Hanze Perspective

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Hanze Perspective

on

Earthquake Education & Training Dr. İhsan Engin BAL

Professor in

Research Group on Earthquake Resistant Structures

www.EQResearch.nl

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European seismic hazard map and… Groningen !?

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Most Dutch students Most students from EQ- prone countries

Competence level of our students in EQ engineering

The 1st goal

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Why earthquake engineering ?

1999 Gölcük EQ

2003 Bingöl EQ

2011 Erciş EQ

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Motivation is the first requirement for our students

Aunt

Friend Family

Uncle

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Video

The guy who saves his tea

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What is an earthquake after all ?

Students need to feel the physics of it first !

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What is an earthquake ?

Earthquake is a Ferrari breaking on a carpet !

Sir Isaac Newton

Force = mass x acceleration F= m x a

The 2

nd

rule of Newton

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What is an earthquake ?

Earthquake is a Ferrari breaking on a carpet !

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Shaken, not stirred - 2017

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Shaken, not stirred - 2017

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Involve students in real work, make their hands dirty!

Involve them in complicated research work to give them a

vision.

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We have a group of 3 Hanze students working with 2 PhD students and 2

researchers from our team on the same topic.

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Axis of our approach in educating our students in earthquake engineering are:

It is already a complicated problem, stick to the theory but make things simpler for the young students

Organize excuses for them to physically feel the problem in hand

Include them in the complicated research, make them a part of the solution, give them a vision

Create environments where they can meet future colleagues

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The Fog

• The earthquake problem in Groningen has become foggy.

• When there is an intense fog, we cannot see even the Martini Tower properly, then how to see the earthquake problem clearly?

• Today, we will try to find our way in the fog.

Martini Tower, Groningen

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Groningen earthquakes are different

• Soil in Groningen is soft (the lowest soil class in the classifications)

• Buildings are not designed for seismic loads

• The earthquakes in Groningen are - shallow (at ~3km depth)

- small magnitude (max. Mw3.6 so far) - short duration (a couple of seconds) Because ...

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Groningen earthquakes are different

• Soil in Groningen is soft (the lowest soil class in the classifications)

• Buildings are not designed for seismic loads

• The earthquakes in Groningen are - shallow (at ~3km depth)

- small magnitude (max. Mw3.6 so far) - short duration (a couple of seconds) An augmented reality

Soil is soft in many other seismic areas (Sakarya, Niigata, Mexico City) This is valid in most places, and is matter of culture, regulations etc.

There are dozens of earthquakes of such every year around the world.

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Groningen earthquakes are different

We should not undermine the Groningen earthquakes

We should not undermine the problem

But, correct cure needs correct diagnosis

• I have not seen a single scientific proof explaining why Groningen earthquakes are different

• And if they are, what does this mean for the structures in the region?

An augmented reality

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Earthquake-proof Buildings

«aardbevingsbestendig» does not mean earthquake-proof

• In earthquake engineering, the term «earthquake-proof» is only

hypothetical, with extremely limited (and questinoable) application to nuclear power plants

• The correct term is «earthquake resistant», which is also the name of our research group

Mission Impossible

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Earthquake-proof Buildings

The earthquake resistant design phylosophy is based on the targets that the buildings will withstand:

- frequent earthquakes with minor damage,

- rare earthquakes with repairable damage, and - very rare earthquakes without collapse.

Mission Impossible, but why?

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Earthquake-proof Buildings

Mission Impossible, but why?

It may be difficult to beleive, but this building was

successful

A certain level of cracks and damage is part of the

succesful seismic design

Even strengthened houses will most probably get cracks in a

design-level earthquake Photo by Ihsan E. Bal in New Zealand, after 2011 Christchurch Earthquake (Mw6.2)

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Damage vs Small Earthquakes

• Today, when there is an earthquake, people claim damages

• The earthquakes create damages, that is a legal liability issue

• And the decision makers try to use engineering tools for finding proof to decline or to accept the claim

• This is a wrong start...

A Wrong Start

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Damage vs Small Earthquakes

• The earthquake-damage relationship is ambigious when the earthquakes are small

A Wrong Start

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Damage vs Small Earthquakes

• A good example to that is Fraeylemaborg

• The royal monument was damaged at least two times seriously in the past.

• What was the reason of these damages? Earthquakes? Soil? Or both?

• It is difficult even for the experienced technical people to find it out.

A Wrong Start

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Monitoring the Earthquakes

Confusion

• The weather forecast of the whole day or even of the whole week can be communicated with the citizens with this simple table

• It is enough to know the basic parameters, such as

temprature, rain precipitation, wind speed etc.

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Monitoring the Earthquakes

• In order to describe an earthquake of 20seconds, we need to look at:

- peak ground acceleration (PGA) Confusion

- spectral acceleration in long periods - bracketed duration

- significant duration - Arias intensity

- Fourier spectra - peak ground velocity

- spectral acceleration at short periods

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Monitoring the Earthquakes

• Monitoring is a serious job, that is very much needed for Groningen

• All monitoring efforts should be combined, data should be anonimized and made public (privacy should not be an iron curtain !)

• We need to abandon the discussion on which sensors, how, where...

These are questions solved by the world decades ago (remember, Groningen earthquakes are not different !!! )

• We use accelerometers and a tiltmeter at Fraeylemaborg, and we are very happy with our monitoring system there

Confusion

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Monitoring the Earthquakes

• are not an alternative for accelerometers, as accelerometers are not an alternative for tilt-meters; these are different types of equipment,

• can provide crucial information about the structure, especially right after an earthquake

• are not stand-alone structural monitoring equipment, but they can be very useful in combination with other sensors

• further research is needed to discover the use of tilt-meters in shallow earthquakes and the detection of surface-wave characteristics

Confusion - Tiltmeters :

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Monitoring the Earthquakes

• The sensors are top quality

• It is an extremely difficult job to collect and maintain all these data

• But the location and mounting of sensors are according to SBR, not according to earthquake engineering standards

• Serious shift of track is needed for better use of this very dense network

• Better monitoring data, better diagnosis, better service to the Groningen people... and we are ready to help

Confusion – 400+ house monitoring:

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Seismic codes, guidelines and NPR

• What is a code? What is a guideline? What are the consequences?

Not a good choice

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Seismic codes, guidelines and NPR

• What is a code? What is a guideline? What are the consequences?

• Buildings in Europe (EU) are designed and built according to Eurocodes 0 to 8

• Eurocode 8 is the seismic design code for all Europe, and the Netherlands deliberately prohibited the use of Eurocode 8

• Apart from the technical issues, this seems to be against the EU competetiveness rules

Not a good choice

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Seismic codes, guidelines and NPR

• Why Eurocode 8 is abandoned and a national guideline/code (NPR) is created from scracth? May be because the Groningen earthquakes are different?

• NPR is more stabilized now than before, but it also created a lot confusion at the beginning because of changing rules (the slalom effect).

• Eurocodes is the result of years of quality work, long discussions, and a European-level concensus. It is a bit too late now to go back to Eurocodes, but I also beleive the NPR was not a good choice at that time.

Not a good choice

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Solving the myhts, correcting the fallacies

We will produce scientific proof against the augmented reality, to show if the Groningen earthquakes are different, and if they are, what this means for the buildings and for the people.

Earthquake-proof buildings is mission impossible, but earthquake resistant buildings, the name of our group, is very much feasible. We will work with all parties, and also with BuildinG and EPI-Kenniscentrum, to show how our buildings can resist the earthquakes, and how engineers can work on that.

What are our plans? (1/3)

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Solving the myhts, correcting the fallacies

Trying to tie the legal compensation to crack detection was a wrong start. We propose a totally new paradigma to the earthquake engineering design phylosophy: Comfort Level Earthquake (CLE). We will establish the scientific background of this in the coming years.

• Monitoring activities in the region, as well as the sensors discussions are confusion for the people. We monitor Fraeylemaborg as a case study to show how structural monitoring is done in the rest of the world.

We are ready to share experience and knowledge to decrease the confusion.

What are our plans? (2/3)

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Solving the myhts, correcting the fallacies

• Abandoning the well established, already tested European regulation, caused us a lot time an effort. It was not a good choice.

• It is very difficult to go back to the Eurocodes now, but we can at least, as done in Grecee, Italy and Turkey, have our national guideline close to the Eurocodes.

• As Hanze Research Group on Earthquake Resistant Structures, we will pursue this option.

What are our plans? (3/3)

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Thank you…

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