1
The International Conference of Composites on Construction (CCC 2003)
Seismic Resistant Properties of
Lightweight Aggregate Concrete
Chung

H
o
Huang, and H
o
w

Ji
Ch
e
n
*
Department of Civil Engineering
National Chung

Hsing University
Taichung
,
Taiwan, R.O.C
.
ABSTRACT
Lightweight aggregate concrete posses
ses
lower unit weight and
better
damping
characteristic
than normal weight concrete. U
sing
it as a building material
can enhance the
seismic resistance of structures
. Th
is
research
investigates
the seismic
resistan
t properties
of
lightweight aggregate concrete
and
compare
s
with
those of
normal weight
concrete
.
T
he
test result
s
of
lightweight aggregate concrete and normal weight
concrete
show that
the unit weight of reinforced lightweight concrete is 20%
app
roximately
lower than that of
reinforced normal weight concrete at same strength level.
For low
strength
concrete
near 20
MPa
, l
ightweight aggregate concrete
appears
larger
damping ratio
.
T
h
e
stiffness
of
lightweight aggregate concrete i
s
similar to
that o
f
normal weight
concrete
.
As the concrete
strength
is
higher
near 40 MPa
,
lightweight aggregate concrete has similar
damping ratio
to
normal weight
concrete
but
the
stiffness is lower. Moreover,
the
natural
frequency and
damping ratio of reinforced concret
e beam
are
low
er than
those of plain concrete beam
because of the
r
einforc
ing
bars
effect.
Keywords
：
lightweight aggregate concrete
、
stiffness
、
natural
frequency
、
damping ratio
*correspondent
How

Ji Chen
Associate Professor of Department of Civil Engineering, National Chung

Hsing University
NO.
250, Kuo

Kwang Road, Taichung 40227, Taiwan
Tel: 886

4

2285
9390
Fax: 886

4

2285
5610
E

mail:
hjchen
@
mail.ce
.nchu.edu.tw
2
I
ntroduction
The seismic force is a response of inertia of ground acceleration.
I
n general,
the
magnitude
of
internal force of member due to
seismic
force is
related
to
the
seismic resistance properties
of structure
such as
the
mass, stiffness,
nature
frequency and damping ratio.
[1

3]
For the seismic force design, to know the
seismic resistance properties of structure building is very important.
U
sing
of lightweight aggregate concrete
(LWAC)
in building structure has
many advantages
,
e
specially reduc
ing
the mass of structure and possesses better
damping
characteristics.
[
4

6
]
the
light
weight
building structure
has
smaller
seismic force
when
subjected to
earthquake.
F
or the seismic resistance of
concrete per unit weight, lightweight aggregate
concrete
is better than normal
weight
concrete (
NWC).
T
his research investigates the seismic resistant
properties of lightweight aggregate concrete such as unit weigh
t of concrete,
stiffness, nature frequency and damping ratio.
T
he results are compared with
those of normal weight concrete.
Experimental
program
A
total of 32 flexural
reinforced
LWAC
beams as well as
NWC
beams were
made.
I
n the meantime, 18 non

reinforc
ed concrete beams were also made.
T
he
size of all specimens was 150 mm
×
200mm
×
1500mm. The test items
include
d
both damping and frequency tests.
B
esides, the reinforced concrete beams were
also tested for stiffness.
T
he summary of the specimen
quantity
are s
how
n
in
Table
1
.
M
aterials
T
he mixture proportions for
LWAC
and
NWC
are
shown
in Tables
2
and
3
.
3
Type
1
Portland cement was used with natural sand having a fineness modulus
of
2.67
. The coarse lightweight aggregate used was expanded
clay
with
maximum size
of
12.5
mm.
The aggregate
properties are
given in Table
4
.
Two sizes of t
he longitudinal reinforcement
were
used in this investigation
(no.4
and no.6 deformed steel bars
)
. The stirrups used were
no.6 deformed steel
bars of Grade 40.
The
different
yield
str
ength in tension
was
283 MPa and
4
45
MPa
for the longitudinal reinforcement
s
and
281
MPa for the stirrup
reinforcement.
C
asting and curing
T
he concrete was place
d
in two layers in the beam and was appropriately
vibrated.
B
esides, six 100
mm*200
mm cylindr
ical specimens were also cast.
Immediately
after casting, all specimens covered with polyethylene sheets to
avoid escape of moisture.
Twenty

Four
hours after casting
,
t
he beams and
cylindrical
specimens were stripped and moved to
curing
room with 100% RH
,
23
℃
for 28 days curing.
S
pecimen details and testing
T
he beams were
divided
into
two
groups
(
reinforced beam and
plain
concrete beam without reinforcement).
The
specimen details are
shown
in
Figure 1.
The
tested variables
included
concrete type, concrete
strength, space
of web reinforcement, amount of tensile reinforcement.
T
he summary of the
specimen
quantity
are show
n
in Table
1
.
T
he test method of compressive strength and modulus of elasticity of
concrete is in accordance with ASTM C469.
Reinforced conc
rete beam
was
4
loaded with a
central point load in the stif
f
ness
test. A
t each end of a reinforced
beam, a hinge was
used to
allow the flexure beam to rotate freely. A linear
voltage differential transducer (LVDT) was used to
measure
the vertical
deflection
at mid

span
section
.
T
he span was 142 mm
in length
. Details of the
test setup
are shown
in Figure 2.
The total load on the test
facility was increased
linearly
with a loading speed of 200 N/sec.
When
t
he total
load
reach
ed 8000 N,
stop test and
release
lo
ad.
T
he outputs from the load cell and LVDT were
continuously recorded by use of a computer and a 7V14M data acquisition
system.
I
n the frequency and damping tests, the bounded condition of the specimens
was
similar
to the stiff test.
T
he specimens were su
pport by two hinges, as
shown in Figure 3.
A
n
accelerometer
was fixed to the central point of the span
for measure the
variation
of
acceleration
. Using a hammer
beat
the
specimen;
let
it
induce a slight free vibration.
T
he frequency and damping of the
spec
imens
were
acquire
d by the
analysis
of
the
decay
ed
acceleration
.
T
he
analytic
method
was
in accordance with
the theory of structur
al
dynamic
.
Results
and Discussions
The
results of the basic properties tests on reinforced concrete beams are
summarized in
Table
4
. Table
5
summarizes frequency and damping of all
beams.
The mechanical
properties
of
concrete
As shown in Table
4
, the concrete
compressive
strength of LWAC was
varied between 27.4 MPa and 43.5 MPa, and varied between 23.1 MPa and 43.7
MPa for NWC.
Although
the
actual
compressive strength is not
complete
5
correspond with
design strength (20 MPa level and 40 MPa level), the
compressive strength of LWAC is
close to
NWC both at 20 MPa level and 40
MPa level.
I
t can
accept
that LWAC and NWC have s
imilar
compressive
strength and can
proceed
to compare other
characteristic
s under the same
strength level.
The
modulus of elasticity of LWAC is increasing with increase the concrete
compressive strength.
Moreover, a
t
the
same concrete strength level, t
he
modulus
of elasticity of LWAC is
smaller than NWC.
T
he results of unit weight of
reinforced
beam are
also
given in Table
4
.
The
unit weight of
reinforced
LWAC beam was
varied between 1800 kg/m
3
and
2000
kg/m
3
, and was about 20% lower than that of
reinforced
NWC b
eam.
T
he
stiffness
of reinforce
d
beam
This test measured the
stiffness
of t
he
simple
beams
;
the beams
were loaded
with a
central point load.
The
central point load
does not
exceed the
proportional limit. The stiffness (K) was defined as the
slope
of the
lo
ad

deflection
curve
(P

Δ
curve
)
, K=P/
Δ
.
T
he
results of the stiffness are
summarize
d in Table
4
. A
nalys
e
s
of the test
data
can
obtain
many
varied
graph,
as shown in Figures 4~6.
Figure 4 shows the unit weight of reinforced LWAC beam is lower than
reinforced NWC beam as concrete s
trength at 20 MPa level, but the stiffness of
reinforced LWAC beam is
similar
to reinforced NWC beam and the test values
are between 18000k
N
/m and 27000k
N
/m. As the concrete strength
attain
s
to
40MPa
level, for reinforced NWC beams, as unit weight increase
s, are
effective
in improving stiffness of simple beams.
F
or reinforced LWAC beams, are
ineffective
in improve stiffness by increasing unit weight.
From the Figure 5 it can be seen that the stiffness of reinforced LWAC beam
6
is
similar
to reinforced NWC bea
m under the same lower concrete strength (20
MPa level). As the concrete strength is higher (at 40 MPa), the stiffness of
reinforced NWC beam is 20% higher than that of reinforced LWAC beam. From
the two
regression
lines
(
in
F
ig
.
5
)
it can be found that th
e slope of NWC
beam
stiffness
is
steep
er than that of LWAC beam.
It means that t
he stiffness of
reinforced NWC beam
increases effectively with increasing the concrete
strength. However,
it is
ineffective
for reinforced LWAC beam.
The
elastic
formula
of sim
ple beam
defection
is
given
follows:
48EI
PL
3
From the
formula
it can be known that the stiffness (K=P/
Δ
) is function of
the material
propert
y (modulus of elasticity E), span of beam (L) and
cross

section
(the beam
’
s moment of inertia I). W
hen the simple beams have the
same
cross

section
and
equal
span,
t
he
stiffness of simple beam will
mainly
relate to modulus of
elasticity
. Using different materials
in reinforced beams
will
change
their stiffness; such as using lightweight aggregate concre
te and
normal weight concrete
because
their
modul
i
of elasticity are
different.
Table
4
shows modulus of
elasticity of
LWAC is 16300 MPa and 21400
MPa for NWC when the concrete strength at 20 MPa. As the concrete strength
attain
s
to
40MPa
level,
modulus of
elasticity of
LWAC is 19800 MPa and 25500
MPa for NWC. The
relationship
between the stiffness of reinforced beam and
modulus of elasticity of
pure concrete beam is shown in Figure 6.
T
he stiffness
of reinforced NWC beam
increases effectively with increasi
ng the
modulus of
elasticity of
concrete.
T
he stiffness of reinforced LWAC beam does not have the
same
behavior
.
A
s the concrete strength is lower (at 20MPa level), the ratio of
the
modulus of elasticity of
LWAC to
that
of NWC is 1.32, it is higher than th
e
ratio of the stiffness of reinforced LWAC beam to the stiffness of reinforced
7
NWC beam (which is about 0.97).
A
s the concrete strength at 40 MPa level, the
ratio of the
modulus of elasticity
(about 1.29) is similar to the ratio of the
stiffness (about 1.
19).
T
herefore
,
i
nfer
the ratio of the stiffness
from the
ratio of
the
modulus of elasticity
is
suitable
at high
strength
concrete, but it may be fail
at low
strength
concrete.
T
he
frequency and damping ratio of beams
T
he
frequency and damping ratio
are t
he basic material property
in seismic
assistance analysis
.
A
n
accelerometer
was used to measure
the
variation of
acceleration
to
investigate
t
he
frequency and damping ratio
of the free vibrated
beams. Every
specimen
tested ten times on
the
frequency
test
a
nd damping ratio
test respectively.
The
experimental results are
shown
in Table
5
.
T
he
analysis
of frequency
At low
strength
concrete level (20 MPa level), the
average
frequency
of
LWAC and NWC beam without reinforcement are 831 rad/sec and 821 rad/sec
tha
t
were obtained from
average
of ten tests of two specimens. As the concrete
strength is higher, the
average
frequency
of LWAC beam is 925 rad/sec and 967
rad/sec for NWC beam.
T
he results mean that increasing the concrete
strength
increases the
frequency
o
f concrete beam.
T
he
main
reason
is
high
strength
concrete
possess more dense texture than
low strength concrete.
For the reinforced concrete beams, the
average
frequency
of reinforced
LWAC beam is 748 rad/sec that is higher than the
average
frequency
of
r
einforced NWC beams
(701
rad/sec)
at lower concrete strength level (20MPa).
As the concrete strength is higher, the
average
frequency
of reinforced LWAC
beam is 746 rad/sec and 723 rad/sec for reinforced NWC beam.
B
ased on the dynamic theory,
the
frequenc
y
(
ω
) is function of the mass (m)
8
and stiffness (K) of
member
(
m
K
ω
).
T
he frequency increases with increasing
the stiffness of structure or decreasing the mass of
member
.
A
s the concrete
strength is lower (at 20MPa level), the stiffness of
reinforced LWAC beam is
similar
to reinforced NWC beam, and the unit weight of LWAC beam is lower
than NWC beam.
Therefore
,
the
frequency
of reinforced LWAC beam is higher
than the
frequency
of reinforced NWC beam.
As the concrete strength
attain
s
to
40MPa
level,
the stiffness and unit weight of reinforced LWAC beam are both
lower than reinforced NWC beam. So, they have a similar frequency.
It can be seen that the
frequency
of reinforced concrete beam
seem to have
no relationship with
space of web reinforce
ment
and
amount of tensile
reinforcement
. However, the
frequency
of reinforced concrete beam is about
10%~25% lower than pure concrete beam
because
installed reinforcement.
T
he
analysis
of
damping ratio
A
s the concrete strength is lower (at 20MPa level), t
he damping ratio of
LWAC beams is 8.11% and 6.89% for NWC beams.
LWAC is better than NWC
in damping
characteristic
. As the concrete strength at
40MPa
level, LWAC
beams and NWC beams have damping ratios of 7.13% and 7.43% respectively.
For the reinforced c
oncrete beams, the damping ratio of reinforced LWAC
beams is varied between 2.52% and 4.22%.
A
s well as reinforced NWC beams,
is varied between 1.73% and 3.85%. At lower concrete strength level (20MPa)
reinforced LWAC beam is better than reinforced NWC bea
ms in damping ratio.
As the concrete strength
attain
s
to
40MPa
level,
they
posses
a similar
behavior
.
From Table 6 it can also be seen that the damping ratio of reinforced
concrete beam
seem to have
no relationship with
space of web reinforcement
and
reinf
orcement ratio
. However, the damping ratio of reinforced concrete
9
beam is lower than pure concrete beam
because
installed reinforcement.
Conclusions
Experimental results of
s
eismic
r
esistant
p
roperties of
l
ightweight
a
ggregate
c
oncret
e
are presented.
On th
e basis of results obtained in
this study the
following conclusions can be drawn.
1.
The stiffness of reinforced NWC beam increases with increasing concrete
strength and modulus of elasticity of concrete. For reinforced LWAC beam
is ineffective.
A
t lower conc
rete strength level (20MPa),
the stiffness of
reinforced LWAC beam is
close
to
that for
reinforced NWC beam.
As the
concrete strength
attain
s
to
40MPa
level,
the stiffness of reinforced NWC
beam is 20% higher than that of reinforced LWAC beam.
2.
For plain co
ncrete beams, increasing concrete strength increases the
frequency.
A
t lower concrete strength level (20MPa level),
the frequency of
LWAC beam is
near that for
NWC beam.
As the concrete strength
attain
s
to
40MPa
level,
the
frequency of LWAC beam is lower t
han that of NWC
beam.
Moreover
, at lower concrete strength level (20MPa level),
the
damping ratio of pure LWAC beam is better than
that for
NWC beam.
As
the concrete strength
attain
s
to
40MPa
level,
the damping ratio of LWAC
beam is
close
to
that for
NWC b
eam.
3.
For reinforced concrete beams, at lower concrete strength level (20MPa
level),
the frequency and damping ratio of reinforced LWAC beam are
higher than
those for
reinforced NWC beam.
As the concrete strength
attain
s
to
40MPa
level,
the frequency and da
mping ratio of LWAC beam
are
close
to
those for
NWC beam.
4.
C
ompar
ing
the seismic resistance properties
between
LWAC and NWC
,
10
unit weight of lightweight aggregate concrete is about 20% lower than
that
for
NWC at the same concrete strength.
A
s the concrete
st
rength
is at
20MPa level, LWAC is similar to NWC in stiffness and possesses better
damping
characteristic
.
A
t higher concrete strength level (at 40MPa level),
LWAC is similar to NWC in damping
characteristic
, but LWAC is lower in
stiffness.
References
1.
Ber
tero, V. V., and Popov, E. P., "Seismic Behavior of Ductile Moment

Resisting
Reinforced Concrete Frames,"
Reinforced Concrete Structures in Seismic Zones
, SP

53,
American Concrete Institute, Detroit, PP. 247

291
(
1977
)
.
2.
Viwathanatepa, S., Popov, E. P., and
Bertero, V. V., "Seismic Behavior of R. C. Interior
Beam

Column Subassemblage," EERC Report No. UCB/EERC

79/14, Earthquake
Engineering Research Center, University of California, Berkeley
(
1979
)
.
3.
Forzani, B., Popov, E. P., and Bertero, V. V., "Hysteretic B
ehavior of Lightweight
Reinforced Concrete Beam

Column Subassemblages," EER Report No. UCB/EERC
79/01, Earthquake Engineering Research Center, University of California, Berkeley
(
1979
)
.
4.
V. V. Bertero, E. P. Popov and B. Forzani, "Seismic Behavior of Lightw
eight Concrete
Beam

Column Subassemblages,"
ACI Journal
, PP. 44

52
(
1980
)
.
5.
Sekhniakshivile, E. A., "
On the Effective Use of Light Concrete and Reinforced Concrete
11
in Construction in Seismic Regions
," Proceedings, Sixth World Conference on Earthquake
Engine
ering, V. 3, PP. 2034

2024
(New Delhi, Jan. 1977)
.
6.
Paramzim, A. M., and Gorovitz, I. G., "
Analysis of Light

weight Concrete Use in
Seismic

Resistant Multistory Buildings
," Proceedings, Sixth World Conference on
Earthquake Engineering, V. 3, PP. 2124

2125
(Ne
w Delhi, Jan. 1977)
.
12
Table 1
T
he summary of the specimen
quantity
LWAC beams
NWC beams
Beam
number
Design
strength
(MPa)
Tensile
steel
Stirrups
quantity
Beam
number
Design
strength
(MPa)
Tensile
steel
Stirrups
quantity
RLC20410
20
4

#4
#3@100mm
2
RC20410
20
4

#4
#3@100mm
2
RLC20610
4

#6
#3@100mm
2
RC20610
4

#6
#3@100mm
2
RLC20415
4

#4
#3@150mm
2
RC20415
4

#4
#3@150mm
2
RLC20615
4

#6
#3@150mm
2
RC20615
4

#6
#3@150mm
2
LC20
0
0
3
NC20
0
0
3
RLC40410
40
4

#4
#3@100mm
2
RC4
0410
40
4

#4
#3@100mm
2
RLC40610
4

#6
#3@100mm
2
RC40610
4

#6
#3@100mm
2
RLC40415
4

#4
#3@150mm
2
RC40415
4

#4
#3@150mm
2
RLC40
6
15
4

#4
#3@150mm
2
RC40
6
15
4

#4
#3@150mm
2
LC40
0
0
3
NC40
0
0
3
Table 2
Mixt proportions of lightweight aggr
egate concrete
Design
strength
(MPa)
Cement
Water
30min
Absorption
(%)
Sand
3/4"~1/2"
1/2"~3/8"
3/8"~#4
20
297
194
29
734
179
213
175
40
480
194
29
664
166
197
162
Table
3
Mixt proportions of normal weight concrete
Design
strength
(MPa)
Cement
Water
Sand
Coarse
aggregate
20
280
197
781
1056
4
0
410
196
675
1056
Illustration of Symbol
：
For example RLC20410,
RLC
:
reinf
orced
lightweight aggregate
concrete
beam
.
20
:
d
esign strength
20MPa
.
4
: #4 longitudinal reinforcement
，
10: the space of
web reinforcement is 100mm
。
13
Table 4
T
he
basic properties
of the specimen
s
LWAC beams
NWC beams
Com.
strength
(MPa)
Elastic
modulus
E(MPa)
Beam
number
Unit
weight
(kg/m3)
S
tiffness
K (Ton/
m)
Com.
strength
(MPa)
Elastic
modulus
E(MPa)
Beam
number
Unit
weight
(kg/m3)
S
tiffness
K
(Ton/m)
27.4
163
00
RLC20410
17
90
190
0
23.1
214
00
RC20410
23
20
207
0
RLC20410
1
800
17
70
RC20410
23
10
189
0
RLC20610
194
0
27
70
RC20610
242
0
2470
RLC20610
1950
24
80
RC20610
2420
226
0
RLC20415
178
0
260
0
RC20415
2320
25
20
RLC20415
179
0
20
50
RC20415
23
30
19
20
RLC20615
19
10
271
0
RC20615
239
0
249
0
RLC20615
191
0
2260
RC20615
238
0
231
0
43.5
19800
RLC40410
19
10
230
0
43.7
255
00
RC40410
236
0
2
8
00
RLC40410
19
10
22
80
RC40410
238
0
258
0
RLC40610
20
20
253
0
RC40610
244
0
297
0
RLC40610
20
20
278
0
RC40610
24
50
28
80
RLC40415
18
50
222
0
RC40415
23
50
28
20
RLC40415
18
60
22
00
RC40415
2320
27
50
RLC40615
1990
24
30
RC40615
24
20
30
80
RLC40615
198
0
2
600
RC40615
24
20
321
0
14
Table 5
T
he
results
of the
f
requency and damping ratio
LWAC
NWC
fc'
(M
P
a)
Beam
number
Frequency
ω
(rad/sec)
Damping
ratio
ζ
(%)
fc'
(M
P
a)
Beam
number
Frequency
ω
(rad/sec)
Damping
ratio
ζ
(%)
27.4
LWAC20
865
(831)
7.59
(8.11)
23.1
NC20
781
(821)
6.84
(6.89)
797
8.61
861
7.00
830
8.12
796
6.82
RLC20410
712
(723)
4.02
(4.22)
RC20410
616
(619)
2.66
(2.57)
733
4.41
621
2.48
RLC20610
810
(816)
2.61
(3.36)
RC20610
727
(729)
2.56
(2.75)
821
4.11
731
2.93
RLC20415
710
(737)
2.85
(3.09)
RC20415
707
(709)
1.63
(1.73)
764
3.32
710
1.83
RLC20615
703
(718)
3.88
(3.28)
RC20615
768
(749)
2.60
(2.54)
732
2.67
730
2.48
43.5
LWAC40
983
(925)
6.46
(7.13)
43.7
NC40
954
(967)
7.76
(7.43)
891
7.23
980
7.77
901
7.71
966
6.77
RLC40410
753
(728)
2.70
(2.60)
RC40
410
769
(745)
2.38
(2.42)
702
2.50
721
2.45
RLC40610
783
(760)
2.63
(2.52)
RC40610
706
(712)
2.30
(2.55)
737
2.40
718
2.79
RLC40415
727
(742)
2.70
(2.70)
RC40415
744
(727)
3.90
(3.85)
757
2.69
710
3.79
RLC40615
755
(756)
3.69
(4.17)
RC40615
720
(708)
2.30
(2.48)
756
4.64
696
2.66
15
Figure 1. Specimen details
Figure 2 Testing setup for stiff test
Figure
3
Testing setup for the test of frequency and damping ratio
0.2m
0.15m
0.13m
0.08m
4#4
#3
0.2m
0.15m
0.13m
0.08m
4#6
#3
MTS
Load
Load cell
Support
LVDT
0.71m
0.71m
Specimen
Accelerometer
0.71m
0.71m
Specimen
16
Figure 4
U
nit weight of reinforced concrete effects on the stiffness
(K)
Figure 5
C
ompressive concrete strength effects on the stiffness (K)
Figure 6
M
odulus of elasticity effects on the stiffness (K)
20
25
30
35
40
45
f
'
c
(
M
P
a
)
16000
18000
20000
22000
24000
26000
28000
30000
32000
34000
K
(
k
n
/
m
)
RLC(20MPa)
RLC(40MPa)
RC(20MPa)
RC(40MPa)
The growing line of K value of RLC
The growing line of K value of RC
16000
18000
20000
22000
24000
26000
E
(
M
P
a
)
16000
18000
20000
22000
24000
26000
28000
30000
32000
34000
K
(
k
n
/
m
)
RLC(20MPa)
RLC(40MPa)
RC(20MPa)
RC(40MPa)
The growing line of the stiffness of RLC
The growing line of the stiffness of RC
1600
1800
2000
2200
2400
2600
T
h
e
u
n
i
t
w
e
i
g
h
t
o
f
r
e
i
n
f
o
r
c
e
d
c
o
n
c
r
e
t
e
(
k
g
/
m
3
)
16000
18000
20000
22000
24000
26000
28000
30000
32000
34000
K
(
k
n
/
m
)
(
b
)
f
'
c
=
4
0
M
P
a
L
e
v
e
l
RLC (40MPa)
RC (40MPa)
1600
1800
2000
2200
2400
2600
T
h
e
u
n
i
t
w
e
i
g
h
t
o
f
r
e
i
n
f
o
r
c
e
d
c
o
n
c
r
e
t
e
(
k
g
/
m
3
)
16000
18000
20000
22000
24000
26000
28000
30000
32000
34000
K
(
k
n
/
m
)
(
a
)
f
'
c
=
2
0
M
P
a
L
e
v
e
l
RLC (20MPa)
RC (20MPa)
17
Design
strength
(MPa)
Cement
Water
30min
Absorption
(%)
Sand
3/4"~1/2"
1/2"~3/8"
3/8"~#4
20
297
194
29
734
179
213
175
40
480
194
29
664
166
197
162
LWAC beams
NWC beams
Beam
number
Design
strength
(MPa)
Tensile
steel
Stirrups
quantity
Beam
number
Design
strength
(MPa)
Tensile
steel
Stirrups
quantity
RLC20410
4

#4
#3@100mm
2
RC20410
4

#4
#3@100mm
2
RLC20610
4

#6
#3@100mm
2
RC20610
4

#6
#3@100mm
2
RLC20415
4

#4
#3@150mm
2
RC20415
4

#4
#3@150mm
2
RLC20615
4

#6
#3@150mm
2
RC20615
4

#6
#3@150mm
2
LC20
20
0
0
3
NC20
20
0
0
3
RLC40410
4

#4
#3@100mm
2
RC40410
4

#4
#3@100mm
2
RLC40610
4

#6
#3@100mm
2
RC40610
4

#6
#3
@100mm
2
RLC40415
4

#4
#3@150mm
2
RC40415
4

#4
#3@150mm
2
RLC40
6
15
4

#4
#3@150mm
2
RC40
6
15
4

#4
#3@150mm
2
LC40
40
0
0
3
NC40
40
0
0
3
Design
strength
(MPa)
Ceme
nt
Water
30min
Absorption
(%)
Sand
3/4"~1/2"
1/2"~3/8"
3/8"~#4
20
297
194
29
734
179
213
175
40
480
194
29
664
166
197
162
Design
strength
(MPa)
Cement
Water
Sand
Coarse
aggregate
20
280
197
781
1056
4
0
410
196
675
1056
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