scholarly journals Damage estimation on concrete gravity dams through artificial accelerograms

2018 ◽  
Vol 211 ◽  
pp. 14001
Author(s):  
Enrico Zacchei ◽  
José Luis Molina
Keyword(s):  
Response Curve ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Damage Index ◽  
Spectral Density Function ◽  
Gravity Dams ◽  
Concrete Gravity Dams ◽  
Power Spectral ◽  
The Time Domain ◽  
Artificial Accelerograms

The aim of this paper is to analyse the damage on gravity dams through artificial earthquakes from two methods. The first procedure defines the performance and the response curve of concrete gravity dams using a harmonic function which establishes linear displacements. The other procedure to obtain the artificial earthquake defines the power spectral density function consistent with the response spectrum. This artificial accelerogram is necessary to quantify the response curve of concrete gravity dams in the time domain. The seismic activity in Spain is not frequent, therefore it is often difficult to select real accelerograms to perform a complete seismic analysis, which makes artificial accelerograms extremely useful. Finally, combining these two procedures, a damage index is determined for assessing the crack’s magnitude. These both efficient and practical procedures are useful to develop further complicated analysis.

Seismic Analysis of Concrete Gravity Dams Considering Foundation Mass Effect

2018 ◽  
Vol 22 (12) ◽  
pp. 4988-4996 ◽  
Author(s):  
Erfan Asghari ◽  
Reza Taghipour ◽  
Mohsen Bozorgnasab ◽  
Mojtaba Moosavi
Keyword(s):  
Seismic Analysis ◽  
Mass Effect ◽  
Gravity Dams ◽  
Concrete Gravity Dams

Seismic Analysis of Concrete Gravity Dams: Nonlinear Fracture Mechanics Models and Size-Scale Effects

2011 ◽  
Vol 82 ◽  
pp. 374-379 ◽  
Author(s):  
Marco Paggi ◽  
Giuseppe Ferro ◽  
Franco Braga
Keyword(s):  
Crack Propagation ◽  
Seismic Analysis ◽  
Scale Effects ◽  
Constitutive Law ◽  
Dam Failure ◽  
Gravity Dams ◽  
Dam Foundation ◽  
Size Scale ◽  
Concrete Gravity Dams ◽  
Nonlinear Dynamic Problem

The phenomenon of interface crack propagation in concrete gravity dams underseismic loading is herein addressed. This problem is particularly important from the engineeringpoint of view. In fact, besides Mixed-Mode crack growth in concrete, dam failure is oftenthe result of crack propagation along the rock-concrete interface at the dam foundation. Toanalyze such a problem, the generalized interface constitutive law recently proposed by the¯rst author is used to proper modelling the phenomenon of crack closing and reopening at theinterface. A damage variable is also introduced in the cohesive zone formulation in order topredict crack propagation under repeated loadings. Special attention is given to the complexityresulting from the solution of the nonlinear dynamic problem and to the choice of the interfaceconstitutive parameters, taking into account the important size-scale e®ects observed in thesecyclopic structures. Numerical examples will show the capabilities of the proposed approachwhen applied to concrete gravity dams.

Generating Seismic Design Power Spectral Density Functions

1989 ◽  
Vol 5 (2) ◽  
pp. 351-368 ◽  
Author(s):  
John T. Christian
Keyword(s):  
Spectral Density ◽  
Density Function ◽  
Power Spectral Density ◽  
Response Spectrum ◽  
Response Spectra ◽  
Spectral Density Function ◽  
Density Functions ◽  
Power Spectral Density Function ◽  
Power Spectral ◽  
Spectral Density Functions

The most widely used way to describe earthquake motions for purposes of design is the response spectrum, but it is often difficult to apply a response spectrum when dealing with multiple degrees of freedom or with complex representations of structural behavior. The power spectral density function, which is a more fundamental description of the frequency content of ground motion, has found increasing use and is essential in the most popular methods of developing artificial earthquake time histories. Although in theory the response spectrum and the power spectral density are closely related, in practice it has proven difficult to compute one from the other. Two integration schemes described in the literature have been implemented in an interactive micro-computer program SPEED and are found to give substantially identical results. When they are used to find a power spectral density function that corresponds to a standard design response spectrum, the results do not converge at frequencies above 10 Hz. Possible explanations for this lie in the shape of the prescribed standard response spectra, the methodology used to generate them, and the lack of statistical variation at high frequencies. When power spectral density functions are calculated for response spectra determined from a statistical evaluation of strong motion across the full range of frequencies, the calculations converge rapidly.

scholarly journals Effect of Linear Soil Condition on Seismic Inputs

2020 ◽  
Vol 2 (1) ◽  
pp. 48-55
Author(s):  
Shishir Bhattarai ◽  
Prem Nath Maskey
Keyword(s):  
Seismic Hazard ◽  
Spectral Density ◽  
Density Function ◽  
Power Spectral Density ◽  
Response Spectrum ◽  
Spectral Density Function ◽  
Source Zone ◽  
Power Spectral Density Function ◽  
Power Spectral ◽  
Hazard Curves

 Seismic inputs to structures in terms of risk consistent response spectrum and seismic hazard curves are developed at bedrock level considering ten independent seismic source zone in the vicinity of the Kathmandu valley. The seismic hazard curve is derived by assuming temporal occurrence of earthquakes to follow Poisson model. Response spectrum is developed using an empirical relationship of spectral ordinates with magnitude of earthquakes and epicentral distance. The seismic risk factor is introduced in response spectrum using conditional probabilities. Power spectral density function consistent with response spectrum is derived and ground acceleration time histories are derived from power spectral density function using Monte Carlo technique. To obtain free field hazard curves and ground motion parameters, one dimensional wave propagation analysis is used for two different underlying soil conditions.

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