Iem Workshop Ec8 2012

8/20/2019 Iem Workshop Ec8 2012

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Seismic Design to EC8

Jack Pappin, Arup, Hong Kong

Topics

• Seismic hazard

• Site response / Liquefaction

• Design of buildings to EC8

• Foundation design to EC8

• Other ground effects


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Ground motion

Plate tectonics


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Observed seismicity

Seismic activity 1990 to 1999 within 100km of the surface: Source USGS website

Section through South America

Plate tectonics


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Earthquake mechanism

Time = 0

Time = 100 years

Time = 101 years

Slippage causing Energy release

Earthquake effects

Moderate

Intensity

Low

Intensity

High

Intensity


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MSK Intensity scale

III - Weak Felt indoors by a few people

V - Strong Buildings tremble, unstable objects overturned

VI - Sl ight damage Sl ight damage to a few br ick bui ld ings

VII - Building damage Large cracks in weak buildings, slight to r.c. building

VIII - Some destruction Partial collapse of weak buildings, a few slopes fail

IX - General damage Large cracks in r.c. buildings, liquefaction observed

X - General destruction Most brick buildings collapse, many landslides

XI - Catastrophe Most buildings collapse

XII - Landscape changes Practically all structures destroyed

IV - Largely observed Felt indoors by many people, doors and dishes rattle

II - Very weak Recorded by instruments

Intensity 7

Newcastle 1989


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Intensity 9Taiwan 1999

gnitude

Magnitude is a measure of the size (or energy release)of the earthquake.

Each unit increase in magnitude scale is about a three

times increase in ground motion for the same distance

from the event. It is also about a 30 times increase in

energy release.


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MagnitudeEnergy

Release

Step 2 - Calculation

Ground motion

Step 1 - desk study


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Step 1 - desk study

M8.5 and 7.9 Southern Sumatra Earthquakes of

12 September 2007 and M7.0 of 13 September 2007


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Seismic Hazard of Western Indonesia – April 2008

What measure should be used to

define ground motion

Intensity - measure of peak observed damage potential

Peak motions - acceleration, velocity or displacement

Ground motion


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ROCK SOIL

Ground motion

12 Sep 2007 Sumatra


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Frequency content - response spectra

What measure should be used to

define ground motion

Intensity - measure of peak observed damage potential


Ground motion

Response spectrum


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30 Sep 2009 Sumatra

30 Sep 2009 Sumatra


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Ground motion - Calculation

Key information for a seismic hazard assessment

Seismic source zones

Active faults

Areas of diffuse seismicity

Attenuation relationship

The behaviour of a measure of ground

motion as a function of the distance

from the source of energy, (EERI 1984).


Example for Peak Ground Acceleration

Distance (km)

P e a

k g r o u n

d A c c e

l e r a

t i o n

( g )

101 100 1000

1.0

0.5

0

M = 7.5

M = 6.5

M = 5.5

Magnitude

measure of the size

(or energy release)

of the earthquake.


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Example of Response Spectra from an event at10km in the Western USA

Fundamental Period (sec)

P e a

k g r o u n

d A c c e

l e r a

t i o n

( g )

10 2

1.0

0.5

0

M = 7.5

M = 5.5

M = 6.5 for Eastern USA

M = 6.5


Variability of Attenuation relationship

100

10

Distance from energy source (km)

P e a

k a c c e

l e r a

t i o n

( % g

)

1

10

6

40

100


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Ground motion - Calculation

2 basic methods to determine design ground motion

to determine the ground motion at

the site due to maximum expected

earthquakes

Deterministic

Probabilistic to determine the ground motion at

the site which has a desired annualprobability of being exceeded

For each source the maximum magnitude

that is expected is estimated.

Deterministic seismic hazard analysis

STEP 2 - distance determination

R 3R 1

R 2

Source 2

Source 1 Source 3

Site

STEP 1 - source model

M 1 M 3

M 2

R 1

STEP 3 - attenuation

M 3

M 2

M 1

Distance

STEP 4 - report

Y =

Y 3

Y 1

Y 2

R 2 R 3

Controlling

earthquake


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Probabilistic seismic hazard analysis

Source 2

Source 1 Source 3

Site

STEP 1 - source model

R

R

R

STEP 2 - rate of earthquake activity

Magnitude M

3

2

1

STEP 3 - attenuation

M = 6

Distance R

M = 7

STEP 4 - result for all M and R

Parameter value y *

7

Aerial photography

Field mappingGround investigation data

Hard copy geological maps

ArcInfo export

geological maps

Satellite imagery (IKONOS)

GIS

Maps

Hazards

Geohazard studies


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Geology & tectonics

Geomorphology

Slip rates

Observed seismicity

Seismic source zones and activity rates

Fault sources -

Geology & tectonics

Observed seismicityObserved seismicity

Areal sources -

2. Instrumental data

Complied by by several agenciese.g. ISC, USGS.

Recent data is more complete

since 1920 for M > 6

since 1963 for M > 4.5

1. plus 2. = Earthquake catalogue

Observed seismicity

1. Historical data

Based on Intensity

more recent data is more complete


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Tectonic

structure

Kuala

Lumpur

-7.5

-5.0

-2.5

0.0

2.5

5.0

7.5

10.0

95.0 97.5 100.0 102.5 105.0 107.5 110.0

Longitude

L a

t i t u d e

5 to 5.4

5.5 to 5.9

6 to 6.9

7 to 7.9

8 to 8.9

9

500km


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Subduction zone model

0

100

200

300

0 100 200 300 400 500 600 700 800

Distance (km)

D e p

t h ( k m

)

5.0 to 5.4

5.5 to 5.9

6.0 to 6.97.0 to 7.98.0 to 8.9

9

Kuala Lumpur

Activity with depth for subduction events

0 50 100 150 200

0-20

20-30

30-40

40-60

60-80

80-100

100-130

130-160

160-200

200-250

250-300

D e p t h ( k m )

number of events


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Seismic activity in Subduction

0.001

0.01

0.1

1

10

4 5 6 7 8 9

Magnitude (M)

A n n u a

l n u m

b e r o

f e v e n

t s > M

18001920

1964

Design

0.001

0.01

0.1

1

10

100

4 5 6 7 8 9

Magnitude (M)

A n n u a l n u m b e r o f e v e n t s > M

1800

1920

1964

Design

1 0 t o 4 0 k m

4 0 t o 1 0 0 k m

0.001

0.01

0.1

1

10

4 5 6 7 8 9

Magnitude (M)

A n n u a l n u m b e r

o f e v e n t s > M

1920

1964

Design

1 0 0 t o

2 0 0 k m

0.001

0.01

0.1

1

10

4 5 6 7 8 9

Magnitude (M)


1964

Design

2 0 0 t o

3 0 0 k m

Sumatra

Fault

model

-7.5

-5.0

-2.5

0.0

2.5

5.0

7.5

10.0

95.0 97.5 100.0 102.5 105.0 107.5 110.0

Longitude

L a t i t u d e

5 to 5.4

5.5 to 5.9

6 to 6.9

7 to 7.9

Series9

Series10


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Sumatra

Faultmodel

0

100

200

300

0 100 200 300 400 500 600 700 800

Distance (km)

D e p

t h ( k m

)

5.0 to 5.4

5.5 to 5.9

6.0 to 6.9

7.0 to 7.9

Kuala Lumpur

SumatraFault Area to the north

and east of the

Sumatra Fault

Subduction

zone

Sumatra fault activity rates

0.001

0.01

0.1

1

10

4 5 6 7 8 9

Magnitude (M)


1800 - 2005

1920 - 2005

1964 - 2005

17mm/yr slip

Background

Total


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93 96 99 102 105 108 111

-12

-9

-6

-3

0

3

6

9

12

Sumatra

Fault M a l a y P e n i n s u l a

52 mm/yr

(N10oE)

57 mm/yr

Seulimeum

Renun

Dikit

Semangko

Palembang

Pekan Baru

Penang

Singapore

L a

t i t u d e

( o ) Barumun

Medan

Sumani

Longitude (o)

S u m

a t r a

S u b d u c t i o n

Eurasian

Plate

Indian-AustralianPlate 60 mm/yr

(N17oE)

500 km0

S u m

a t r a

Java

Kuala Lumpur

Ground-Motion

Attenuation Relationships

for Sumatra Earthquakes

Developed by Megawati

(NTU, Singapore)

Attenuation Subduction earthquakes (Megawati 2006)

0.001

0.01

0.1

1

10

0 200 400 600 800 1000

Distance (km)

1 s e c o n d R S A ( m / s 2 )

9

8

7

6

5

Standard deviation = * 1.8


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Attenuation Sumatra Fault earthquakes (Megawati 2006)

0.001

0.01

0.1

1

10

0 200 400 600 800 1000

Distance (km )

1 s e c o n d R S A ( m / s 2 )

9

8

7

6

5

Standard deviation = * 2.6

Normal

distribution

0

0.2

0.4

0.6

0.8

1

-3 -2 -1 0 1 2 3

Standard deviations from mean

L i k e l i h o o d


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Calculated response spectra

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.01 0.1 1 10

Period (sec)

S p e c t r a l A c c e l e r a t i o n ( m / s 2 )

2% in 50 year

10% in 50 year

50% in 50 year

5% damping

1 3

6 3

1 1 3

1 6 3

2 1 3

2 6 3

3 1 3

3 6 3

4 1 3

4 6 3

5 1 3

5 6 3

6 1 3

6 6 3

7 1 3

7 6 3

8 1 3

8 6 3

9.25

8.25

7.25

6.25

5.25

0

2

4

6

8

10

% C o n t i b u t i o n t o H a z a r d

Distance (km)Magnitude (M)

2% in 50 year (0.2sec)

De-aggregation2% in 50 year

0.2 second period

1833 type event

Subduction 0 to 40km deep



Sumatra Fault

Northeast Sumatra

Sunda Plate

1 3

6 3

1 1 3

1 6 3

2 1 3

2 6 3

3 1 3

3 6 3

4 1 3

4 6 3

5 1 3

5 6 3

6 1 3

6 6 3

7 1 3

7 6 3

8 1 3

8 6 3

9.25

8.25

7.25

6.25

5.25

0

2

4

6

8

10

12

Distance (km)Magnitude (M)

2% in 50 year (1s)

1 second period

1 3

6 3

1 1 3

1 6 3

2 1 3

2 6 3

3 1 3

3 6 3

4 1 3

4 6 3

5 1 3

5 6 3

6 1 3

6 6 3

7 1 3

7 6 3

8 1 3

8 6 3

9.25

8.25

7.25

6.25

5.25

0

2

4

6

8

10

12

14

16

18

20

Distance (km)Mag

2% in 50 year (5s)5 second period


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Scenario events

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.01 0.1 1 10

Period (sec)


2% in 50 year 10% in 50 year 50% in 50 year

Subd M9.3@530 * 1.9 Subd M9.0@530 * 1.7 Subd M8.7@550 * 1

Sum Flt M8@400 * 6 Sum Flt M8@400 * 3.5 Sum Flt M8@400 * 1.5

Local M6@130 * 2.3 Local M6@210 * 2 Local M6@240 * 1

5% damping

Incorporation of uncertainty

Example of a logic tree analysis

Att enuat ion Magn itu de Maximum

model distribution magnitude

0.18


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Time histories

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.01 0.1 1 10

Period (sec)

S p e c t r a l A c c e l e r a t i o n ( m / s

2 )

2% in 50 year 10% in 50 year 50% in 50 year

2% in 50y rs - S hort 10% in 50y rs - S hort 50% in 50y rs - S hort

2% in 50y rs - Long 10% in 50y rs - Long 50% in 50y rs - Long

5% damping

Time histories

Time [sec]

4038363432302826242220181614121086420

A c c e

l e r a

t i o n

[ m / s e c

2 ]

0.3

0.25

0.2

0.15

0.1

0.05

0

-0.05

-0.1

-0.15

-0.2

-0.25

T i m e [ s e c ]

8 007 507 0 06 506 0055 05 0 045 040 035 03 002 502 001 5 01 0 05 00

A c c e

l e r a

t i o n

[ m / s e c

2 ]

0 .2

0 . 1 5

0 .1

0 . 0 5

0

- 0 . 0 5

- 0 . 1

- 0 . 1 5

- 0 . 2

T i m e [ s e c ]

80 075 070 065 060 055 050 045 040 035 030 025 020 015 010 0500

A c c e

l e r a

t i o n

[ m / s e c

2 ]

0. 2

0 . 1 5

0. 1

0 . 0 5

0

- 0 . 0 5

- 0 . 1

- 0 . 1 5

.

5

.2

15

.1

5

0

5

.1

15

.2

5

Long Period

Short Period Same scale


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2% in 50 year bedrock motion

0

1

2

3

4

5

6

7

0.01 0.1 1 10

Period (sec)


Hong Kong

Kuala Lumpur

New York (IBC2006)

5% damping


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USGS catalogue since 1972 - 0 to 50 km depth



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Section R1


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Section R2

Section R3


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Magnitude recurrence plots

0

1

2

0.01 0.1 1 10

B e d r o c k S p e c t r a l a c c e l e r a t i o n ( m / s 2 )

Structural period (s)

Semporna

Sandakan

Kota Kinabalu

Kuala Lumpur

Penang

Kuantan

Kuching

10% in the next 50 year bedrock response spectra

5% damping


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Comparison with Eurocode 8 rules (3.2.1(4))

0.15 0.4 2

Comparison with Eurocode 8 rules (for bedrock)


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0

1

2

0.01 0.1 1 10

S p e c t r a l a c c e l e r a t i o n

( m / s 2 )


Semporna

Sandakan

Kota Kinabalu

Kuala Lumpur

Penang

Kuantan

Kuching

Seismicdesign notrequired

Seismicdesign

requiredwith ductile

detailing


5% damping

Concern with seismicity near to KL


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Events observed since 2004

2.2 2.7 3.2 3.7 4.2

0.1

1

10

A n n u a l e x c e e d a n c e

r a t e

Magnitude

10% in the next 50 year bedrock response spectra

0

1

2

0.01 0.1 1 10

S p e c t r a l a c

c e l e r a t i o n

( m / s 2 )


Kuala Lumpur

KL with localevents


Seismicdesign


detailing


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Bedrock

?

Site Response

• 2 week visit two weeks after

the event

Mexico City - 1985


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Mexico City - 1985

Earthquake source

Mexico City

Epicentre

Magnitude 8.1

D

D

D


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Mexico City

5 km

Mexico City

5 km


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Television studio

Mexico City

5 km


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Recorded ground motion

Recorded ground motion


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Response spectra

Observed building damage

43%


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Notable non-damage

Lake bed

ground

conditions


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Cyclic triaxial testing of

lake bed clay

Nottingham University

Response spectra


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IBC 2000+ Classification of soil profile types

The upper 30m of the soil profile are considered

Soil Profile Shear wave SPT Undrained shear

Type velocity (m/sec) N value strength (kPa)

A - Hard rock >1,500 - -

B - Weak to medium rock 750 - 1,500 - -

C - Dense stiff soil 375 - 750 > 50 > 100

D - Medium dense firm soil 180 - 375 15 - 50 50 - 100

E - Loose soft soil < 180 < 15 < 50

F - Deep soft soils that require site specific investigations

Site Response Effects – US approach

IBC 2000+ Soil amplification factors

Site Response Effects

Approximate Peak Ground Acceleration (g)

S o

i l A m p

l i f i c a t i o

n F a c

t o r

E

D

C

B A

0

1

2

3

4

0 0.1 0.2 0.3 0.4 0.5 0.6

Short period motion (0.2 sec)

Soft soil

Hard Rock

Long period motion (1 sec)

E

D

C

B A


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Eurocode classification

IBC



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0

1

2

3

0.1 1 10

S o i l a m p l i f i c a t i o n

f a c t o r


EC8 : 10% in 50 year bedrock response spectra

Class D

Class C

Class B


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0

1

2

3

0.1 1 10

S

o i l a m p l i f i c a t i o n

f a c t o r


EC8 : 10% in 50 year bedrock respons e spectra

Class D

Class C

Class B

IBC 2000+ Soil amplification factors

Approximate Peak Ground Acceleration (g)

D

C

B

0

1

2

3

4

0 0.1 0.2 0.3 0.4 0.5 0.6

Short period motion (0.2 sec)

Soft soil

Hard Rock

Long period motion (1 sec)

D

C

B

Oasys SIREN site response analysis

Soil Surface

Bedrock

Output motion

F

= F

Input motion


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Gsec

Gmax or G0

Soil shear behaviour

G0

Gsec

Backbone

curve

log

Gsec

G0

1.0Modulus

reduction curve

G0(ij) = vs(ij)2 where G0(ij) is the elastic shear modulus

is the bulk density of soil and

vs(ij) is the shear wave velocity through soilVs(vh)

Vs(hh)

Vs(hv)

v

h1h2

Soil

triaxial

specimen

Bender

element

1

1

2 2

33

Mid-plane

pore

pressure

probe

Porous

stone

Bender

element

(vs(vh))

Base

pedestal

Bender element embedded in base platen

Bender element (vs(hv))

Bender element (vs(hh))

Bender element probe

Mid-plane pore pressure probeBender element probe

Hall-effect gauge (radial)Hall-effect gauge (axial)


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Cyclic shear strain (%)

Gsec

G0

1.0

010.0001 0.001 0.01 0.1 10

10.0001 0.001 0.01 0.1 10

D a m p

i n g

r a t i o

( % )

0

10

2030

PI =0

50

15

100

200

Variation

withstrain

Geophysical methods for G0

Up hole Down hole

G0 = VS2

Cross hole - simple Cross hole - accurate


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Down hole

seismic conetesting

Oasys SIREN is a computer programme for a non-linear model

which solves the one dimensional site response problem in the

time domain using the explicit finite difference method.

Soil Surface

Output motion

F

= F

Input motion

Bedrock

Displacement


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Site Class Definition – EC8

Class C profiles, 10% in 50-year ground mot ion, long period

0

1

2

3

4

5

6

7

0.01 0.1 1 10

Period (s)

S p e c t r a l R a t i o

CK1OR4BH3 Alex RdBH 2 Alex RdBH ARN5BH ARN1BH 1936-3BH 799-TB8BH 2111-5BH 1263-4BH 1808-6BH 91F-86BH 703-69ABH 1222-6BH 460-14BH 2122-15BH 348-31

Average

+2 Sigma

+1 Sigma

Average

-1 Sigma

-2 Sigma

Class E profiles, 10% in 50-year ground motion, long period

0

1

2

3

4

5

6

7

8

9

0.01 0.1 1 10

Period (s)

S p e c

t r a

l R a

t i o

BH 233-11BH 1982-25BH 1754-4BH 1626-25BH 1627-23BH 1144-505-1BH 24B-PP2BH 144K-5BH 2131-2BH 1493-13BH 262-D19BH 424-9DTL/20/PZS/VSTDTL/31/VSTDTL/43/PZM/VSTDTL/45/VSTM2019M2020

Average

+2 Sigma

+1 Sigma

Average

-1 Sigma

-2 Sigma

Spectral

Ratios

B

D


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Resulting Spectra

10% in 50 year - Long period

0

0.5

1

1.5

2

0.1 1 10Period (s)

S p e c t r a l A c c e l e r a t i o n ( m / s / s )

Bedrock

Site Class C

Site Class D

Site Class E

Site Class F

B

C

D

S

Displacement spectra

10% in 50 year - Long period

0.01

0.1

1

0.1 1 10Period (s)

S p e c t r a l D i s p l a c

e m e n t ( m )

Bedrock

Site Class C

Site Class D

Site Class E

Site Class F

B

C

D

S


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Design spectra

0

1

2

0.1 1 10

Structural Period (s)


Site Class B

Site Class C

Site Class D

Site Class E

Site Class F

B

C

D

S

Bedrock

Spectral ratios

0

1

2

3

4

5

0.1 1 10

S p e c t r a l R a t i o

Period T

10% in 50 year spectral ratios

Site Class B

Site Class C

Site Class D

Site Class S

0

1

2

3

0.1 1 10

S o i l a m p l i f i c a t i o n

f a c t o r


EC8 : 10% in 50 year bedrock response spectra

Class D

Class C

Class B


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Eurocode classification for KL / Penang

0

1

2

0.1 1 10

S p e c t r a l A c c e l e r a t i o n

( m / s 2 )


10% in 50 year design spectra

Site Class C

Site Class D

Site Class S

C Equation

D Equation

E Equation

C 1.6 0.4 1.1 10.4

D 2.5 0.9 1.6 4.6

S1 3.2 1.6 2.4 2.4

ag = 0.175 m/s2

0

1

2

0.01 0.1 1 10


( m / s 2 )


Semporna

Sandakan

Kota Kinabalu

Kuala Lumpur

Penang

Kuantan

Kuching


Seismicdesign


detailing


5% damping


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Comparison with IBC rules

0

1

2

0.1 1 10

S p e c

t r a l a c c e l e r a t i o n ( m / s 2 )


IBC: (2/3 2% in 50 year) response spectra

KL Rock

KL Soil C

KL Soil D

KL Soil S

seismicdesign notrequired

Seismic designrequired with no

ductility

Seismic designrequired with

ductility

Comparison with IBC rules

0

1

2

0.1 1 10


( m / s 2 )


IBC: (2/3 2% in 50 year) respo nse spectraBedrock

Kuala Lumpur

Kota Kinabalu

Semporna



ductility


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Comparison

with IBC rules

0

1

2

3

0.1 1 10

S p e c t r a

l a c c e l e r a t i o n ( m / s 2 )


IBC: (2/3 2% in 50 year) respon se spectraSoil Class D

Kuala Lu mpur

Kota Kinabalu

Semporna



ductility

Comparison with

Eurocode 8 rules (with soil)

0

1

2

0.01 0.1 1 10

B e d r o c k S p e c t r a l a c c e l e r a t i o n ( m / s 2 )


Semporna

Sandakan

Kota Kinabalu

Kuala Lumpur

Penang

Kuantan

Kuching

Group D ; S = 1.35

Semporna D

KK D

KL D


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57

0

1

2

3

0.01 0.1 1 10

S p e c t r a l a c c e l e r a t i o n ( m / s 2 )


10% in 50 year response spectraSoil Class D

Kuala Lumpur

Kota Kinabalu

Semporna

EC 8 Ductile

EC 8 Design

Comparison

with EC 8

Possible EC8 Zoning map for Malaysia


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58

0

1

2

0.01 0.1 1 10


( m / s 2 )


Semporna

Sandakan

Kota Kinabalu

Kuala Lumpur

Penang

Kuantan

Kuching


Seismicdesign


detailing


5% damping


0

1

2

0.1 1 10

S p e c t r a l A c c e

l e r a t i o n

( m / s 2 )



Site Class C

Site Class D

Site Class S

C Equation

D Equation

E Equation

C 1.6 0.4 1.1 10.4D 2.5 0.9 1.6 4.6

S1 3.2 1.6 2.4 2.4

ag = 0.175 m/s2


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59

Possible EC8 Zoning map for Malaysia

8%g6%g


60/108

60

Liquefaction

Liquefaction


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61

Liquefaction

Philippines 1989

Turkey 1999Liquefaction


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62

No Liquefaction

BUT

When you are designing the structure,

can you rely on liquefaction happening?

Turkey 1999

Liquefaction

Standard method of assessing the likelihood of liquefaction

500 10 20 30

0.2

40

0.1

0.3

0.4

0.5

Corrected SPT N value (N1) A v e r a g e p e a

k s

h e a r s

t r e s s / v e r t

i c a

l e

f f e c

t i v e s

t r e s s

Percent fines (%) 35 15


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63

Estimation of shear stress

10 0.2 0.4 0.6

15

0.8

20

10

5

0

Stress reduction factor r d

D e p

t h ( m )

25

Modify soil Densify Vibroflotation

Dynamic compaction

Displacement piling

Stabilise Grouting

Improve drainage

Liquefaction

How to overcome


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64

Vibro-replacement

Ground Improvement

• Typical methods include stone

columns, dynamic compaction,

grouting, soil cement mixing,

dewatering.

• Suitability of method must bechecked by field trials.

• For example stone columns do not

work well with a high fines content

(>15%).

Modify soi l Densi fy Vibrof lo tat ion

Dynamic compaction

Displacement piling

Stabilise Grouting

Improve drainage

Change foundation Float

Pile

Liquefaction

How to overcome


65/108

65

Liquefaction

How to overcome: Float

Liquefied soil

Shearfailure

Basement void


66/108

66

Liquefaction

How to overcome: Pile

Liquefied soilDuctile

detailing

Liquefaction - Lifelines

Loose backfillFlow of

liquefied

soil

Jet grout walls

Flotation

Stone columns

Hashash et al, 2001


67/108

67

Building Design to EC8

134

Background to Eurocodes

• Set of unified design codes bringing together structural,civil, and geotechnical disciplines

• Adopted by all 28 member states of the European Union

• Conflicting national standards withdrawn by March 2010

• Main objective is:

“the elimination of technical obstacles to trade and theharmonisation of technical specifications”

(European Committee for Standardisation)


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68

How are they Organised?

Eurocode Basis of Design

EN 1990

Eurocode1

Actions onStructures

Eurocode2

Design ofConcreteStructures

Eurocode3

Design of SteelStructures

Eurocode4

Design ofCompositeSteel andConcreteStructures

Eurocode5

Design ofTimber

Structures

Eurocode6

Design ofMasonry

Structures

Eurocode7

GeotechnicalDesign

Eurocode8

Design ofStructures forEarthquakeResistance

National Annex

Eurocode9

Design of AluminiumStructures

From Bond & Harris


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69

Eurocode 8 - Part 1: General Rules

Eurocode 8 – Parts 2 to 6


70/108

70

Eurospeak

Loads Actions

Dead LoadsPermanent Actions

ImposedLoads

Variable Actions

‘DesignValue’

CharacteristicValue

Construction Execution

140

Eurospeak• Principles: Denoted by ‘P’ after the clause number – mandatory requirements

• Application Rules: Generally recognised rules that comply with the principles and satisfytheir requirements

• Example


71/108

71

141

Eurostyle

• General, Non-prescriptive, Flexible

• “Performance Specification for Design”

Pros•Gives designer freedomto choose appropriatemethod•Economies are possible•Allows for evolving designmethods

•Can be applied to widerange of design situationsin different locations

Cons

•Can be daunting for

those with little design

experience

•Less straightforward to

use

•Could be ambiguous

142

Design Philosophy

• Limit State Design is adopted in all Eurocodes

• Defined in EN 1990

• Fundamentally, all ULS and SLS shall be considered andverified where applicable

• Verification of Limit States should be carried out by eitherthe partial factor, or probabilistic methods

• Important Considerations:- Design Working Life

- Design Situations, e.g. normal use, transient, accidental, seismic


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72

Limit State Design Philosophy

d d R E

d M k repF d a X F E E ;;

d M k repF d a X F R R ;;

Probability of Failure (Eurocode Target


73/108

73

145

The Partial Factor Method

Input‘Characteristic’

Values

MaterialParameters

X k

Geometry

ak

Actions

F rep

‘Design’Values

MaterialParameters

X k ×γ m =X d

Geometry

ak + ∆a = ad

Actions

F rep×γ F = F d

CalculationModel

CalculateDesign

Resistance

R d =f ( X d ,ad )

CalculateDesign Effect

of Actions

E d =f (F d , X d ,ad )

ULS verified?

R d > E d ?

146

q factor

displacement

force

elastic

Real behaviour

Sd

Design force

(= elastic / q)


74/108

74

EC8 detailing DCL low ductility; q = 1.5

Lc

0.6Sc

Sb

Densified zones

Beam

C o l u m n

Sc

Sb < 0.75x effective depth of beam

20 x minimum main bar diameter

The lesser of the column dimension

400 mm

The larger of column dimension

Lc larger of Length of lapped joints, minimum 3transverse reinforcement bars

Diameter of transverse reinforcement bars not less than 6 mm or ¼of the maximum diameter of the longitudinal bars

Sc min of

EC8 detailing DCM moderate ductility; q = 3.9

L c

S c

Lb

Sb

Densified zones

Beam

C

ol

u

m

n

Horizontal reinforcement in beam-column joints not less than that in the critical region

of columns

24 times the stirrup diameter

8 x smallest main bar diameter

beam depth / 4225 mm

Lb > beam depth

8 x minimum main bar diameter

Sc < minimum of half the width of the column confined concrete core

175 mm

1/6 clear height of the column

Lc > maximum of Largest column section dimension

450mm

Note that the shear capacity of the beams and columns must be able to

resist a shear force derived from the bending moment strength capacities

considering actual reinforcement provided and material overstrength

(material probable strength being higher than the design strength value)

Sb < minimum of


75/108

75

3 Storey building in KK

0.5M

M

M

Height(m)

10.5

7

3.5

Lateral force

distribution

10.5*0.5M = 5.3M

7*M = 7.0M

3.5*M = 3.5M

Sum = 15.8M

Period T = 0.05 * H0.75 = 0.29 s

For KK with Soil Class D

Lateral base shear = 0.85*Sa = 0.85*2.5*1.35 * 6% = 17% g

Lateral shear = 0.17*2.5M = 0.42M

Force

0.42*5.3/15.8 = 0.14M

0.42*7.0/15.8 = 0.19M

0.42*3.5/15.8 = 0.09M

Shear

28%

22%

17%



76/108

76

3 Storey building in KL

0.5M

M

M

Height(m)

10.5

7

3.5

Lateral force

distribution

10.5*0.5M = 5.3M

7*M = 7.0M

3.5*M = 3.5M

Sum = 15.8M

Period T = 0.05 * H0.75 = 0.29 s

For KL with Soil Class D

Lateral base shear = 0.85*Sa = 0.85 * 6% = 5% g

Lateral shear = 0.05*2.5M = 0.13M

Force

0.13*5.3/15.8 = 0.044M

0.13*7.0/15.8 = 0.058M

0.13*3.5/15.8 = 0.029M

Shear

9%

7%

5%


0

1

2

0.1 1 10

S p e c t r a l A c c e

l e r a t i o n

( m / s 2 )



Site Class C

Site Class D

Site Class S

C Equation

D Equation

E Equation

C 1.6 0.4 1.1 10.4D 2.5 0.9 1.6 4.6

S1 3.2 1.6 2.4 2.4

ag = 0.175 m/s2


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77

Example building from Hong Kong – D11

• 15 storey residential

• H = 41m, W = 7200t

Mode shapes

0

5

10

15

20

25

30

35

40

-1 0 1 2

H e i g h t ( m )

Displacement

Normalised mode shapes

Mode 1

Mode 2

Mode 3


78/108

78

Modal contributions - KL

0

5

10

15

20

25

30

35

40

-5 0 5 10 15 20

H e

i g h t ( m )

Displacement (mm)

Scaled mode shapes

RSS

Mode 1

Mode 2

Mode 3

0

5

10

15

20

25

30

35

40

-1 0 1 2 3

H e i g h t ( m )

Shear (MN)

Shear

RSS

Mode 1

Mode 2

Mode 3

0

5

10

15

20

25

30

35

40

-20 0 20 40 60 80 100

H e i g h t ( m )

Moment (MNm)

Moment

RSS

Mode 1

Mode 2

Mode 3

Modal contributions - KK

0

5

10

15

20

25

30

35

40

-10 0 10 20 30 40

H e

i g h t ( m )

Displacement (mm)

Scaled mode shapes

RSS

Mode 1

Mode 2

Mode 3

0

5

10

15

20

25

30

35

40

-5 0 5 10

H e i g h t ( m )

Shear (MN)

Shear

RSS

Mode 1

Mode 2

Mode 3

0

5

10

15

20

25

30

35

40

-50 0 50 100 150 200

H e i g h t ( m )

Moment (MNm)

Moment

RSS

Mode 1

Mode 2

Mode 3


79/108

79

Modal contributions - Semporna

0

5

10

15

20

25

30

35

40

-10 0 10 20 30 40 50

H e

i g h t ( m )

Displacement (mm)

Scaled mode shapes

RSS

Mode 1

Mode 2

Mode 3

0

5

10

15

20

25

30

35

40

-5 0 5 10 15

H e i g h t ( m )

Shear (MN)

Shear

RSS

Mode 1

Mode 2

Mode 3

0

5

10

15

20

25

30

35

40

-100 0 100 200 300

H e i g h t ( m )

Moment (MNm)

Moment

RSS

Mode 1

Mode 2

Mode 3

Shear

0

5

10

15

20

25

30

35

40

0 5 10 15 20 25

H e i g

h t ( m )

Shear (%)

Shear (q = 1.5)

KL

KK

Semporna


80/108

80

Example building from Hong Kong – D17

• 53 storey residential

• H = 158m, W = 33000t

Mode shapes

0

20

40

60

80

100

120

140

160

-1 0 1 2

H e i g h t

( m )

Displacement

Normalised mode shapes

Mode 1

Mode 2

Mode 3


81/108

81

Modal contributions - KL

0

20

40

60

80

100

120

140

160

-50 0 50 100 150 200 250 300

H e

i g h t ( m )

Displacement (mm)

Scaled mode shapes

RSS

Mode 1

Mode 2

Mode 3

0

20

40

60

80

100

120

140

160

-2 0 2 4 6 8 10

H e i g h t ( m )

Shear (MN)

Shear

RSS

Mode 1

Mode 2

Mode 3

0

20

40

60

80

100

120

140

160

-200 0 200 400 600 800 1000

H e i g h t ( m )

Moment (MNm)

Moment

RSS

Mode 1

Mode 2

Mode 3

Modal contributions - KK

0

20

40

60

80

100

120

140

160

-100 0 100 200 300

H e

i g h t ( m )

Displacement (mm)

Scaled mode shapes

RSS

Mode 1

Mode 2

Mode 3

0

20

40

60

80

100

120

140

160

-5 0 5 10 15

H e i g h t ( m )

Shear (MN)

Shear

RSS

Mode 1

Mode 2

Mode 3

0

20

40

60

80

100

120

140

160

-500 0 500 1000 1500

H e i g h t ( m )

Moment (MNm)

Moment

RSS

Mode 1

Mode 2

Mode 3


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82

Modal contributions - Semporna

0

20

40

60

80

100

120

140

160

-200 0 200 400 600

H e

i g h t ( m )

Displacement (mm)

Scaled mode shapes

RSS

Mode 1

Mode 2

Mode 3

0

20

40

60

80

100

120

140

160

-10 0 10 20 30

H e i g h t ( m )

Shear (MN)

Shear

RSS

Mode 1

Mode 2

Mode 3

0

20

40

60

80

100

120

140

160

-500 0 500 1000 1500 2000 2500

H e i g h t ( m )

Moment (MNm)

Moment

RSS

Mode 1

Mode 2

Mode 3

Shear

0

20

40

60

80

100

120

140

160

0 5 10 15

H e i g

h t ( m )

Shear (%)

Shear (q = 1.5)

KL

KK

Semporna


83/108

83

Foundation design

Failure Modes of Pad Foundations

SlidingBearing capacity

Overturning Structural


84/108

84

Failure by Sliding

Provided structure can hold itself together the onlyrequirement is for No damage

Design check

Small movement in 50% in 50 year ground motion

Failure by Bearing Capacity

Due to uncontrolled displacement the Life safety check will be

required. If the structure could collapse as result of bearing failure of

the foundation then the No collapse check is required.

Design check

Controlled displacement in the 10% in 50 year ground motion.

Possibly required to check for failure 2% in 50 year ground motion.


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85

Mexico City 1985

Failure by Overturning

If the structure could collapse due to overturning capacity failure then

the No collapse check is required. Otherwise the only requirement is

for No damage. For buildings on a raft failure could lead to collapse.

Design check

Small movement in 50% in 50 year ground motion.

For a raft, required to check for failure in 2% in 50 year ground motion


86/108

86

Structural Failure

Due to uncontrolled displacement the Life safety check will be

required. If the structure could collapse as result of structural failureof the foundation then the No collapse check is required.

Design check

Structural integrity in the 10% in 50 year ground motion.

Possibly required to check for failure 2% in 50 year ground motion.

Failure Modes of Piles - Vertical Loads

Stiff Clay

Soft Clay

Fill


87/108

87

Mexico City - 1985

Mexico City - 1985


88/108

88

Mexico City - 1985

Soft

clay

Sand

Building in Mexico City – 1 year later


89/108

89

Failure Modes of Piles - Vertical Loads

Stiff Clay

Soft Clay

Fill

Building in Taiwan - 1999


90/108

90

Building in Taiwan - 1999

The Hermes is buil t on a narrow sit e in

Tokyo’s central Ginza distric t. It uses a

new structural system that relieves

seismic forces vertically through a

lifting rear column at ground floor level,

restrained by dampers.

This ‘stepping column’ system is able

to move wi th the earthquake, thereby

reducing forces and foundation and

steelwork costs .

Yielding Piles - Hermes Tokyo


91/108

91

Case Study - Hermes Tokyo

Effects on Piles


92/108

92

Pile Failure - Lateral Loads

Bedrock

Stiff Clay

Soft Clay

Fill

500 250

Bending Moment (kNM)

Piles - Lateral Loads

0 50 100 150

Horizontal displacement (mm)

Soil displacement

from SIREN

Pile

displacement

100 : 30

combination rule


93/108

93

Case Study - LNG Tanks, Trinidad

Dynamic soi l-pile-tank interaction study to assess

loads in the piles and tank.

• 1-D soil colu mn modelled in Oasys LS-DYNA.

• Took account of the effect of liquefaction.

• Took account of stif fening effect of the piles.

• Analysed the en ti re probl em in one s tep.

Typical cross-section through the tank and foundation system



94/108

94

Driven Steel Tube Piles

Preferred Solution

Foundation Design Options

• Foundation types considered included:

• Ground replacement.

• Closely spaced stone columns.

• Lowered foundation scheme.

• Bored piles.

• Driven piles (combined with stone columns).

• There was no clear cost advantage in any of

the foundation types examined.


1-D Soil Model



95/108

95

Soil Column Analysis


Site Response Results



96/108

96

Soil-Pile Model


Effect of Piles on Response



97/108

97

Complete SSI Model


Analysis of Complete SSI System



98/108

98

Bending Moments in the Piles


Soil displacement

Effects on raking piles


99/108

99

Raking Piles

Raking Piles


100/108

100

Other ground effects

Bedrock

Effects on Railways / Basements

Stiff Clay

Soft Clay

Fill

0 50 100 150



101/108

101

Cut and cover tunnel box

68mm

A pseudo static Horizontal Acceleration (=3%g) is applied to whole model

68mm

results of pseudo static model

Horizontal earth pressures


102/108

102

Lifelines - Longitudinal Motion

• Maximum ground strain is Vm / CWhere Vm is the peak ground velocity and

C is the propagation velocity

• If this strain is too large then further analysis is required

Lifeline (EA)

Elastic/plastic spring tomodel movement

between lifeline and soil

Point of applied groundmotion displacement

O’Rourke and Liu, 1999

Observed Damage to Water Pipe Systems

0.01 0.02 0.05 0.1 0.2 0.5 1

1

0.5

0.2

0.1

0.05

0.02

0.01

0.005

0.002

0.001 P i p e D a m a g e R a t i o ( r e p a i r s p e r k i l o m e t r e )

Peak Horizontal Parti cle Veloci ty (m/s)


103/108

103


Propagation Velocities

Measured apparent S - wave propagation velocities

Event Site condit ionsC

(km/s)

Japan 23/1/68 60 m soft alluvium 2.9

Japan 1/7/68 60 m soft alluvium 2.6

Japan 9/5/74 70 m silty clay, sand &silty sand 5.3



San Fernando 9/2/71 Variable 2.1

Imperial Valley 15/10/79 > 300 m alluvium 3.8

Imperial Valley 15/10/79 > 300 m alluvium 3.7

Turkey 1999

Fault Rupture


104/108

104

Turkey 1999

Fault Rupture

Gölcük Stepover Fault

(2.5m vertical movement)

(0.7m horizontal movement)

D

U

Example -

Factory in

Turkey


105/108

105

Gölcük Stepover Fault

(2.5m vertical movement)

(0.7m horizontal movement)

Body

Shop

D

U

Example -

Factory inTurkey

Example - Factory in Turkey

Tilting of columns Differential settlement Lateral displacement

Damage to Body Shop


106/108

106

Fault Rupture - Lifelines

Elastic/plastic spring to

model movement between

lifeline and soil

Point of applied ground

motion displacement


Slope stability


107/108

107

Slope stability

Slope stability

Standard method of considering down-slope movement

If Ac / Am is greater than 0.5 then movements are small

Ac is the

acceleration

required to

cause the slope

to have afactor of safety

of one


108/108

Bedrock

Slope Stability - Effects on Piles

0 50 100 150


500 250

Bending Moment (kNM)

Documents

Iem Workshop Ec8 2012