Seismic Design Analysis of Underground Station Structure in Rail Transit Engineering

2021 ◽  
Keyword(s):  
Seismic Design ◽  
Design Analysis ◽  
Rail Transit ◽  
Underground Station ◽  
Station Structure

Appropriate Damping on Seismic Design Analysis for Inelastic Response Assessment of Piping

2018 ◽  
Author(s):  
Tomoyoshi Watakabe ◽  
Masaki Morishita
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Response Spectrum ◽  
Response Assessment ◽  
Design Analysis ◽  
Stress Factors ◽  
Design Rule ◽  
Inelastic Analysis ◽  
Current Design ◽  
Seismic Design Method

The current seismic design rule on piping assumes elastic analysis without the effect of response reduction due to plasticity, although some degree of plasticity is allowed in its allowable limits. Damping for the seismic design analysis is conservatively determined depending on the number of supports and thermal insulation conditions. These conservative assumptions lead to large amount of design margin. Based on such recognition, to provide a more rational seismic design method, a new Code Case for seismic design of piping is now under development in the framework of JSME Nuclear Codes and Standards as an alternative rule to the current design rule. The Code Case provides detailed inelastic analysis with using shell or solid FEA models as a more rational method. Simplified analysis with an additional damping taking the response reduction due to plasticity into account is now under consideration to incorporate the convenience in design. In this study, a series of analysis was made to see the adequacy of the simplified inelastic analysis. Design margins contained in the current design analysis method composed of response spectrum analysis and stress factors was quantitatively assessed in the view point of additional damping.

Combination of modal responses in linear spectral method: comparison of different formulae for correlation coefficients

2021 ◽  
pp. 32-42
Author(s):  
Alexander G. Tyapin
Keyword(s):  
Spectral Method ◽  
Static Analysis ◽  
Seismic Design ◽  
Method Comparison ◽  
Correlation Coefficients ◽  
Design Analysis ◽  
Common Method ◽  
The Common ◽  
The One ◽  
Mode Response

Linear-spectral method (LSM) is still the common method for the seismic design analysis. "One-component one-mode" responses, obtained by static analysis in the conventional variant of LSM, are combined twice: first for different modes but for each single excitation component separately, then for the different excitation components. In the alternative LSM variant presented in the Russian code SP 14.13330, first one chooses the "most dangerous" direction of the one-component excitation for each mode; then calculates the "one-mode" response for this excitation, and finally these responses are combined. In both cases the combination is performed using the complete quadratic combination (CQC) rule. Different documents suggest different formulae for the correlation coefficients. In the paper different formulae are compared to each other. The goal is to limit the number of calculated coefficients and decrease the amount of calculations.

Research on Seismic Reduction and Isolation Measures for Urban Underground Station Structure

2020 ◽  
pp. 2150012
Author(s):  
Guobo Wang ◽  
Feng Ba ◽  
Xianfeng Ma ◽  
Jielin Zhao ◽  
Yifei Yue
Keyword(s):  
Underground Structure ◽  
Reaction Force ◽  
Wave Impedance ◽  
Internal Force ◽  
Finite Element Models ◽  
Isolation Layer ◽  
Dimensional Finite Element ◽  
Reduction Effect ◽  
Underground Station ◽  
Station Structure

Based on a rectangle underground station structure, two-dimensional finite element models are established in this study to explore the effectiveness of different seismic reduction and isolation measures for underground structure, where Davidenkov model is adopted to consider the soil nonlinearity and the underground structure is considered elastic. The performances of the seismic reduction and isolation measures are evaluated by assessing the structure internal force and deformation responses. Depending on the ratio of wave impedance between the isolation layer and the structure, the isolation layers are divided into rigid and flexible types. The effects of the length and elastic modulus of rigid isolation layer as well as that of the thickness and shear modulus of flexible isolation layer are investigated. The results show that the seismic reduction effect of rigid isolation layer is better with the increase of stiffness, and the effect of flexible isolation layer is more obvious with the decrease of stiffness, which are consistent with the classical impedance theory. Furthermore, the middle column of subway station is usually the most vulnerable during seismic shakings, and one viable way to improve its seismic behavior is to reduce the column end constraints. Therefore, different column constraints consisting of swing, hinge, sliding connection and isolation bearing are considered. The numerical results suggest that among the different column end constraints considered, the sliding connection is comparatively more favorable, which can effectively limit the lateral deformation of column while imposing no horizontal reaction force.

Discussion on the Seismic Design Analysis Method of Masonry Building

2010 ◽  
Vol 163-167 ◽  
pp. 3952-3957
Author(s):  
Xiao Song Ren ◽  
Yu Fei Tao
Keyword(s):  
Shear Strength ◽  
Seismic Performance ◽  
Seismic Design ◽  
Design Analysis ◽  
Masonry Building ◽  
Analysis Method ◽  
Seismic Capacity ◽  
Major Earthquake ◽  
Moderate Earthquake ◽  
Seismic Design Code

The main seismic objective in China is defined as “no failure under minor earthquake, repairable damage under moderate earthquake and no collapse under major earthquake”. Both strength and deformation are important to evaluate the seismic performance. For masonry building, only the shear strength check under minor earthquake is stipulated in the current Chinese seismic design code. Due to the poor ductility of masonry building, the seismic design analysis method may not guarantee the collapse-resistant capacity under major earthquake. For the achievement of the seismic objective, the demand of ductility is discussed. A typical severely damaged masonry building by the 5.12 Wenchuan Earthquake of 2008 is presented for the analysis of the through X-shape crack on the load-bearing wall. In order to enhance the collapse-resistant capacity, the authors suggest more shear strength margin to take the influence of structural ductility into consideration. The feasible way can be easily realized as a target to raise the limitation for the shear strength check parameter under minor earthquake and to keep uniform seismic capacity in two directions. The investigated building is also illustrated here as an example to process the shear strength check for better seismic performance by the authors’ suggestion.

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