OpenSees

OpenSees is the developer and publisher of the OpenSees software framework, an open-source platform dedicated to the simulation of structural and geotechnical systems. The project, maintained through its public GitHub repository, provides a computational environment for developing applications that model how structures and soil systems respond to demanding loading conditions, with particular emphasis on earthquakes and other dynamic events. The framework belongs to the engineering simulation and finite element analysis software category, serving researchers, civil and structural engineers, academics, and students who require advanced tools for performance-based design and assessment. Typical use cases include nonlinear static and dynamic analysis of buildings, bridges, and other infrastructure, evaluation of soil-structure interaction, investigation of material and geometric nonlinearities, and sensitivity or reliability studies that support research into seismic performance. Because it is distributed as an extensible framework rather than a closed application, OpenSees allows users to build custom analysis procedures, implement new material and element models, and script complex simulation workflows, which has made it a common reference platform in earthquake engineering research communities. Its open-source distribution model encourages collaboration between universities and research institutions, enabling contributors to share models, validation studies, and improvements across the user community. The publisher's product range is focused on this single flagship framework, concentrating development effort on computational accuracy, flexibility, and extensibility rather than offering a broad catalog of commercial tools. Users typically interact with the software through scripting interfaces and command-line workflows, integrating it into larger research pipelines for structural analysis, hazard assessment, and the validation of experimental findings in laboratories and field studies worldwide.