Presentation sildes on Seismic Design Code of Nepal

7/27/2019 Presentation sildes on Seismic Design Code of Nepal

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RISHI RAM PARAJULI

PHASE CONSIDERATION INSEISMIC DESIGN CODE FOR

STRUCTURES IN NEPAL


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Introduction

Worldwide trend in change of codes

Consideration of phase for design ground motion

Discussion

Conclusion

OUTLINE


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INTRODUCTION

URBANAIZATION

Development

Economy

Population


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POPULATION AND DISTRIBUTION SCENARIO OF NEAPL

INTRODUCTION

Urban17%

Rural83%

Population Distribution


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MEGA CITY ???????

INTRODUCTION

Population >10 millionDensity >2000/sq.Km.

UN projects for 60% of world population will be in cities by2030.

We have now just 17% of our population are in urbanareas.

Hence we must have to step for big cities.


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EXPECTATION !!!!!!

INTRODUCTION

Who have to own this??


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What we (Engineers) have to do

INTRODUCTION

Obviously Perception of needs to society.

Planning and executionMaintenance and operation

What we must consider

Safety Cost


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Are we in safe zone????

Obviously Perception of needs to society.

Planning and executionMaintenance and operation

What we must consider

Safety Cost

N

Major Earthquakes in Himalaya

Indian plate moving toward north at a rate of 2 to 5 cm per year and the occurrence

of frequent seismic activities along the Himalaya and its surroundings

During past 120 years, five great earthquakes occurred along the Himalayan front

Brahmaputra

River


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anwest

andlike

this??

INTRODUCTION


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What can we do.

INTRODUCTION

For Public facilities owned by Government,

Safety first.Specific Design and Construction guidelines.

Quality of result

Private owned Public Facilities,

Strict regulations and monitoring on guidelines.

Private owned,

Awareness about disasters.


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Can we make structures earthquake proof ???

INTRODUCTION

No!!!!!

What we consider

We can make it safe against life of people to some limit butnot for life of structure in all case.

Damage

Demand

Death


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WORLDWIDE TREND IN CHANGING

DESIGN CODES AFTER DISASTER


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TRENDS .

Japan

1923

Kanto earthquake (142,000 Fatalities)

They start to consider seismic design as seismic coefficient0.2

1995

Kobe earthquake (5100 + death)

Devastating structural damage

Propose new independent seismic design code

2011

Great East Japan earthquake

Structures performance was considerably good but deathtoll high due to tsunami.


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TRENDS .

USA

1971

San Fernando Earthquake

They start to consider seismic design.

1989

Loma Prieta earthquake

Change in design codes


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TRENDS .

NEW ZEALAND

1992

They prepare seismic design code forbuilding.

1994 Prepare seismic design code for bridges

2010

Canterbury earthquake

Changing in seismic design codes.


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TRENDS .

INDONESIA

1970

They have seismic design code for main islands.

Seismic coefficient 0.1g for PADANG City

1987 Change in seismic design code, for Padang City 0.28-0.36 g

2002

Sumatra earthquake

Changing in seismic design codes as 0.8g seismic coefficient.

2009

Padang earthquake

Changing in seismic design codes as 1.9g seismic coefficient.


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Main Causes in revision (case of Indonesia)

TRENDS .

Less researches cause not much data to analyze and make

accurate design methodologies.Design is mostly ok but construction methodologies and

quality of construction.

Thought of economical only not about safety.


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Constraints in our door .

TRENDS .

Same as Indonesia, less researches and data records, so no

much data to analyze and make accurate designmethodologies.

Construction industry is not even fully enter in to

professionalism.

Initial cost of well designed structure is obviouslyexpensive but life cycle cost is cheaper than now a days

practice. So we have to force.


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Phase angle of wave is most useful.

Consideration of phase for design groundmotion

We can see the ground motion in to summation of

sinusoidal waves.X(t)= Asin(t+)

Phase of wave can represent the characteristic of ground

motion on that area.

Hence we can consider phase angle of recorded dataset andcan simulate the ground motion.


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We can see .

Consideration of phase for design groundmotion

0 5 10 15 20 25 30 35 40 45-0.2

0

0.2

0.4

0.6

Time (sec)

accele

ration(m/s2)

i i l

i

i i l

i

i i l

0 5 10 15 20 25 30 35 40 45-1

-0.5

0

0.5

1

Time (sec)

acceler

ation(m/s2)

i i l

i

i i l

0 5 10 15 20 25 30 35 40 45-0.5

0

0.5

1

Time (sec)

acceleration

(m/s2)

i i l

0 5 10 15 20 25 30 35 40 45-0.4

-0.2

0

0.2

0.4

Time (sec)

acceleration

(m/s2)

i i l

i i l

Kobe Earthquake El Centro Earthquake

Amplitude Kobe phase El Centro Amplitude El Centro phase Kobe


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How can we use .

Discussion

We can simulate the design ground motion according to

the design response spectra too when we can collect andanalyze ground motion data.

Source of earthquake and soil properties with bed rock

depth are influential for phase of ground motion.

After getting phase of data we can generate design groundmotion keeping phase as constant and changing

amplitude.


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Beneficial for us.

Conclusion

We are in benchmark of development phase, hence for

Urban development we have to move toward safestructures against earthquake too.

For major cities we can prepare different design ground

motion if more irregularities considering soil type and

possible source of earthquake.


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To be continue.

Future work

We are starting to do some research in phase and its

relations to site specific condition. Hence hope we willsuccess to deliver better result in making design ground

motion.

Research in its early phase, these are preliminary way

outs.


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THANK YOU FOR YOUR KIND ATTENTION

Presentation sildes on Seismic Design Code of Nepal

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