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14th World Conference on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures
September 9-11 2015 San Diego, Ca USA
1
DESIGN OF A 24-STORY DAMPED STEEL FRAME BASED ON CHINESE
AND JAPANESE BUILDING CODES
Demin FENG
Technology Development Division, Fujita Corp.
Ono 2025-1, Atsugi City, 243-0125, Japan
Hui XIA
NPO Asia Construction Technology Promotion Organization
Higashi Nippori 4-33-7-3F, Arakawa-ku, Tokyo 116-0014, Japan
Wenguang LIU
Department of Civil Engineering, Shanghai Univ.
No 149, Yan-Chang Road, 200072 Shanghai, China
ABSTRACT - In Japanese and Chinese building codes, a two-stage design philosophy, damage limitation
(small earthquake, Level 1) and life safety (extreme large earthquake, Level 2), is adopted. It is very
interesting to compare the design method of a damped structure based on the two building codes. In the
Chinese code, in order to be consistent with the conventional seismic design method, the damped structure is
also designed at the small earthquake level. The effect of damper systems is considered by the additional
damping ratio concept. The design force will be obtained from the damped design spectrum considering the
reduction due to the additional damping ratio. The additional damping ratio by the damper system is usually
calculated by a time history analysis method at the small earthquake level. The velocity dependent type
dampers such as viscous dampers can function well even in the small earthquake level. But, if steel damper
is used, which usually remains elastic in the small earthquake, there will be no additional damping ratio
achieved. On the other hand, a time history analysis is used in Japan both for small earthquake and extreme
large earthquake level. The characteristics of damper system and ductility of the structure can be modelled
well. An existing 24-story steel frame is modified to demonstrate the design process of the damped structure
based on the two building codes. Viscous wall type damper and low yield steel panel dampers are studied as
the damper system.
Keywords: damper, dynamic response analysis, building code, damping ratio, energy absorption
1 INTRODUCTION
In Japan and China, the application number of the damped building has been increased significantly.
In Japan, there have been more than 1191 buildings in the end of 2013. But neither the design
criteria of the damped buildings nor manufacturing inspection criteria of the dampers are covered in
the building code. JSSI (2013) has published a manual book concerning the mechanism, design,
fabrication, testing, quality control, and analytical modelling of various types of dampers, as well as
design, construction, and analysis of damped buildings. On the other hand, the energy dissipation
technology has been used widely in the high-rise buildings with the construction boom in China.
Both the design criteria of the damped buildings and manufacturing inspection criteria of the
2
dampers have been well documented in the building code.
In this paper, the design flow chart and the features of the two building code on damped
buildings are summarized first. In both Japanese and Chinese building codes, a two-stage design
philosophy, damage limitation (small earthquake, Level 1) and life safety (extreme large earthquake,
Level 2), is adopted. In Japanese code, allowable stress elastic design is used in Level 1 and non-
linear design in Level 2 earthquake. In order to utilize the energy dissipation technology, the
designer has to do non-linear dynamic response analysis and the damped building has to be certified
by the Ministry. Usually, the damped building has better performance target than aseismic one. In
Chinese code, elastic design is used in Level 1 and specification design in Level 2. In accordance
with the aseismic design, the damped building is also designed at small earthquake level (Level 1)
where the earthquake load is decreased by considering the additional damping ratio contributed by
the dampers. But hysteric dampers like BRB or steel panel dampers will not yield in Level 1, so
only stiffness contribution will be considered. Since the response shape such as drift angle at Level
1 and Level 2 is different much, the damper’s performance cannot be evaluated well only basing on
the response values at Level 1. The performance target is set the same as the aseismic one usually in
China.
An existing 24-story steel frame is modified to demonstrate the design process of the damped
structure based on the two building codes. Velocity dependent type viscous wall type damper and
hysteric type low yield steel panel dampers are studied as the damper system. The response values
and energy absorption are compared.
2 DAMPED STRUCTURE DESIGN IN CHINESE BUILDING CODE
The damped structure design method is adopted in the building code GB50011-2001 at first,
and then updated in GB50011-2010. The manufacturing inspection criteria of the dampers are
covered in the code JG/T209-2012. JGJ 297-2013 gives detailed technical specifications of damped
structure design and manufacturing inspection criteria of the dampers. The damped structure design
method based on the building code GB50011-2010 is summarized here.
The limit state design concept is adopted in the aseismic design. The response values
calculated from Level 1 are combined by various factors and checked with the design strength of
materials. Specification design is conducted in Level 2 to meet the requirements of ductility and
deformation capacity. The response spectrum analysis method is usually used to design. There are
four segments in the design response spectrum which are combined functions of the zone factor, the
site class and the response reduction factor as shown in Eq. (1) and Fig. 1. For design of a damped
structure, the earthquake load is decreased by considering the additional damping ratio contributed
by the dampers. The calculation of the additional damping ratio is shown in Eq. (2).
0.65)]5(2.0[
5)(
1.0
1.0)1.0
45.045.0(
)(
max12
max2
max2
max2
TTTT
TTTT
T
TT
TT
g
gg
gg
g
g
(1)
Where, max: seismic zone factor;
: spectrum shape coefficients;
: response reduction factor defined in Eq. (A.1)
Tg: characteristic period related to the site soil profile;
: effective damping ratio of the damped structure.
3
63.0
05.09.0
0,324
)05.0(02.0 11
(A.1)
55.0,6.108.0
05.01 22
)4/(1
n
j
scjd WW (2)
where, d: additional damping ratio of dampers;
Wcj: total energy dissipated by dampers;
Ws: total input earthquake energy;
The additional damping ratio of dampers is usually calculated by the average response values
from multiple Level 1 input motions using elastic time history analysis. In addition to Eq.(2), it can
be calculated also by comparing response values such as top displacement value, story drift angle,
shear force or resistant moment of base story. The effective damping of the damped structure is a
sum of the additional damping ratio with the structure damping ratio, which is usually 5% for RC
structure, 3% for steel structure. The pseudo velocity spectra with damping ratio of 5%, 8% and
12% were calculated from Eq.(1) and shown in Fig.1, where Intensity 8, Tg=0.4s were used. It can
be seen, the response pseudo velocity value increased with the period which usually have a constant
value in other building codes. The reduction due to the damping ratio is smaller (Feng, 2006).
Figure 1 - The pseudo velocity spectra with damping ratio of 5%, 8% and 12% (Intensity 8,
Tg=0.4s)
3 DAMPED STRUCTURE DESIGN IN JAPANESE BUILDING CODE
In Japan, there have been more than 1191 buildings in the end of 2013. But neither the design
criteria of the damped buildings nor manufacturing inspection criteria of the dampers are covered in
the building code. JSSI (2013) has published a manual book concerning the mechanism, design,
fabrication, testing, quality control, and analytical modelling of various types of dampers, as well as
design, construction, and analysis of damped buildings. AIJ (2014) recommended provisions for
steel dampers such as BRB and panel dampers.
In Japanese code, allowable stress elastic design is used in Level 1 and non-linear design in
Level 2 earthquake. In order to utilize the energy dissipation technology, the designer has to do
non-linear dynamic response analysis and the damped building has to be certified by the Ministry.
4
The number of damped buildings and classification of dampers used are shown in Fig.2 (JSSI,
2015). The hysteric damper is most popular one due to its cheap cost. However, in the Great East
Japan (Tohoku) Earthquake on March 11, 2011, there observed ground motions having strong long
period and long duration time. The velocity dependent type dampers such as oil damper (bi-linear
property with velocity) and viscous damper increased more and more.
The performance target of a damped building is usually higher than the aseismic one as
shown in Table 1. Moreover it is important to check the cumulative deformation on hysteric type
dampers.
Figure 2 - The number of damped buildings and classification of dampers (JSSI, 2015).
Table 1 - The performance target of a damped building
Level 1 Level 2
Ground
motions
Three motions compatible with
design spectrum and three
recorded motions with peak
velocity normalized to 25cm/s
Three motions compatible with
design spectrum and three recorded
motions with peak velocity
normalized to 50cm/s
Super-
structure
Drift angle < 1/300
(aseismic: 1/200)
stress ≦ short term allowable
strength
Drift angle < 1/150
(aseismic: 1/100）
Story ductility factor < 2
Member ductility factor < 4
Hysteric
damper
Checking cumulative deformation
4 A DAMPED STRUCTURE MODEL
A 24-story damped steel structure (Feng, 2013) is analysed to understand the design
procedure of both building codes. Two types of damper system: velocity dependent viscous wall
damper and hysteric low yield steel panel damper are used (JSSI, 2013).
5
4.1 Structure model
For dynamic response analysis, the super-structure was modelled as a nonlinear bending-shear
type multiple-degree-of-freedom system. The parameters used in the model were obtained from a
static pushover analysis and shown in Table 2. In Fig.3 are shown typical story shear model
parameters comparing with the pushover analysis results, which agreed very well. The bending
spring was assumed as elastic. The shear spring model was modelled as tri-linear or bi-linear
depending on the column materials. The CFT columns in 1st and 2
nd stories are modelled as tri-
linear, while the steel columns above 3rd
story as modelled as bi-linear model. By using the bending
shear model, the shear deformation relating with dampers can be calculated directly. A varying-
stiffness proportional damping system was assumed in the time history analysis. The damping ratio
for bending spring was assumed as 0.02, while the damping ratio for shear spring was assumed as
0.02 corresponding 1st natural period. The three natural periods were obtained from the mode
analysis as 3.292s, 1.107s and 0.659s, respectively
To limit analysis cases, only one synthetic input motion was used which is compatible with
Chinese design spectrum (Intensity 8, Tg=0.4s) (Feng, 2006). The peak acceleration was 0.397g.
Time duration and time interval were 120s and 0.01s, respectively. The synthetic motion was used
as Level 2 motion directly in both building codes. For Chinese Level 1 motion, the peak
acceleration value was normalized to 0.07g. The pseudo velocity spectra of both Level 1 and Level
2 motion are compared with Chinese and Japanese design spectra in Fig.4.
40x103
30
20
10
0
Sh
ea
r fo
rce
(kN
)
6050403020100
Displacement (mm)
1F
10F
15F
20F
3F
Figure 3 - The story shear model parameters comparing with pushover analysis results
Figure 4 - The pseudo velocity spectra of both Level 1 and Level 2 motion comparing with Chinese
and Japanese design spectra.
6
Table 2 – Parameters of the super-structure bending-shear MDOF model
Floor Mass Height TypeBending
stiffness
Elastic
stiffnessRatio of Ratio of Crack load Yield load
Kr K1 K2/K1 K3/K1 Qc Qy
(t) (m) (KN・m/rad) (KN/mm) (kN) (kN)
RF 216 84.75 Bilinear 1.508E+08 137.9 - 0.324 - 1794
23F 1067 80.55 Bilinear 2.298E+09 403.1 - 0.460 - 5037
22F 1078 76.25 Bilinear 5.123E+09 660.1 - 0.454 - 7418
21F 1073 72.95 Bilinear 5.654E+09 697.7 - 0.454 - 9370
20F 1073 69.65 Bilinear 5.969E+09 723.1 - 0.447 - 11215
19F 1080 66.35 Bilinear 7.449E+09 768.1 - 0.426 - 12922
18F 1083 63.05 Bilinear 7.537E+09 788.0 - 0.428 - 14507
17F 1085 59.75 Bilinear 7.555E+09 802.5 - 0.398 - 16091
16F 1085 56.45 Bilinear 7.556E+09 805.1 - 0.304 - 17499
15F 1087 53.15 Bilinear 7.537E+09 802.1 - 0.202 - 18977
14F 1086 49.85 Bilinear 7.506E+09 801.3 - 0.131 - 20202
13F 1087 46.55 Bilinear 7.519E+09 811.7 - 0.091 - 21173
12F 1088 43.25 Bilinear 7.469E+09 816.5 - 0.065 - 22125
11F 1088 39.95 Bilinear 7.420E+09 831.0 - 0.048 - 23053
10F 1091 36.65 Bilinear 7.351E+09 845.7 - 0.038 - 23892
9F 1091 33.35 Bilinear 7.283E+09 851.3 - 0.032 - 24632
8F 1091 30.05 Bilinear 7.216E+09 858.8 - 0.029 - 25345
7F 1094 26.75 Bilinear 7.819E+09 884.3 - 0.027 - 25972
6F 1097 23.45 Bilinear 7.736E+09 893.9 - 0.028 - 26419
5F 1098 20.15 Bilinear 7.952E+09 919.5 - 0.031 - 26722
4F 1098 16.85 Bilinear 7.879E+09 1001.7 - 0.038 - 26629
3F 1098 13.55 Bilinear 7.773E+09 1574.9 - 0.062 - 23692
2F 1669 10.25 Trilinear 1.503E+10 2518.0 0.284 0.044 5238 28847
1F 1787 5.25 Trilinear 1.540E+10 4766.5 0.330 0.060 5912 29519
K2: Stiffness after crack; K3: Stiffness after yield
4.2 Dampers
Two types of damper system: velocity dependent viscous wall damper and hysteric low yield
steel panel damper are used (JSSI, 2013). The viscous wall damper is modelled by Maxwell model.
The steel panel damper is modelled by bi-linear model.
5 DYNAMIC RESPONSE ANALYSIS RESULTS
Dynamic response analysis results of Level 1 and Level 2 motions are summarized following
mainly Chinese code. In Level 1 analysis, the procedure to calculate the additional damping ratio of
dampers is demonstrated. In Level 2 analysis, the performance target is set to story drift angle
required by both codes, and the story ductility factor following Japanese code.
5.1 Response Analysis of the Aseismic Model
Dynamic response analyses were carried out on the aseismic model at Level 1 and Level 2
input motions. The story drift angle and energy absorption diagram at Level 2 are shown in Fig.5.
The maximum of story drift angle at Level 1 was 1/375, smaller than code requirement of 1/250.
The maximum of story drift angle at Level 2 was 1/42, larger than code requirement of 1/50. From
the energy absorption diagram in Fig.5, it can be understood that at Level 2 input, the super-
7
structure became yielding and absorbed half of the input energy. Thus the story ductility factor was
so much high as 5.1 in 3rd
story.
RF
20F
15F
10F
5F
1F
Flo
or
30x10-320100
Drift angle (rad.)
1/100
Level 1 Level 2
60x103
50
40
30
20
10
0E
ner
gy
(k
N m
)
120100806040200
Time (s)
Ei
Ed
Ek
Es
Aseismic, Level 2
Ei: input energy; Ed: energy absorbed by structure’s damping;
(a) Story drift angle Es: energy absorbed by structure’s plasticity; Ek: kinetic energy
(b) Energy absorption diagram at Level 2 input
Figure 5 - The story drift angle and energy absorption diagram at Level 2 input
The performance target of the damped structure at Level 2 input was set as: the story drift
angle less than 1/100; the story ductility factor less than two.
In Chinese code, the dampers’ effect is evaluated at Level 1 input. It is usually better to place
dampers according the response results at Level 1 input. In this study, the performance target of the
damped structure was set at Level 2 input, so the dampers’ planning was carried out based on the
Level 2 response results. The dampers planning are shown in Table 3.
Table 3 – The dampers planning
Type Number C(kN/[m/s])K(KN/mm) Type Number K(kN/mm) Fy(KN) β
14F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 1 1048 2099 0.01
13F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 1 1048 2099 0.01
12F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 1 1048 2099 0.01
11F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 1 1048 2099 0.01
10F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 1 1048 2099 0.01
9F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 1 1048 2099 0.01
8F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 2 2096 4198 0.01
7F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 2 2096 4198 0.01
6F VFD-NL×2500×60 4 23484 2360 MYD-S×2000×2.0 2 2096 4198 0.01
5F VFD-NL×2500×60 4 23484 2360 MYD-S×2000×2.0 2 2096 4198 0.01
4F VFD-NL×2500×60 4 23484 2360 MYD-S×2000×2.0 2 2096 4198 0.01
3F VFD-NL×2500×60 4 23484 2360 MYD-S×2000×2.0 3 3144 6297 0.01
2F VFD-NL×2000×60 3 14091 1410 MYD-S×2000×2.0 1 1048 2099 0.01
1F MYD-S×2000×2.0 1 1048 2099 0.01
Low yield steel panel damperViscous wall damperFloor
F=CV0.45
8
5.2 Response Analysis of the Damper Structures at Level 1 Input
Response analysis results of the damper structures at Level 1 input are shown in Fig.6. In the
case of viscous wall damper, all response results: story drift angle, story shear force coefficient and
floor acceleration became smaller. In the case of steel panel damper, the dampers did not yield at
Level 1 input and contributed stiffness to the main structure. The natural periods of the damped
structure with steel dampers became shorter as: 2.452s, 0.945s and 0.557s. Thus, the story drift
angle became smaller, while shear force coefficient and floor acceleration became larger.
The energy absorption diagram of the damped structure with viscous damper is shown in
Fig.7. From Eq.(2), the additional damping ratio of the dampers was calculated as 5.5%.
0.160.120.080.040.00
Response acc. (g)
RF
20F
15F
10F
5F
1F
3.0x10-32.01.00.0
Drift angle (rad.)
0.160.120.080.040.00
Shear force coefficient
Aseismic
Viscous
Steel
Figure 6 - Response analysis results of the damper structures at Level 1 input
1400
1200
1000
800
600
400
200
0
En
erg
y (
kN
m)
120100806040200
Time (s)
Ei
Ed
EkEs
Em
Viscous damperLevel 1
Ei: input energy; Em: energy absorbed by viscous dampers; Ed: energy absorbed by structure’s damping;
Es: energy absorbed by structure’s plasticity; Ek: kinetic energy
Figure 7 - The energy absorption diagram of the damped structure with viscous damper
9
5.3 Response Analysis of the Damper Structures at Level 2 Input
Response analysis results of the damper structures at Level 2 input are shown in Fig.8. In both
cases of viscous wall damper and steel panel damper, the performance target was satisfied. The
story drift angle was less than 1/100, and the story ductility factor was 1.6.
In the case of viscous wall damper, all response results: story drift angle, story shear force
coefficient and floor acceleration became smaller like the response results at Level 1 input. The
energy absorption diagram of the damped structure with viscous damper is shown in Fig.9. From
Eq.(2), the additional damping ratio of the dampers was calculated as 6.1% for reference.
In the case of steel panel damper, although not good as the viscous wall damper, all response
results became smaller than the aseismic model.
From Table 3, it can be seen for the same performance target, the amount of viscous wall
dampers was more than that of steel panel dampers. The natural period of the model is about 3.3s,
thus the story velocity was small. The damping force by the viscous wall dampers was 60% of the
rating damping force. In Table 4, is shown the shear force ratio between dampers and main
structures. Although the number of steel panel dampers was fewer, the ratio was larger.
0.40.30.20.10.0
Response acc. (g)
RF
20F
15F
10F
5F
1F
25x10-320151050
Drift angle (rad.)
1/100 0.40.30.20.10.0
Shear force coefficient
Aseismic
Viscous
Steel
Figure 8 - Response analysis results of the damper structures at Level 2 input
60x103
50
40
30
20
10
0
En
erg
y (
kN
m)
120100806040200
Time (s)
Ei
Ed
EkEs
Em
Viscous damper, Level 2
120100806040200
Time (s)
Ei
Ed
EkEs
Eh
Steel damper, Level 2
Ei: input energy; Em, Eh: energy absorbed by dampers; Ed: energy absorbed by structure’s damping;
Es: energy absorbed by main structure’s plasticity; Ek: kinetic energy
Figure 9 - The energy absorption diagram of the damped structure at Level 2 input
10
Table 3 – The shear force ratio between dampers and main structure
Floor Viscous Steel
14F 0.073 0.111
13F 0.065 0.105
12F 0.058 0.100
11F 0.056 0.093
10F 0.059 0.089
9F 0.062 0.085
8F 0.068 0.181
7F 0.070 0.174
6F 0.126 0.168
5F 0.133 0.164
4F 0.134 0.161
3F 0.198 0.253
2F 0.092 0.070
1F - 0.065
SUM 1.194 1.819
6 CONCLUSIONS
In this paper, the design flow chart and the features of the Chinese and Japanese building code
on damped buildings were summarized. An existing 24-story steel frame was modified to
demonstrate the design process of the damped structure. Velocity dependent type viscous wall type
dampers and hysteric type low yield steel panel dampers were studied as the damper system. The
response values and energy absorption diagram were compared.
The viscous wall type dampers had better performance and reduced responses of the main
structure at both Level 1 and Level 2 inputs. The additional damping ratios of the dampers based on
Chinese code were 5.5% at Level 1 input and 6.1% at Level 2 input, respectively.
The steel panel dampers contributed stiffness at Level 1 input and had good performance at
Level 2 input.
The optimization of damper planning should be carried out based on the response values at
Level 2 input.
References
Architectural Institute of Japan (AIJ) [2014], Recommended provisions for seismic damping systems
applied to steel structures (in Japanese).
Feng, D., etc. [2006] “A comparative study of seismic isolation codes worldwide (Part I, II)”, 1st
ECEES, Geneva, No.63, No.66,
Feng, D., etc. [2013] “Response analysis on a 24-story damped steel structure”, 10th
Japan-China
building structure technology symposium, Nanjing (in Chinese)
Japan Society of Seismic Isolation (JSSI) [2013], Manual for design and construction of passively-
controlled Buildings (3rd
edition) (in Japanese).
Japan Society of Seismic Isolation (JSSI) [2015], Annual meeting report (in Japanese).
Ministry of Construction, P.R.China [2010], Code for seismic design of buildings, GB50011-2010
(in Chinese).
Ministry of Construction, P.R.China [2012], Dampers for vibration energy dissipation of buildings,
JG/T209-2012 (in Chinese).
Ministry of Construction, P.R.China [2013], Technical specification for seismic energy dissipation
of buildings, JGJ 297-2013 (in Chinese).
