Seismic waves are causing non-stationary effects that threaten the safety of transport infrastructure in Europe. Although vibration intensity and frequency are known to be inherently non-stationary, studies so far have mostly used stationary random vibration theory. The 'Non-stationary response of spatially extended structures' (NOTES) project focused on studying the effects of spatially varying earthquake ground motions on large structures such as bridges or tunnels. It also analysed the soil non-stationary response induced by vehicle vibrations. Project members from Ireland who are experts in signal processing and wavelet-based non-stationary response analysis collaborated with a leading Netherlands-based software company regarding geotechnical products. NOTES allowed the latter to take advantage of the latest developments in vibration analysis and signal processing techniques. To this end, two training courses on MatLab code and wavelet processing took place, focusing on seismic signal spectral characterisation and vehicle dynamics. Academia researchers were exposed to industry practices of finite element modelling of spatially extended structures. By using the company software, they were trained on analysing structure seismic responses. Furthermore, algorithms for generating multi-point spatially correlated excitations were developed. This helped to investigate the non-stationary responses of large structures. Another activity was to develop a finite element model for the non-stationary response propagating in soil that is induced by vehicle vibrations. An important project achievement was the software plug-in development for seismic- and vehicle-induced vibrations. NOTES succeeded in creating a pool of highly skilled and experienced researchers with the knowledge required to create better analytical and computational techniques for analysing geotechnical systems. The project also resulted in numerous publications.
Seismic response, non-stationary response, spatially extended structure, vehicle vibration, soil