scholarly journals Three-dimensional earthquake analysis of roller-compacted concrete dams

2012 ◽  
Vol 12 (7) ◽  
pp. 2369-2388 ◽  
Author(s):  
M. E. Kartal
Keyword(s):  
Ground Motion ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Time History ◽  
Hydrodynamic Pressure ◽  
Reservoir Water ◽  
Hardening Material ◽  
Roller Compacted Concrete ◽  
Contraction Joints ◽  
Non Linear

Abstract. Ground motion effect on a roller-compacted concrete (RCC) dams in the earthquake zone should be taken into account for the most critical conditions. This study presents three-dimensional earthquake response of a RCC dam considering geometrical non-linearity. Besides, material and connection non-linearity are also taken into consideration in the time-history analyses. Bilinear and multilinear kinematic hardening material models are utilized in the materially non-linear analyses for concrete and foundation rock respectively. The contraction joints inside the dam blocks and dam–foundation–reservoir interaction are modeled by the contact elements. The hydrostatic and hydrodynamic pressures of the reservoir water are modeled with the fluid finite elements based on the Lagrangian approach. The gravity and hydrostatic pressure effects are employed as initial condition before the strong ground motion. In the earthquake analyses, viscous dampers are defined in the finite element model to represent infinite boundary conditions. According to numerical solutions, horizontal displacements increase under hydrodynamic pressure. Besides, those also increase in the materially non-linear analyses of the dam. In addition, while the principle stress components by the hydrodynamic pressure effect the reservoir water, those decrease in the materially non-linear time-history analyses.

scholarly journals A Nonlinear Inverse Design Problem for a Pipe Type Heat Exchanger Equipped with Internal Z-Shape Lateral Fins and Ribs

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6424
Author(s):  
Cheng-Hung Huang ◽  
Chih-Yang Kuo
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Design Problem ◽  
Direct Problem ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Design Variables ◽  
Non Linear ◽  
Inverse Design Problem ◽  
Η Value

A non-linear three-dimensional inverse shape design problem was investigated for a pipe type heat exchanger to estimate the design variables of continuous lateral ribs on internal Z-shape lateral fins for maximum thermal performance factor η. The design variables were considered as the positions, heights, and number of ribs while the physical properties of air were considered as a polynomial function of temperature; this makes the problem non-linear. The direct problem was solved using software package CFD-ACE+, and the Levenberg–Marquardt method (LMM) was utilized as the optimization tool because it has been proven to be a powerful algorithm for solving inverse problems. Z-shape lateral fins were found to be the best thermal performance among Z-shape, S-shape, and V-shape lateral fins. The objective of this study was to include continuous lateral ribs to Z-shape lateral fins to further improve η. Firstly, the numerical solutions of direct problem were solved using both polynomial and constant air properties and then compared with the corrected solutions to verify the necessity for using polynomial air properties. Then, four design cases, A, B, C and D, based on various design variables were conducted numerically, and the resultant η values were computed and compared. The results revealed that considering continuous lateral ribs on the surface of Z-shape lateral fins can indeed improve η value at the design working condition Re = 5000. η values of designs A, B and C were approximately 13% higher than that for Z-shape lateral fins, however, when the rib numbers were increased, i.e., design D, the value of η became only 11.5 % higher. This implies that more ribs will not guarantee higher η value.

scholarly journals Numerical assessment of vertical ground motion effects on highway bridges

2020 ◽  
Vol 47 (7) ◽  
pp. 790-800 ◽  
Author(s):  
Hadi Aryan ◽  
Mehdi Ghassemieh
Keyword(s):  
Ground Motion ◽  
Numerical Study ◽  
Three Dimensional ◽  
Vertical Component ◽  
Time History ◽  
Highway Bridges ◽  
Vertical Excitation ◽  
Vertical Ground Motion ◽  
Field Evidence ◽  
Vertical Ground

Field evidence of recent earthquakes shows serious bridge damages due to the direct compression or tension in the columns and some flexural and shear failures caused by the variation in axial force of the columns. These damages could not be produced solely by the horizontal seismic excitations; the vertical component of the earthquake is involved. This paper presents a numerical study highlighting the presence of vertical seismic excitation. Nonlinear time history analyses are conducted on detailed three-dimensional models of multi-span simply supported and multi-span continuous bridges using a suite of representative ground motions. The results showed the significant influence of vertical excitation on the bridge responses. Therefore, it is imperative to include more efficient criteria to upgrade the design codes and extend practical techniques that consider and cope with the structural effects of vertical ground motion along with the horizontal excitations.

Response of Transmission Lines under Three-Dimensional Seismic Excitations

2012 ◽  
Vol 166-169 ◽  
pp. 2259-2264
Author(s):  
Li Tian ◽  
Hong Nan Li ◽  
Wen Ming Wang
Keyword(s):  
Transmission Line ◽  
Ground Motion ◽  
Transmission Lines ◽  
Three Dimensional ◽  
Time History ◽  
Maximum Response ◽  
Nonlinear Time History Analysis ◽  
Seismic Excitations ◽  
Practical Engineering ◽  
Nonlinear Time History

The behavior of transmission line under three-dimensional seismic excitations is studied by numerical simulation. According to a practical engineering, the transmission towers are modeled by frame elements and the transmission lines are modeled by cable element account for the nonlinearity of the cable. The effects of single-dimensional, two-dimensional and three-dimensional ground motions on the responses of transmission line are investigated using nonlinear time history analysis method, respectively. The results indicate that the longitudinal maximum response of transmission lines can be obtained considering longitudinal ground motion excitation only. The transverse maximum response of transmission lines can be obtained considering transverse ground motion excitation only. Neglecting multiple nature of ground motion in analysis will significantly underestimate the vertical responses of the transmission lines. To obtain an accurate seismic response of transmission lines, three-dimensional ground motion inputs are required.

scholarly journals A modified cubic B-spline differential quadrature method for three-dimensional non-linear diffusion equations

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 453-463 ◽  
Author(s):  
Sumita Dahiya ◽  
Ramesh Chandra Mittal
Keyword(s):  
Numerical Solutions ◽  
Differential Quadrature Method ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Initial Boundary ◽  
Differential Quadrature ◽  
Quadrature Method ◽  
Linear Diffusion ◽  
B Spline ◽  
Non Linear

AbstractThis paper employs a differential quadrature scheme for solving non-linear partial differential equations. Differential quadrature method (DQM), along with modified cubic B-spline basis, has been adopted to deal with three-dimensional non-linear Brusselator system, enzyme kinetics of Michaelis-Menten type problem and Burgers’ equation. The method has been tested efficiently to three-dimensional equations. Simple algorithm and minimal computational efforts are two of the major achievements of the scheme. Moreover, this methodology produces numerical solutions not only at the knot points but also at every point in the domain under consideration. Stability analysis has been done. The scheme provides convergent approximate solutions and handles different cases and is particularly beneficial to higher dimensional non-linear PDEs with irregularities in initial data or initial-boundary conditions that are discontinuous in nature, because of its capability of damping specious oscillations induced by high frequency components of solutions.

Three Dimensional Seismic Response Analyses on the Isolated Spatial Beam String Structure

2011 ◽  
Vol 255-260 ◽  
pp. 2526-2531
Author(s):  
Nan Zhao ◽  
Yang Jiang
Keyword(s):  
Linear Time ◽  
Three Dimensional ◽  
Great Influence ◽  
Time History ◽  
Gravity Load ◽  
Spatial Beam ◽  
Non Linear ◽  
String Structure ◽  
Rare Earthquake ◽  
Filtering Effect

Three dimensional seismic responses of an isolated spatial beam string structure are studied by applying the non-linear finite element theory. The filtering effect of the main structure, which amplifies the ground input, is investigated. The results indicate that the vertical rare earthquake has great influence on the isolated spatial beam string structure, and stresses of cables, frames and slab shells under vertical rare earthquake are all much greater than that under gravity load. Results of non-linear time history analysis show that elements’ stresses are in elastic stage, thus the spatial beam string structure with isolation keeps safe under rare earthquake.

scholarly journals Optimal Design of Earthquake-Resistant Buildings Based on Neural Network Inversion

2021 ◽  
Vol 11 (10) ◽  
pp. 4654
Author(s):  
Carlo Calledda ◽  
Augusto Montisci ◽  
Maria Cristina Porcu
Keyword(s):  
Neural Network ◽  
Optimal Design ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Structural Response ◽  
Time History ◽  
Optimal Choice ◽  
Design Parameters ◽  
Earthquake Resistant ◽  
Non Linear

An effective seismic design entails many issues related to the capacity-based assessment of the non-linear structural response under strong earthquakes. While very powerful structural calculation programs are available to assist the designer in the code-based seismic analysis, an optimal choice of the design parameters leading to the best performance at the lowest cost is not always assured. The present paper proposes a procedure to cost-effectively design earthquake-resistant buildings, which is based on the inversion of an artificial neural network and on an optimization algorithm for the minimum total cost under building code constraints. An exemplificative application of the method to a reinforced-concrete multi-story building, with seismic demands corresponding to a medium-seismicity Italian zone, is shown. Three design-governing parameters are assumed to build the input matrix, while eight capacity-design target requirements are assigned for the output dataset. A non-linear three-dimensional concentrated plasticity model of the structure is implemented, and time-history dynamic analyses are carried out with spectrum-consistent ground motions. The results show the promising ability of the proposed approach for the optimal design of earthquake-resistant structures.

scholarly journals Earthquakes Effect on the Behavior of Multi-Story RC Building Using Non-Linear Dynamic Analysis

2019 ◽  
Vol 2 (2) ◽  
pp. 307-316
Author(s):  
M Nadir Olabi ◽  
Osman Kirtel ◽  
Naci Caglar
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Ground Motions ◽  
Nonlinear Modeling ◽  
Time History ◽  
Shear Walls ◽  
Base Shear ◽  
Linear Dynamic ◽  
Non Linear ◽  
Rc Building

One of the buildings that were designed depending on the old Syrian Code is selected and modeled using SAP2000 by taking its non-linear properties to be checked under dynamical loading. Three earthquake records are taken and applied to the model as Time History loading cases. The dynamical displacement of the top roof of the building and the hysterical diagrams of the relation between base shear and roof displacement is compared and discussed. Asymmetry of shear walls and cores is responsible of the differences in responses of building elements, and insufficient nonlinear modeling of shear walls prevents from finding the real capacity of the system, although comparing pushover curves with hysteric loops from the applied ground motion excitations shows that the building is capable, depending on its old design, to withstand various types of extreme ground motions and earthquakes.

Response of Sluice-Dam Structure on a Strong Earthquake Excitation

2013 ◽  
Vol 444-445 ◽  
pp. 874-878
Author(s):  
Lei Ge ◽  
Li Xiang Zhang ◽  
Ze Li
Keyword(s):  
Strong Earthquake ◽  
Large Scale ◽  
Complex Structure ◽  
Three Dimensional ◽  
Time History ◽  
Dynamical Response ◽  
Rock Foundation ◽  
Earthquake Excitation ◽  
Reservoir Water ◽  
High Rise

For a high-rise complex structure built at an earthquake zone, response characteristics to an earthquake action are always needed to be as an important index to evaluate its dynamical performances. This article carried out a three-dimensional dynamical response analyses of a large-scale complex sluice-dam structure by using the software of ANSYS under a strong earthquake excitation by nonlinear finite element method. Through the analyses of the time history response of the high-rise complex structure to the specified earthquake records, the seismic performances of the structure system under consideration of the rock foundation-sluice structure-reservoir water interaction were well evaluated.

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