scholarly journals The effect of non-uniformity in ground motions on the seismic response of arch dams

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Mohammad Reza Pouya ◽  
Morteza Sohrabi-Gilani ◽  
Mohsen Ghaemian
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
Dam Foundation ◽  
Finite Element Program ◽  
Common Assumption ◽  
Arch Dams ◽  
Time Histories ◽  
Element Program ◽  
The Common ◽  
Spatially Varying

AbstractRecorded ground accelerations at various locations of Karun III Dam during November 20, 2007, were recorded by an array of accelerometers located on the dam. In terms of amplitude and phase, these accelerations show non-uniformities in different elevations. In this paper, the effect of these non-uniform ground motions on the seismic response of the dam taking dam-reservoir-foundation interaction into account is investigated. The EACD-3D-2008 finite element program and ABAQUS Software are used for carrying out the seismic analyses. For this purpose, time histories of the earthquake accelerations are interpolated at nodal points located on the dam foundation interface. The analysis has been repeated, considering the common assumption of uniform ground motions. Comparing the results obtained from these two analyses reveals that the computed displacements in the crest due to the spatially varying excitations are in more conformity with the recorded information. Moreover, neglecting the non-uniform nature of ground motions in the model leads to underestimating the tensile stress values within the dam body.

Influence of effective parameters of non-orthogonal smeared crack approach in seismic response of concrete arch dams

2003 ◽  
Vol 30 (5) ◽  
pp. 890-901 ◽  
Author(s):  
Radin Espandar ◽  
Vahid Lotfi ◽  
Ghani Razaqpur
Keyword(s):  
Seismic Response ◽  
Nonlinear Dynamic Analysis ◽  
Arch Dam ◽  
Effective Parameters ◽  
Finite Element Program ◽  
Cracking Behavior ◽  
Arch Dams ◽  
Smeared Crack Approach ◽  
Element Program ◽  
Smeared Crack

A rigorous and relatively efficient algorithm based on the non-orthogonal smeared crack approach is coded in a special finite element program to study the seismic response of arch dams. The formulation is briefly presented. The 130 m high Shahid Rajaee arch dam in Iran subjected to the Friuli-Tolmezzo earthquake is selected to present a practical application of the technique. Under the same geometry and loading conditions, six nonlinear analyses with different parameters are performed, and the results are compared with each other and a linear case. The varied parameters include secant and elastic unloading–reloading options, threshold angle, and tensile strength of the material. It is concluded that the non-orthogonal smeared crack approach can redistribute the state of stresses and produces a more realistic profile of stresses in the dam. A drift in the crest displacements forms the prominent characteristics of the cracking behavior. The results also suggest that the dam can suffer significant cracking during a strong earthquake and still remain stable. Moreover, the influences of the mentioned parameters in the seismic response of the dam are comprehensively discussed.Key words: nonlinear dynamic analysis, concrete arch dam, smeared crack approach.

Research of Longitudinal Seismic Response of Self-Anchored Cable-Stayed Suspension Bridge under Pile-Soil-Structure Interaction

2011 ◽  
Vol 255-260 ◽  
pp. 1167-1170
Author(s):  
Feng Miao ◽  
Wang Bo ◽  
Guan Ping
Keyword(s):  
Seismic Response ◽  
Soil Structure ◽  
Suspension Bridge ◽  
Soil Structure Interaction ◽  
Response Analysis ◽  
Fe Model ◽  
Longitudinal Displacement ◽  
Finite Element Program ◽  
Structure Interaction ◽  
Element Program

Based on scheme of Dalian gulf cross-sea bridge, in this paper, a 3-dimensional FE model for Self-anchored cable-stayed suspension bridge is established with finite element program and pile-soil-structure interaction is simulated by use of the equivalent embed fixation model. Based on the FE model, model analysis is carried out and the effects of pile-soil-structure interaction on dynamic behavior of long-span self-anchored cable-stayed suspension bridge are specially studied. The seismic response analysis result considering that pile-soil-structure interaction was compared with that of without considering such interaction. The analysis result show that interaction extend the nature period of structure, has the greatest impact to the first vibration mode; meanwhile, enlarged longitudinal displacement and moment of stiffening beam in middle of main span, longitudinal displacement on top of tower and axial force at bottom, but reduced the moment of tower at bottom. The research results provide some theoretical foundation to composite structure system.

Computational Modeling of Interaction Between Actions and Action Effects of FPSO Topside Structures Subject to Jet Fire

2010 ◽  
Author(s):  
G. M. Katsaounis ◽  
D. Katsourinis ◽  
M. S. Samuelides ◽  
M. Founti ◽  
Jeom Kee Paik ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Constitutive Relations ◽  
Finite Element Program ◽  
Effect Analysis ◽  
Ansys Cfx ◽  
Commercial Code ◽  
Time Histories ◽  
Element Program ◽  
Computational Fluid Dynamics Cfd ◽  
Nonlinear Elastic

This paper presents a computational modeling of accidental fire actions on the topside structures of a floating, production, storage and offloading (FPSO) unit. According to the assumed scenario, the accident results in a jet fire, which loads the structure by temperature increments and pressures generation on their exposed surfaces. Temperature distributions were obtained by computational fluid dynamics (CFD) simulations, using the ANSYS CFX commercial code. The temperature versus time histories computed were first approximated (idealized) by smoother curves, based on fewer time-points, while retaining the maximum and minimum values. A similar procedure was also followed for the pressure variations. For the consequence (action effect) analysis the LSDYNA nonlinear finite element program was employed and the structures were modeled using shell finite elements with nonlinear (elastic-thermal plastic) constitutive relations. On the structure surfaces non coinciding grids were used for the two kinds of analyses (i.e., the CFD and FEM), in order to accommodate the diverse requirements of the different problems. The procedure of assignment the pressure and temperature loadings directly from the CFD results to the FEM model is described and representative results are given through the application of the methodology to a sample problem.

Contribution of local site-effect on the seismic response of suspension bridges to spatially varying ground motions

2016 ◽  
Vol 10 (5) ◽  
pp. 1233-1251 ◽  
Author(s):  
Suleyman Adanur ◽  
Ahmet C. Altunisik ◽  
Kurtulus Soyluk ◽  
A. Aydin Dumanoglu ◽  
Alemdar Bayraktar
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
Site Effect ◽  
Suspension Bridges ◽  
Local Site Effect ◽  
Local Site ◽  
Spatially Varying Ground Motions ◽  
Spatially Varying

Identification of Linear Structural Systems With a Limited Set of Input-Output Measurements

2009 ◽  
Vol 76 (3) ◽  
Author(s):  
Jun Yu ◽  
Maura Imbimbo ◽  
Raimondo Betti
Keyword(s):  
Nonlinear Least Squares ◽  
Order Model ◽  
Common Assumption ◽  
Stiffness Matrices ◽  
Time Histories ◽  
Uniqueness Of The Solution ◽  
Robustness To Noise ◽  
Least Squares Optimization ◽  
The Common ◽  
Response Output

In this paper, a methodology is presented for the identification of the complete mass, damping, and stiffness matrices of a dynamical system using a limited number of time histories of the input excitation and of the response output. Usually, in this type of inverse problems, the common assumption is that the excitation and the response are recorded at a sufficiently large number of locations so that the full-order mass, damping, and stiffness matrices can be estimated. However, in most applications, an incomplete set of recorded time histories is available and this impairs the possibility of a complete identification of a second-order model. In this proposed approach, all the complex eigenvectors are correctly identified at the instrumented locations (either at a sensor or at an actuator location). The remaining eigenvector components are instead obtained through a nonlinear least-squares optimization process that minimizes the output error between the measured and predicted responses at the instrumented locations. The effectiveness of this approach is shown through numerical examples and issues related to its robustness to noise polluted measurements and to uniqueness of the solution are addressed.

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