Question About Vulnerability Model

[Amir Azizi]

Hi Dear All, 

This is a sample of Vulnerability Model for structural .

1-How we can calculate the "mean loss ratio for a set of intensity measure levels" ?

 

2- Can somebody explain this code exactly ?(special the highlights)

BR,

Amir Azizi

<?xml version="1.0" encoding="utf-8"?>

<nrml xmlns="http://openquake.org/xmlns/nrml/0.5">

  <vulnerabilityModel id="Nepal" assetCategory="buildings" lossCategory="structural">

    <vulnerabilityFunction dist="LN" id="Wood">

      <imls imt="PGA"> 0.0001 0.2 0.4 0.6 0.8 1.0 1.2 1.4 </imls>

      <meanLRs> 0.0001 0.05 0.21 0.4 0.56 0.67 0.76 0.82 </meanLRs>

      <covLRs> 0.3 0.3 0.3 0.1 0.1 0.1 0.1 0.1 </covLRs>

    </vulnerabilityFunction>

    <vulnerabilityFunction dist="LN" id="Unknown">

      <imls imt="PGA"> 0.0001 0.2 0.4 0.6 0.8 1.0 1.2 1.4 </imls>

      <meanLRs> 0.0001 0.05 0.21 0.4 0.56 0.67 0.76 0.82 </meanLRs>

      <covLRs> 0.3 0.3 0.3 0.1 0.1 0.1 0.1 0.1 </covLRs>

    </vulnerabilityFunction>

    <vulnerabilityFunction dist="LN" id="Stone-Masonry">

      <imls imt="PGA"> 0.0001 0.2 0.4 0.6 0.8 1.0 1.2 1.4 </imls>

      <meanLRs> 0.0001 0.25 0.63 0.82 0.91 0.95 0.98 0.99 </meanLRs>

      <covLRs> 0.3 0.3 0.1 0.1 0.1 0.1 0.1 0.1 </covLRs>

    </vulnerabilityFunction>

    <vulnerabilityFunction dist="LN" id="Adobe">

      <imls imt="PGA"> 0.0001 0.2 0.4 0.6 0.8 1.0 1.2 1.4 </imls>

      <meanLRs> 0.0001 0.28 0.67 0.85 0.93 0.96 0.98 0.99 </meanLRs>

      <covLRs> 0.3 0.3 0.1 0.1 0.1 0.1 0.1 0.1 </covLRs>

    </vulnerabilityFunction>

    <vulnerabilityFunction dist="LN" id="Concrete">

      <imls imt="PGA"> 0.0001 0.2 0.4 0.6 0.8 1.0 1.2 1.4 </imls>

      <meanLRs> 0.0001 0.25 0.61 0.8 0.9 0.94 0.97 0.98 </meanLRs>

      <covLRs> 0.3 0.3 0.1 0.1 0.1 0.1 0.1 0.1 </covLRs>

    </vulnerabilityFunction>

    <vulnerabilityFunction dist="LN" id="Unreinforced-Brick-Masonry">

      <imls imt="PGA"> 0.0001 0.2 0.4 0.6 0.8 1.0 1.2 1.4 </imls>

      <meanLRs> 0.0001 0.2 0.55 0.76 0.87 0.93 0.96 0.98 </meanLRs>

      <covLRs> 0.3 0.3 0.1 0.2 0.1 0.1 0.1 0.1 </covLRs>

    </vulnerabilityFunction>

  </vulnerabilityModel>

</nrml>

[Luís Martins]

Good morning Amir,

I will try to answer your questions in the paragraphs below

1) Vulnerability assessment is a very vast field and the subject of many PhD thesis and publications. Broadly you can divide vulnerability assessment in two categories i) empirical and ii) analytical. In empirical you collect the loss data from different past events and create your estimates of Loss vs IML from there. In analytical methods you generally start with some kind of numerical model of the building class you care about and apply to an earthquake load with known intensity  (e.g. ground motion records, response spectra). Repeat over a range of intensities, estimate the expected losses given by the response of your model and the outcome is your vulnerability model.

2) The values you highlighted are simply the mean loss ratios and their respective uncertainty that define the vulnerability curve.

Hope this helps you. 

Cheers

L.M.

[Amir Azizi]

Dear Luis 

And Thanks alot , my education background is in Computer Eng. and I have no information about Earthquake Eng. Would you please tell me how I should calculate the mean loss ratios , (Highlights ) is it Related to PGA?

Best Regards

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[Luís Martins]

Dear Amir,

indeed the mean loss ratios are losses expected for the PGA levels listed in the line  <imls imt="PGA"> 0.0001 0.2 0.4 0.6 0.8 1.0 1.2 1.4 </imls>.

If you want to compute vulnerability functions I can recommend you  to try the Vulnerability Modellers ToolKit (https://github.com/GEMScienceTools/VMTK-Vulnerability-Modellers-ToolKit). There is also a companion publication that you read for understanding the toolkit and also to get a brief literature review on vulnerability modelling that might be useful for you (https://link.springer.com/article/10.1007/s10518-021-01187-w)

Cheers

L.M.

[Amir Azizi]

Dear Luis, I really appreciate you .

BR

Amir

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[Amir Azizi]

Hi Luis, I read the article and also Installed  VMTK. 

I have a question :

to calculate the loss ratio I want to select :EDP-to -loss  in conversation type , so what is the conversation model and also EDPs. 

I mean for these parameters what type of files should be prepared and what is the content of these parameters?

Would you please inform me about that?

BR,

Amir.

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[Luís Martins]

good morning Amir,

if you want to follow the EDP-to-loss route you'll need to create a csv with 2 column array where the first is the EDPs (i.e. structural displacements of floor accelerations) and the second is the expected loss for that level of structural response.  

Please note that this file will be different for each building class you are studying. Say for example you have a reinforced concrete and an unreinforced masonry building both with 2 storeys, and that both experienced say 4cm of top displacement. Their corresponding loss will be very different, since the reinforced concrete might only have suffered moderate damage while the masonry is likely to have reached collapse. This is the reason why each building class must have an appropriate EDP-to-Loss model.

Cheers
 

[Amir Azizi]

Dear Luis

Would you please inform me what is the Fragility Folder and also Conversion Model in Damage-to-loss model ?

Do you have some sample data for input and run all part of toolkit for better understanding?

BR,

Amir

[Luís Martins]

Hi Amir,

In the GUI 'Fragility folder' is simply the path to the directory where you stored the fragility functions you calculated previously. The conversion model when you are using the damage-to-loss option is exactly that a damage to loss model (you can find an example of this file at ~/VMTK-Vulnerability-Modellers-ToolKit/demonstration_files/capacity/dam_2_loss.csv.)

Cheers 

[Amir Azizi]

Hi  , Dear Luis, 

Would you please inform me how I can reach the sample file for test the section I specified in attachment?
I mean I want to run a sample for better understanding and also for find the file format. and I would like that the output as another file I attached .

As I said before I have no background in Civil or Earthquake Engineering :)

I am looking forward to your reply.

Best Regards,

Amir

[Luís Martins]

Good morning Amir,

I can't tell for sure which building class from the demo files you are using, but you can find an example of the imls and edps files at ~/VMTK-Vulnerability-Modellers-ToolKit/demonstration_files/outputs/test/CR_LFINF-CDN_H1.

I'm not sure if you are using a damage-to-loss model in your 'conversion mode' but you should make sure that if you are using the demo file I suggested in the last message your option for 'conversion type' is set to 'damage-to-loss'. Something I forgot to write you in the last message is that a damage-to-loss is simply a model that assigns a level of loss to a type of damage. Taking for example Fig 10 from the VMTK's companion paper, the way to interpret this damage-to-loss model is that, for example, at Slight damage (DS1) you are expecting the losses to be about 5% of the replacement cost of the building.

 EDP-to-loss requires a custom file for each building class as I told you in a previous message (this is due to the fact that different structures behave very differently). I'm attaching a sample file to this message. The way this files is constructed is by listing in each row the level of structural response (e.g. displacement) and the respective expected loss. In this particular example I simply got the spectral displacement at each damage state in Fig 8 from the capacity curve and linked these thresholds with their respective loss from Fig 10.

let me know if this helped and feel free to reach out if you have any other questions.

Cheers

[Amir Azizi]

Dear Luis , Good Morning

Ok , I got it . So if I want to run  Damage-to-loss mode in the Conversation model using the file you attached , the fragility folder should be the output of Fragility Analysis.

in the Fragility Analysis Tab :I selected MLE-censored with Censoring Factor =1.5 and Building-to-Building Sigma=0.3 , so where can I find a sample file for use in:  EDPs folder , Damage Model files and also IMs file ?(Just for test and understand the process steps).

I am looking forward to hearing from you.

Best Regards,

Amir

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[Luís Martins]

Good morning Amir,

The 'EDPs folder' is the path you specified in the structural analysis tab to store the results of the dynamic analyses. In any case you can find examples of the files at ~/VMTK-Vulnerability-Modellers-ToolKit/demonstration_files/outputs/test/CR_LFINF-CDN_H1. The structural displacements file stored at 'max_displacements.csv' and the peak floor accelerations is stored at 'max_accelerations.csv'  

Cheers
L.M.

[Amir Azizi]

Hi , Dear Luis,

Would you please check the attachment and inform me if the files and folders selected are correct?

Best Regards,

Amir

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[Luís Martins]

Good morning Amir,

the damage model file is not correct. It seems you are uploading the structural displacements file. you can find a damage model in this location ~\VMTK-Vulnerability-Modellers-ToolKit\demonstration_files\capacity\damage_models. 

Cheers

L.M.

[Amir Azizi]

Hi , Dear luis

I corrected that, but in the Building Class Box I can not see anything !

BR,

Amir

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