October 15, 2019 Software Open Access

NHERI-SimCenter/pelicun: pelicun v2.0.0

Adam Zsarnoczay

Probabilistic Estimation of Losses, Injuries, and Community resilience Under Natural disasters

What is it?

pelicun is a Python package that provides tools for assessment of damage and losses due to natural hazards. It uses a stochastic damage and loss model that is based on the methodology described in FEMA P58 (FEMA, 2012). While FEMA P58 aims to assess the seismic performance of a building, With pelicun we provide a more versatile, hazard-agnostic tool that estimates losses for several types of assets in the built environment.

Detailed documentation of the available methods and their use is available at http://pelicun.readthedocs.io

What can I use it for?

pelicun quantifiies losses from an earthquake or hurricane scenario in the form of decision variables. This functionality is typically utilized for performance-based engineering and regional risk assessment. There are several steps of performance assessment that pelcicun can help with:

• Describe the joint distribution of asset (e.g. building) response. The response of a structure or other type of asset to an earthquake or hurricane wind is typically described by so-called engineering demand parameters (EDPs). pelicun provides methods that take a finite number of EDP vectors and find a multivariate distribution that describes the joint distribution of EDP data well. You can control the type of target distribution, apply truncation limits and censor part of the data to consider detection limits in your analysis. Alternatively, you can choose to use your EDP vectors as-is without resampling from a fitted distribution.

• Define the damage and loss model of a building. The component damage and loss data from the first two editions of FEMA P58 and the HAZUS earthquake and hurricane models for buildings are provided with pelicun. This makes it easy to define building components without having to collect and provide all the data manually. The stochastic damage and loss model is designed to facilitate modeling correlations between several parameters of the damage and loss model.

• Estimate component damages. Given a damage and loss model and the joint distribution of EDPs, pelicun provides methods to estimate the amount of damaged components and the number of cases with collapse.

• Estimate consequences. Using information about collapse and component damages, the following consequences can be estimated with the loss model: reconstruction cost and time, unsafe placarding (red tag), injuries and fatalities. 

Why should I use it?

1. It is free and it always will be. 
2. It is open source. You can always see what is happening under the hood.
3. It is efficient. The loss assessment calculations in pelicun use numpy, scipy, and pandas libraries to efficiently propagate uncertainties and provide detailed results quickly.
4. You can trust it. Every function in pelicun is tested after every commit. See the Travis-CI and Coveralls badges at the top for more info. 
5. You can extend it. If you have other methods that you consider better than the ones we already offer, we encourage you to fork the repo and extend pelicun with your approach. You do not need to share your extended version with the community, but if you are interested in doing so, contact us and we are more than happy to merge your version with the official release.

Major changes in v2.0:

• Migrated to the latest version of Python, numpy, scipy, and pandas see setup.py for required minimum versions of those tools.
• Python 2.x is no longer supported.
• Improve DL input structure to
  • make it easier to define complex performance models
  • make input files easier to read
  • support custom, non-PACT units for component quantities
  • support different component quantities on every floor
• Updated FEMA P58 DL data to use ea for equipment instead of units such as KV, CF, AP, TN.
• Added FEMA P58 2nd edition DL data.
• Supported EDP inputs in standard csv format.
• Add a function that produces SimCenter DM and DV json output files.
• Add a differential evolution algorithm to the EDP fitting function to do a better job at finding the global optimum.
• Enhance DL_calculation.py to handle multi-stripe analysis (significant contributions by Joanna Zou):
  • recognize stripe_ID and occurrence rate in BIM/EVENT file
  • fit a collapse fragility function to empirical collapse probabilities
  • perform loss assessment for each stripe independently and produce corresponding outputs

Major changes in v1.2:

• Support for HAZUS hurricane wind damage and loss assessment
• Add HAZUS hurricane DL data for wooden houses
• Move DL resources inside the pelicun folder so that they come with pelicun when it is pip installed
• Add various options for EDP fitting and collapse probability estimation
• Improved the way warning messages are printed to make them more useful