Dynamic Response of UAE Buildings
Earthquakes
Dr. Jamal A. Abdalla, M. ASCE, M. EERI
Associate Professor and Chair of Civil Engineering Department
American University of Sharjah
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Outline
• Geology, tectonics and seismicity of UAE
• Seismic hazard assessment of UAE
• Types of Buildings in UAE
• Earthquake Resistant Design Provisions
• Dynamic response of Villas to
earthquakes
• Results and discussions
• Conclusion and Future Work
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Geology of UAE
• Geologically, the features of UAE
follow that of the Arabian Platform
• The rocks in the Arabian Platform
accumulated on stable marine shelf
• sandstones, siltstones,
carbonates and salt basin
characterize the region
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Tectonics of UAE
• Tectonically, UAE is situated in the South-Eastern part of the
Arabian plate that is composed of sedimentary rocks that
range in thickness from zero to 10 km, in addition to basalt and
oceanic basin
• There are several major fault systems that surround the Arabian
Plate.
• The northwest boundary of the Arabian Plate is the left-lateral
Dead Sea Fault Zone.
• The southeast boundary of the Arabian Plate is the Owen
Fracture Zone (OFZ) in the northwestern Indian Ocean.
• The western boundary of the Arabian Plate is the Red Sea Rift
and Sheba Ridge systems.
• The seismicity of few of these directly affects the seismicity of
UAE.
• The eastern boundry of the Arabian Plate is the Zagros Fold &
Thrust Belt and Makran Subduction Zone which are the only
two fault systems that have direct effect on UAE seismicity.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Tectonics of UAE
Eurasian
Plate
Turkish
Plate
Zagros
Fold Belt
Dead
Sea
Fault
Makran
Subduction
Arabian
Plate
African
Plate
Owen Fracture Zone
Red Sea
Fault
Indian
Plate
Gulf Seismic Forum 2005
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Seismicity of UAE
30.00
29.00
28.00
27.00
Iran
Bahrain
North Latitude
26.00
Qatar
Arabian/Persian Gulf
25.00
Gulf of Oman
24.00
United Arab Emirates
23.00
22.00
Sultanate of Oman
Kingdom of Saudi Arabia
21.00
20.00
50.00
51.00
52.00
53.00
54.00
55.00
56.00
57.00
East Longitude
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
58.00
59.00
60.00
Siesmic Hazard Assessment
• The eastern portion of the Arabian Peninsula (UAE,
Qatar, Bahrain, Kuwait, Northern Oman) were
excluded from previous SHA studies
• A seismic hazard assessment was conducted for UAE
and its vicinity
• The probabilistic approach, that takes into account
the uncertainties in the level of earthquake magnitude,
its hypocentral location, its recurrence relation and its
attenuation relation is used
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Seismic zoning map of UAE and its vicinity for
50 years period with 10% probability of being
exceeded
30.00
29.00
Zone 3
28.00
Zone 2B
27.00
Bahrain
Zone 2A
North Latitude
26.00
Iran
Arabian/Persian Gulf
25.00
Qatar
Zone 1
Gulf of Oman
24.00
United Arab Emirates
23.00
Zone 0
22.00
21.00
20.00
50.00
Sultanate of Oman
Kingdom of Saudi Arabia
51.00
52.00
53.00
54.00
55.00
56.00
57.00
East Longitude
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
58.00
59.00
60.00
Seismic Zone Factor (Z)
• Large parts of UAE, specifically Southern
UAE, lies within Zone 0 Greater Abu
Dhabi area lies within Zone 1.
• Fujaira, greater Dubai, Sharjah and
Ajman area lies within Zone 2A.
• No part of UAE lies within Zone 2B or
Zone 3.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Factors affecting Dynamic
Response of buildings
• To design buildings to resist earthquake forces, several
factors must be considered. Such factors can be divided
into the following five categories:
• seismological factors such as seismic zone on which
the structure is to be constructed
• geotechnical factors such as soil type, soil profile, soil
dynamic properties and its liquefaction potential
• structural factors such as lateral force resisting
systems and dynamic properties of the buildings
• architectural factors such as building shape and form
• social factors such as building occupancy importance.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Analysis Methods
• To include the earthquake ground motion effect,
buildings can be analyzed using different static
and dynamic methods. Such methods include:
• Equivalent static method
• Response spectrum method
• Time history method
• Push-over method.
• For low and medium rise regular buildings in low
and moderate seismic activity zones, the
equivalent static method has been adopted
predominately by almost all building codes. The
equivalent static method formula is very much a
function of similar factors.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Equivalent Static Method
• The most widely used equivalent static method formula is that
of the Uniform Building Code (UBC-94) adopted from SEAOC.
This formula is the basis of most formulas found in other codes
and it will be adopted here.
• The equivalent static method calculates the lateral seismic base
shear which is a function of many factors.
• The base shear in a buildings can be calculated using the
following formula (UBC-94):
ZIC
V 
W
Rw
where:
Z = Seismic zone factor; I = Importance factor; W = Weight of the building, total
dead load and a percentage of live load; Rw = Numerical seismic coefficient
(Response Modification Factor); C = Numerical coefficient.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Seismic Zone Factor (Z)
• The Z-value represents the maximum effective
peak acceleration (EPA) and is expressed as a
fraction of the gravitational acceleration, g. The
peak ground acceleration (PGA) are adjusted
to give the effective peak acceleration EPA.
The results are listed below
Zone Number
PGA ( g)
Z
0
Less than 0.05
0.05
1
0.05 - 0.1
0.08
2A
0.1 - 0.20
0.16
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Spectral Acceleration Coefficient (C)
• This coefficient is to account for the spectral amplification of ground
motion based on structure fundamental period (T) and site response
factor (S).
C 
1.25S
T
2
3
The empirical formula for calculating fundamental period of vibration of
buildings (in seconds) according to (UBC-94) is given by:
T  Ct (hn )
3
4
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Other Factors I and Rw
• The importance factor, I, is determined based on the
building importance and is used to provide for more
conservative design for important facilities. The
importance factor ranges from 1.0 for single family
dwellings to 1.5 for building needed immediately after
earthquake such hospitals, power stations and the like.
• The response modification factor, Rw, is introduced to
account for the reduction in structural response caused
by damping of the structure and its inelastic response.
The response modification factor ranges from 5 for
masonry bearing wall system to 12 for dual systems with
special-moment-resisting frame.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Types of Building in UAE
• Concrete buildings are the dominant types of
structural systems in UAE.
• Modern single family residential buildings are
predominately two story reinforced concrete buildings
with a substantial set back in their third story.
• Old houses are one story reinforced concrete or
masonry structures.
• Industrial and commercial buildings range from three
stories to 30 stories with the majority in the range of
five to ten stories.
• There are few steel structures which are mainly
industrial hangers and warehouses.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Types of Building in UAE
• Floor systems used on constructing buildings in
UAE include slabs with beams, flat plate, hollow
block slabs and occasionally waffle slabs and they
can be modeled as rigid diaphragms.
• Residential buildings are characterized by vertical
geometric irregularities, mass irregularities and
plan structural irregularities.
• Most modern reinforced concrete buildings can be
classified as ordinary moment resisting frames
(OMRF) with fixed bases.
• The commercial buildings usually have mezzanine
wooden floors that can be modeled as flexible
diaphragms and shear walls that classify them as
dual systems.
Gulf Seismic Forum 2005
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Types of Building in UAE
Single Family villa
Apartment Building
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Commercial Building
Near-Field vs Far-Field
Earthquakes
• Near-Field Earthquake
– Characterized by:
• Large amplitudes
• Large frequency
• High velocity pulses
• Far-Field Earthquakes
– Characterized by:
• Small amplitudes
• Small frequency
• More consistent movements
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Acceleration Time History for Dibba
Earthquake, October 21, 2004
0.01
0.008
0.006
displacement
0.004
0.002
0
-0.002
-0.004
-0.006
-0.008
-0.01
0
1
2
3
4
East-West Direction
5
time
6
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
7
8
9
10
Acceleration Time History for Dibba
Earthquake, October 21, 2004
0.01
0.008
0.006
displacement
0.004
0.002
0
-0.002
-0.004
-0.006
-0.008
-0.01
0
1
2
3
4
5
time
6
North-South Direction
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
7
8
9
10
Acceleration Time History for Dibba
Earthquake, October 21, 2004
0.01
0.008
0.006
displacement
0.004
0.002
0
-0.002
-0.004
-0.006
-0.008
-0.01
0
1
2
3
4
5
time
6
7
Vertical Direction
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
8
9
10
Acceleration Time History Recorded at
AUS Station in Masafi, December 2002
0.04
0.03
Acceleration (g)
0.02
0.01
0
-0.01
-0.02
-0.03
-0.04
0
1
2
3
4
Time (s)
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
5
6
7
Acceleration Response Spectra (AUS
Station in Masafi, December 2002)
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Conclusions and Future Work
•
•
•
•
•
•
•
•
•
•
•
Three major elements of an earthquake design code, mainly seismic zoning,
dynamic characteristics of common types of buildings and design
response spectra were addressed in details and some recommendations were
made. However, there are several factors that need to be specialized for UAE.
In order to do so the following miles stones need to be achieved
Evaluation of relationship between buildings types, their width, their height and
their fundamental period of vibration (T).
Determination of local site effect (S) and soil parameters for the common
types of soils in UAE for amplification or attenuation of ground motion.
Development of design response spectra for areas of critical structures.
Evaluation of response modification factor (Rw) for buildings.
Evaluation of importance factors for buildings (I), elements, components and
equipments.
Development of attenuation relationships for UAE to fine tune the seismic
hazard map developed based on Zagros attenuation relation.
Study of the liquefaction potential of the different types of soils of UAE.
Installation of strong motion recorders (Seismometers) to record strong
ground motion in different parts of the country and in major installations.
Instrumentation of critical and historical buildings and monitoring of their
response.
Study earthquake codes of surrounding countries.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Acknowledgment
The support for the research presented in
this paper had been provided by the
American University of Sharjah, Faculty
Research Grant. Strong motion records are
recorded by AUS Earthquake
Observatory. This support is gratefully
acknowledged. The views and conclusions
are those of the author and should not be
taken as those of the sponsor.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Thank You
EARTHQUAKE RESISTANT
DESIGN CODES: BACKGROUND
•
•
•
•
•
The objectives of an earthquake resistant design code in general is to
promote and protect the health, life and the economic well-being of the
society in the event of severe and moderate earthquakes
Codes usually specify minimum standards for construction material,
minimum strength for structural elements to prevent failure and maximum
deformations or displacements (serviceability) to prevent excessive
deflection, vibration and cracking.
Specification of structural detailing is usually given to ensure the desired
ductile behavior of structural elements.
The code intention is to provide minimum probability of failure and largest
probability of serviceability.
It is observed that engineered buildings are unlikely to experience structural
damage or complete failure or collapse as the result of the effects of dead,
live, or wind loads. However, in the event of severe earthquakes buildings
are likely to behave in-elastically and the ultimate objective of the
earthquake resistant design code is to prevent collapse of buildings while
tolerating reasonable amount of structural damage.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
EARTHQUAKE RESISTANT
DESIGN CODES: BACKGROUND
•
•
•
•
•
Almost all developed codes follow one the following pioneering code which
are based on similar concept.
The pioneering code is the Uniform Building Code that is greatly
influenced by the Structural Engineering Association of California
(SEAOC) recommendations.
These recommendations have been adopted and embraced by many code
developing agencies and organizations such as the National Earthquake
Hazard Reduction Program (NEHRP), and later the International Building
Code (ICC2000).
These codes had influenced many codes around the world. Other codes
that have influenced are the Building Standard Law of Japan;
Eurocode7and New Zealand Building Standard Law.
The above mentioned codes are predominately prescriptive codes which
specify minimum strength and stiffness for structural members. There are
new emerging Performance-Based Design (PBD) codes that have
different philosophy than that of the prescriptive ones. Performance-based
design codes permit the designer to meet certain standard performance
objectives, independent of meeting the prescriptive strength and stiffness
criteria. In other words quantifiable levels of damage for specified levels of
hazard are permitted.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Earthquake Resistant Design
Provisions
• To design buildings to resist earthquake forces, several
factors must be considered. Such factors can be divided
into the following five categories:
• seismological factors such as seismic zone on which
the structure is to be constructed
• geotechnical factors such as soil type, soil profile, soil
dynamic properties and its liquefaction potential
• structural factors such as lateral force resisting
systems and dynamic properties of the buildings
• architectural factors such as building shape and form
• social factors such as building occupancy importance.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Analysis Methods
• To include the earthquake ground motion effect,
buildings can be analyzed using different static
and dynamic methods. Such methods include:
• Equivalent static method
• Response spectrum method
• Time history method
• Push-over method.
• For low and medium rise regular buildings in low
and moderate seismic activity zones, the
equivalent static method has been adopted
predominately by almost all building codes. The
equivalent static method formula is very much a
function of similar factors.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Equivalent Static Method
• The most widely used equivalent static method
formula is that of the Uniform Building Code
(UBC-94) adopted from SEAOC. This formula is
the basis of most formulas found in other codes
and it will be adopted here. The equivalent static
method calculates the lateral seismic base shear
which is a function of the factors mentioned
above. The base shear in a building can be
calculated using the following formula (UBC-94):
•
ZIC
V 
Rw
W
where:
Z = Seismic zone factor; I = Importance factor; W = Weight of the building, total
dead load and a percentage of live load; Rw = Numerical seismic coefficient
(Response Modification Factor); C = Numerical coefficient determined.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Siesmic Hazard Assessment
• Seismic hazard zoning studies were conducted for
different countries of the Arabian Peninsula
• The eastern portion of the Arabian Peninsula (UAE,
Qatar, Bahrain, Kuwait, Northern Oman) were
excluded from previous SHA studies
• Some extrapolated result shows hazard levels of
almost 0.5g at the northern most part of the UAE. This
result is very high and unrealistic.
• This study is intended to include UAE and its
surrounding areas and improves on previous
extrapolated SHA result.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Seismic hazard assessment
• There are two prevalent methods for seismic
hazard analysis; the deterministic approach
and the probabilistic approach
• The probabilistic approach, used in this
investigation, takes into account the
uncertainties in the level of magnitude of
earthquake, its hypocentral location, its
recurrence relation and its attenuation relation
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Steps of the Probabilistic
Seismic
Hazard
The steps for seismic hazard assessment can be
(1)
(2)
(3)
(4)
(5)
(6)
summarized as follows:
Modeling of seismic source regions;
Evaluation of recurrence relation, i.e., frequencymagnitude relation;
Evaluation of attenuation laws for intensity or peak
ground acceleration;
Evaluation of activity rate for earthquake-probability of
occurrence;
Evaluation of basic parameters such as lower and upper
bound for earthquake magnitude and distribution of
seismic events and
Evaluation of local site effects such as soil type,
geotechnical characteristics of sediments, topographic
effects, etc.
Gulf Seismic Forum 2005
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Modeling of seismic source
regions
The seismic source regions are:
• Source Region I: Main Zagros Thrust Region.
• Source Region II: North East Arabian Gulf Region.
• Source Region III: Northern Emirates Region
• Source Region IV: Lut Region
• Source Region V: Central Iran Region.
• Source Region VI: Makran Region.
• Source Region VII: South East Arabian Gulf
Region
Gulf Seismic Forum 2005
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Seismic source regions of
UAE and its surrounding
(for M≥4 from 1964-2002 and for M≥6 from 1900-1964)
30.00
29.00
Region V
Region I
Region II
28.00
Region IV
27.00
North Latitude
26.00
25.00
Bahrai
n
Iran
Region III
Qata
Arabian/Persian Gulf
r
Region VII
Region VI
Gulf of Oman
24.00
United Arab Emirates
23.00
22.00
Sultanate of Oman
Kingdom of Saudi Arabia
21.00
20.00
50.00
51.00
52.00
53.00
54.00
55.00
56.00
57.00
East Longitude
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
58.00
59.00
60.00
Recurrence and Attenuation
Relations
• Gutenberg and Richter had devised this
logarithmic relationship (G-R formula) for
seismic hazard analysis
log N  a  bM
• An attenuation relation that resulted from
calibration and adjustment of constants to reflect
the region characteristics such as transmission
path, soil type, source, etc., developed by IIEES
[Zare, 2002] is used in the current study. The
general form of the attenuation equation is in the
following form:
log a  C1 M  C2 R  log R  ci S i  ( ) P
Gulf Seismic Forum 2005
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Seismic Hazard Parameters
Source Region
No.
Total No. of
Events
(N)
Minimum
Magnitude
Maximum
Magnitude
Mw
Mw
b-Values
a-Values
I
866
4.0
7.0
1.22
10.17
II
106
4.0
6.0
0.94
6.99
III
30
4.0
6.0
0.70
5.22
IV
369
4.0
6.8
1.11
9.01
V
140
4.0
7.2
0.89
7.34
VI
6
4.0
6.7
0.35
2.74
VII
29
4.0
7.5
0.57
4.88
Gulf Seismic Forum 2005
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Seismic Hazard Results
• Seismic Hazard Analysis for
three time spans has been
conducted
• Mainly, 50, 100 and 200 years
• Seismic zone map for 475 years
return period is generated
Gulf Seismic Forum 2005
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PGA (
) for 50 years
time span
cm / sec 2
30.00
29.00
28.00
Iran
27.00
Bahrain
North Latitude
26.00
25.00
Qatar
Arabian/Persian Gulf
Gulf of Oman
24.00
United Arab Emirates
23.00
22.00
21.00
20.00
50.00
Kingdom of Saudi Arabia
51.00
52.00
53.00
54.00
Sultanate of Oman
55.00
56.00
57.00
58.00
East Longitude
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
59.00
60.00
PGA ( cm / sec ) for 100 years
time span
2
30.00
29.00
28.00
Iran
27.00
Bahrain
North Latitude
26.00
25.00
Qatar
Arabian/Persian Gulf
Gulf of Oman
24.00
United Arab Emirates
23.00
22.00
Sultanate of Oman
Kingdom of Saudi Arabia
21.00
20.00
50.00
51.00
52.00
53.00
54.00
55.00
56.00
57.00
58.00
East Longitude
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
59.00
60.00
PGA ( cm / sec ) for 200 years
time span
2
30.00
29.00
28.00
27.00
Iran
Bahrain
North Latitude
26.00
25.00
Qatar
Arabian/Persian Gulf
Gulf of Oman
24.00
United Arab Emirates
23.00
22.00
21.00
20.00
50.00
Kingdom of Saudi Arabia
51.00
52.00
53.00
Sultanate of Oman
54.00
55.00
56.00
57.00
East Longitude
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
58.00
59.00
60.00
Summary of PGA (in g) with a
10% probability of being
exceeded in time span
Regions
Source Name
50 Years
100 Years
200 Years
I
Main Zagros Thrust Region
0.30
0.40
0.51
II
North East Arabian Gulf Region
0.24
0.32
0.41
III
Northern Emirates Region
0.22
0.30
0.38
IV
Lut Region
0.26
0.34
0.45
V
Central Iran Region
0.25
0.33
0.43
VI
Makran Region
0.19
0.26
0.34
VII
South East Arabian Gulf Region
0.16
0.22
0.30
Gulf Seismic Forum 2005
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Seismic zoning map of UAE and its vicinity for
50 years period with 10% probability of being
exceeded
30.00
29.00
Zone 3
28.00
Zone 2B
27.00
Bahrain
Zone 2A
North Latitude
26.00
Iran
Arabian/Persian Gulf
25.00
Qatar
Zone 1
Gulf of Oman
24.00
United Arab Emirates
23.00
Zone 0
22.00
21.00
20.00
50.00
Sultanate of Oman
Kingdom of Saudi Arabia
51.00
52.00
53.00
54.00
55.00
56.00
57.00
East Longitude
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
58.00
59.00
60.00
Seismic Zone factor (Z)
• The Z-value represents the maximum effective peak acceleration
(EPA) and is expressed as a fraction of the gravitational
acceleration, g. The peak ground acceleration (PGA) in Table 1
need to be adjusted to give the effective peak acceleration EPA. The
results are listed below
PGA ( g)
Z
0
Less than 0.05
0.05
1
0.05 - 0.1
0.08
2A
0.1 - 0.20
0.16
Zone Number
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Seismic Zone Factor (Z)
Large parts of UAE, specifically
Southern UAE, lies within Zone Zero
Greater Abu Dhabi area lies within Zone
1. Fujaira, greater Dubai, Sharjah and
Ajman area lies within Zone 2A. No part
of UAE lies within Zone 2B or Zone 3.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Spectral Acceleration Coefficient (C)
• This coefficient is to account for the spectral amplification of ground
motion based on structure fundamental period (T) and site response
factor (S).
C 
1.25S
T
2
3
The empirical formula for calculating fundamental period of vibration of
buildings (in seconds) according to (UBC-94) is given by:
T  Ct (hn )
3
4
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Other Factors I and Rw
• The importance factor, I, is determined based on the
building importance and is used to provide for more
conservative design for important facilities. The
importance factor ranges from 1.0 for single family
dwellings to 1.5 for building needed immediately after
earthquake such hospitals, power stations and the like.
• The response modification factor, Rw, is introduced to
account for the reduction in structural response caused
by damping of the structure and its inelastic response.
The response modification factor ranges from 5 for
masonry bearing wall system to 12 for dual systems with
special-moment-resisting frame.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Acceleration Time History Recorded at
AUS Station in Masafi, December 2002
0.04
0.03
Acceleration (g)
0.02
0.01
0
-0.01
-0.02
-0.03
-0.04
0
1
2
3
4
Time (s)
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
5
6
7
Acceleration Response Spectra (AUS
Station in Masafi, December 2002)
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Conclusions and Future Work
•
•
•
•
•
•
•
•
•
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Three major elements of an earthquake design code, mainly seismic zoning,
dynamic characteristics of common types of buildings and design
response spectra were addressed in details and some recommendations were
made. However, there are several factors that need to be specialized for UAE.
In order to do so the following miles stones need to be achieved
Evaluation of relationship between buildings types, their width, their height and
their fundamental period of vibration (T).
Determination of local site effect (S) and soil parameters for the common
types of soils in UAE for amplification or attenuation of ground motion.
Development of design response spectra for areas of critical structures.
Evaluation of response modification factor (Rw) for buildings.
Evaluation of importance factors for buildings (I), elements, components and
equipments.
Development of attenuation relationships for UAE to fine tune the seismic
hazard map developed based on Zagros attenuation relation.
Study of the liquefaction potential of the different types of soils of UAE.
Installation of strong motion recorders (Seismometers) to record strong
ground motion in different parts of the country and in major installations.
Instrumentation of critical and historical buildings and monitoring of their
response.
Study earthquake codes of surrounding countries.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Acknowledgment
The support for the research presented in
this paper had been provided by the
American University of Sharjah, Faculty
Research Grant. The support is gratefully
acknowledged. The views and conclusions
are those of the author and should not be
taken as those of the sponsor.
Gulf Seismic Forum 2005
February 20-23, 2005, Al-Ain, UAE
Thank You
• ATC-19: This report , Structural Response Modification
Factors, was funded by NSF and NCEER. The report
addresses structural response modification factors (R
factors), which are used to divide seismic forces that
would be associated with elastic response to obtain
design force levels. Available through the ATC office.
(Published 1995, 70 pages)
• Abstract: The report documents the basis for current R
values; how R factors are used for seismic design in
other countries: a rational means for decomposing R into
key components, a framework (and methods) for
evaluating the key components of R, and the research
necessary to improve the reliability of engineered
construction designed using R factors.
Earthquake catalogue of UAE
• There are several catalogs available for the region
of interest. These mainly include: The National
Earthquake Information Center (NEIC),
International Seismological Center (ISC),
International Institute of Earthquake
Engineering and Seismology (IIEES), British
Geological Survey (BGS), National Oceanic
and Atmospheric Administration (NOAA) and
others
• The IIEES catalog (Farahbod and Arkhani, 2002)
is adopted and supplemented with additional
events covering the region under study
Conclusion
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The significant results of this investigation are:
review of tectonics and seismotectonics of the studied area
generation of seismic zone map that can be used, however with caution,
as a guide for determining the design earthquake and Z factor.
Generation of the C factor which is a function of T and S
Limitations are:
The hazard assessment is done for an ideal bed-rock condition,
therefore care should be taken when using the results for sites with
special local conditions. In such cases, evaluation of local site effects
should be considered for microzonation of mega cities (S factor).
The attenuation relation used in this investigation is for Zagros fold zone.
Attenuation relations for the region should be developed when sufficient
strong motion data become available.
The I, Rw, and C factors need more work