EQ1 INTRODUCTION TO EARTHQUAKE ENGINEERING. EQ2 Sequence Plate movement Type of faults Wave...

INTRODUCTION TO INTRODUCTION TO

EARTHQUAKE EARTHQUAKE

ENGINEERINGENGINEERING

SequenceSequence

Plate movementPlate movement

Type of faultsType of faults

Wave motionWave motion

Energy releaseEnergy release

Urban earthquake riskUrban earthquake risk

Structural performance levelStructural performance level

Evaluation approachEvaluation approach

8/108/10

Large EarthquakesLarge Earthquakes

Elastic Rebound TheoryElastic Rebound Theory

Indian PlateIndian Plate

Historical Earthquakes in the HimalayaHistorical Earthquakes in the Himalaya

Southern AsiaSouthern Asia

4-5 m slip@1 cm/yr=4-500 years

Plate Movement

Tibetan PlateauHimalayasIndian Plate

TibetIndian Plate

Tibetcritical stress

great earthquake

Tibet

4-10 m

2-20 msurface rupture 1.5 m co-seismic

subsidence

the longer the inactivity the bigger the 'quake’

FaultsFaultsThrough the study of faults and their effects, much can be learned

about the size and recurrence intervals of earthquakes. Faults

also teach us about crustal movements that have produced

mountains and changed continents. Stresses often continue to

build until they exceed the strength of the bond in that section of

crust. The rock then breaks, and an earthquake occurs,

sometimes releasing massive amounts of energy.

Faults vary in length from a few centimeters to hundreds of

kilometers across. Displacements of one side of the fault over the

other vary from fractions of a meter to many kilometers. In many

cases the displacement is not confined to a single fracture but is

distributed throughout a fault zone. Many faults do not rupture the

surface, but when the surface is broken, the fault line is visible as

a fault trace or outcrop.

Contd…

Vertical or horizontal movement may occur along a fault plane.

Sometimes both vertical and horizontal movement occur

simultaneously. Faults are named according to the type of

movement that has occurred. The term slip is used to indicate

relative displacement across the fault. When the movement along

the fault plane is generally horizontal, it is a strike-slip fault. These

are also called lateral faults. Offset streams are found along active

strike-slip faults. A transform fault is a zone of lateral movement

along which the ridges and rises have been offset and along

which the displacement suddenly stops or changes form and

direction. When the movement along the fault plane is

predominately vertical, it is a dip-slip fault. There are sub-

classifications within this category.

Contd…

FaultsFaults

A normal fault occurs when the earth above the fracture moves down in respect to the earth below the fracture. A reverse fault occurs when the rocks above the fracture move up with respect to those below. A reverse fault with an angle of less than 45 degrees is called a thrust fault. Thrust faults are generally characterized by older rocks resting on younger rocks, although in some cases younger rocks may be thrust over older rocks.

FaultsFaults

Left Lateral FaultLeft Lateral Fault

Right Lateral FaultRight Lateral Fault

Normal FaultingNormal Faulting

Normal FaultNormal Fault

Thrust FaultingThrust Faulting

Thrust FaultThrust Fault

Wave MotionWave Motion

Wave PathWave Path

Energy ReleaseEnergy Release

HAZARDSHAZARDSHAZARDSHAZARDS

ELEMENTS OF ELEMENTS OF URBAN EARTHQUAKE URBAN EARTHQUAKE RISKRISKELEMENTS OF ELEMENTS OF URBAN EARTHQUAKE URBAN EARTHQUAKE RISKRISK

EXPOSUREEXPOSUREEXPOSUREEXPOSURE

VULNERABILITYVULNERABILITYVULNERABILITYVULNERABILITY LOCATIONLOCATIONLOCATIONLOCATION

RISKRISKRISKRISK

Structural Performance LevelsStructural Performance Levels

Joe’s

GreatGreatFood!Food!

Serviceability CollapsePrevention

Joe’s


ImmediateOccupancy

Damage0% 99%

Serviceability LevelServiceability Level

Negligible structural Negligible structural and nonstructural and nonstructural damagedamage

Utilities are availableUtilities are available Facility is available Facility is available

for immediate re-use for immediate re-use Repair costs are Repair costs are

minimal to nilminimal to nil

Joe’s


Immediate Occupancy LevelImmediate Occupancy Level

Negligible structural damageNegligible structural damage

Minor nonstructural damageMinor nonstructural damage

Building is safe to occupy but Building is safe to occupy but

may not functionmay not function

Limited interruption of Limited interruption of

operationsoperations

Repair Cost < 15%Repair Cost < 15%

Joe’s


Immediate OccupancyImmediate Occupancy

Life-SafetyLife-Safety

Collapse Prevention LevelCollapse Prevention Level

Extensive structural and Extensive structural and

non-structural damagenon-structural damage

Extended loss of useExtended loss of use

Repair may not be Repair may not be

practicalpractical

Repair costs >> 30%Repair costs >> 30%

Collapse PreventionCollapse Prevention

CollapsedCollapsed

Global Response & PerformanceGlobal Response & Performance

Structural Displacement

Lo

adin

g S

eve

rity

Joe’sGreatGreatFood!Food!

Joe’s


Evaluation ApproachEvaluation Approach

0 .5 1.0 1.5 2.0 2.5

Spectral Acceleration at Period T

10-1

10-2

10-3

10-4

10-5

Annual Pro

babili

ty o

f Exce

edance

1- Select Hazard Level

2- Determine groundMotion Sa

t

3- Run Analysis

4- DetermineDrift & ComponentDemands

Lateral Displacement -

La

tera

l Fo

rce

- V

CP0

Collapse Preventionmargin = 1.0

Life Safetymargin = 1.33to 1.5

LS

Collapse margin > 1.0

ImmediateOccupancy

Joe’s

Beer!Beer!Food!Food!

Joe’s


5- Determine Performance

6- Pass or Fail Criterion evaluated on component by component basis

EQ1 INTRODUCTION TO EARTHQUAKE ENGINEERING. EQ2 Sequence Plate movement Type of faults Wave...

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Transcript of EQ1 INTRODUCTION TO EARTHQUAKE ENGINEERING. EQ2 Sequence Plate movement Type of faults Wave...