OpenSees

OpenSees is an open source software framework for structural and geotechnical applications in both sequential and parallel environments. It has been developed in the research community as a means of sharing research ideas and developments via a common software platform. It has elements and materials for structural beam-column analysis and continuum analysis, geotechnical continuum analysis and soil-structure interaction. It provides many options for solution algorithms, integration schemes, and equation solvers.

A number of applications are provided for sequential and parallel usage.

It is primarily written in C++, though it makes use of many legacy routines written in c and fortran. Element and materials API's allow new elements and materials to be written in C or fortran, which can be dynamically linked to run with the existing interpreters.