bar if upper part bar tying on
location (apply B class splice of tension bar on the rest location)
ⓑ Cut bar type
- Union type of outer beam and slab
0.3L or 0.3L1
big value
0.3L or 0.3L1
big value
90°standard
hook
apply A class splice of tension bar if upper part bar tying on
location (apply B class splice of tension bar on the rest location)
- Union type of outer wall and slab
0.3L or 0.3L1
big value
0.3L or 0.3L1
big value
wall
apply A class splice of tension bar if upper part bar tying on
location (apply B class splice of tension bar on the rest location)
③ Rebar arrangement details of slab stepped pulley
In case H < 75mm or t/4
H≤75mm or t/4
In case t/4 < H < t and H < 150
splice length of tension bar
standard
hook
splice length of tension bar
1-HD13 or over main bar
In case t < H < 2t
4-HD13 or over main bar
standard hook
slab arrangement distance
using closed type STR
※ In case H > 2t, consult with structure planner.
※ In case there are stepped pulley on slab center part, you should fix by using 90°
standard hook for slab lower part rebar.
outside
wall
inside
slab
90 standard hook
④ Slab and wall union details
⑤ Tolerance range of slab , beam , pillar , wall rebar arrangement
ⓐ Allow to
6mm as tolerance of D in case under 600mm of slab, beam, pillar,
wall.
Allow to
10mm as tolerance of D in case over 600mm of slab, beam, pillar,
wall.
ⓑ Allow to
50mm as tolerance in case bent point or end point of length
direction rebar(but, except for end of concrete)
ⓒ Big bar of pillar and stirrup of beam can get the space till 0~6mm as space
cover thickness
cover thickness
length from main bar
2) Principle of rebar arrangement
① The worker measures the real length between beams and arranges the
reinforcement bars consulting the drawing, main bars in the short direction and
sub. bars in the long direction.
② Bent bars at the top should be extended into the exterior beam reinforcement, and
be sure for the bars at the top and bottom to be hooked and tied considering tensile
and compressive force to slabs.
It is not allowed if you put on slab upper part rebar as it is or put into the beam
under 10D of rebar thickness of lower part rebar.
Slab bar arranges over 80mm space from side of beam bar. (There are no need to
fixing by bending if you can get fixed length from end of beam)
※ The arrangement in slabs should be in accordance with the drawing and be sure
not to bend if it is a web reinforcement.
③ It is quite advised to use spacer and bar support to keep the required shape and
strength, and tie the reinforcement every other grid.
The placement of concrete should be conducted after all the reinforcements and
ties are assured.
④ In case the thickness of slab is 120mm, the height of bent bar should be 60mm.
Use bar support in order to maintain the space between bars at the top and bottom
and then the distance will be correct.
Lower part bar will be worked by maintaining cover with spacer.
⑤ Tie the bars at the top and the bottom irrespectively.
Tying the bars is conducted in alternate and do not let the tying positions coincide
with each other, so that the bars at the top sustains upper loads and the bars at the
bottom handles undesirable loads.
3) Calculation of slab plate
It is wrong method in case you cut the length of cut bar(top point) in advance by
calculating
point from center to center of beam.
Therefore, you determine the end by calculating
as the criterion of short LX from
the rest plate by deducting both width parts.
L
calculate end
※ When bending in slab, using the hunch former will enhance the accuracy and
workability.
Hunch former can be made with bars on construction site.
If the bar is bent with hands, the length and the height of hunch will different
whenever it is made.
Please work with hunch former because bent bar decline to left/right side if you
bending too slantly to fit the height with hunch angle 45°.
inner end
4) Sequence of slab rebar arrangement
center
upper part
end
lower part
upper part bar(TOP)
lower part bar(BOTTOM)
end
center
<A-A section>
inner end
① lower main bar of transverse direction
② end lower part bar of longitudinal direction
③ end upper part bar of longitudinal direction
④ bending after tying
⑤ center lower part bar of longitudinal direction
⑥ end upper part bar of transverse direction
⑦ bending after tying
⑧ upper part cut bar of longitudinal direction
⑨ upper part cut bar of transverse direction
※ Phenomenon in case there are no formal arrangement of slab
① In slab arrangement, bent bar should arrange (bend on return bend point) by above
procedure. But total length is not fit by coming inside as diagonal length to bend
after assembling upper part bar, lower part bar completely when using arrangement
method on construction site regularly.
② In formal rebar arrangement, it consists of main bar, sub bar(upper part 2 layer,
lower part 2 layer). But it has difficulty in maintaining rebar up/down distance by
folding top sub bar over main bar and sub bar(upper part 3 layer, lower part 3 layer).
5) Sequence of base slab rebar arrangement
Lx
Lx/4
fixed length of tension bar
which has standard hook
inner end
Lx/4
center
end
Lx/4
underground tiebeam obtains the
cover thickness over 80mm for
arrangement of slab lower part bar
upper part bar
Lx/2
Lx/4
Lx/4
Lx/2
Lx/4
end
center
inner end
<A-A section>
lower part bar
① lower main bar of transverse direction
(end center part)
② center lower part bar of longitudinal direction
(center part)
③ tying bent bar of longitudinal direction
④ center upper part bar of longitudinal direction
⑤ tying bent bar of transverse direction
tying bent bar of longitudinal direction
(bend opposite side after tying)
⑥ end lower part bar of longitudinal direction
bending bent bar of transverse direction
(bend opposite side after tying)
⑦ end upper part bar of longitudinal direction
⑧ center upper part bar of transverse direction
⑨ end upper part bar of transverse direction
※ Arrange the bars in numerical order suggested above.
※ Use spacer and bar support to install within 1m each transverse & longitudinal
direction for upper & lower part rebar and also install to 1st rebar for each end.
6) Check after assembling slab
After construction of slabs, the supervisor should check following matters.
① Are pillars of adjacent floor(usually upper floor) well positioned having intended
dimensions?
② Is cover depth of slab well distributed and balanced?
③ Is there any abnormally inclined bent bar?
④ Are spacer and bar support rightly installed to be strong bar splice all right?
⑤ Is slab Bar splice all right?
⑥ Is reinforcement at the opening acceptable?
⑦ Enough splice length to the next floor?
Any dissatisfaction with items above will lead to poor construction and safety
problems.
In particular, if it is the matter of columns, it is very difficult to rebuild it and has poor
appearances.
And it is also an economical burden to the builder.
7) Position of slab tying
direction
direction
direction
direction
tension splice
good position for tying
8) Understanding of slab drawing
① If all bottom of slab symbol is different per span, rebar arranged to main bar
direction for short side. If span will be reverse direction, you should check in
advance because main bar will be reverse direction. (especially in case slab
stepped pulley)
down 200mm to right side from
left side of solid line
SLAB DOWN
plane
open part plane figure
section
cross section
In the plane drawing of open part, you can see the inside as above when you see to
arrow direction with dotted line and also you can know in detail with chart about the
size of beam and also which rebar will be installed.
Especially, you should check section drawing well.
If you cut plane, you can see elevation(verticality), reversely if you cut elevation, you
can see plane.
In any drawing and plane, we mark section for the part to understand difficultly to
help you for processing and arrangement on right section of drawing.
It is best way to get the training of supervisor and you must study symbols on
drawings.
② 1S1(1 means 1st floor , S means Slab , 1 means #1(type))
slab thickness 120mm
Y1(upper part bar)
HD10@250 distance
slab thickness 150mm
Y1(upper part bar)
HD10@300
distance
Y1(upper part bar)
HD10@300 distance
Y2(lower part bar)
HD10@300 distance
Y2(lower part bar)
HD10@300 distance
Y2(lower part bar)
HD10@250 distance
X1(upper part bar)
HD10@250 distance
X2(lower part bar)
HD10@250 distance
※ Reference : dot line means lower part rebar , solid line means upper part rebar
Classification Symbol
1st
floor
Type
Thickness
1S2
B
1S1
A
Transverse direction(Lx)
Longitudinal direction(Ly)
X1
X2
Y1
Y2
150
HD10@200
HD10@200
HD10@200
HD10@200
120
HD10@250
HD10@250
HD10@300
HD10@300
③ Detailed drawing of beam and slab's connected part
SLAB upper part rebar doesn’t tie to beam main bar
※ Author's viewpoint : If you did not study shop drawing completely, you will solve
question if you will start construction by discussing to check wrong one after
visiting construction site after checking the drawing under construction over
80%.(especially, carpenter's process is over 80%).
9) Principle of ground slab
① Bar arrangement in the floor slab begins 50mm from the slab wall side having
constant spacing.
② Arranged bars should be strong enough not to deflect when a person steps on
them.
Unscreened gravel and bricks can not be used in order to keep spacing between
bars, and specified bar supports and spacers should be used to maintain the
dimensions and shapes of the slab as intended.
③ After arrangement, single bar might need to be cut off with oxy-acetylene cutting
in the requirements of collecting well or manhole.
In such cases, there could be cracks at the end tips of bars, and therefore more
reinforcement and splice should be adopted here.
tension splice
tension splice
※ The most important thing in floor slab - Base Tamping
▶ After shovelling , the land must be tamped with vibration compactor.
▶ Even though drawing does not refer to tamping, the worker must bear it in
mind as specification indicates.
However, it is real situation that there are little workers to keep it.
▶ Both the client and the builder should hold it in common that even the neglect
of construction rules and standards will lead to fatal harms to both of them.
18. Wall rebar arrangement
1) Sequence of rebar arrangement
① The worker is not allowed to change the rules and instructions of reinforcement
without permission. All the reinforcement should be in accordance with drawings
and specifications. Especially in retaining walls, if the retaining wall, which needs
double reinforcement, is placed in the sequence of the first main bar, assist bar, the
second main bar and then another assist bar, it might be an easy way but wrong
one. All the placement should be in the specified sequence.
② Placement sequence of wall suggested below
main bar
width fixing bar
sub bar
width fixing bar
reinforcement bar
③ Place the stirrup closing bar densely and keep the thickness exactly. Especially in
the reinforcement of water tank, fabricate the reinforcement as specifically
suggested. And place the reinforcement at a time. In case the tank is big, the
reinforcement should be in zigzag and in the top span tying wire should be wound
at least one time before tying. If not, main bar would swing and would not
maintain the required shape. Simple cut bar reinforcement or hooking in the bar is
also a wrong reinforcement.
2) Principle of assembly and rebar arrangement binding
saddle tie with twist
corner
it should be tied with 1,2 times
wound depending on @ distance
tying to maintain distance of upper part
Assist bars might deflect when concrete is cast-in or due to loose bindings.
To avoid this undesirable deflection, width-fixing bar, which is similar to stirrup in
shape is fabricated to place in assist bars.
① Begin the placement of assist bars from 100mm above the floor place the stirrup
② Stirrup(closing bar) at every third step
※ Caution in reinforcement of retaining wall
When numbers of bars are placed in the retaining wall, the worker should be
considerate.
If the tie between main bars and assist bars is loosened, the reinforcement would
lean toward.
Make sure that tying of main bars and fixing bars always go together in turn.
3) Crosspoint main bar and horizontal rebar arrangement
<Single arrangement>
<Single and double arrangement>
U bar
wall vertical rebar
wall horizontal rebar
U bar
wall horizontal rebar
<Double arrangement>
U bar
<Straight wall>
wall horizontal rebar
4) Details of wall on top floor
<Top floor outer wall>
<Top floor inner wall>
slab upper part bar
90°standard hook
roof floor slab
tension splice
roof floor slab
wall vertical bar
wall horizontal bar
over 150
slab lower part bar
wall
※ The end of wall vertical rebar on top floor should obtains unification by fixing
correctly on slab and processed to get 90°standard hook.
※ The upper part rebar of slab to contact outer wall should be fixing splice or making
tension folding splice and wall outer vertical rebar.
5) Tying position of revetment(retaining wall)
As a rule, bar splice in pillars and beams is not allowed, and if horizontal bar is better
to be anchored in the pillar of every span.
<resistance wall>
pillar
<underground retaining wall>
pillar
horizontal bar
inside
inside outside
beam
vertical bar
outside
outside
inside
foundation beam
good position to tie
<stirrup closing bar>
B class tension splice
※When the inserting bars as arranged straight bar are inserted at the underground beam
tension
splice
tension
splice
fixed length
no problem if fixed
length will be obtained
※ As shown above left, there is a possibility for stirrup vertical bar to be protruded
by the lack of cover thickness of fixing part.
It is recommended to adjust to fix the bar into the stirrup.
6) Indication of revetment(retaining wall)
arrange to 300mm distance of vertical High Density 16mm rebar
arrange to 200mm distance of vertical High Density 19mm rebar
arrange to 200mm distance of horizontal Density 16mm rebar
arrange to 200mm distance of horizontal Density 19mm rebar
<Symbol on wall >
RW(Retaining Wall) = Underground wall(wall to resist against ground pressure)
Wall = Wall
THK = Thickness of wall
V = Vertical rebar
H = Horizontal rebar
T = Width Tie bar
H = Hunch, it is classify easily per type against tie hoop
19. Other rebar arrangement
1) Stairway rebar arrangement
ⓐ Place the bars in the suggested sequence according to drawing.
Double reinforcement should not be bent.
ⓑ There are a few extended bars from pillars or beams to the stairs .
You should assemble by using standard hook(anchor) in case of assembling to cut
without bending bars for this working.
Example)
ⓐ Place the bars in the numerical order shown below
ⓑ Bend ④ bars after binding
ⓒ Cut ⑥ after binding
tension fixation
lower part bar upper part bar
※ Special notice for the bar-arrangement
fix to corner pass rebar
(lower part rebar)
ten
sio
nf
ixe
dl
en
gth
tension fixed length
2) Balcony(Cantilever)
tension fixation
upper support rebar
spacer
spacer
vertical/horizontal
D10-@220
tension fixation
upper support rebar
spacer
spacer
① The most important part in cantilever is the bar at the top above distribution bars.
It is common to anchor the top bars into a beam, however, they can be anchored in
a slab so long as there is no difference between their levels.
To obtain adequate fixed length is most important.
② Bars at the bottom should be anchored securely to provide for earthquake and
tornado.
③ When the level of cantilever and slab plate are different, bars in the slab should be
anchored onto the beam.
If the bars at the top are bent to be anchored onto the opposite slab, there might be
a crack due to tensile strength.
The bars at the top should be maintained with bar support.
3) Parapet rebar arrangement
The expansion of topping concrete at the top of a building due to variations of
daylights will pass out great compression load to the parapet.
Therefore, the double reinforcement
in the parapets are better to be
D13(reinforcement bar)
anchored onto beams or slabs.
Parapet might occur vertical crack mainly
because the length is long.
It is effective to avoid crack by arranging
to outside of horizontal rebar.
tension fixed
length
4) Reinforcement of slab open point
in
L<1000
m
min. 600
.1
20
minimize
open part
0
Reinforce each rebar to both open part as
rebar distance 75mm for +1 unit of rebar Q’ty to
be cut existing rebar from open part.
In case open part is over 300mm,
4 edges should reinforce 1-HD16
Use 90°standard hook rebar
Explanation :
1) In case the length of open part is
over 1,000mm , you should arrange
after receipt of permission of
structure supervisor if there are no
rebar arrangement detailed drawing.
2) *mark :arrange to single arrangement
if established rebar arrangement is
single arrangement arrange to double
arrangement if established rebar
arrangement is double arrangement
3) ----- is established slab rebar
4) Rebar to not specified of rebar size
must use same size rebar as
established arrangement
5) Details of reinforced rebar on concrete wall open point
① Circle type open part
circle type open part distance should be over “D”
max. 600
max. 600
1-HD16
In case of over D>450mm
1-HD16×1800mm
Explanation :
1) In case the size of open part is D<150mm, omit vertical & horizontal rebar
2) mark : arrange to single arrangement if established rebar arrangement as
siugle(double arrangement as double)
② Square type open part
min. 600(TYP)
min. 600
open part
6) Rebar arrangement of slope way in main entrance
90°standard hook
D10→120
lamp slab rebar
arrangement
7) Trench rebar arrangement
ten
si
len on f
gt ixe
h d
tension fixed
length
tension fixed length
tension fixed
length
tension fixed
length
20. Steel frame(Deck plate S-ring)
In arranging the bars at the top, mount the deck plate and place the bars on the
furrows of deck plate firstly.
And then arrange the top bars above deck plate and connect these top bars with what
lied on the deck plate using hook to maintain the constant space between them.
※ What is Deck plate S-ring ?
In order to connect working of lower part & upper part rebar in deck plate, the
arranged method shows on drawing.
As you can see as below, there are rebar arrangement operation by using rebar
D10 Deck plate S-ring.
However, if some construction site would like to reinforce D10 rebar by hand,
there are possibility to reinforce rebar roughly because its working is very hard
and with low efficiency.
If so, it is weak point of construction carry-out and high possibility of problem
after construction.
"S"-shaped ready-made hook manufactured by Taeyeon Machinery Co. Ltd. is
convenient to install and has efficiency to keep distance and keep cover.
21. Caution and consideration of
construction carry-out
1) A man-day
The amount of reinforcement that a skilled worker can place a day is, in case of slabs,
0.26acre ~ 0.33acre in area, about 500kg~700kg if converted in weight.
※ Daily work capacity(varies with working environment)
Classification
Q’ty(kg)
factory, school
over 700
apartment, house
below 700
KR
130,000 per worker’s labor cost in
2006 year.
<processing separately>
Classification
Q’ty(kg)
D10 stirrup, tie hoop
600
D13 stirrup
800
bending
5ton/1 person
<cutting separately>
2) Weight of concrete
① Specific weight of plain concrete(without reinforcement) is 2,300kg/1m3
② Specific weight of concrete with reinforcement in it is 2,400kg/1m3
③ Specific gravity of lightweight concrete with perlite or gas-foaming agent is only
0.6~1.2
3) Load and external force
In construction, load and external force are critically important factors to be
considered.
Load is classified as fixed load and occupied load, where the former is the weight of
building itself and the later is the weight of people, furniture, equipment, etc..
Occupied load is classified again as long-term load and short-term load.
① The weight that 1m2 (square meter) sustains in long-term loading is
ⓐ Human or furniture 200kg/1m2
ⓑ Snow load 50kg/1m2
② If weak at the long-term load : There might be a crack in walls or beams.
③ If weak at the short-term load : There might be not a crack but part breakage due
to external impact.
4) Crack and shrinkage
① Crack of concrete is not simple problem to catch with several symptom such as
crack direction, etc but it is required to the inspection of professional.
Regularly, the crack under 0.3mm will be happened by dry shrinkage for
beginning vulcanization.
② Shrinkage of the building
If the length of the building is longer than 50,000mm, there is expansion or
shrinkage of the building, 10mm ~ 20mm, within temperature range from -18°C
~36°C.
(temperature difference×10-5×the length of building = difference length by
temperature gap(expansion or shrinkage))
③ In case of Korea, temperature difference is 54°C, from -18°C in winter to 36°C in
summer, According to the formula above, expansion in Korea is 27mm maximum
from 54°C×(
×50,000mm) = 27mm, hence there should be expansion
splice in some parts on high building & walls to prevent crack of the building.
5) Caution if construction work does
① Distance of main bars against girder(beam)
ⓐ Beam plays an important part in a building, receiving the load from slabs and
passing it out to pillar.
Therefore the reinforcement in beams should be seriously taken into
consideration and accuracy.
Top bars, bottom bars, reinforcement bars, bent bars and middle bars are placed
in beams and distance of reinforcement should be more than 25mm or 1.25
times of the largest aggregate that is in the mixed concrete, over 1.5times
distance of rebar diameter.
ⓑ Splice length of top bar in beams should be required fixed length if it extends to
the center of column and therefore sustains tensile force.
Splice of the bottom bars in beams should be within
from the end of beams,
where load is almost 0, and the top bars should avoid the end span of
beams.(min. rebar cost will be over 0.35%)
② Pillar
ⓐ Pillar also has important role to divide total weight and compression power of
building.
Distance of main bar also arrange bar fairly, distance per rebar and rebar will be
over 40mm or over 1.5times of rebar using.
ⓑ The minimum size of column is more than 200mm and cross sectional area
should be more than 600cm2
ⓒ Splice length applies B class splice length.
6) Reinforcement to prevent shrinkage of wall
The building might get shrinkage on building by the expansion of temperature in day
or the down of temperature in night.
Rebar concrete has expansion or shrinkage, and so there are possibility of unexpected
rebar.
Therefore, the point of crack possibility must reinforce outer wall without open part.
Arrangement direction of correct reinforced bar, it can be checked crack correctly, it is
principle to arrange bars vertically against crack direction.
If there are crack on both edges of wall by the expansion of roof, reinforced bar is
principle to arrange bars vertically against crack direction and you reinforce the
reinforced bar of highest wall to outer top pillar & retaining wall of building.
The expansion ratio of roof will be bigger toward outside and very small roof on
center of building.
Also, 1st floor contacts ground do not effected of the influence of temperature.
Therefore , the part of highest influence by expansion & shrinkage of roof is outside
wall and there are expecting many cracks.
Without marking on shop drawing, you must arrange construction with your sincerity
with our experiences.
7) Cleaning
It is better to install concrete after cleaning always before installing concrete.
When you checking construction site, there are many other materials to decline the
quality of concrete such as soil, sawdust, trash.
You must delete it inevitably.
After concrete job, you must break concrete of ground and brush concrete on rebar
with hammer drill, wire brush , hammer on next floor splice part, wall, pillar.
8) Problem if oxy-acetylene cutting does
① Don't use the oxygen arc cutter near the pile of unused bars.
If you use the oxygen arc cutter near the piled bars, high heat from cutting rod will
be transferred to unused bars causing thermal deformation or unexpected failure.
Automated cutting machine and bending machine are recommended.
② Oxygen arc cutter will drop tensile strength of the bar, which is critically important
to the reinforcement of the structure, and there might be problems in structural
safety.
③ Manual bar cutters have been normally used in the construction sites so far.
However, in order to increase the effectiveness and ensure perfectness, automated
cutting machines and bending machines are highly recommended.
<Reference>
Rebar arrangement should arranged by the shop drawing.
Technicians must increase the ability to see shop drawing if it is the recent drawing by
limit strength plan method.
22. Gas pressure welding of Rebar
1) Definition of gas pressure welding
It is welding method directly of raw material itself to press under the condition which is
before heat melting(1,200°C~1,300°C) for junction part with oxy-acetylene gas to fix on
both side rebars to connect in carrying out of rebar concrete structure building. Also, it is
economic splice method than folded tying (lap splice), mechanical spiral tying(mechanical
splice) and also the strength of junction part is stronger than raw material.
※ Rebar splice is classified to folded tying (lap splice) , mechanical spiral tying(mechanical
splice), compressed tying(welded splice). Folded tying (lap splice) is commonly have used as
important method for rebars of small diameter before. However, Folded tying (lap splice) has
irrationality such as complexity of rebar arrangement and bigger material section and also the
increase of mold cost and so it is prohibited to folded tying (lap splice) for over D29 deformed
rebar on Korean concrete standard specification and mechanical spiral tying(mechanical splice),
compressed tying(welded splice) will be applied frequently. Therefore, compressed
tying(welded splice) is stronger and economical splice method than Folded tying (lap splice) if
rebar arrangement with density or rebar diameter is bigger and it is using for the rebar over D29.
2) Composition of automatic pressure welding equipment
<Welding units>
① Oxygen pressure controller
② Acetylene pressure controller
③ Acetylene outlet hose
④ Oxygen outlet hose
⑤ Welding torch
⑥ Welding tip(4 edges)
<Compressor units>
① Pump
② Pedal pump
③ Hydraulic pressure hose
④ RAM cylinder
⑤ External cylinder
⑥ Fixed clamp
⑦ Flexible clamp
⑧ Rebar
3) Working sequence to tie gas pressure welding
The method of gas compressed tying(welded splice) is classified to manual gas
compression and automatic gas compression method and the principle is same but
difference is by manual or automatically for splicing.
① Grinding the section of rebar with flat by using grinder
② Install rebar for splicing to pressure welding equipment
③ Heat and pressure
- Heat rebar with gas mixed oxygen acetylene
- Heat machine will be used multi-hole burner
- Heat and pressure at the same time
- Don't heat till the temperature of rebar melting but heating to 1,300°C as rebar
exterior temperature (it is different from welding splice)
- Pressure to 300~400kg/cm2 per rebar 1cm
- Use hydraulic regularly for pressure machine
1st heat pressure 2nd heat pressure
pressure
power
3rd heat pressure
temperature
temperature
pressure
power
time(second)
< Time passage of heat, pressure power >
- It shows time-passage of standard heat, pressure power as above graph.
- If starting heat, pressure from A point, the section space will be decreased on B
point and finally adhere completely to D point.
- It makes inflation by increasing pressure between F-G to keep this temperature
4) Required time to heat for pressure welding per diameter
Rebar diameter
Required heat time
Rebar diameter
Required heat time
HD16
40 ~ 50sec
HD25
1min 15sec ~ 1min 45sec
HD19
50 ~ 60sec
HD29
1min 45sec ~ 2min 15sec
HD22
60 ~ 1min 20sec
HD32
2min 15sec ~ 2min 55sec
5) Inspection of gas pressure welding
Instruction of welded part includes visual inspection, ultrasonic detecting test and
tensile test, etc.
Selection of inspection test should be determined in accordance with suggestions on
the drawings.
① Visual inspection
welding distortion, deflection, shape and dimension and any other defect can be
inspected with eyes.
② Tensile test
- In case of manual welding equipment, tensile test is conducted for sampled
specimen
- In case of automated welding machine, test piece is manufactured for tensile test
③ Ultrasonic detecting test
In inspection of welded part, visual inspection and destructive or nondestructive
test are run parallel in general.
Among these, destructive test not only takes times and costs but also had some
errors because only a few test pieces are sampled from the entire welding spliced
bars.
As a solution, reliable nondestructive test is conducted to find out defects from all
welded parts
6) Caution if pressure welding works
① The builder will get the admission of person in charge to select gas pressure
welding worker.
② You must check and maintenance inevitably before working for oxygen , acetylene
instrument and protect it from direct rays.
③ The compression section should be decreased by cutting of plane after deleting oil,
paint, cement piece, etc but to be cut the neighbor surface by grinder.
④ The final pressure of rebar discharge direction should be over 300kgf/cm2 per
dimension.
The diameter of compression protrusion part should be over 1.4times of rebar
diameter and diameter of compression protrusion part should over 1.2times and
the form should be smooth.
But , it is followed by in case it is fixed by shop drawing separately.
23. Mechanical tying of Rebar
1) What is mechanical tying of rebar?
It is essential construction method for large scale civil engineering construction such
as high-building, bridge, dam, etc and underground building anti-earthquake plan and
also special construction. It is a splice method for strong economic quality assurance if
folded tying method is impossible in case rebar arrangement with density and rebar
diameter is bigger and so by the increase of rebar strength & concrete strength. It is
applicable for deformed rebar to use rebar concrete building. In foreign countries, it
was verified from 1960 and it is using for Korean construction site from mid-1990.
2) Type of mechanical tying of rebar
screw type
inflation compression joint rib
cut type
type
type
site tie type
taper
type
joint fixed body
adhesion type
others
joint rib compressed
jack adhesion type
hydraulic
mortar
gas
injection type compression compression type
3) Screw-type tying of rebar
rebar warehouse-in → make rebar screw process drawing → start processing of screw type
→ deliver to construction site(3~10days from order date)
process type
inflation type
compression type
bury rebar joint rib by
process inflate of rebar processing
part largely by mold
mold (example) rebar
type
(example) rebar 25mm - M30 25mm - M25.5
case screw type
screw processing case screw type
prove the confidence
prove the confidence after
after processing of low
processing of low-mid
carbon steel bar(SD300) carbon steel bar(SD300,400)
available for large
available for large
merit
production
production
available for production on
construction site
demerit
the inflation processing end
might has low confidence if
it is caused by processing
vulcanization of mold in
case high carbon steel bar
low confidence after
binding 2 rebars
low confidence in case of
bending
the compression
processing end might has
low confidence if it is
caused by processing
vulcanization of mold in
case high carbon steel bar
low confidence in case of
bending
joint rib cut type
taper type
processing screw after deleting
screw processing with
rebar joint rib with fixed size
angle of rebar front end
(example) rebar 25mm - M26
case screw type
cut screw type
prove the confidence after
processing of low-midhigh carbon steel
bar(SD300,400,500)
available for large production
available for production on
construction site
prove the confidence
after processing of low
carbon steel bar(SD300)
available for production
on construction site
coupler size is 10%
longer than inflation &
compression type by the
deviation of size of
rebar joint & rib
low confidence of
omission & untying for
testing tension strength
and repeat test
inflation screw
swage screw
joint-rib screw
taper screw
cut processing
cut processing
cut processing
cut processing
pre-cut after mold inflation
mold compression
pre-cut processing
angle processing
case screw
case screw
case screw
cut screw
4) Site connection-type tying of rebar
outbreak of splice → carry-in of parts(arrival to site within 12hours after ordering) →
assembly & construction carry-out → inspection comparing other splice part
classification
joint fixed body adhesion type
process type
precision processing & molding per part of splice
part base on joint groove of rebar(no artificial
processing of rebar)
precision processing & molding per part of splice
part base on nominal diameter of rebar(no artificial
processing of rebar)
available to assemble without processing screw on
rebar
available to assemble without processing screw on
rebar
ease to bind regardless of rebar type(foreign &
domestic rebar , deformed rebar , comb-pattern
rebar , X type)
available for large production per rebar title
available for deformed rebar only in Korea and low
confidence of binding in case disorder of tolerance
of rebar joint rib and trademark
need pre-education for building assembler
need pre-education for building assembler
merit
outer diameter of coupler
demerit
double faced
compression jack
coupler
fixed pin
rebar
lock nut
length after binding
joint rib compressed jack adhesion type
connection jack
lock coupler
fixed body
5) Other tying of rebar
classification
process
type
merit
demerit
mortar injection type
gas compression type
splice part to perform platform on heat & compression splice
rebar joint & rib groove & inside method of both ends of rebar by
of connection part
using oxygen & acetylene
hydraulic compression type
splice method to adhere sleeve by
pressing outside sleeve after
closing rebar to soft sleeve
using to pre-cast(PC) splice
construction method
using in Japan mostly and prove
the confidence of tension
compression
using in europe partly
splice part is large and long
excessively and low confidence
per rebar type
difficulty of confidence proof
of construction site carry-out
product
big tolerance of construction
site carry-out per condition of
temperature
difficulty of confidence proof
of construction site carry-out
product
troublesome of purchase
separately of compressed rebar
for compression reinforcement
to classify to produce
compression bar & regular bar
difficulty of reinforcement
because the possibility of
displacement of pressure
strength for 1pc & 100pcs and
also the movement of pressure
tool