ISSARS: An integrated system for structural analysis and earthquake records selection

Despite the major advancements in earthquake engineering research and the novelty of most modern seismic codes, the selection of the earthquake ground motions used for the design or assessment of structures in the framework of structural analysis still induces significant dispersion in the calculated dynamic response of structures. For this reason, the current study presents a new, freely available, computational system developed for improving the reliability of the code-based earthquake record selection and scaling procedure, as a means to reduce the resulting structural response scatter. Through a set of preliminary criteria, related to the magnitude, epicentral distance, soil conditions, intensity measure (i.e., PGA), components of excitation (2D or 3D) and structural system (building or bridge), the proposed algorithm searches through internet the entire PEER-NGA Strong motion Database for appropriate seismic records and then ranks them in terms of their spectral matching to a target response spectrum within a prescribed frequency range. A key feature of the software is that it implements the new Application Programming Interface (API) of the computer program SAP2000 and proceeds in applying the selected records to the finite element model that the designer is assumed to have prepared at the background. In this way, both the variation of the response quantities in the time domain and the relative structural response dispersion under various records are automatically retrieved. The presentation concludes with a demonstration regarding the assessment of a real, irregular in plan, multi-storey, RC building, where the importance of adopting a structure-specific earthquake record selection process is highlighted.