OQ-VMTK v1.0.0

OQ-VMTK Release Notes

Vulnerability Modeller's Toolkit (OQ-VMTK) – Version 1.0.0

The OQ-VMTK is an open-source toolkit developed by the Global Earthquake Model (GEM) Foundation for earthquake engineers and vulnerability modellers. It enables modeling and assessment of structures via single- and multi-degree-of-freedom (SDOF/MDOF) systems, supporting both linear and nonlinear analyses, with a focus on improving the reliability of regional vulnerability models for large-scale earthquake risk applications.

Key Features

• Ground Motion Record Processing: Calculate ground shaking intensity based on various intensity measure (IM) types such as PGA, SA(T), Sa_avg, FIV3, etc.

• Modeling & Calibration: Define and model idealised stick-and-mass models with user-specific storey count and force-deformation relationships, powered by OpenSeesPy.

• Analysis Suite

  • Modal Analysis: Calculate modal properties (i.e., periods of vibration and mode shapes)
  • Nonlinear Static: Conduct static or cyclic pushover analyses to characterise the lateral load-resisting and energy dissipation capacity of the idealised model.
  • Nonlinear Dynamic: Conduct nonlinear time-history analyses (NLTHA) and extract engineering demand parameters such as peak floor displacements and accelerations, as well as inter-storey drifts.

• Fragility & Vulnerability

  • Probabilistic seismic demand modeling (IM-EDP relationships)
  • Fragility function fitting with multiple approaches (lognormal CDF, GLM, ordinal).
  • Generate storey loss functions (SLFs) to leverage the seismic demands from NLTHA for refined loss assessment applications
  • Vulnerability curve (Loss vs IM) modelling with uncertainty treatment.

• Visualization

  • Plot model overviews, peak response distributions, fragility functions, SLFs and vulnerability models.

Installation

• Supports Windows and Linux (Python 3.11/3.12).
• Virtual environment recommended.
• Install dependencies from requirements.txt and install the package in editable mode.

Getting Started

• Includes demo scripts accessible via Jupyter Lab.
• Documentation: https://gemsciencetools.github.io/oq-vmtk

License

• Licensed under AGPL v3.