Structural Selection and Economic Analysis of
Isolated and Non-isolated Shopping Mall Located
at Seismic Intensity 9
Speaker: Chi Miao
Supervisor: Ying Zhou
College of Civil Engineering
Tongji University
2013.08
Outline
1. Introduction
2.1 Comparison of Mechanic Behavior
3. Conclusions
Outline
2. What I did
2.2 Economic Analysis
Introduction
Because of the isolation layer,
the natural periods of isolated structures will
become longer and the influence of
earthquake on structures will thus be
effectively reduced.
1.1 Introduction: Theory of Isolation
Isolation
1.1 Introduction: Theory of Isolation
Seismic Response Spectrum in Chinese Specification
There are more than 2000 isolated buildings all over
the world, about half of which located in Japan.
1. 2 Introduction: Practical Projects
Isolation layer
The first isolated hospital in the world was constructed in America:the University of Southern California Teaching Hospital.
1.2 Introduction: Practical Projects
Strong earthquake with Magnitude 6.7 broke out in California in 1994
USC Teaching Hospital Olive View Hospital
Story\ Acceleration USC Teaching Hospital Olive View Hospital
Base 490 gal 820 gal
Top 210 gal 2310 gal42.8% 281.7%
1. Chinese specifications not only have the role of guiding, but also are laws to
which the structural design must conform. And Chinese specifications were written
based on Chinese conditions.
Whether the isolation technology is also that effective in China?
2. Most isolated buildings were constructed in the developed countries.
Since China is a developing country, whether the isolation technology is economical?
Questions
What I did
2.1 What I did: Comparison of Mechanic Behavior
2.1.1 Concept of Seismic Intensity 9 in Chinese Specification
Based on the exceeding probability of intensity in 50 years, there
are mainly 5 categories of regions in China, as blow:
(1)Regions where earthquake influence may not be considered.
(2)Seismic Intensity 6 Basic Design Acceleration: 50gal
(3)Seismic Intensity 7 Basic Design Acceleration: 100gal
(4)Seismic Intensity 8 Basic Design Acceleration: 200gal
(5)Seismic Intensity 9 Basic Design Acceleration: 400gal
Peak ground acceleration of elastic analysis: 140gal
Peak ground acceleration of elastic-plastic analysis: 620gal
2.1 What I did: Comparison of Mechanic Behavior Chinese Zoning Map of Peak Ground Acceleration
PGA
(unit: g)
2.1 What I did: Comparison of Mechanic Behavior
2.1.2 Three Analytical Models (Etabs) and Lead Rubber Bearings
(1) 3-D Analytical Model of the Frame-Shear Wall Structure
Plan layout of the 1st floor of the
frame-shear wall structure
3-D analytical model of the frame-
shear wall structure
2.1 What I did: Comparison of Mechanic Behavior
(2) 3-D Analytical Model of the Small-bay Frame Structure
Plan layout of the 1st floor of the
small-bay frame structure
3-D analytical model of the small-
bay frame structure
2.1 What I did: Comparison of Mechanic Behavior
(3) 3-D Analytical Model of the Isolated Frame Structure
Plan layout of the 1st floor of the
isolated frame structure
3-D analytical model of the
isolated frame structure
LRB700
2.1 What I did: Comparison of Mechanic Behavior
(4) Lead Rubber Bearings in the Isolated Frame Structure
Factors of rubber isolation bearing
Lead
Rubber Layers
Installation of LRB
Type
DiameterDiameter
of lead
Vertical
stiffnessMechanic behavior of shear deformation of 100%
(mm) (mm) (kN/mm)
Yield
strength
Initial
stiffness
Stiffness
after yielded
Equivalent
Stiffness
Damping
ratio
(kN) (kN/mm) (kN/mm) (kN/mm) %
LRB700 700 110 3509 76 14.37 1.105 1.661 20.4
2.1 What I did: Comparison of Mechanic Behavior
2.1.2 Time History Analysis of Three Models
(1) Natural periods of isolated and non-isolated structures (s)
Frame-shear wall
structure
Small-bay frame
structure
Isolated
frame structure
The 1st period
The 2nd Period
The 3rd Period
0.230
0.168
0.116
0.421
0.363
0.320
2.216
2.120
1.782
It can be seen that the seismic action of non-isolated structures
in high seismic intensity zones may possibly reach their
maximum code limits which could be greatly reduced by
applying isolation technique.
Around 0.4
2.1 What I did: Comparison of Mechanic Behavior
Seismic Response Spectrum in Chinese Specification
0.4 2.0
0.230 0.421 2.216
Decrease
2.1 What I did: Comparison of Mechanic Behavior
(2) Natural and Artificial Records for Analysis
Natural earthquake records for time history analysis under minor earthquakes
Name of the natural records Base station Year
NGA_800LOMAP.SJW_FP SALINAS JOHN & WORK 1989
NGA_838LANDERS.BRS_FN BARSTOW 1992
NGA_1489CHICHI.TCU049_FN TCU049 1999
NGA_2752CHICHI04.CHY101_FP CHY101 1999
NGA_3276CHICHI06.CHY037_FP CHY037 1999
Natural earthquake records for time history analysis under major earthquakes
Name of the natural records Base station Year
NGA_800LOMAP.SJW_FP SALINAS JOHN & WORK 1989
NGA_1489CHICHI.TCU049_FN TCU049 1999
NGA_176IMPVALL.H-E13_FP
NGA_1489CHICHI.TCU049_FP
NGA_1493CHICHI.TCU053_FN
EL CENTRO ARRAY #13
TCU049
TCU053
1979
1999
1999
2.1 What I did: Comparison of Mechanic Behavior
Natural earthquake records for time history analysis under
minor earthquakes
2.1 What I did: Comparison of Mechanic Behavior
Natural earthquake records for time history analysis under
major earthquakes
2.1 What I did: Comparison of Mechanic Behavior
(3) Elastic inter-story drift of time history analysis
X StoryFrame-shear
wall structure
Small-bay
frame
structure
Isolated
frame
structure
Y StoryFrame-shear
wall structure
Small-bay
frame
structure
Isolated
frame
structure
4 1/941 1/831 1/1975 4 1/1107 1/832 1/1759
3 1/1911 1/1025 1/1408 3 1/1319 1/755 1/1282
2 1/5956 1/963 1/1100 2 1/2147 1/625 1/1037
1 1/13107 1/1022 1/1060 1 1/4895 1/857 1/950
As is shown, the maximum inter-story drift of isolated
structure (1/950) is less than that of frame-shear wall structure
and small-bay frame structure, which is 1/941 and 1/625
separately.
2.1 What I did: Comparison of Mechanic Behavior
(4) Inter-story shear of time history analysis (N)
As is shown, the inter-story shear forces of isolated structure are far
less than those of non-isolated structure. In the first story where the
maximum inter-story force occurs, the inter-story shear forces of
isolated structure in X and Y direction are merely 28.2%, 20.3% and
21.1%, 19.9% of frame-shear wall structure and small-bay frame
structure separately.
X Story
Frame-shear
wall
structure
Small-bay
frame
structure
Isolated
frame
structure
Y Story
Frame-shear
wall
structure
Small-bay
frame
structure
Isolated
frame
structure
4 7.16E+05 7.77E+05 1.39E+05 4 6.27E+05 6.00E+05 1.36E+05
3 2.04E+06 2.17E+06 4.58E+05 3 2.75E+06 2.40E+06 4.31E+05
2 3.24E+06 3.94E+06 9.14E+05 2 4.15E+06 4.22E+06 8.51E+05
1 4.08E+06 5.44E+06 1.15E+06 1 5.58E+06 5.68E+06 1.13E+06
20.3%
28.2%
19.9%
21.1%
2.1 What I did: Comparison of Mechanic Behavior
(5) Floor acceleration (m/s2)
X Story
Frame-shear
wall
structure
Small-bay
frame
structure
Isolated
frame
structure
Y Story
Frame-shear
wall
structure
Small-bay
frame
structure
Isolated
frame
structure
4 10.58 7.30 1.49 4 7.05 6.02 1.51
3 3.79 3.67 1.08 3 4.18 4.03 1.09
2 2.07 2.67 0.80 2 2.89 2.87 0.82
1 1.72 1.91 0.72 1 1.95 1.70 0.72
As is shown, the floor accelerations of isolated structure under
minor earthquake are far less than those of non-isolated structures.
In the top story where the maximum acceleration occurs, the floor
accelerations of isolated structure in X and Y direction are merely
14.1%, 20.9% and 20.4%, 24.5% of frame-shear wall structure and
small-bay frame structure, separately.
20.9%14.1%
24.5%20.4%
2.1 What I did: Comparison of Mechanic Behavior
(6) Dynamic magnification factors of floors
As is illustrated, the dynamic magnification factor of
isolated structure is far lower than that of non-isolated
structure which indicates that the isolation bearing reduces
earthquake energy input efficiently.
X direction Y direction
2.1 What I did: Comparison of Mechanic Behavior
(7) Elastic-plastic inter-story drift of the isolated structure
As is shown, the maximum elastic-plastic inter-story drift of isolated
frame structure is 1/343 under rare earthquake which is merely 14.58%
of the 1/50 code limit specified by term 5.5.5 of seismic code. This
indicates that the isolation bearings reduce the upper structure
deformation significantly thus ensures the structure safety.
Direction\Story 1st 2nd 3rd 4th
X 1/382 1/461 1/615 1/947
Y 1/343 1/404 1/535 1/806
2.2 What I did: Economical Analysis
2.2 What I did: Economical Analysis
2.2.1 Reinforced concrete consumption of the upper structures (t)
The material consumption of isolated upper structure is equivalent to 79.7% of
the frame-shear wall structure and 74.9% of the small-bay frame structure.
2.2.2 Average longitudinal rebar ratio of columns (%)
StoryFrame-shear
wall structure
Small-bay
frame
structure
Isolated
frame
structure
4 1.86 1.35 1.15
3 1.06 1.12 1.1
2 1.13 1.43 1.22
1 1.3 3.79 2.34
Frame-shear
wall structure
Small-bay
frame
structure
Isolated frame
structure
1.20E+03 1.28E+03 9.59E+02
In addition to cross section dimension reduction, the reduction in seismic
effect can enormously reduce the reinforcement ratio. The reinforcement ratio
of isolated structure is merely 61.74% of the small-bay frame structure.
2.2 What I did: Economical Analysis
2.2.3 Information from other practical projects
The direct building costs was reduced by 6%.
Museum in Shantou
2.2 What I did: Economical Analysis
The paper Economy analysis of seismic isolated structure [4]
provides 4 examples of actual construction cost of projects in
Gansu Province.
In combination with the analysis and information above, a
conclusion could be drawn:
For multi-story reinforced concrete buildings in high seismic
intensity zones, the direct construction cost of isolated
structures could be 1% to 5% lower than the non-isolated
scheme under the condition that the isolated structure is well-
designed.
The mechanic
behaviors of
isolated
structure are
much better
than that of the
non-isolated
structure.
When isolated
structures are
designed
reasonably,
construction cost
could be reduced.
At least, there is
no more economic
obstacles.
The isolation
technology has a
bright future in
the places with
high seismic
intensity in China.
3. Conclusion
[1] Zhou Fulin. Structure seismic control[M].Beijing: Seismological
Press,1996.
[2] Architecture Institute of Japan. Designing methods of base-isolated
buildings[M]. Beijing: Seismological Press,20066.
[3] Chen Huaming, Liu Qingwei, Ge Wei. Base isolation design of a brick
masonry residence building supported with frame-shear wall[J]. Structural
Engineers.2004,20(4):55-59.(in Chinese)
[4] Dang Yu, Du Yongfeng, Bi Changsong. Economy analysis of seismic
isolated structure[J].Earthquake Resistant Engineering and
Retrofitting,2006,28(4):37-40.(in Chinese)
[5] Wei Dan, Shi Weixing, Zhu Yan. Comparative testing research on seismic
performance of several types of isolators[J]. Structural
Engineers.2011,27(4):121-127.(in Chinese)
[6] Ministry of Construction of the People’s Republic of China. GB 50011-
2010 Code for seismic design of buildings [S]. Beijing: China Architecture
and Building Press, 2010
[7] OSAKI Yorihiko(Author), Tian Qi(Translator). SHIN JISHINDO NO
SPECTRE KAISEKI NYUMON[M].Beijing: Seismological Press,2008
Inference:
Thanks for attention !!Thanks for your attention!!