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A platform for research: civil engineering, architecture and urbanism
Modification of direct-FE method for nonlinear seismic analysis of arch dam-reservoir-foundation system considering spatially varying ground motion
Abstract The present paper aims to modify an existing direct finite element method for nonlinear seismic analysis of high arch dam-reservoir-massed foundation systems to consider the effects of spatially varying ground motion at the bottom of the foundation rock with the non-stationary frequency characteristics. Viscous-damper boundaries are used to model the semi-unbounded foundation rock and the reservoir domains. In the existing direct finite element method, it is assumed that incident waves propagate vertically upwards from beneath the foundation rock towards the ground surface, and the effective seismic forces starting from the control motion on the foundation surface are applied to the bottom and the side vertical boundaries of the foundation rock. Three components of the motion recorded at Parkfield fault zone 16 during the 1983 Coalinga earthquake are selected as the free-field control motion at the surface of the foundation rock. On the other hand, in the modified direct FE method, fully non-stationary spectrum-compatible ground motion time histories, including both wave passage and incoherency effects, are simulated at a number of locations at the foundation bottom. Then the generated ground motions are used as multiple input incident motions to compute effective seismic forces applied to the bottom and the side boundaries of the foundation rock in the dam-reservoir-massed foundation system. Step-by-step procedures for computing the effective earthquake forces in the existing and the modified direct FE methods are presented. The nonlinearity originates from opening/sliding of the vertical contraction joints within the dam body. The reservoir–structure interaction is accounted for via the finite element method assuming compressible reservoir. The Karoun-I, a double curvature high arch dam, is selected as a case study. Several numerical validation models are conducted and compared with the benchmark solutions to indicate the accuracy of the existing direct FE method. It was seen that applying effective earthquake forces determined from the modified direct finite element method increases the nonlinear seismic response of the dam-reservoir-massed foundation system in terms of the crest displacements and stress levels.
Highlights Modification of Direct-FE method for analysis of dam-reservoir-foundation system with spatially varying ground motion.. Numerical validations compared with the benchmark solutions. Applying appropriate viscous-damper boundaries and also effective earthquake forces to these boundaries. Applying a non-iterative spectral-representation-based methodology for simulating spatial variation of ground motions. Seismic performance evaluation of concrete dams.
Modification of direct-FE method for nonlinear seismic analysis of arch dam-reservoir-foundation system considering spatially varying ground motion
Abstract The present paper aims to modify an existing direct finite element method for nonlinear seismic analysis of high arch dam-reservoir-massed foundation systems to consider the effects of spatially varying ground motion at the bottom of the foundation rock with the non-stationary frequency characteristics. Viscous-damper boundaries are used to model the semi-unbounded foundation rock and the reservoir domains. In the existing direct finite element method, it is assumed that incident waves propagate vertically upwards from beneath the foundation rock towards the ground surface, and the effective seismic forces starting from the control motion on the foundation surface are applied to the bottom and the side vertical boundaries of the foundation rock. Three components of the motion recorded at Parkfield fault zone 16 during the 1983 Coalinga earthquake are selected as the free-field control motion at the surface of the foundation rock. On the other hand, in the modified direct FE method, fully non-stationary spectrum-compatible ground motion time histories, including both wave passage and incoherency effects, are simulated at a number of locations at the foundation bottom. Then the generated ground motions are used as multiple input incident motions to compute effective seismic forces applied to the bottom and the side boundaries of the foundation rock in the dam-reservoir-massed foundation system. Step-by-step procedures for computing the effective earthquake forces in the existing and the modified direct FE methods are presented. The nonlinearity originates from opening/sliding of the vertical contraction joints within the dam body. The reservoir–structure interaction is accounted for via the finite element method assuming compressible reservoir. The Karoun-I, a double curvature high arch dam, is selected as a case study. Several numerical validation models are conducted and compared with the benchmark solutions to indicate the accuracy of the existing direct FE method. It was seen that applying effective earthquake forces determined from the modified direct finite element method increases the nonlinear seismic response of the dam-reservoir-massed foundation system in terms of the crest displacements and stress levels.
Highlights Modification of Direct-FE method for analysis of dam-reservoir-foundation system with spatially varying ground motion.. Numerical validations compared with the benchmark solutions. Applying appropriate viscous-damper boundaries and also effective earthquake forces to these boundaries. Applying a non-iterative spectral-representation-based methodology for simulating spatial variation of ground motions. Seismic performance evaluation of concrete dams.
Modification of direct-FE method for nonlinear seismic analysis of arch dam-reservoir-foundation system considering spatially varying ground motion
Varmazyari, Mehdi (author) / Sabbagh-Yazdi, Saeed-Reza (author)
2020-10-21
Article (Journal)
Electronic Resource
English
Nonlinear Seismic Response Analysis of High Arch Dams to Spatially-Varying Ground motions
| Springer Verlag | 2019
Nonlinear Seismic Response Analysis of High Arch Dams to Spatially-Varying Ground motions
| Springer Verlag | 2018
Earthquake response of arch dams to spatially varying ground motion
| Online Contents | 2010