2008
42
6
0
0
بررسی پایداری لرزهای سدهای باطله مطالعه موردی سد سرچشمه
2
2
Tailings dams, due to methods and materials used in their construction are vulnerable structures to earthquake. In many cases storage of water over tailings is required to prevent aerial pollution or reduction in water consumption by the means of a recycling system, therefore failure of these kinds of dams not only induce affects similar to conventional water dams, but also may lead to irreversible damage to their surrounding environment due to toxic content of tailings. Sarcheshmeh Tailings dam, a rockfill dam with an inclined clay core, is 70 m height and necessity for increasing reservoir capacity has led to dam upgrading to a minimum level of 90 m; using downstream method. Different options have been studied in order to get the safest and most economical alternative. Vulnerability of dam site to earthquake has considerably affected the design issue. This paper represents the results of dynamic and pseudostatic analyses of this tailings dam. Dynamic analysis is carried out using the finite difference code FLAC (Fast Lagrangian Analysis of Continua, ITASCA).This code is able to take into account pore water pressure generation during construction and earthquake. Different acceleration time history records and soil models are used and results have been compared.
1

657
667


Paria
Afsharchi
Iran


Ali Asghar
Mirghasemi
Iran
Tailings Dam
Sarcheshmeh Dam
Dynamic Analysis
طراحی سکوهای ثابت فلزی بر اساس ترازبندی بارگذاری دریا در منطقه پارس جنوبی
2
2
1

669
680


Amir Hossein
Izadparast
Iran


Mohammad Sadegh
Marefat
Iran
Jacket Platform
Sea State Loadings
Ultimate Level
Design Level
South Pars Field
بررسی آزمایشگاهی عملکرد میان قاب های مصالح بنایی در قاب های بتنی
2
2
An experimental study is conducted on three ½ scales, singlestory, singlebay, frame specimens. The first specimen was a reinforced concrete frame with solidbrick infill. The second specimen was a reinforced concrete frame with hollow clay perforatedbrick infill. The last specimen was a reinforced concrete frame without any infill. These three specimens were tested by pseudostatic method. Different response parameters are investigated and results are compared with those resulted from analytical approach. The results of the experimental and analytical studies indicate that use of masonry infill increases the lateral stiffness of the reinforced concrete frame. The increase in the stiffness is almost the same for both types of infill considered in this study. Use of masonry infill also increases the ultimate strength of the reinforced concrete frame. However, the strength of the frame in the case of hollow clayblock decays much faster in compare with frame infilled with solid claybricks because of a faster rate of failure in hollow blocks. Using masonry infill increases the energy dissipation capability of the reinforced concrete frame. In the case of frame with solid claybricks infill, a much more uniform distribution of damages is observed in columns. Comparisons with analytical approach show that analytical method provides a good estimation of initial stiffness of solidbrick infill but its estimations of initial stiffness of perforatedbrick infill and inelastic response of both types of masonry infill frames are not in good agreement with the experimental results.
1

681
690


Farzad
Parsa
Iran


Abdorreza
Sarvghad Moghaddam
Iran
Reinforced Concrete Frame
Masonry Infill
Strut Mechanisms
Perforated Brick
Solid Brick
مدلی ساده برای تحلیل تیر های پیوند عمیق با آرماتورگذاری قطری
2
2
In this research, using the Modified Compression Field Theory (MCFT), a new truss based model is proposed to predict the behavior of reinforced concrete coupling beams with diagonal reinforcement. The model is able to consider the effects of shear and axial forces and bending moment, simultaneously. The proposed model includes a nonlinear shear spring, an axial spring, two inclined truss members and some nonlinear springs for considering bending deformations. The results of the proposed model were compared with several test results conducted by the authors and other researchers. The comparison shows that the proposed model can predict shear behavior of coupling beams, appropriately.
1

723
737


Masoud
Riazi
Iran


Mohammad Reza
Esfahani
Iran
Coupling Beam
Diagonal Reinforcement
Reinforced Concrete
Shear Wall
بررسی نقش عوامل مؤثر بر فراوانی حوادث در لولههای اصلی آب رسانی با استفاده از الگوی رگرسیونی ترکیبی
2
2
A water distribution network is one of the important parts of infrastructure systems. The efficient management and proactive planning of capital investment of these assets are fundamental for efficient and effective service delivered by water companies. The direct economic costs (i.e. rehabilitation investment, repair costs, water loss, etc.) as well as indirect costs (i.e. service and traffic interruptions, etc.) related to water pipe bursts are rapidly increasing. The ability to predict burst rate in pipes is an important strategic key in order to optimization of rehabilitation decision in water distribution systems. Most networks suffer from lack of enough and reliable data for bursts and failures. In this study basic variables which influence on pipes burst and burst statistical analysis have been identified and evaluated. Then common methods for burst predicting are discussed. In order to identify logical, useful and understandable patterns of breaks data, a data mining methodology named evolutionary polynomial regression (EPR) is described. Starting from a hybrid evolutionary strategy, EPR searches for patterns in data and returns symbolic expressions/models. This approach is demonstrated through a detailed case study. Required data were collected from the Mashhad Water Company which includes both asset and bursts data recorded for year 1384. The whole database was divided into 8 material/diameter classes (from 64 mm to 300 mm). The resulting models for burst prediction in different zones contain explicitly recognizable independent variables. The expression models confirm that pipe age, diameter and length are the most important variables leading to pipe bursts. Also the effects of pressure on pipe burst prediction were implicitly investigated. It was found that pressure is an important parameter which influences number of breaks in a pipe network.
1

691
703


Masoud
Tabesh
Iran


Arash
Aghaei
Iran


Jalil
Abrishami
Iran
Water Distribution Networks
Pipes Failure
Data Mining
Failure Parameters
Failure Prediction Methods
Evolutionary Polynomial Regression
داده کاوی
مطالعه عوامل مؤثر بر مقدار کلر بحرانی یک سازه بتنی قدیمی آسیب دیده در جزیره کیش
2
2
1

765
773


Mohammad
Shekarchizadeh
Iran


Farhad
Porgar
Iran
Chloride Threshold Values
Concrete Structure
Kish Island
اثر عامل حالت در بهبود پیش بینی رخداد نوار برشی در خاک های دانه ای
2
2
The capability of sand constitutive models is remarkably improved by taking into account the effect of soil state in their formulations. In this study, it has been shown that considering the effect of soil state leads to better simulation of soil instability of shear banding type. To this aim, constitutive equations of a state dependent sand model are explained first. Consequently, the general conditions of instability and then, the special condition of instability with respect to the model formulation has been obtained. Using the result of a number of plane strain tests, the state dependent model predictions for shear band have been compared with experiment results. It has been shown that, predictions obtained from a similar model which neglect the effect of soil state are less favorable.
1

775
783


Ali
Lashkari
Iran


Manouchehr
Latifi
Iran
روش مسیر یابی ذره به منظور پیش بینی حرکت نفت در دریا
2
2
A twodimensional twophase numerical model is developed to predict transport and fate of oil slicks which resulted the concentration distribution of oil on the water surface. Two dimensional governing equation of fluid flow which consists mass and momentum conservation was solved using the finite difference method on the structured staggered grid system. The resulted algebric equations were solved by use of ADI (Alternating Direction Implicit) technique. In addition the wind speed and coriolis effect can be included in the current hydrodynamic model. Transport of oil slick was pridect by the two dimensinal particle tracking approach consists of Lagrangian method for advection processes, the Random Walk technique for horizontal diffusion process and the empirical equations for the fate processes. Different processes are considered and included in the developed model which are: advection, spreading, turbulent diffusion, evaporation, dissolution, vertical dispersion, emulsification, shoreline deposition and adsorption by bed sediment. Oil is divided into eight hydrocarbon components so this model is capable of considering the oil composition of some fractions with theirs characteristics. Comparison of results with analytical solution for standard problems represent a good degree of similarity. In addition, model is used in a case of oil spill in Persian Gulf to represent the application of model to real case studies.
1

795
807


Mohsen
Naghibi
Iran


Morteza
Kolahdouzan
Iran
Numerical Modeling
Particle Tracking Method
Transport and Fate
Coastal waters
(بررسی فنی و اقتصادی روسازه های بتنی در خطوط راه آهن مسافری (یادداشت فنی
2
2
Ballast as a part of the railway system plays an important role in the operation of the railways and also has a great impact on repair and maintenance activities. Hence most of the repair and maintenance activities in traditional railway systems are due to the defections in the ballast layer and therefore most of the maintenance budget is spent on repairing these defects. These repair and maintenance activities are usually very costly and time consuming and force the line to be closed for quite a long time. These kinds of problems led to the elimination of the ballast layer and the use of some other elements such as concrete slabs or beam in railways. The results show that the time and money needed for repair and maintenance of concrete slab tracks are much less than ballasted tracks, the technical and economical evaluations also confirm these results. In this paper technical and economical aspects of slab track systems were investigated with the help of national and international experiences and it was concluded that they are competitive solutions to the ballasted tracks in passenger railways.
1

705
711


Abolfazl
Hassani
Iran


Seyyed Hamed
Mada'eni
Iran
Railway
Slab Track
Ballast
Infrastructure
Life Cycle Cost
قالب جزء محدود پوسته استوانه ای
2
2
Curls and curves of a shell interweave its various strain modes and link them together. This interactional behavior has yet frustrated all attempts for the construction of shell templates, which needs for an individual element test in traditional approaches. Such a test fails to work for shell elements and must be reconstructed. In this paper, it is tried to study shell interactional behavior and strain entanglements via a microscopic investigation. This new view to the shell behavior reveals a simple method, in which shell templates are constructed by partitioning the stiffness matrix of a sample shell element into its components. Surly, sample elements have been qualified for their convergence in practice. The method is examined for axisymmetric cylindrical shell element.
1

713
721


Mohammad Reza
Pajand
Iran


Reza
Khajavi
Iran
Axisymmetric Shell
Basic Function
Cylindrical Shell
Eigenstiffness
Finite Element Template
Partitioning
Principal Stiffness Matrix
Stiffness Matrix of Strain Mode
Strain Gradient Notation
Strain Mode
بازتاب و شکست موج SH در مرز ناهموار بین دو محیط ایزوتروپ جانبی
2
2
The existing theory for wave propagation through a soil layer are not compatible with the real soil layers because in the theory the layers are flat and the sublayers are parallel, while in real the soil layers are not flat and they may not be parallel. Thus, wave propagations through a corrugated interface are so important. In this paper, a twodimensional SHwave propagation through a corrugated interface between two linear transversely isotropic halfspaces is assessed. In order to do this, Lord Rayleigh's method is accepted to express the nonflat surface by a Fourier series. In this way, the amplitude of the reflected and transmitted waves is analytically determined in terms of the incident SHwave amplitude. It is shown that except for the regular reflected and refracted waves, some irregular reflected and refracted waves are exist, and the amplitudes of these waves vary in terms of the angle and frequency of incident wave, equation of surface, and the material properties of the domains. The numerical computations for some cases of different amplitude/wavelength ratio of the interface are done. This work is an extension of Asano's paper (1960) for a more complicated interface, where more nonzero coefficients are considered in expressing the equation of surface in the form of Fourier series. The analytical results for some simpler case of isotropic domain are collapsed on Asano's results (1960). In addition, the numerical evaluation is in good agreement with Asano's.
1

751
763


Navid
Shad Manaman
Iran


Morteza
Eskandari Ghadi
Iran
SH
Wave
Irregular Reflection and Refraction
Corrugated Interface
Rayleigh's Method
بررسی خواص مصالح پایه سیمانی مسلح به الیاف فولادی مجعد با مقاومت کششی و شکل پذیری بالا
2
2
1

785
794


Ghods
Nazarali
Iran


Farshid
Jandaghi Alaei
Iran
High Performance
Cementitious
Composite
Crimped Steel Fibre
ارزیابی حسّاسیّت موجشکنهای مرکب کیسونی به مشخصه های هیدرولیکی و ژئوتکنیکی
2
2
Breakwaters are the important and the costly ones of the marine structures. Composite breakwater is one of the common types in the world. Because of the sensitivity of composite breakwaters to environmental conditions, also construction costs, difficulty of repair and maintenance and importance of equipments on and behind the breakwater, design of composite breakwater must be very accurate. Goal of present research is assessment of effect of environmental parameters in design of composite breakwater. In this way sensitivity of geometric parameters of this structure to hydraulic specifications such as period, height and direction of waves and depth of water, has been analyzed. Also effect of sea bed soil type in dimensions of this structure has been evaluated. Comparison between analytical and experimental formulas in evaluation of wave forces on composite breakwaters has been done. The results of this research have been expressed in some applied graphs for evaluation of effects of hydraulic and geotechnic parameters in dimensions of composite breakwaters. Thus results of present work can be used for attentively design of these structures in different environmental conditions of sea.
1

739
749


Ali Reza
Soltankouhi
Iran


Khosro
Bargi
Iran
Composite Breakwater
Caisson
Sensitivity Analysis
Environmental Conditions
Numerical Modeling of Launching Offshore Jackets from Transportation Barge & the Significance of Water Entry Forces on Horizontal Jacket Members
2
2
Development of a numerical model which describes launching of offshore jackets from barge is presented in this paper. In this model, in addition to capabilities of commercial softwares, water entry forces on jacket members and an implicit Newmark solution technique are included. The results are in general agreement with other numerical software’s available (SACS). Fluid forces acting on jacket and the importance of each one is discussed. It is observed that water entry forces on horizontal jacket members are very significant and may locally govern the design of these members. This force is more important for horizontal slender members near the mudline, which do not experience significant environmental loading in operating conditions. Therefore the water entry impact force with large magnitude can cause overstress and/or ovalling of near mudline members. It is also observed that taking water entry forces in account modifies the jacket trajectory only in a little extent.
1

809
821


Nikzad
Nourpanah
Iran


Moharram
Dolatshahi Pirooz
Iran
SACS
Launch
Offshore Jacket
Hydrodynamic Force
Water Entry Force
Newmark