List of Articles Near-field

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  1 - Reduction of Cramer-Rao Bound in Arbitrary Pre-designed Arrays Using Altering an Element Position
  Hamidreza Bakhshi Mohsen Abedini
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  2 - Development of Seismic Criteria for Seismic Responses of Regular and Irregular Structures in Plan considering Vertical Component of the Near-field Records
  Maryam Firoozi Nezamabadi Fariborz Yaghoobi Vayeghan
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  3 - Full-Wave Investigation of Far- and Near- Fields of a Vessel and Extracting Far-Field from Near-Field Data Scattered in X Frequency Band
  Farzad Khajeh-Khalili Reza Jokar
  In this paper, the far- and near-fields of a vessel are discussed in the full-wave CST software environ­ment. In this regard, the far-field is extracted with the help of the data obtained from the scattered near-field. First, to explain the method used to calculate More

  In this paper, the far- and near-fields of a vessel are discussed in the full-wave CST software environ­ment. In this regard, the far-field is extracted with the help of the data obtained from the scattered near-field. First, to explain the method used to calculate the scattered near-field, a simple structure (metal cube) is simulated. Then, by simulating the full-wave of a vessel with the dimensions of 130.8×20×23.1 cm3 or 1.54×103 λ3 at 8.5 GHz from the X-band, its far- and near-fields were calculated and reported according to the mentioned method. In the following, the far-field of this vessel is obtained with the help of the available data from the scattered near-field. The characteristic of the radar cross section (RCS) of this vessel is also calculated using the Asymptotic solver of the CST software. The maximum RCS of the vessel at 8.5 GHz is equal to 2.51 m2. In order to calculate all near- and far-electric fields, the Time Domain solver has been used. The simplicity of calculating the far-field from the near-field presented in this paper makes it possible to analyze similar structures using the same method. Manuscript profile
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  4 - Evaluation of the Seismic Performance of Rocking Motions and its Effects on the Controlling Provisions of Special Steel Moment-resisting‎ Systems Dual with CBF Bracing
  Ali Parvari Ehsan Azizi
  In this study, 4-, 8-, and 12-Story steel special concentrically braced frame (SCBFs) structures were considered in area with high seismically hazard and soil type II according to Iranian's 2800 code provision. Structures are residential use and have regularity in plane More

  In this study, 4-, 8-, and 12-Story steel special concentrically braced frame (SCBFs) structures were considered in area with high seismically hazard and soil type II according to Iranian's 2800 code provision. Structures are residential use and have regularity in plane and vertical distribution. Structures were modeled using Sap 2000 software to investigate the effect of self-centering ‎motion under seven near-field earthquakes. All models assumed with and without dual system controlling provisions. The results of this research indicate that without dual system provisions, considering the self-centering ‎motion in ‎4-, 8-, and 12-Story SCBFs‎ reduces base shear of structures in contrast with increasing deformation of top floor and column axial force. In average, the self-centering ‎motion‎ dissipate energy more than fixed base one. With controlling dual system provisions, considering the self-centering ‎motion in ‎4-, 8-, and 12-Story ‎SCBFs‎ reduces base shear of structures, whereas increases deformation of top floor ‎and column axial force. Moreover, in this case of study, energy dissipation are more than with controlling ‎one. Considering the self-centering ‎motion in ‎8-, and 12-Story ‎SCBFs‎ reduces base shear of ‎structures and top floor deformations, meanwhile column axial force‎ was increased. It can be seen that in ‎4-, and 12-Story ‎SCBFs considering code provisions had a better results, whereas in ‎8-Story ‎SCBFs ‎neglecting code provisions was accepted. Manuscript profile
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  5 - Evaluation the Performance and Seismic Comparison of Steel Moment Dual Systems in Rocking Frames with CBF and EBF Bracing
  Ali Parvari Arman Beglar
  In recent years, considering vertical movement in structures, which is known as self-centering motion, is one of the methods used to dissipate the earthquake energy. In this study, 4-, 8-, and 12-Story steel structures with special concentrically braced frame (SCBFs) an More

  In recent years, considering vertical movement in structures, which is known as self-centering motion, is one of the methods used to dissipate the earthquake energy. In this study, 4-, 8-, and 12-Story steel structures with special concentrically braced frame (SCBFs) and eccentrically braced frames ‎(SEBFs) ‎were considered in order to investigate the effect of self-centering ‎motion under seven near-field earthquakes using Sap 2000 software. The results of this research indicate that considering the self-centering ‎motion, the behavior of structures are changing in SCBFs and SEBFs. In ‎, 4-, 8-, and 12-Story SEBFs structures with considering the self-centering ‎motion, the column and bracing ‎forces were increased which this was different with SCBFs ‎ structures. Considering the self-centering ‎motion, more plastic joints are formed in the beams. Therefore, in the self-centering ‎of the columns, the beams outside the bay are more affected. In general, the results indicate that the self-centering ‎motion is better in the SCBFs. Manuscript profile
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  6 - Optimal intensity measures for probabilistic seismic demand modeling of multi-span continuous concrete box girder bridges subjected to near-field earthquakes
  Hoodean Malekzadeh Hassan Abbasi Mahmood Hooseini Armin Aziminejad Mohammadreza Adib Ramezani
  10.30495/civil.2021.684416
  Seismic intensity measures (IMs) perform a pivotal role in probabilistic seismic demand modeling. Past studies investigated appropriate IMs for structures, including the vital component of the transportation system, the highway bridges. These studies were mainly focused More

  Seismic intensity measures (IMs) perform a pivotal role in probabilistic seismic demand modeling. Past studies investigated appropriate IMs for structures, including the vital component of the transportation system, the highway bridges. These studies were mainly focused on far-field earthquakes and did not consider the strong vertical component of ground motions in near-field earthquakes.  In order to evaluate the optimal IMs for the multi-span continuous concrete box girder bridges subjected to near-field earthquakes, ten sample bridges were modeled and then subjected to three-component records of 164  near-field earthquakes applying the OpenSees software framework. In the present research, 5 engineering demand parameters considering the most critical response parameters related to columns and deck were selected, along with 24  intensity measures considering the horizontal and vertical components of ground motions. Base on the optimality investigation method, parameters such as efficiency, practicality, proficiency, sufficiency, and relative sufficiency were considered. In total, 8200 nonlinear time-history analyses were conducted. The results presented that the peak ground velocity of the horizontal component (PGVH), velocity spectrum intensity of the horizontal components(VSIH), and Housner intensity of horizontal components (HIH) were the optimal intensity measures, and vertical component of ground motions in near-field earthquakes should be considered in optimality investigation. Manuscript profile
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  7 - Investigation of seismic Fragility and collapse capacity of RC Moment Frames Considering the increase of stiffness of the column relative to the beam under far and near field earthquakes
  siamak saboonchi ashkan khodabandehlou
  10.30495/civil.2023.699218
  In the present research, the seismic fragility and collapse capacity of concrete moment frames have been investigated by considering different ratios for the weak beam-strong column rule in the optimization process in the performance-based design framework. In order to More

  In the present research, the seismic fragility and collapse capacity of concrete moment frames have been investigated by considering different ratios for the weak beam-strong column rule in the optimization process in the performance-based design framework. In order to implement performance-based optimization, the center of mass metaheuristic algorithm has been applied in this research. The philosophy of design approach based on performance and even traditional design methods allows the structure to suffer damage facing strong and relatively strong earthquakes. Therefore, in order to estimate the level of safety of the structure against earthquakes, it seems necessary to use quantitative indicators of seismic safety and the collapse capacity of the structure. In order to predict the collapse capacity of each optimal structure, using incremental dynamic analysis, the modified collapse safety margin ratio under far and near fault earthquakes has been calculated. Two examples, 3-span three and six floor frames have been studied in this research, which are designed in the performance-based optimization framework and considering the coefficients of 0.8, 1.2 and 1.6 to control the weak beam-strong column rule in the optimization process. The results indicate that increasing the rigidity of the column compared to the beam in this research actually affects the ductility of the structure, and by choosing structures with greater rigidity of the column compared to the beam, it leads to an increase in the collapse capacity and a decrease in the fragility of the structure. Manuscript profile
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  8 - Comparison of Exploitation Criteria and Acceleration of Long Diagrid Steel Structures with Environmental Frame System Based on Dynamic Wind Analysis
  mehdi hooshmand Hassan Haji Kazemi Seyed Alireza Zareei
  10.30495/civil.2023.707070
  Considering the widespread use of diagrid systems in tall buildings, it is necessary to investigate the behavior of this structural system against the wind and control comfort criteria based on acceleration. According to different regulations, it is evident that there i More

  Considering the widespread use of diagrid systems in tall buildings, it is necessary to investigate the behavior of this structural system against the wind and control comfort criteria based on acceleration. According to different regulations, it is evident that there is not much guidance for the design of this structural system and its requirements have not yet been included in the design regulations. Therefore, one of the most important goals of the current research is to investigate and use the Diagrid structural system as one of the modern structural systems in high-rise buildings. Another goal of this research is to compare the performance of the diagrid system with the environmental pipe system. Accordingly, the effect of various parameters including the acceleration of floors and shear of the base under dynamic wind load has been evaluated. It is expected that the performance of the diagonal network will be evaluated with a more detailed understanding of the diagonal network in tall structures and the evaluation of the operation and comfort criteria based on the acceleration against the wind load using dynamic time history analysis applying Cholesky, ergodic and AP methods. The results have been compared with the formulas of the ASCE7 regulation and the AIJ-GBV-2004 and ISO 10137:2007 comfort criteria and the National Building Code of Canada (NBCC). These investigations indicate that the acceleration of the diagrid system floors based on ASCE7 wind dynamic response prediction equations, has exceeded the permissible limit of ASCE 7 regulation by 20 milli-g (20Gal). This is due to the high estimation of ASCE 7 equations compared to the results of wind time history analysis. In such a way that in the 50-, 70-, and 100-story buildings, the maximum accelerations of the roof obtained from the ASCE 7 equation are 1.83, 2.07, and 1.87 times the results of the dynamic analysis of wind time history, respectively. Manuscript profile
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  9 - The effect of far- and near-field earthquakes on the collapse capacity of performance based optimization of RC moment frames
  siamak saboonchi ashkan khodabandehlou
  10.30495/civil.2023.701926
  Performance-based design is a new approach to topics of the seismic design of structures, which unlike the traditional methods of force-based design, is based on changing the location of the structure. The use of this approach in the process of structure design results More

  Performance-based design is a new approach to topics of the seismic design of structures, which unlike the traditional methods of force-based design, is based on changing the location of the structure. The use of this approach in the process of structure design results in the access to structures with proper performance and an acceptable level of reliability. The main goal of this contribution is to investigate the impact of near- and far- field earthquakes on the collapse capacity and fragility of performance based optimization of RC moment frames using the center of mass meta-heuristic algorithm. Push over analysis has been utilized in the optimization process to control the responses of the studied frames at functional levels and incremental dynamic analysis has been used to evaluate the fragility of the obtained optimal frames. According to the results for the collapse margin ratio and the adjusted collapse margin ratio for the 3-, 6-, and 12-story frames, it is indicated that the collapse margin ratio and therefore the seismic safety under far-field earthquakes are 7%, 16%, and 8% higher than those of the near-field earthquakes, respectively. In other words, the optimized frames in this study against near-field earthquakes have low seismic safety and more fragility than far-field earthquakes. Manuscript profile
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  10 - Seismic Fragility Analysis of Base-Isolated Buildings resting on Sloping Ground under real earthquake ground motions
  RAMA DEBBARMA
  10.1007/ijase.2022.692296
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  11 - Evaluation of Wavelet Energy for the Vibration of a Single Pile Embedded in Sand under the Effect of Near-Field and Far-Field Earthquakes
  Navid Hasanpouri Notash روزبه دبیری Masoud Hajialilue Bonab Larissa Khodadadi فریبا بهروز سرند
  Evaluating pile performance against seismic loading is one of the most important issues in geotechnical engineering. Various approaches are used in the evaluation of this performance, which can be referred to as continuous and discrete approaches. In the continuous appr More

  Evaluating pile performance against seismic loading is one of the most important issues in geotechnical engineering. Various approaches are used in the evaluation of this performance, which can be referred to as continuous and discrete approaches. In the continuous approach, two-dimensional and three-dimensional analyzes can be used. One of the very important disadvantages that can be pointed out in the three-dimensional analyzes of piles is the increase in computational costs. Therefore, improving the accuracy of two-dimensional analyzes in order to reduce computational costs is inevitable. The present study has used Abaqus finite element software to evaluate the response of a single pile embedded in single— and double-layer sand under two earthquake records (far-field and near-field). The subsequent stage involved employing the wavelet transformation technique to analyze the signal derived from the pile cross-section. The present study utilized the acceleration time histories of the pile head as the input signal for wavelet transformation. The result showed that the wavelet energy for the pile head signal was higher in the near-field record than in the far-field record. The analysis indicated an 11% and 41% increase in wavelet energy for single-layer and double-layer profiles, respectively. This increase in wavelet energy is due to the significant increase in horizontal displacement of the pile under near-field records compared to far-field records. Therefore, by implementing signal processing analysis employing continuous wavelet transformation on the horizontal acceleration of the pile section, relevant information regarding the type of earthquake records that occurred at the site can be extracted. Manuscript profile