Faramarz Khoshnoudian's research while affiliated with Amirkabir University of Technology and other places

Publications (110)

Article
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Damage detection of bridge structures plays a crucial role in in-time maintenance of such structures, which subsequently prevents further propagation of the damage, and likely collapse of the structure. Currently, the application of machine learning algorithms are growing in smart damage detection of structures. This work focuses on application of...
Article
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The aim of this paper is to extend a stochastic model for simulation of highly nonstationary ground motions (GMs). In this model, the dual-tree complex discrete wavelet transform (DT-CDWT) is applied to a recorded ground motion to extract its wavelet coefficients and then the Smooth Transition Generalized Autoregressive Conditional Heteroscedastic...
Article
Full-text available
Damage detection is of great importance in reducing maintenance cost and preventing collapse of structures. Despite existing damage detection methods, the current literature lacks a comprehensive method, which: (i) is applicable to complex structures with large degrees of freedom, (ii) captures even low-level damages, and (iii) gives reasonable acc...
Article
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The main objective of this study is to employ a probabilistic approach to determine the appropriate value of the strong column-weak beam ratio (SCWBR) for three mid- to high-rise moment frames. These buildings are subjected to pulse-type ground motions. The nonlinear soil-structure interaction (SSI) is also involved as another seismic energy dissip...
Article
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The aim of this paper is to develop a stochastic-parametric model for the generation of synthetic ground motions (GMs) which are in accordance with a real GM. In the proposed model, the dual-tree complex discrete wavelet transform (DT-CDWT) is applied to real GMs to decompose them into several frequency bands. Then, the gamma modulating function (G...
Article
Buildings are found to be more vulnerable in near-fault regions such that they should be designed with higher strength. In this study, the importance of pulse period and peak ground velocity on the efficiency of the strong column-weak beam ratio (SCWBR) is evaluated through incremental nonlinear dynamic analysis. This work involved two aspects: imp...
Article
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Offshore wind turbines are complex systems operating in harsh environment. The dynamic demands in these systems often differ from values used in design, leading to unexpected mechanical and structural failures. This signifies the importance of remote monitoring technologies for damage diagnosis and prognosis in offshore wind turbines. This study is...
Article
In this paper, it is aimed to perform clustering analysis on a large set of near-fault ground motions based on the intensity of velocity pulses. For this purpose, the velocity pulses of these ground motions are extracted based on the asymmetric Gaussian chirplet model (AGCM), the adapted dictionary-free orthogonal matching pursuit (ADOMP) algorithm...
Article
In this paper, a method which is based on the asymmetric Gaussian chirplet model (AGCM), adapted dictionary-free orthogonal matching pursuit (ADOMP) algorithm, and Newton method, is proposed for detection and extraction of velocity pulses. In the proposed method, the ADOMP algorithm and the Newton method find the most correlating AGCM atom at each...
Article
Transfer function (TF) data are recognized as diagnostic features in damage detection procedure. The objective of this paper is to present a damage detection method in Bayesian paradigm based on TF data due to ground excitation. The measured seismic responses of the structure in the frequency domain are adopted to obtain displacement TFs and the st...
Article
In this paper, a stochastic-parametric model is developed for simulating the temporal and spectral nonstationary characteristics of ground motion sequences. In the proposed model, after extracting the wavelet coefficients of a ground motion sequence by using the complex discrete wavelet transform and smoothing them by the Normal kernel function, th...
Article
Transfer function (TF) represents the ratio of structure’s response to the loading and can be utilised for the identification of damage in a structure. The capability of distinguishing between changes of the TF due to damage in the existing structure and due to idealised boundary conditions of the analytical model (such as soil-foundation effects o...
Article
Damage indices based on structural dynamic characteristics are often used to detect damage in the structures. In this study, a new index for identifying damages in base-isolated structures is proposed using the frequency response function (FRF). Since calculation of the FRF data is time-A nd memory-consuming for problems of large size, the two-dime...
Article
In seismic design codes and documents, the period and damping ratio of a linear fixed–base single degree-of-freedom (SDOF) system are tuned to return the dynamic response of a given nonlinear fixed–base SDOF structure through a so-called equivalent linearization method. The period and damping ratio of the equivalent linear system are referred to as...
Article
The reliability of structures isolated with Triple Concave Friction Pendulum (TCFP) bearings subjected to near-field earthquakes is investigated. An extensive study is conducted to reveal the effect of superstructure mass eccentricity on the probability of failure (Pf) as well as the reliability index (β) of the structure supported on TCFPs with di...
Article
The aim of this research is to develop a stochastic model for generating synthetic ground motions in accordance with a recorded ground motion. In this model, Complex discrete wavelet transform is used to extract wavelet coefficients of a ground motion, and the Gaussian mixture distribution to capture the statistical behavior and simulate these coef...
Article
In the current study, a new pattern recognition‐based damage detection technique is developed using the frequency response function of the structure. Principal component analysis is employed as an authoritative feature extraction method for dimensional reduction of the measured frequency response function data and constructing distinct feature patt...
Article
Most of the developed sensitivity-based damage detection methods are based on the application of external excitations which could be prohibitive due to infeasible excitation of all structural degrees of freedom. In this regard, identification of damage properties using seismic structural response would be advantageous. In this research, sensitivity...
Article
Damage identification using the sensitivity of the dynamic characteristics of the structure of concern has been studied considerably. Among the dynamic characteristics used to locate and quantify structural damages, the frequency response function (FRF) data has the advantage of avoiding modal analysis errors. Additionally, previous studies demonst...
Conference Paper
Fatigue is a common issue in steel structures such as wind turbine towers, which is caused by cyclic wind and wave excitations. Therefore, estimation of the remaining fatigue life of the structural and foundation system is of concern. For this purpose, continuous monitoring of the structure is necessary to obtain strain data at fatigue critical poi...
Article
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Recent studies show that rotational components of earthquakes can amplify the floor acceleration in a base-isolated structure. As a result, the seismic force of nonstructural components could be significantly increased. In this paper, a simple rectangular deck with various geometrical properties mounted on triple concave friction pendulum (TCFP) be...
Article
Full-text available
A method is proposed to detect structural damages in the presence of damping using noisy data. This method uses Frequency Response Function (FRF) and Mode-Shapes as the input parameters for a system of Couple Sparse Coding (CSC) to study the healthy state of the structure. To obtain appropriate patterns of FRF for CSC training, Principal Component...
Article
The purpose of this paper is to present a sensitivity-based finite element model (FEM) updating method using earthquake displacement response in the frequency domain and the frequency response function of structure due to ground excitation. The obtained sensitivity equation is solved by linear least square method through defining constraints on the...
Article
Seismic Fragility curves of asymmetric steel structures isolated with Triple Concave Friction Pendulum (TCFP) bearings are studied in this paper. To consider the record-to-record uncertainty an ensemble of 45 sets of near-fault ground motion is selected. The main sources of eccentricity in torsionally coupled base-isolated structures, namely mass e...
Article
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The effects of vertical component of earthquakes on torsional amplification due to mass eccentricity in seismic responses of base-isolated structures subjected to near-field ground motions are studied in this paper. 3-, 6- and 9-story superstructures and aspect ratios of 1, 2 and 3 have been modeled as steel special moment frames mounted on Triple...
Article
Vibration-based damage assessment approaches use modal parameters, such as frequency response functions, mode shapes, and natural frequencies, as indicators of structural damage. Nevertheless, these parameters are sensitive not only to damage but also to temperature variations. Most civil engineering structures are exposed to varying environmental...
Article
In this paper, attempts are made to demonstrate the effects of the rotational components of near-fault ground motions on asymmetric base-isolated structures. The effects of mass eccentricity in intensifying the impact of rotational components are investigated as well. A reasonable variety of superstructures with different aspect and slenderness rat...
Article
This paper is focused on effects of near-fault pulse characteristics on seismic performance of soil-structure systems considering foundation uplifting and soil yielding. To this end, an extensive parametric study is conducted. Mid-to-high rise building structures with a wide range of slenderness ratio rested on shallow mat foundations are investiga...
Article
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In this paper, a damage detection method based on modal parameters, which deals with incomplete measurement, is presented. Intact and damaged structures are modeled using the finite-element method. Damage in structure is assumed as a reduction in elastic modulus. This study utilizes an approximate stiffness matrix of damaged structure to improve th...
Article
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The present investigation illustrates the performance of structure-Tuned Mass Damper (TMD) system to suppress the excessive vibration of structure buildings subjected to near-field ground motions involving the nonlinear effects of three dimensional soil–structure interaction (SSI). Accordingly, three medium-to-high-rise controlled structures based...
Article
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A pattern recognition-based damage detection method using a brand-new damage index (DI) obtained from the frequency response function (FRF) data is proposed in this paper. One major issue of using the FRF data is the large size of input variables. The proposed method reduces the dimension of the initial FRF data and transforms it into new damage in...
Article
Full-text available
In this paper, the effects of mass eccentricity of superstructure as well as stiffness eccentricity of isolators on the amplification of seismic responses of base-isolated structures are investigated by using mathematical near-fault pulse models. Superstructures with 3, 6 and 9 stories and aspect ratios equal to 1, 2 and 3 are mounted on a reasonab...
Article
Full-text available
In this study, a promising pattern recognition based approach is introduced for structural damage identification using the measured dynamic data. The frequency response function (FRF) is preferably employed as the input of the proposed algorithm since it contains the most information of structural dynamic characteristics. The 2D principal component...
Article
In this paper, a finite element model updating method using frequency response functions is experimentally validated. The method is a sensitivity-based model updating approach which utilizes a pseudo-linear sensitivity equation. The method is robust against the adverse effects of incomplete measurement, measurement errors and modeling errors. The e...
Article
Full-text available
This study is devoted to investigate the effects of mass eccentricity on seismic responses of base-isolated structures subjected to near-field ground motions. Superstructures with 3, 6 and 9 stories with aspect ratios equal to 1, 2 and 3 have been idealized as steel special moment frames resting on a reasonable variety of triple concave friction pe...
Article
The torsion in the seismic behaviour of base-isolated structures due to two horizontal components of ground motion was studied, simultaneously. To this end, the variation in essential parameters, such as the number of storeys, the ratio of the uncoupled torsional frequency to the lateral frequency in the superstructure and isolation system, the rat...
Article
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The present study investigated the effects of vertical components of earthquakes on the responses of 5, 15, and 25 story steel frames by taking into account Soil-Structure Interaction (SSI). The frames were modeled on a fixed base and simulated using two shear waves velocities for the soil (100 and 250 m/s according to NEHERP soil code types E and...
Article
In this paper, attempts are made to investigate the responses of torsionally coupling base-isolated structure supported on Triple Concave Friction pendulum bearing (TFP) subjected to near field ground motions. Nonlinear dynamic analyses are conducted to study the effects of essential parameters such as superstructure and isolation system eccentrici...
Article
Friction isolators are one of the most important types ofbearings used to mitigate damages of earthquakes. The adaptive behavior of these isolators allows them to achieve multiple levels of performances and predictable seismic behavior during different earthquake hazard levels. There are three main types of friction isolators. The first generation...
Article
The effects of input parameters of pulse-like ground motions on the response of soil–structure systems are investigated through employing an ensemble of 64 ground motions. The soil and superstructure are idealised as a semi-infinite cone and a non-linear multiple-degrees-of-freedom shear building, respectively. The results confirm that the location...
Article
The effects of input parameters of pulse-like ground motions on the response of soil–structure systems are investigated through employing an ensemble of 64 ground motions. The soil and superstructure are idealised as a semi-infinite cone and a non-linear multiple-degrees-of-freedom shear building, respectively. The results confirm that the location...
Article
In this investigation, attempts are made to examine the effects of soil-structure interaction on the deflection modification factor of multistory buildings and to clarify the role of deformable soil on this factor. A comprehensive study is conducted to investigate the effect of inertial interaction on displacement demand ratios in soil-structure sy...
Article
Consequences of near-fault ground motions to strength reduction factors of flexible-base multi-story structures are addressed by employing synthetic pulses. For this purpose, three non-dimensional parameters are adopted as the key parameters of interacting systems: (1) non-dimensional frequency as the structure-to-soil stiffness ratio, (2) aspect r...
Article
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Structural model updating by estimation of stiffness and mass parameters via monitoring of dynamic characteristics has attracted much attention in recent decades. In this study, frequency response functions (FRF) are utilized in order to identify unknown structural parameters using a sensitivity-based model updating approach. A sensitivity equation...
Article
This paper reports on an investigation into the optimum design for a passive tuned mass damper system which takes account of soil–structure interaction. A multi-objective optimisation approach for minimising the displacement, velocity and acceleration of the structure is adopted. Three-dimensional structural models of five-, ten- and 15-storey buil...
Article
Seismic performance of rocking soil-structure systems subjected to near-fault pulses is investigated considering foundation uplifting and soil plasticity. An extensive parametric study is conducted including medium-to-high-rise buildings with different aspect ratios based on shallow raft foundation at stiff-to-rock sites. Mathematical directivity a...
Conference Paper
Bridge structures as a part of infrastructure and transportation network must operate safely. However, structures deterioration during their lifetime is unavoidable. By identifying structural damage in its initial stage, extra operational cost or catastrophic failure could be prevented. The accuracy of available damage detection methods depends hig...
Article
Full-text available
A parametric study is devoted to investigating the dynamic instability of soil-structure systems under far-fault earthquakes. The superstructure and soil are simulated as a bilinear single-degree-of-freedom (SDOF) oscillator and based on the cone model concept, respectively. The results show that soil flexibility makes the system dynamically more u...
Article
In this study, the role of soil material damping in the engineering demand parameters (EDPs) of soil-structure systems is investigated. For this purpose, a superstructure is modeled as a two-dimensional nonlinear multi-story shear building. The soil beneath the foundation is simulated based on the concept of the cone model. The effects of various p...
Article
In this research, the effects of rotational components of earthquakes on seismic responses of Triple Concave Friction Pendulum (TCFP) base-isolated structures are investigated elaborately. Although it is common to ignore the influence of rotational components of earthquakes on structural analysis, this investigation demonstrates the significant eff...
Article
Full-text available
This research has been conducted in order to investigate the effects of peak ground velocity (PGV) of near-field earthquakes on base-isolated structures mounted on Single Friction Pendulum (SFP), Double Concave Friction Pendulum (DCFP) and Triple Concave Friction Pendulum (TCFP) bearings. Seismic responses of base-isolated structures subjected to s...
Conference Paper
Full-text available
Damage index method is a promising approach for the identification of structural damage using measured dynamic data. Accordingly, a lookup table-based damage detection method using a damage index obtained from a frequency response function (FRF) data is presented in this paper. A major obstacle of using FRF data is the large size of input variables...
Article
Recent studies show that slender structures with shallow foundations located on soil medium can benefit from rocking isolation effects during strong earthquakes. In such condition, foundation uplifting and soil yielding provide supplemental energy dissipation potential at substructure level. As a result, the structural demands would be significantl...
Article
SUMMARY Conventional pushover analyses despite of extensive applications are unable to estimate the general responses of asymmetric-plan tall buildings because of ignoring the effects of higher modes and torsion. A consecutive modal pushover procedure is one of the recent nonlinear static pushover procedures that used to analyse the seismic respons...
Article
Full-text available
This study is devoted to investigate the effects of inertial soil–structure interaction (SSI) on the constant-strength inelastic displacement ratios of elastoplastic single-degree-of-freedom systems using a suit of 91 pulse-like ground motions. The soil beneath the foundation is simulated based on the cone model. A local minimum for the inelastic d...
Article
In this paper, a comprehensive study is carried out to examine the possibility of dynamic instability produced in soil-structure systems using an ensemble of 50 pulse-like records. A number of structural models with various vibration periods varying from 0.1 to 2 s are used in this study. The superstructure is simulated as a non-linear SDOF oscilla...
Article
Full-text available
Performance based design becomes an effective method for estimating seismic demands of buildings. In asymmetric plan tall building the effects of higher modes and torsion are crucial. The consecutive modal pushover (CMP) procedure is one of the procedures that consider these effects. Also in previous studies the influence of soil-structure interact...
Article
This paper aims to extend the consecutive modal pushover (CMP) procedure for estimating the seismic demands of two-way unsymmetric-plan tall buildings subjected to bi-directional seismic ground motions taking the effects of higher modes and torsion into account. Multi-stage and single-stage pushover analyses are carried out in both X and Y directio...
Article
This study is devoted to estimate higher-mode effects for multi-story structures with considering soil-structure interaction subjected to decomposed parts of near-fault ground motions. The soil beneath the super-structure is simulated based on the Cone model concept. Two-dimensional structural models of 5, 15, and 25-story shear buildings are ideal...
Article
This paper is devoted to investigate the effects of near-fault ground motions on the seismic responses of nonlinear MDOF structures considering soil-structure interaction (SSI). Attempts are made to take into account the effects of different frequency-content components of near-fault records including pulse-type (PT) and high-frequency (HF) compone...
Article
Full-text available
This paper is devoted to investigate the effects of SSI on strength reduction factor of multistory buildings. A new formula is proposed to estimate strength reduction factors for MDOF structure-soil systems. It is concluded that SSI reduces the strength reduction factor of MDOF systems. The amount of this reduction is relevant to the fundamental pe...
Article
Full-text available
The double concave friction pendulum bearing is a new kind of friction pendulum bearing that consists of two sliding surfaces. To study the seismic responses of three-dimensional base-isolated structures using double concave friction pendulum systems during impact with adjacent structures, after deriving the coupled differential equations of motion...
Article
In this study, attempts are made to investigate the effects of inertial soil–structure interaction (SSI) on damping coefficients subjected to pulse-like near-fault ground motions. To this end, a suit of 91 pulse-like near-fault ground motions is adopted. The soil and superstructure are idealized employing cone model and single-degree-of-freedom (SD...
Article
SUMMARY Dynamic analysis of structures deals with scaling of ground motions, which is vital for estimation of seismic responses. A major source of variability in seismic responses of structures arises from scaling of ground motions. In this paper, the accuracy of six conventional scaling methods on estimation of engineering demand parameters of soi...
Article
Currently, nonlinear base isolation systems are widely used in the construction of earthquake resistant structures. However, they are found to be vulnerable in near‐fault regions as a result of long‐period pulses that may exist in near‐source ground motions. Various control strategies including passive, active and semi‐active control systems have b...
Data
a b s t r a c t In this paper, effects of Soil-Structure Interaction (SSI) on Inelastic Displacement Ratios (IDRs) of super-structure are addressed. Four non-dimensional parameters are employed as the crucial parameters which affect the IDRs of soil-structure systems: (1) non-dimensional frequency as the structure-to-soil stiffness ratio; (2) aspec...
Article
In this paper, the effects of pulse period associated with near-field ground motions on the seismic demands of soil–MDOF structure systems are investigated by using mathematical pulse models. Three non-dimensional parameters are employed as the crucial parameters, which govern the responses of soil–structure systems: (1) non-dimensional frequency a...
Article
In the current paper the accuracy of the International Building Code equivalent static method for base-shear distribution is evaluated to determine the response of seismically isolated structures under near-field earthquakes. For this purpose two-, three-, four- and six-storey building models are designed according to the equivalent lateralresponse...
Article
It has been pointed out the static lateral response procedure for a base-isolated structure proposed in International Building Code (IBC) somewhat overestimates the seismic story force. That is why in the current paper, vertical distribution of base shear over the height of isolated structures considering higher mode effects under near field earthq...
Conference Paper
Full-text available
In recent years using of base isolation systems due to improve in seismic performance of liquid storage tank was expanded. In this paper, the seismic behavior of the Liquid storage tank supported on DCFP isolation system under seven ground motions was investigated. The effects of essential parameters including slender of tank, period and coefficien...
Conference Paper
Full-text available
Nowadays, architects tend to create more complex structures than before. So engineers should become compatible with these ideas especially when they would be located on hazarded areas. For gaining this, two different kinds of 10-story structures for considering Different degrees of coupling between translational and torsional modes, have created fr...
Conference Paper
Full-text available
Up to now, few studies have been done on seismic behavior of elevated water tanks, despite the necessity of water tanks for consuming water and firefighting, especially after earthquake. The scope of this paper is to propose new lateral load patterns to evaluate seismic responses of elevated water tanks supported on concrete shaft and also modeling...
Conference Paper
In this paper, attempts have been made to address the strength reduction factors of soil-MDOF structure system under idealized pulses. The soil beneath the super-structure is simulated based on the concept of Cone model and the super-structure is modeled as a nonlinear 15-story shear building. Three non-dimensional parameters are employed as the cr...
Conference Paper
Evaluation of the target displacement by means of the simplified nonlinear static procedures (NSPs), known as the Coefficient Method, is presented in FEMA 356 and FEMA 440 documents. In this method, C 1 is defined as modification factor to obtain the expected maximum displacement of an inelastic SDOF oscillator from displacement of the correspondin...
Article
Full-text available
In the current paper, the seismic response of elevated liquid storage tanks using double concave friction pendulum bearings (DCFP) considering bi-linear and tri-linear behaviors have been investigated. After deriving the coupled differential equations of motion, the MATLAB programming language is employed to solve the differential equations in each...
Article
One of the most important types of bearings used to mitigate damages of earthquakes is friction isolators. The adaptive behaviour of these isolators makes to achieve multiple performances and predictable seismic behaviour during different earthquake hazard levels. The friction isolators include three main types. The first generation with one slidin...
Conference Paper
Full-text available
Up to now, few studies have been done on seismic behavior of elevated water tanks, despite the necessity of water tanks for consuming water and firefighting, especially after earthquake. The scope of this paper is to propose new lateral load patterns to evaluate seismic responses of elevated water tanks supported on concrete shaft and also modeling...
Conference Paper
Full-text available
Nowadays, architects tend to create more complex structures than before. So engineers should become compatible with these ideas especially when they would be located on hazarded areas. For gaining this, two different kinds of 10-story structures for considering Different degrees of coupling between translational and torsional modes, have created fr...
Article
Full-text available
The current investigation has been conducted to examine the effect of the vertical component of earthquake on the responses of base-isolated structures mounted on a triple concave friction pendulum (TCFP) bearing. The varying inherent stiffness and damping of this new generation of friction isolators make smart behavior to mitigate damages during d...
Article
The application of fuzzy algorithms in the response control of a base isolated building with MR dampers is investigated in this paper. Most of the previous researches in this field have been focused on fuzzy algorithms with linear membership function however in the current study; the membership functions are assumed to be Gaussian and their effecti...