Earthquake-resistant structures are structures designed to protect buildings to some or greater extent from earthquakes. While no structure can be entirely immune to damage from earthquakes, the goal of earthquake-resistant construction is to erect structures that fare better during seismic activity than their conventional counterparts. According to building codes, earthquake-resistant structures are intended to withstand the largest earthquake of a certain probability that is likely to occur at their location. This means the loss of life should be minimized by preventing the collapse of the buildings for rare earthquakes while the loss of the functionality should be limited for more frequent ones
2. CONTENT
ďś LOADS AND FACTORS AFFECTING BUILDING STRUCTURALLY.
ďś EARTHQUAKE DEFINITION AND CONCEPT.
ďś EARTHQUAKE PRONE AREAS IN INDIA AND ANALYSIS.
ďś WHAT ARE EARTHQUAKE RESISTANT DESIGNS.
ďś EARTHQUAKE RESISTANT TECHNIQUES.
ďś CASE STUDIES.
1. BUILDING INFORMATION AND DETAILS
2. CONSTRUCTION TYPE
3. EARTHQUAKE RESISTANT TYPE AND ANALYSIS
4. LIFE AND HOW EARTHQUAKES ARE RESISTED IF OCCURRED ANY.
4. CONCEPT
1.WHEN THE QUAKES
STRIKES THE SYSTEM
DISSIPATES ENERGY IN
THE BUILDING CORES
AND EXTERIORS.
2.THE FRAMES ARE FREE
TO ROCK UP AND DOWN
WITHIN FITTINGS FIXED
AT THEIR BASES
EARTHQUAKE RESISTANT Definition
A SUDDEN VIOLENT SHAKING OF THE GROUND ,TYPICALLY CAUSING GREAT
DESTRUCTION,AS A RESULT OF MOVEMENTS
WITHIN THE EARTHâS CRUST OR VOLCANIC ACTION.
WHAT ARE EARTHQUAKE RESISTANT BUILDING.
EARTHQUAKE RESISTANT BUILDUNG
CROSS-BRACING
SHOCK ABSORBERS
1.EARTHQUAKE âRESISTANT STRUCTURES
ARE STRUCTURES DESIGNED TO
WITHSTAND EARTHQUAKES.
2.WHILE NO STRUCTURE CAN BE ENTIRELY
IMMUNE TO DAMAGE FROM
EARTHQUAKES,THE GOAL OF
EARTHQUAKE-RESISTANT CONSTRUCTION
IS TO ERECT STRUCTURES THAT FARE
BETTER DURING SEISMIC ACTIVITY
THAN THEIR CONVENTIONAL
COUNTERPARTS.
3.ACCORDING TO BUILDING CODES,EARTHQUAKE-RESISTANT ARE TO WITHSTAND
THE LARGEST EARTHQUAKE OF ACERTAIN PROBABILITY THAT IS LIKELY OCCURAT THEIR
LOCATION.
4.THIS MEANS THE LOSS OF LIFE SHOULD BE MINIMIZED PREVENTING COLLAPSE
OF THE BUILDINGS FOR RARE EARTHQUAKES WHILE THE LOSS FUNCTIONALITY
SHOULD BE LIMITED FOR MORE FREQUENT ONES.
5. LOADS & FACTORS AFFECTING BUILDING STRUCTURALLY.
TO DESIGN BUILDINGS TO RESIST EARTHQUAKES FORCES,
SEVERAL FACTORS CAN BE DIVIDED INTO THE FOLOWING FIVE
CATEGORIES:
⢠SEISMOLIGICAL FACTORS such as seismic zone on which the
structure is to be constructed.
⢠GEOTECHNICAL FACTORS such as soil type, soil profile, soil
dynamic properties & its liquefaction potential.
⢠STRUCTURAL FACTORS such as building shape & form.
⢠SOCIAL FACTORS such as building occupancy importance.
⢠ENVIRONMENTAL FACTORS such as wind flow, snow, thermal
stresses, ground pressures, etc.
DIAGRAM DEPICTS THE LOAD FACTORS AFFECTING THE BUILDING.
LATERAL LOADS
6. ⢠INDIA LIES AT THE NORTHWESTERN END OF THE INDOAUSTRALIAN PLATE, WHICH ENCOMPASSES INDIA,
AUSTRALIA, A MAJOR PORTION OF THE INDIAN OCEAN AND OTHER SMALLER COUNTRIES. THIS PLATE IS
COLLIDING AGAINST THE HUGE EURASIAN PLATE AND GOING UNDER THE EURASIAN PLATE.
⢠THIS PROCESS OF ONE TECTONIC PLATE GETTING UNDER ANOTHER IS RESPONSIBLE FOR MAKING INDIA
A EARTHQUAKE PRONE COUNTRY.
⢠A NUMBER OF SIGNIFICANT EARTHQUAKES OCCURRED IN AND AROUND INDIA OVER THE PAST
CENTURY. SOME OF THESE OCCURRED IN POPULATED AND URBANIZED AREAS AND HENCE CAUSED
GREAT DAMAGE.
⢠THUS, A SEISMIC ZONE MAP IS REQUIRED TO IDENTIFY THESE REGIONS.
⢠THE MAJOR REASON FOR THE HIGH FREQUENCY AND INTENSITY OF THE EARTHQUAKES IS THAT THE
INDIAN PLATE IS DRIVING INTO ASIA AT A RATE OF APPROXIMATELY 47 MM/YEAR.
⢠GEOGRAPHICAL STATISTICS OF INDIA SHOW THAT ALMOST 54% OF THE LAND IS VULNERABLE TO
EARTHQUAKES.
⢠A WORLD BANK & UNITED NATIONS REPORT SHOWS ESTIMATES THAT AROUND 200 MILLION CITY
DWELLERS IN INDIA WILL BE EXPOSED TO STORMS AND EARTHQUAKES BY 2050.
⢠THE LATEST VERSION OF SEISMIC ZONING MAP OF INDIA GIVEN IN THE EARTHQUAKE RESISTANT DESIGN
CODE OF INDIA [IS 1893 (PART 1) 2002] ASSIGNS FOUR LEVELS OF SEISMICITY FOR INDIA IN TERMS OF
ZONE FACTORS. IN OTHER WORDS, THE EARTHQUAKE ZONING MAP OF INDIA DIVIDES INDIA INTO 4
SEISMIC ZONES (ZONE 2, 3, 4 AND 5) UNLIKE ITS PREVIOUS VERSION, WHICH CONSISTED OF FIVE OR SIX
ZONES FOR THE COUNTRY.
⢠ACCORDING TO THE PRESENT ZONING MAP, ZONE 5 EXPECTS THE HIGHEST LEVEL OF SEISMICITY
WHEREAS ZONE 2 IS ASSOCIATED WITH THE LOWEST LEVEL OF SEISMICITY.
SEISMIC ZONES OF INDIA
7. ⢠The MSK (Medvedev-Sponheuer-Karnik) intensity broadly associated with the various seismic zones is V I (or less), VII, VIII and
IX (and above) for Zones 2, 3, 4 and 5, respectively, corresponding to Maximum Considered Earthquake (MCE).
⢠Each zone indicates the effects of an earthquake at a particular place based on the observations of the affected areas and can
also be described using a descriptive scale like Modified Mercalli intensity scale or the MedvedevâSponheuerâ Karnik scale.
ZONE 5
⢠Zone 5 covers the areas with the highest risks zone that suffers earthquakes of
intensity MSK IX or greater. The IS code assigns zone factor of 0.36 for Zone 5.
⢠Structural designers use this factor for earthquake resistant design of
structures in Zone 5.
⢠The region of Kashmir, the western and central Himalayas, North and Middle
Bihar, the North-East Indian region and the Rann of Kutch fall in this zone.
⢠Generally, the areas having trap rock or basaltic rock are prone to earthquakes.
ZONE 4
⢠This zone is called the High Damage Risk Zone and covers areas liable to MSK VIII.
The IS code assigns zone factor of
0.24 for Zone 4.
⢠The Indo-Gangetic basin and the capital of the country (Delhi), Jammu and
Kashmir fall in Zone 4. In Maharashtra,
the Patan area (Koyananager) is also in zone no-4.
⢠In Bihar the northern part of the state like- Raksaul, Near the border of India and
Nepal, is also in zone no-4.
8. ZONE 3
⢠The Andaman and Nicobar Islands, parts of Kashmir, Western Himalayas fall
under this zone.
⢠This zone is classified as Moderate Damage Risk Zone which is liable to MSK
VII. and also 7.8.
⢠The IS code assigns zone factor of 0.16 for Zone 3.
ZONE 2
⢠This region is liable to MSK VI or less and is classified as the Low
Damage Risk Zone. The IS code assigns zone factor of 0.10 (maximum
horizontal acceleration that can be experienced by a structure in this
zone is 10% of gravitational acceleration) for Zone 2.
9. ⢠Active System ACTIVE control systems are devices
integrated with real-time processing evaluators for improved
service and safety.
⢠Passive control systems are conventional devices to resist
or absorb the energy produced during Earthquake. For
example: Viscous Dampers
Other Techniques â
⢠Avoid weak column and strong beam design
⢠Provide thick slab which will help as a rigid diaphragm
⢠Provide cross walls which will stiffen the structures
⢠Provide shear walls in a symmetrical fashion
â˘Increase in the transverse (Shear) reinforcement.
⢠Horizontal lintel band should be provided
⢠The building must be regular and symmetrical in shape
⢠Reinforcing bars should be provided at the corners and the
junctions of the walls 30
WHAT ARE EARTH QUAKE RESISTANCE BUILDINGS
EARTHQUAKE RESISTANCE TECHNIQUES
Earthquake-resistant structures are structures designed to protect
buildings from earthquakes. While no structure can be entirely immune to
damage from earthquakes, the goal of earthquake-resistant construction is
to erect structures that fare better during seismic activity than their
conventional counterparts.
10. EARTHQUAKE RESISTANCE TECHNIQUES
SHEAR WALLS
Shear walls resist lateral and gravity loads
BRACING
In construction, cross bracing is a
system utilized to reinforce
building structures in which
diagonal supports intersect. Cross
bracing can increase a building's
capability to withstand seismic
activity. Bracing is important in
earthquake resistant buildings
because it helps keep a structure
standing.
Types of bracings
BRACING
Wooden cross bracing technique adopted for low
rise structures with structural support
Cross bracing technique adopted for in
china with structural steel.
13. ďś The foundations of the building with a thickness of 9 m and a depth of
15.85m is the result of a continuous pour concrete for 24 hours for 3 days
combined with steel beams, creating a compact unit designed to move
during earthquakes.
ďś The unique structural feature of this building is tapered armor system over
which the first floor of the four-sided pyramid rises. Timber frame in X
supports both the vertical load as horizontal bracing with overhead allowing
torsional movement of the building around its vertical axis.
ďś Its structure was carefully calculated to withstand the frequent
earthquakes in the city. The Loma Prieta earthquake with a magnitude of
7.1 jolted the Bay Area. Although the 48 floors of the Pyramid were
shaken for more than a minute the building was not damaged and no one
was seriously injured.
(A network of diagonal beams at the base supports the
building against both the horizontal and vertical forces.)
TRANSAMERICA PYRAMID (SAN FRANCISCO)
14. The unique structural feature of this tapered building is the
truss system above the first floor
ďś The truss system supports both vertical and horizontal loading. The
building is carefully engineered to take large horizontal base shear forces.
Note that the nearby San Andreas and Hayward Faults are sources of
major earthquakes.
ďś The overhead X-bracing resists torsional movement of the building
about its vertical axis.
Horizontal X-bracing
15. ⢠Official Name: Burj Khalifa Bin Zayed
⢠Also Known As: Burj Dubai
⢠Built: 2004-2010
⢠Cost: $4,100,000,000
⢠Designed By: Skidmore, Owings & Merrill
⢠Structural engineer : William F. Baker
⢠Main contractor: Samsung C&T
⢠Developer: Emaar Properties
⢠Type: Skyscraper
⢠Total Stories: 206
⢠Inhabited Stories :106
⢠Elevators: 57 , speed:10m/sc
⢠Maximum Height: 2,717 Feet / 828 Meters
⢠Total area: 4,000,000 sq.m
⢠Location: No. 1, Burj Dubai Boulevard, Dubai, United Arab
LATERAL LOAD RESISTING SYSTEM : The consideration loads on the tower The towerâs lateral load
resisting system consists of high performance, reinforced concrete ductile core walls linked to the
exterior reinforced concrete columns through a series of reinforced concrete shear wall panels at the
mechanical levels. The core walls vary in thickness from 1300mm to 500mm. The core walls are
typically linked through a series of 800mm to 1100mm deep reinforced concrete link beams at every
level. These composite ductile link beams typically consist of steel shear plates, or structural steel built-
up I-shaped beams, with shear studs embedded in the concrete section. The link beam width typically
matches the adjacent core wall thickness . At the top of the center reinforced concrete core wall, a very
tall spire tops the building, making it the tallest tower in the world in all categories. The lateral load
resisting system of the spire consists of a diagonal structural steel bracing system from level 156 to the
top of the spire at approximately 750 meter above the ground. The pinnacle consists of structural steel
pipe section varying from 2100mm diameter x 60mm thick at the base to 1200mm diameter x 30mm
thick at the top (828m).
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16. Gravity Load Management : The consideration loads on
the tower: Gravity load management is also critical as it
has direct impact on the overall efficiency and performance
of the tower and it should be addressed at the early design
stage, during the development and integration of the
architectural and structural design concept. The limitations
on the wall thicknesses (500-600mm) of the center core and
the wing walls thickness (600mm) allowed, art of working
with concrete, the gravity load to flow freely into the center
corridor Spine web walls (650mm) to the hammer head
walls and nose columns for maximum resistance to lateral
loads. Core wall elevation Wing B core wall elevation Set
back level Outrigger wall
Wind Engineering Management The consideration loads on the
tower The wind engineering management of Burj Khalifa was
achieved by : Varying the building shape along the height while
continuing, without interruption, the building gravity and lateral load
resisting system. reducing the floor plan along the height, thus
effectively tapering the building profile. Using the building shapes to
introduce spoiler type of effects along the entire height of the tower,
including the pinnacle, to reduce the dynamic wind excitations.
Change the orientation of the tower in response to wind directionality,
thus stiffening the structure normal to the worst wind direction.
Importance of wind loads Building height Relationship between
importance of wind and height
Earthquake Analysis : The consideration loads on
the tower: Dubai outside the scope of the seismic
activity . Liquefaction analysis of Burj Khalifa soil
showed that it is not a problem Burj Khalifa is
located in Dubai, which is a UBC97 Zone 2a seismic
region (with a seismic zone factor Z = 0.15 and soil
profile Sc). Thus Earthquake loads did not govern
the concrete tower design (wind loads govern) but it
does govern the design of the steel spire above the
concrete tower. How ever, Burj Khalifa resisted
earthquake of M5.8 magnitude that occurred in
southern Iran on July 20, 2010. While the
magnitude of this earthquake was diminished when
it reached Dubai and was relatively small (less than
1milli- g at BK site),
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17. ⢠ARCHITECT â C.Y.LEE & PARTNERS
⢠ADDRESS â TAIPEI CITY ,TAIWAN.
⢠CONST. MATERIAL â STEEL,IN SITU CONCRETE AND
GLASS
⢠YEAR STARTED â JUNE 1998 (MALL ALREADY OPEN)
⢠DATE COMPLETED â DEC 2004
⢠TOTAL HEIGHT â 508M
⢠NO. OF FLOORS â 101
⢠PLAN AREA â 50M X 50M
⢠COST â $ 700 MILLION
⢠BUILDING USE â OFFICE COMPLEX + MALL
TAIPEI 101 ⢠STRUCTURAL FACADE: TAIPEI 101âS CHARACTERISTIC BLUE-
GREENGLASS CURTAIN WALLS ARE DOUBLE PANED AND GLAZED,
OFFER HEAT AND UVPROTECTION SUFFICIENT TO BLOCKEXTERNAL
HEAT BY 50 PERCENT, AND CAN SUSTAIN IMPACTS OF 7 TONNES .
⢠THE FACADE SYSTEM OF GLASS AND ALUMINUM PANELS INSTALLED
INTO AN INCLINED MOMENT-RESISTING LATTICES CONTRIBUTES TO
OVERALL LATERAL RIGIDITY BY TYING BACK TO THE MEGA-COLUMNS
WITH ONE-STORY HIGH TRUSSES AND AT EVERY EIGHTH FLOOR. THIS
FACADESYSTEM IS THEREFORE ABLE TO WITHSTANDUP TO 95MM OF
SEISMIC LATERALDISPLACEMENTS WITHOUT DAMAGE.
BUILDING FRAME :
ď Materials
⢠60ksi Steel
⢠10,000 psi Concrete
ď Systems
⢠Outrigger Trusses
⢠Moment Frames
⢠Belt Trusses
ď Lateral Load Resistance
⢠Braced Moment Frames in the
buildingâs core
⢠Outrigger from core to perimeter
⢠Perimeter Moment Frames
⢠Shear walls
ď ARCHITECTURALSTYLE
⢠STRUCTURE DEPICTS A BAMBOO STALK
YOUTH
AND LONGEVITY
⢠EVERLASTING STRENGTH
ď PAGODA STYLE
⢠EIGHT PROMINENT SECTIONS
⢠CHINESE LUCKY NUMBER â8â
⢠IN CHINA, 8 IS A HOMONYM FOR
PROSPERITY
⢠EVEN NUMBER = âRHYTHM AND
SYMMETRYâ
18. CHALLENGES FACED:
TAIPEI BEING A COASTAL CITY THE PROBLEMS PRESENT ARE:
⢠WEAK SOIL CONDITIONS (THE STRUCTURES TEND TO SINK).
⢠TYPHOON WINDS (HIGH LATERAL DISPLACEMENT TENDS TO TOPPLE
STRUCTURES).
⢠LARGE POTENTIAL EARTHQUAKES (GENERATES SHEAR FORCES).
CONSTRUCTION TECHNIQUE USE FOR PREVENTING
EARTHQUAKE:
Tuned mass damper One of Taipei 101âs most famous engineering features is its
tuned mass damper, which is the secret weapon behind its disaster survival
techniques. Itâs essentially a giant pendulum, which swings in the opposite direction
of the sway of the building, preventing it from swaying too far. As you might imagine,
for a building this size, the counterweight has to be huge, too; itâs the worldâs largest,
at 5.5 meters in diameter (18 ft), and the heaviest, at 660 metric tons (730 short
tons).
But it doesnât just swing back and forth on its suspension cables; itâs hydraulically
controlled so its movements correspond precisely with the movement of the
building, rather than swinging freely.
TUNED MASS DAMPER