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Influence of Foundation Modelling on the Seismic Response of a Concrete Dam
It is of great importance to ensure the structural safety of dams during earthquakes since a failure may cause catastrophic consequences. Conventional computation of the structural response of dams is based on a simplified approach where the foundation is considered as massless. However, recent developments have produced several new analysis methods that consider the foundation mass, modelled with absorbing boundaries and free-field forces. These newer methods are intended to simulate the seismic structural response more accurately, optimize the design and minimise future unnecessary reparations. The aim of the thesis was to investigate the influence of foundation modelling in seismic time history analyses. This was done by comparing the established massless foundation approach to two approaches with foundation mass and free-field forces included; the analytical approach presented by Song et al. (2018) and the direct FE approach by Løkke (2018). Both the efficiency of the seismic wave propagation simulation and the structural response of the dam were of interest, and points on the dam and foundation were studied to accurately compare these modelling approaches. The time history analyses showed that the massless approach corresponded perfectly with the ideal theoretical velocity at the foundation surface when studying only the foundation block, as expected. The analytical and direct FE however, differed slightly from the theoretical value but still gave an accurate representation. Both methods using free-field forces obtained equivalent and realistic structural responses when studying the dam-reservoir-foundation model. The massless method however,strongly overestimated the dam response and was therefore found to not capture the actual behavior of the dam accurately, despite modifications such as increased material damping in the concrete. Additionally, another aim was to analyse the influence of modelling in 2D versus 3D for determining the dynamic characteristics of the dam such as natural frequencies and ...
Influence of Foundation Modelling on the Seismic Response of a Concrete Dam
It is of great importance to ensure the structural safety of dams during earthquakes since a failure may cause catastrophic consequences. Conventional computation of the structural response of dams is based on a simplified approach where the foundation is considered as massless. However, recent developments have produced several new analysis methods that consider the foundation mass, modelled with absorbing boundaries and free-field forces. These newer methods are intended to simulate the seismic structural response more accurately, optimize the design and minimise future unnecessary reparations. The aim of the thesis was to investigate the influence of foundation modelling in seismic time history analyses. This was done by comparing the established massless foundation approach to two approaches with foundation mass and free-field forces included; the analytical approach presented by Song et al. (2018) and the direct FE approach by Løkke (2018). Both the efficiency of the seismic wave propagation simulation and the structural response of the dam were of interest, and points on the dam and foundation were studied to accurately compare these modelling approaches. The time history analyses showed that the massless approach corresponded perfectly with the ideal theoretical velocity at the foundation surface when studying only the foundation block, as expected. The analytical and direct FE however, differed slightly from the theoretical value but still gave an accurate representation. Both methods using free-field forces obtained equivalent and realistic structural responses when studying the dam-reservoir-foundation model. The massless method however,strongly overestimated the dam response and was therefore found to not capture the actual behavior of the dam accurately, despite modifications such as increased material damping in the concrete. Additionally, another aim was to analyse the influence of modelling in 2D versus 3D for determining the dynamic characteristics of the dam such as natural frequencies and ...
Influence of Foundation Modelling on the Seismic Response of a Concrete Dam
Harrison, Stella (Autor:in) / Nöjd, Siri (Autor:in)
01.01.2021
Hochschulschrift
Elektronische Ressource
Englisch
DDC:
621
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