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Issue Info: 
  • Year: 

    2020
  • Volume: 

    52
  • Issue: 

    6
  • Pages: 

    1539-1554
Measures: 
  • Citations: 

    0
  • Views: 

    114
  • Downloads: 

    0
Abstract: 

Shear keys are bridge components that support the superstructure in transverse direction and may experience large displacements and extensive damages during earthquakes. Shear keys are designed to limit damage to abutment walls and piles by restraining the transverse movements. The shear force transferred to the abutments is controlled by the design and detailing of the shear keys. Damage to shear keys during earthquakes may affect significantly on seismic behavior of the abutments and consequently the bridge system. In this paper, a damage index is proposed for damage assessment of the bridge shear keys. The proposed damage index is defined based on the friction behavior and the ratio of the energy dissipation capacity to input energy. To evaluate the reliability of the damage index in damage assessment of the shear keys, finite element models of shear keys units, previously tested under cyclic loadings are developed and the proposed damage index is calculated. In addition, seismic response of shear key specimens are obtained under seven earthquake records using incremental dynamic analysis and the damage index is calculated for the shear keys in different PGA values of earthquakes. The results indicate that the proposed damage index can predict the damage progression in shear keys throughout loading histories and can provide reliable values for damage levels of shear keys with respect to the experiment observations.

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Author(s): 

ISHIKAWA J. | TEI S. | HOSHINO D.

Issue Info: 
  • Year: 

    2010
  • Volume: 

    -
  • Issue: 

    -
  • Pages: 

    9-12
Measures: 
  • Citations: 

    1
  • Views: 

    108
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2017
  • Volume: 

    31
  • Issue: 

    1
  • Pages: 

    105-118
Measures: 
  • Citations: 

    0
  • Views: 

    1426
  • Downloads: 

    0
Abstract: 

The main objective of the present study was determination of the economic value of irrigation water and simulation of the farmers’ behavior in response to reducing available water resources policy in Takestan Township, in Qazvin province. To achieve this goal, we used the positive mathematical programming (PMP) method and state wide agricultural production (SWAP) functions. First, the economic value of irrigation water in the studied township was determined. Then, framer's response to the scenarios of 5%, 10%, 20% and 30 percent reduction in available water resources was investigated. The required data belonged to crop year 2013-2014. To solve the presented experimental, software GAMS Version 24/1 was used. After solving the model, the economic value of irrigation water in Takestan Township was calculated at 1690 Rial. The results showed that there was huge difference between the economic value of irrigation water and water charge rates in this township. In addition, the results showed that with reduction in irrigation water availability in Qazvin, economic value of irrigation water increases and farmers' gross profit decreases. Finally, in order to avoid the indiscriminate use of water in agriculture sector, it is recommended to determine water charge for farmers of Takestan Township according to trend of changes in economic value and considering equity.

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Author(s): 

ZENER C.

Journal: 

PHYSICAL REVIEW

Issue Info: 
  • Year: 

    1937
  • Volume: 

    52
  • Issue: 

    3
  • Pages: 

    230-235
Measures: 
  • Citations: 

    1
  • Views: 

    253
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Journal: 

PATHOBIOLOGY RESEARCH

Issue Info: 
  • Year: 

    2010
  • Volume: 

    13
  • Issue: 

    1
  • Pages: 

    57-67
Measures: 
  • Citations: 

    0
  • Views: 

    1053
  • Downloads: 

    0
Abstract: 

Objective: To investigate the friction of rabbit’s knee joint with designed pendulum friction tester to diagnose and evaluate different pathological and therapeutic conditions following haemarthrosis, osteoarthritis, and other joint disorders. Materials and Methods: Friction coefficient of 10 adult male Albino rabbit’s joint (5 right and 5 left knees) weighted 1.59 ± 0.27 Kg, after designing and compiling the instrument and its processing software in the Physiotherapy department of Tarbiat Modares University were measured. Maximaum pendulum rotation, number of oscillations to reach equilibrium, coefficient of friction with Stanton’s equation, exponential and linear curve fitting, average logarithmic and linear decrement methods were measured. Results: Maximum rotation after pendulum releasing in the left joints were higher than the right ones, P<0.001. Number of oscillations to reach equilibrium in the left knees were also greater than the right knees, P=0.005. All different friction estimation methods had the same results and showed greater friction in the right in comparison to the left side. Conclusion: The pattern of the joints amplitude decay did not have a linear behaviour and the rabbit’s knee joint coefficient of friction with nonlinear estimations was less than linear ones. The findings revealed that selecting a separate control group in such investigation is essential and the contralateral limb could not be considered as control group. Pendulum friction tester has the capability of evaluating changes in coefficient of friction after application of different therapeutic methods. These changes have important role in diagnosis, evaluation of joint diseases and developing techniques for treating those pathologies.

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Author(s): 

ZENER C.

Journal: 

PHYSICAL REVIEW

Issue Info: 
  • Year: 

    1938
  • Volume: 

    53
  • Issue: 

    1
  • Pages: 

    90-99
Measures: 
  • Citations: 

    1
  • Views: 

    241
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

VAKIL ALI | FIROUZABADI B.

Journal: 

SCIENTIA IRANICA

Issue Info: 
  • Year: 

    2006
  • Volume: 

    13
  • Issue: 

    3
  • Pages: 

    245-254
Measures: 
  • Citations: 

    0
  • Views: 

    492
  • Downloads: 

    188
Keywords: 
Abstract: 

When velocities in the piping systems change rapidly, spectacular accidents occur, due to transient-state pressures where the elastic properties of the pipe and liquid must be considered. This hydraulic transient is commonly known as water hammer. A conventional widely-used technique for analyzing this phenomenon is the Method Of Characteristic (MOC), in which, by introducing the characteristic lines, two ordinary differential equations, in lieu of the governing partial differential equations, are produced. In the undisturbed form of the equations, the energy dissipation is evaluated by the steady or quasi-steady approximation. But, there is experimental and theoretical evidence which shows that the velocity profiles in unsteady-flow conditions have greater gradients and, thus, greater shear stresses, than corresponding values in steady-flow. Moreover, the numerical integration of the friction-loss is based on the values at the previous time step. This paper employs the External Energy Dissipator, Karney's method, to apply the boundary conditions in a network. To investigate the effect of the unsteady friction formula, the cross characteristic mesh, based on the Vitkovsky formulation, is completely derived and incorporated in the network. At last, the effect of the weighting term in the integration of the friction-loss term is examined. The paper shows that if the maximum head rise were to be practically considered, it would not need the unsteady friction term to be taken into account. Moreover, the weighting integration constant has the slightest effect on the text network.

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Author(s): 

HAN S.I. | CHO Y.S. | JIN S.M.

Issue Info: 
  • Year: 

    2009
  • Volume: 

    -
  • Issue: 

    -
  • Pages: 

    4971-4976
Measures: 
  • Citations: 

    1
  • Views: 

    139
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

MISHRA R.S. | MA Z.Y.

Issue Info: 
  • Year: 

    2005
  • Volume: 

    50
  • Issue: 

    -
  • Pages: 

    1-78
Measures: 
  • Citations: 

    2
  • Views: 

    179
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Author(s): 

MALEKZADEH M. | TAGHIKHANI T.

Journal: 

SCIENTIA IRANICA

Issue Info: 
  • Year: 

    2010
  • Volume: 

    17
  • Issue: 

    2 (TRANSACTION A: CIVIL ENGINEERING)
  • Pages: 

    81-88
Measures: 
  • Citations: 

    0
  • Views: 

    686
  • Downloads: 

    725
Abstract: 

Double Concave Friction Pendulum (DCFP) bearing is a new generation of friction isolator that contains two separate concave sliding surfaces with different properties. Accommodating enhanced performance, compared to the Friction Pendulum System (FPS), is one of the most important benefits of DCFP. Herein, the seismic behavior of structures isolated by DCFP bearings is compared with the response of the same buildings using the FPS bearing. Accordingly, a series of nonlinear dynamic analyses are carried out under ensembles of ground motions at three different hazard levels (SLE, DBE and MCE). Moreover, the adaptive behavior of DCFP and its advantages in protecting secondary systems is investigated. The probability of exceedance curves of peak roof acceleration, peak inter-story drift and peak isolator displacement is compared for two types of isolation system. The result supports the advantages of DCFP isolation systems.

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