NOTES · Non-stationary respOnse of spaTially Extended Structures

Non-stationary respOnse of spaTially Extended Structures

Executive Summary: EU FP7 IAPP Marie Curie Project: NOTES (Grant No. 230663) Summary 1. Objectives NOTES (Nonstationary respOnse of spaTially Extended Structures) project focuses on two areas: earthquake induced vibrations in spatially extended structures (e.g., tunnels, pipelines, bridges) and traffic/transportation induced vibrations in soil-structure medium. The project objectives are as follows: • to transfer knowledge on efficient non-stationary analysis of spatially extended infrastructure systems from the Structural Dynamics and Vibrations Group (SDVG) in TCD to Plaxis B.V, • to transfer knowledge about Finite Element analysis of geotechnical systems and software interface standards from Plaxis B.V. to TCD SDVG, • to expose TCD SDVG researchers to software and user modelling of infrastructure systems, • to train algorithm developers at Plaxis B.V. in the state-of the art of wavelet based vibration analysis and signal processing algorithms, and • to identify key areas in which wavelet based analysis information could enhance the analysis and behaviour of infrastructures in a meaningful way. 2. Main results achieved WP1. Industry practices of finite element in spatially extended structures: Training exercises have been developed as a part of this WP. The researchers were trained at PLAXIS BV on finite element modelling for seismic analysis using the PLAXIS software. This involved accounting for soil-structure interaction, i.e. considering an underground or a superstructure and a soil medium around the structure. The researchers were also trained on the fundamentals of wave propagation for vehicle soil interaction using the PLAXIS software. This involved training on modelling of the wave propagation of soil medium. WP2. Training in wavelet based response analysis for soil dynamics: Two training courses on MATLAB and wavelet processing have been developed. In the first course, one of the more experienced researchers (MER) from TCD instructed on the use of MATLAB as a computational tool and led the researchers from PLAXIS BV through a series of short projects using MATLAB as a tool for wavelet analysis with special reference to spectral characterisation of seismic ground motions. The researchers from Plaxis BV have been instructed by the TCD MER in the development of algorithms for non-stationary multi-support excitations. Fourier-based analysis has been used to introduce non-stationary frequency content effects and appropriate time delay due to shift in arrival time of waves. These effects are coupled with coherence functions for spatial coherence. The first training course resulted in a paper presented and published in the Proceedings of the 6th European Workshop on Structural Health Monitoring (EWSHM2012). In the second course, the TCD MER instructed on the use of MATLAB as a computational tool and led the researchers from PLAXIS BV through a series of short projects using MATLAB as a tool for wavelet analysis with special reference to vehicle dynamic problems. WP3. Time histories with frequency non-stationary and spatial correlation resulted in an algorithm for generation of multi-supported spatially correlated non-stationary excitation. A paper was presented and published in the Proceedings of the 15th World Conference on Earthquake Engineering (WCEE15) and another paper has been prepared for submission to the journal of Earthquake Engineering and Structural Dynamics. WP4. Seismic analysis of spatially extended structures: The effects of the generated multi-point spatially correlated excitation in the non-stationary response of spatially extended structures have been investigated. The resulting paper on wavelet-based evolutionary response of multi-span structures including wave-passage and site-response effects has been accepted for publication in Journal of Engineering Mechanics (ASCE). Other two papers have been presented and published in the Proceedings of the Fifth Asian-Pacific Symposium on Structural Reliability and its Applications and in the Proceedings of the 6th European Workshop on Structural Health Monitoring. WP5. Response analysis due to vehicle induced vibrations: The non-stationary response propagating in the soil medium due to vibrations from vehicular movement has been analyzed, the non-stationary load induced has been characterised and the non-stationary effects with proper boundary conditions have been studied. A finite element model has been developed, which allows for the dynamic calculation of spatially changing loads. The results have been published in a paper in the Key Engineering Materials Journal. Another paper is being prepared for submission to the journal of Structural Control and Health Monitoring. WP6. Software plug-in development for seismic and vehicle induced vibrations: Three plug-ins, namely EQSIM (EarthQuake SIMulator), ANOTES (Analysis of NOn-stationary response of spaTially-Extended Structures), and VIVA (Vehicle Induced Vibration Analysis) have been developed. EQSIM is the conditional simulation program resulting from WP2 that was completed, validated and submitted to PLAXIS BV together with the User Manual, Theory and Benchmark Reports. ANOTES is a computer program for unconditional simulations of spatially-varying non-stationary earthquake motions (resulting from WP3) and for analysis of non-stationary response of spatially-extended structures (resulting from WP4). ANOTES have been developed in Trinity College Dublin. The user manual of ANOTES has also been prepared. ANOTES is being tested, further developed and is currently being used by TCD researchers and students. VIVA is a computer program for analysis vehicle-induced vibrations based on finite elements and allows for the dynamic calculation of spatially varying loads. 3. Impacts: The results on earthquake induced vibrations in spatially extended structures can be useful for various structures such as tunnels, pipelines, bridges and dams. The results in traffic/transportation induced vibrations in soil-structure medium is applicable to vehicles moving in tunnels, railroad tracks with high speed trains or highway bridges with moving vehicles. The project helps to fill some of the gaps in the scientific understanding and knowledge in the area of earthquakes-induced and traffic/transportation-induced vibrations and the effects on soil-structure systems. For more information please visit the official website of NOTES project at http://notesproject.webs.com

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