PowerPoint Presentation
EARTHQUAKE RISK MANAGEMENT AND EARTHQUAKE RESISTANT DESIGN1Dr.
Ajay Sharma, Associate ProfessorB.E. (Hons.), M.E. (Structural
Engg.), Ph.D. IIT Bombay(Earthquake Engg.)Department of Structural
Engineering,MBM Engineering College JodhpurSeminar on Earthquake
Risk Management PWD Dungarpur Rajasthan2
World Earthquake Fault Lines
www.forceborne.com/FBW/Tech/fault_line_chart.htm3
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Earthquakes6
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What do Structural Engineers do?Structural engineering's combine
their knowledgeof science and design making as they constructbetter
framework for buildings and other structuresto safely resist
natural and made-made forces. They are involved in physicaltesting,
mathematical modeling, computer simulation all of which support
decisions that Aid in the creation and maintenance of safe and
economical structures.http://www.seaint.org
/http://cee-ux49.cee.uiuc.edu/strweb/home.htmlwww.earthscience.org/.../geopro/seismic/seismic.html
9What is Earthquake Engineering?Earthquake engineers are
concerned with creating earthquakes resistant designs and
construction techniques to build of all kinds of bridges, roads and
buildings. Earthquake engineers are faced with many uncertainties
and must be smart in their decisions in developing safe solutions
to challenging problems. They rely on state-of-the-art technology,
materials science, laboratory testing and field monitoring.
www.sciencedaily.com 10
http://www.berkeley.edu/news/berkeleyan/2006/01/18_resumption.shtmlNorthridge
Earthquake Southern California 199411Kobe Earthquake Japan 19956.9
MagnitudeHomes and building construction was older built with heavy
tile roofs that collapsed
http://www.seismo.unr.edu/ftp/pub/louie/class/100/effects-kobe.html12Another
anomaly was the large number of about 20-year-old high rise
buildings that collapsed at the fifth floor. The older version of
the code they were built under allowed a weaker superstructure
beginning at the fifth floor.
http://www.seismo.unr.edu/ftp/pub/louie/class/100/effects-kobe.html13Behind
this completely collapsed wood-frame house is a house of reinforced
concrete that suffered no structural damage. The number of wood
versus masonry buildings that collapsed in Kobe astonished most
observers, as wood-frame structures are usually thought to be much
better at resisting shear forces. Possibly the concrete house was
better-designed and stronger even for its greater weight. The
proportionally heavier tile roofs on wooden houses also might have
been a factor.
http://www.seismo.unr.edu/ftp/pub/louie/class/100/effects-kobe.html14
http://www.niksula.hut.fi/~haa/kobe.html15
http://www.city.kobe.jp/cityoffice/15/020/quake/disaster/d-index_e.html16Mexico
City Earthquake, 19858.1 MagnitudePoorly constructed buildings
caused thousands of deaths
http://www.johnmartin.com/earthquakes/eqshow/647003_06.htm17
Damage to the Intercontinental Hotel during Mexico City's 1985
earthquake was severe even though the building was relatively new
http://www.calstatela.edu/dept/geology/G351.htm18Northridge
Earthquake, 1994 Southern California, USA6.7 Magnitude most houses
were wooden and did not collapse
www.survival1.com/ 19Problems for Building Structures when
Seismic Waves pass For tall buildings the top may sway in the
opposite direction as the base
Buildings in close proximity with one another may collide do to
differing phase motions.
Changing types of wave motion cause damage.
Buildings with different resonant frequencies will be affected
differently by passing seismic waves depending on the wave
frequency.
http://www.mines.utah.edu/~schuster/gg103/res/resonance.html20
http://www.scarborough.k12.me.us/wis/teachers/dtewhey/webquest/nature/earthquake_images.htm21Loma
Prieta Earthquake, 1989San Francisco Bay, California7.1
magnitudeMany homes were damaged because of old construction-
unreinforced bricks and mortarMany building and homes were built on
were unconsolidated flood plain sedimentary land (In contrast,
nearby sections of the city experienced only minor damage. These
areas contain sturdy wood frame houses built on relatively stable
marine terraces.)22
As the second story of this building collapsed, its facade fell
into the street, knocking down the tree which in turn damaged the
car. This building in downtown was one of the heavily damaged
buildings situated on the unconsolidated flood plain sediments of
the San Lorenzo River.
http://www.es.ucsc.edu/~es10/fieldtripEarthQ/Damage2.html23
An automobile lies crushed under the third story of this
apartment building in the Marina District. The ground levels are no
longer visible because of structural failure and sinking due to
liquefaction http://pubs.usgs.gov/dds/dds-29/24
Collapsed brickwork from a corner apartment building, Marina
District. http://pubs.usgs.gov/dds/dds-29/25Oakland Support
failure
http://pubs.usgs.gov/dds/dds-29/26
http://pubs.usgs.gov/dds/dds-29/27
Oakland Bridge failurehttp://pubs.usgs.gov/dds/dds-29/28
http://pubs.usgs.gov/dds/dds-29/29
http://pubs.usgs.gov/dds/dds-29/3031Bhuj Earthquake, 2001Gujrat,
India7.7 magnitude
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38WHAT A EARTHQUAKE CAN DO TO OUR ASSETS
Damage of buildings(Photos from Hokkaido Journal) Earthquake is
sudden shaking and vibration at the surface of the earth resulting
from underground movement along a fault plane of from volcanic
activity a disturbance that is extremely disruptive. 39
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Damage of Oil Tank(Photos from Hokkaido Journal)41
Damage of roads(Photos from Hokkaido Journal)42
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Damage of Lifeline structuresFirst way to design Traditionally
Seismic Resistant (e.g., adding structural components to resist
horizontal Load like shear wall, braced frames etc., shape of plan
etc.) Sufficiently strong, stiff to withstand inelastic
deformations, Motif is to have inherent strength to Dissipate
seismic energy up to certain level of Acceptable deformation and
damage.DisadvantagesLarge interstory driftLocalized damages to
structural components and secondary systemsStrengthening further
attracts more earthquake forces
44SEISMIC RESISTANT DESIGN45
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Indias Vulnerability to Disasters57% land is vulnerable to
earthquakes. Of these, 12% is vulnerable to severe earthquakes.68%
land is vulnerable to drought.12% land is vulnerable to floods.8%
land is vulnerable to cyclones.Apart from natural disasters, some
cities in India are also vulnerable to chemical and industrial
disasters and man-made disasters.
Seismic Activity in India 180 AD - 2004
Distribution of epicenters of earthquakes greater than magnitude
5.0 for the period 1976-2000, South East Asia and Indian Ocean
Areas of ConcernActivating an Early Warning System network and
its close monitoringMechanisms for integrating the scientific,
technological and administrative agencies for effective disaster
managementTerrestrial communication links which collapse in the
event of a rapid onset disasterVulnerability of critical
infrastructures (power supply, communication, water supply,
transport, etc.) to disaster eventsAreas of ConcernFunding :
Primacy of relief as disaster response.Preparedness and Mitigation
very often ignored.Lack of integrated efforts to collect and
compile data, information and local knowledge on disaster history
and traditional response patterns.Need for standardised efforts in
compiling and interpreting geo-spatial data, satellite imagery and
early warning signals.Weak areas continue to be forecasting,
modelling, risk prediction, simulation and scenario analysis,
etc.
Areas of ConcernAbsence of a national level, state level, and
district level directory of experts and inventory of
resources.Absence of a National Disaster Management Plan, and State
level and district level disaster management plans.Sustainability
of effortsEffective Inter Agency Co-ordination and Standard
Operating Procedures for stakeholder groups, especially critical
first responder agencies.Emergency medicine, critical care
medicine, triage, first aidNodal Agencies for Disaster
ManagementFloods : Ministry of Water Resources, CWCCyclones :
Indian Meteorological DepartmentEarthquakes : Indian Meteorological
DepartmentEpidemics : Ministry of Health and Family WelfareAvian
Flu: Ministry of Health, Ministry of Environment, Ministry of
Agriculture and Animal HusbandryChemical Disasters : Ministry of
Environment and ForestsIndustrial Disasters : Ministry of
LabourRail Accidents : Ministry of RailwaysAir Accidents : Ministry
of Civil AviationFire : Ministry of Home AffairsNuclear Incidents :
Department of Atomic EnergyMine Disasters : Department of
MinesDynamics of DisastersThere is a high probability of a low
probability event happening somewhere sometime soonThe
unpredictability of disaster events and the high risk and
vulnerability profiles make it imperative to strengthen disaster
preparedness, mitigation and enforcement of guidelines, building
codes and restrictions on construction of buildings in flood-prone
areas and storm surge prone coastal areas.New Directions for
Disaster Management in IndiaThe National Disaster Management
Authority (NDMA) has been set up as the apex body for Disaster
Management in India, with the Prime Minister as its
Chairman.Disaster Management Authorities will be set up at the
State and District Levels to be headed by the Chief Ministers and
Collectors/Zilla Parishad Chairmen respectively. New Directions for
Disaster Management in IndiaA National Disaster Mitigation Fund
will be administerd by NDMA. States and districts will administer
mitigation funds.A National Disaster Response Fund will be
administerd by NDMA through the National Executive Committee.
States and Districts will administer state Disaster Response Fund
and Disaster Response Fund respectively.8 Battalions of National
Disaster Response Force (NDRF) are being trained and deployed with
CSSR and MFR equipments and tools in eight strategic locations.A
National Disaster Management Policy and National Disaster Response
Plan will also be drawn up.Lessons Learnt Be Prepared :
Preparedness and Mitigation is bound to yield more effective
returns than distributing relief after a disaster.Create a Culture
of Preparedness and Prevention.Evolve a code of conduct for all
stake-holdersFuture DirectionsEncourage and consolidate knowledge
networksMobilise and train disaster volunteers for more effective
preparedness, mitigation and response (NSS, NCC, Scouts and Guides,
NYK, Civil Defence, Homeguards)Increased capacity building leads to
faster vulnerability reduction.Learn from best practices in
disaster preparedness, mitigation and disaster responseFuture
DirectionsMobilising stakeholder participation of Self Help Groups,
Womens Groups, Youth Groups, Panchayati Raj
InstitutionsAnticipatory Governance: Simulation exercises, Mock
drills and Scenario AnalysisIndigenous knowledge systems and coping
practicesLiving with Risk: Community Based Disaster Risk
ManagementInclusive, participatory, gender sensitive, child
friendly, eco-friendly and disabled friendly disaster
managementTechnology driven but people ownedKnowledge Management:
Documentation and dissemination of good practicesPublic Private
PartnershipInvest in PreparednessInvestments in Preparedness and
Prevention (Mitigation) will yield sustainable results, rather than
spending money on relief after a disaster.Most disasters are
predictable, especially in their seasonality and the disaster-prone
areas which are vulnerable.Communities must be involved in disaster
preparedness.Best Practices
On 12 November, 1970 a major cyclone hit the coastal belt of
Bangladesh at 223 km/hr. with a storm surge of six to nine meters
height, killing an estimated 500,000 people.Due to the Cyclone
Preparedness Program, the April 1991 cyclone with wind speed of 225
km/hr. killed only 138,000 people even though the coastal
population had doubled by that time.In May 1994, in a similar
cyclone with a wind speed of 250 km/hr. only 127 people lost their
lives.In May 1997, in a cyclone with wind speed of 200 km/hr. only
111 people lost their lives.
New possibilitiesNational Urban Renewal Mission for 70 cities:
recent experience of unprecedented extreme weather conditions in a
few major metros and megacities100,000 Rural Knowledge Centres ( IT
Kiosks): Need for Spatial e-Governance for informed decision making
in disaster-prone areas: before, during and after disasters
71Second way is applying additional structural control-passive,
active or semi-active, objective is to control structural response
by either reduce the amount of energy transfer into the structure
from the ground motion or to absorb some of the earthquake energy
after it has been transmitted to the structure.SEISMIC RESISTANT
DESIGNStructural ControlPassive ControlActive controlSemiactive
ControlHybrid Control72Earthquake-Resistant StructureBuilding
designed to prevent total collapse, preserve life, and minimize
damage
http://nisee.berkeley.edu/elibrary/getpkg?id=GoddenD50-69http://www.infinityfoundation.com/mandala/t_es/t_es_agraw_quake.htm73
74Structural ControlPASSIVE CONTROLNo Power requirement, Very
reliable, dissipate energy either by structures own relative motion
within control devices or converting kinetic energy into heat. Low
maintenance, do not destabilize structureTypesBase IsolationTMDs,
TLDsMetallic Yield DampersViscous Fluid and Friction Dampers
Base-IsolationDecouple the Superstructure from Ground with or
without Flexible Mounting Period of the total System is ElongatedA
Damper- Energy Dissipating Device provided at the Base
MountingsRigid under Wind or Minor EarthquakeAdvantages of Base
Isolation-Reduced floor Acceleration and Inter-storey Drift-Less
(or no) Damage to Structural Members-Better Protection of Secondary
Systems -Prediction of Response is more Reliable and Economical
LRB, NZ, FPS, R-FBI, VFPS, VFPI, VCFPS etc. are some common type of
isolators7576Isolation BearingsElastomeric Bearings
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Lead-Rubber Bearings
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Friction Pendulum System
Friction Pendulum Bearing80 Base Isolation System DampersLead
damper
Oil damperFriction damper with Coned disc springsSteel damperThe
Concept of Base Isolation81
Fixed BaseBase IsolatedPeriodResponseSignificantly Increase the
Period of the Structure and the Damping so that the Response is
Significantly ReducedDuring a Richter 8.0 Earthquake a Seismically
Isolated Building Will Behave as if it Were Experiencing a 5.5
Earthquake
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Location: Rancho Cucamonga California.Isolator :HDREngineers:
Taylor & Gaines; Reid & Tarics.Year :1985The Washington
State Emergency Operations Center at Camp Murray is an essential
facility used for the central coordination of emergency responses
for the State of Washington. The building houses critical
communications and computer equipment. The Friction Pendulum TM
seismic isolation bearings were designed to enable the building to
withstand the maximum credible earthquake for the Seattle region.
The building is located 8 miles from the epicenter of the Magnitude
6.8 earthquake that shook the Seattle region on February 28, 2001.
The building and all its equipment and contents remained fully
operational after the earthquake.
8384
Location: Los Angeles, California.Isolator : LRBEngineers:
KPFFYear :199185
Location: Sendai, Miyako ProvienceIsolator :HDRYear :199086
The U.S. Court of Appeals is a 350,000 sq. ft. building listed
in the National Register of Historic Places. The building has an
elaborate granite exterior and interiors of marble, decorative
plaster and hardwoods. Installation of 256 Friction Pendulum TM
bearings completed in June 1994, it became the largest building in
the world to have been retrofitted with seismic isolators. .
8788
Location: 1 k.m. SW of PelabuhanBuilding : 4-Story MR
RCC.Isolator : 16 HDRManufacturer: MRPRA, UK
212 Friction Pendulum TM bearings.
89LNG storage tanksRevithoussa, AthensCapacity: 38 million
gallons (226 ft dia. x 106 ft. high)The largest and heaviest tanks
in the world to use seismic isolation90
The American River Bridge & installed friction pendulum
bearing 91I-40 Mississippi River Bridge Memphis, Tennessee
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ACTIVE CONTROL93Requires External power to operate Actuators
that supply control. Directly add the force to system, Usually
require large external power source to operate.Use responses of the
structure such as displacement, velocity and acceleration to
calculated needed forcesRequire sensors and real-time data
processing systemMore complicate than passive control force to
structures.Active mass Dampers
Hydraulic actuatorActive mass damper- Provides force by moving
the mass with suitable acceleration May activate the higher modes
of structures and make more damageSemi-active control94Required
small external power sourceUse structures movement to generate
control forceStiffness and damping can be easily changedRequired
sensors and data processor to calculate control forceDefaults to a
passive device when no power is availableExample of a semi-active
device (MR-Damper)
MR Dampers95
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Hybrid control97Combine controls system togetherPassive +
ActivePassive + Semi-ActiveSmart base-isolationReduce external
power requirementImprove reliabilityWhen loss of electric during
earthquake, hybrid control can act as a passive controlReduce
construction and maintenance costs due to active or semi-active
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Thank you
Figure 7.2 Foothill Communities Law and Justice Center,
Rancho Cucamonga,California (photo by I.D. Aiken).
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Figure 7.3 University of Southern California, University
Hospital
(Photo by P.W. Clark).
PAGE 69
Figure 7.9 Tohoku Electric Power Company, Japan (Kelly,
1997).
PAGE 74
San Francisco city hall
Figure 7.1 Demonstration building in Indonesia (1994)
Current Status
United States
22 New Buildings on Base-Isolation - Foot Hill Communities Law
and Justice Centre,
California 1985
Hayward City Hall, December 1997
18 Buildings Retrofitted Salt Lake City and Country Building,
Utah, 1989
Asian Art Museum, SF, October 2000
City Halls at San Francisco, Los Angeles
Isolation Systems
LRB, HDR, HDR+PTFE Slider, FPS, FPS+Dampers
Japan - More than 100 Buildings
Europe - 2 Buildings/Several Bridges
New Zealand - 10 Buildings (Lead Rubber Bearing)