Seismic Response of a Large-Span Roof Diaphragm

1989 ◽  
Vol 5 (2) ◽  
pp. 337-350 ◽  
Author(s):  
Mehmet Celebi ◽  
Giovanni Bongiovanni ◽  
Erdal Safak ◽  
A. Gerald Brady
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Response ◽  
Ground Level ◽  
Element Model ◽  
Structural Damping ◽  
Peak Acceleration ◽  
The West ◽  
Flexible Diaphragm ◽  
Code Provisions

Records obtained from the West Valley College Gymnasium in Saratoga, California during the 1984 Morgan Hill earthquake are used to study the dynamic behavior of the overall gymnasium as well as its flexible diaphragm. The ground-level motions recorded in the two orthogonal axes of the structure differ considerably in peak acceleration and amplify by approximately 1.5 times at the roof edges and by 4-5 times at the center of the diaphragm. The diaphragm responds with a frequency of approximately 4 Hz in both orthogonal axes. A simple finite-element model is used to match the fundamental frequency of the diaphragm with that from the records. Using this model and the ground-level motions as input, the diaphragm center displacements are calculated by varying the structural damping. Best comparisons are obtained for 5% damping. These results are discussed in terms of the code provisions.

scholarly journals The Effect of Shear Sliding of Vertical Contraction Joints on Seismic Response of High Arch Dams with Fine Finite Element Model

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Shengshan Guo ◽  
Jianxin Liao ◽  
Hailong Huang ◽  
Hui Liang ◽  
Deyu Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Response ◽  
Element Model ◽  
Arch Dam ◽  
Slip Condition ◽  
Dead Load ◽  
High Arch Dam ◽  
Arch Dams ◽  
Contraction Joints

The contraction joints of arch dams with and without shear keys are simplified to be with no-slip condition and with relative sliding condition, respectively. Based on the Lagrange multiplier method, a contact model considering the manner of independent cantilever dead load type with no-slip condition and relative sliding condition is proposed to model the nonlinearities of vertical contraction joins, which is special to the nonlinear analysis of arch dams considering the manner of dead load type. Different from the conventional Gauss iterative method, the strategy of the alternating iterative solution of normal force and tangential force is employed. The parallelization based on overlapping domain decomposition method (ODDM) and explicit message passing using distributed memory parallel computers is employed to improve the computational efficiency. An existing high arch dam with fine finite element model is analyzed to investigate the effect of shear sliding of vertical joints on seismic response of the arch dam. The result shows that the values of maximum principal tensile stress under relative sliding condition are significantly greater than those under no-slip condition.

scholarly journals Seismic Response of Multi-Story Structure Strengthened with Micropiles

2020 ◽  
Vol 9 (6) ◽  
pp. 369-379
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Response ◽  
Soil Layer ◽  
Element Model ◽  
Soil Behavior ◽  
Deep Foundation ◽  
Story Structure ◽  
Study Results ◽  
Wide Range

Micropiles are reinforced grouted piles that have small diameters commonly not higher than 30 cm. They are widely used for slope stabilization, controlling structural settlement, and in some cases, as retaining structures. Also, they are used for resisting dynamic uplift loads, seismic retrofit mainly in restrictive and low headroom areas, and retrofitting of historical monuments. The main goal of this research is to develop a finite element model that can capture the different aspects of seismic behavior of multi-story structure supported with deep foundation via using of micropiles. Also, a main target for the executing numerical modelling is to show the influence of the surrounding soil on this system and vice versa. Firstly, a representative two-dimensional finite element model is conducted to represent the soil-structure interaction system under seismic excitation supported with proper boundary conditions in PLAXIS 2D V20 for dynamic analysis based on previous recommendations considering the nonlinear soil behavior. The behavior of micropiles is studied and verified using previous results. Based on these models, the effect of lateral dynamic loads on the response of a structure with different foundation types is investigated. Also, a wide range of parametric studies, considering structure properties, earthquake magnitude, micropile diameter, micropile length, and the number of micropiles, have been carried out in order to investigate the actual interaction between soil, substructure, and superstructures. The study results showed that the seismic response of the structure is highly affected by the properties of the sub-surface soil layer. Consequently and similarly, analysis results established that underpinning using micropiles is an efficient technique for controlling the seismic response of existing structures.

A Parametric Study for the Seismic Response Analysis of a Nuclear Reactor Building by Using a Three-Dimensional Finite Element Model

2016 ◽  
Author(s):  
Byunghyun Choi ◽  
Akemi Nishida ◽  
Norihiro Nakajima
Keyword(s):  
Finite Element ◽  
Research And Development ◽  
Finite Element Model ◽  
Seismic Response ◽  
Parametric Study ◽  
Three Dimensional ◽  
Element Model ◽  
Response Analysis ◽  
Seismic Response Analysis ◽  
Uncertainty Parameters

Research and development of three-dimensional vibration simulation technologies for nuclear facilities is one mission of the Center for Computational Science and e-Systems of the Japan Atomic Energy Agency (JAEA). A seismic intensity of upper 5 was observed in the area of High-Temperature Engineering Test Reactor (HTTR) at the Oarai Research and Development Center of JAEA during the 2011 Tohoku earthquake. In this paper, we report a seismic response analysis of this earthquake using three-dimensional models of the HTTR building. We performed a parametric study by using uncertainty parameters. Furthermore, we examined the variation in the response result for the uncertainty parameters to create a valid 3D finite element model.

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