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  1. admin
    Evaluating the Liquefaction Potential of Soil in the South and Southeast of Tehran based on the Shear Wave Velocity through Empirical Relationships M Khalili Noutash; R Dabiri; M Hajialilue Bonab The liquefaction resistance of soil can be evaluated using laboratory tests such as cyclic simple shear, cyclic triaxial, cyclic torsional shear as well as field methods like Standard Penetration Test (SPT), Cone Penetration Test (CPT) and Shear Wave Velocity (Vs). In this regard, this study attempts to compare the results of the SPT based on the simplified procedure proposed by Seed and Idriss (1985) and those of the Vs on the basis of Andrus et al.’s (2004) process using empirical relationships between them. Iwasaki’s (1982) method is used to measure the liquefaction potential index for both of them. The study area is a part of the south and southeast of Tehran. It is observed that there is not a perfect agreement between the results of the two methods based on five empirical relationships assuming cemented and non-cemented condition for soils. Moreover, the liquefaction potential index (PL) value in the SPT method is more than that of the Vs method. منبع دانلود JSEG211348691400.pdf
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    Free Vibration Analysis of Repetitive Structures using Decomposition, and Divide-Conquer Methods L Shahryari This paper consists of three sections. In the first section an efficient method is used for decomposition of the canonical matrices associated with repetitive structures. to this end, cylindrical coordinate system, as well as a special numbering scheme were employed. In the second section, divide and conquer method have been used for eigensolution of these structures, where the matrices are in the block tri-diagonal form. In the third section a comparison of the results is presented. In order to illustrate the efficiency of the aforementioned methods, repetitive structures are considered in the form of barrel vault space structures. منبع دانلود JSEG201348691400.pdf
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    The Influence of Pet Fibers on the Properties of Fresh and Hardened Concrete N Shamskia There is a worldwide interest in using fibers of different types in concrete mixtures. In this regard, as the use of PET fibers has gradually increased during the last decade, this study aims to investigate the effects of PET fibers on the mechanical properties of hardened concrete and the workability of fresh concrete. To this end, different contents of PET fibers (PC= %0, %0.5, %1 and %1.5) are added to a concrete mixture and the workability of fresh concrete samples are measured by the slump tests. Furthermore, the load-displacement behavior of the concrete samples is investigated in flexural and compression samples. Results of this study reveal that PET fibers can noticeably change the energy absorption of concrete samples, especially in flexural specimens. منبع دانلود JSEG191348691400.pdf
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    Effects of the Soil-Foundation-Structure Interaction on the Component Demand Modifier Factor of Concrete Gravity Beams based on ASCE 41-06 Standard A Azarbakht; E Rajabi The aim of the present paper is to evaluate the influence of the Soil- Foundation- Structure Interaction (SFSI) effects on the component demand modifier factor of concrete gravity beams based on ASCE 41-06 standard. To this end, the beam on the nonlinear Winkler foundation approach is employed which is a simple and efficient method. At first, four sets of 3-, 6-, 10- and 15-storey concrete moment-resisting frames founded on soft, medium and hard soils are designed and analysed for the case of fixed-base and flexible-base assumptions. A comparison is then made between the results of the nonlinear response history analysis of each frame in the flexible-base and fixed-base conditions with the response based on the equivalent linear static approach. The findings show that the equivalent linear static approach loads for gravity beams, which are controlled by deformation actions, can lead to non-conservative predictions of seismic demand. Finally, a modified load combination is proposed to be used in the equivalent linear static approach to avoid this imperfection. منبع دانلود JSEG181348691400.pdf
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    جزئیات تفاهم‌‌نامه‌ جدید شهرداری و سازمان نظام مهندسی محمد سالاری در گفت‌وگو با خبرنگار اجتماعی خبرگزاری تسنیم،‌ درباره جزئیات تفاهم‌نامه شهرداری و سازمان نظام مهندسی،‌ اظهار داشت: شهرداری تهران در نهم فروردین به صورت یک‌طرفه تفاهم‌نامه‌ خود با سازمان نظام مهندسی در خصوص ارجاء کار به مهندسین ناظر را لغو کرد. وی با بیان اینکه این موضوع اعتراض مسئولان ذیربط از جمله وزارت راه و شهرسازی، سازمان نظام مهندسی و شورای شهر تهران را در پی داشت‌، ادامه داد: جلسات مشترکی با محوریت شورای شهر تهران و با حضور مسئولان مرتبط برگزار شد. از جمله دلایلی که شهرداری برای انجام این کار در جلسات عنوان کرد این بود که در فرآیند ارجاع کار از سوی سازمان نظام مهندسی به مهندسین اشکالاتی وجود دارد که باعث طولانی شدن زمان صدور پروانه شده و طی آن خلاف مقررات ملی ساختمان عمل می‌شود. رئیس کمیسیون معماری و شهرسازی شورای شهر تهران تصریح کرد: در بررسی‌های جلسه مشترک بسیاری از اشکالاتی که شهرداری مطرح کرد مورد قبول بود ولی رئیس سازمان نظام مهندسی نیز اعلام کرد اقداماتی برای رفع این اشکالات آغاز کرده‌اند و در مدت زمان معقول آن اقدامات اعمال خواهد شد. وی با بیان اینکه تلاش ما رفع اشکالات موجود بود تا مردم اذیت نشوند، افزود: از جمله مواردی که قرار شد اصلاح شود این است که ارجاع کار به مهندسین ناظر 3 روز نهایتا تا یک هفته به طول بینجامد. اگر مهندس اول که در نوبت قرار دارد حاضر به پذیرش کار نشد، به مهندس دوم وقت انتخاب داده می‌شود، اگر وی نیز نپذیرفت کار به مهندس سوم پیشنهاد و در صورت نپذیرفتن آن نیز کار از مدار نوبت خارج و به عهده فرد داوطلب سپرده می‌شود؛ پیش از این،‌ بنا بر ادعای شهرداری این روند سه ماه به طول می‌انجامید. سالاری خاطرنشان کرد: نقشه‌های فاز دو نیز که بر اساس تفاهم‌نامه قبلی به سازمان نظام مهندسی ارجاء داده می‌شد تا مورد بازبینی و کنترل مضاعف قرار گیرد،‌ فاصله زمانی زیادی نیاز داشت این در حالی بود که دقت لازم در بررسی نقشه‌ها صورت نمی‌گرفت و فرآیند انجام کارها نیز طولانی می‌شد در حالی که بر اساس مقررات ملی ساختمان یک ماه برای این کار تعیین شده بود. وی تصریح کرد: شهرداری گلایه داشت که چرا سازمان نظام مهندسی به مدت زمان مذکور پایبند نیست، رئیس سازمان نظام مهندسی نیز اعلام کرد عمده مواردی که بیش از یک ماه به طول می‌انجامد به دلیل این است که نقشه دارای ایراداتی بوده و مالک آنها را اصلاح نکرده است. در نهایت مقرر شد مکانیسمی تدوین و در نرم افزار لحاظ شود که این کار حداکثر طی 40 روز انجام شود. رئیس کمیسیون معماری و شهرسازی شورای شهر تهران خاطرنشان کرد: موارد دیگری مانند آزمایش مکانیک خاک از نظر شهرداری ایراداتی داشت که در نهایت مقرر شد تغییراتی در فرآیند بررسی آن انجام شود و کنترل مضاعفی صورت گیرد. منبع: [Hidden Content]
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    Strength Characteristics of Clay Mixtures with Waste Materials in Freeze-Thaw Cycles Mahya Roustaei; Mahmoud Ghazavi Waste tires, rubbers, plastic and steel materials, normally produced in every society, enter the environment and cause serious problems. These problems may, to some extent, be reduced by finding applications for them in engineering, for example, they can be used for geotechnical applications as backfill material and solving problems with low shear strength soils. Such materials may be subjected to freeze-thaw cycles, resulting in strength reduction. Freeze–thaw cycling is a weathering process which is normal in cold climates. In these cycles, thermodynamic conditions at temperatures below C cause translocation of water and ice which can change the engineering properties of soils. The present study investigates the effect of reinforcing soil with tire chips and steel fibers to reduce the effects of freeze-thaw cycles. To this aim, reinforced kaolinite clay was compacted in the laboratory and exposed to a maximum of 6 closed-system freeze-thaw cycles. The results of the study reveal that adding tires to clay prevents strength reduction due to freeze-thaw cycles. The soil samples which were mixed with 2% of steel fibers and 10% of tire chips were not affected by the freeze and thaw cycles as the pure samples were. These materials can reduce the effects of freeze and thaw cycles especially in cold regions. منبع دانلود JSEG171329597000.pdf
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    Analysis of Circular Reinforced Tunnels by Analytical Approach Ahmad Fahimifar1 ; Masoud Ranjbarnia 2 This paper addresses the problem of quantifying the mechanical contribution of rockbolts installed systematically around tunnels (regularly spaced around the tunnel) excavated in rock masses. Assuming that the mechanical contribution of grouted rockbolts is that of increasing internal pressure within a broken rock mass, a new procedure for computation of ground response curves for a circular tunnel excavated in strain softening material and then reinforced with systematically active grouted rockbolts is presented. In this work, the equation of the ground response curve for a tunnel which has been reinforced with passive grouted rockbolts is also derived. The proposed model allows one to take into account the effect of the distance of the bolted section to the tunnel face, the effect of increasing rockbolts spacing, the influence of increasing pretension load in calculating of the ground response curve, and the effect of increasing the cross-section area of rockbolts. The results show that decreasing rockbolts spacing increases the support system stiffness rather than preloading of them. منبع دانلود JSEG161329597000.pdf
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    Buckling of Cylindrical Steel Shells with Random Imperfections due to Global Shear Nima Rahmani1 ; Mehran S. Razzaghi 2 ; Mahmoud Hosseini3 This study aims to investigate the effects of geometric imperfections on buckling of thin cylindrical shells due to global shear. To this end, more than 320 finite element models of cylindrical shells with different diameter to thickness ratios were prepared. Random imperfections with different amplitudes were applied to numerical models. The results revealed that global buckling of cylindrical shells are susceptible to imperfection patterns. It was also shown that Yamaki’s expression can be considered as upper band for plastic shear buckling of thin cylindrical shells. منبع دانلود JSEG151329597000.pdf
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    Evaluation of Effective Parameters on the Underground Tunnel Stability Using BEM M Panji 1 ; J Asgari Marnani2 ; Sh Tavousi Tafreshi2 There are various parameters that affect stability and expansion of failure zones in under pressure tunnels. Among the important parameters that affect failure zones around the tunnels are cohesion and internal friction angle of the rock mass. In addition, the cross sectional shape is the considerable point in failure distribution around the tunnels. The stress analysis method is one of the applicable methods for evaluating stability and recognizing failure zones in underground tunnels. On the other hand, numerical stress analysis method, because of obtaining results with simplicity and desirable accuracy, is one of the best methods in stability evaluation of the tunnels. The Boundary Element Method (BEM) has unique advantages in stability analysis of infinite continuums. In this paper, using Hoek-Brown failure criteria and also BEM, failure zones around the tunnels with various section shapes are studied numerically and the effects of cohesion and internal friction angle of rock mass on formation and distribution of failure radii are evaluated. It deserves mentioning that the behavior of the rock mass around the tunnels is assumed to be elastic and the formulations are based on plane strain. منبع دانلود JSEG141329597000.pdf
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    Bending Fatigue Tests and Finite Element Models of Steel Rectangular Hollow Sections [sRHS] islam Ezz El-Arab 1 ; W Gray2 The Welding in cold formed areas is not only an open question for statically loaded sections (brittle fracture) but also for dynamically loaded structures (fatigue resistance). A lot of structures are subjected to dynamic loadings and unfortunately very little information about the influence of welding in the cold formed areas on fatigue resistance is available. In order to establish the fatigue behavior of welded and non-welded rectangular hollow sections specimens, a large number of 4-point bending tests are performed at the Saud Bin Laden Group SBG with cooperation with Buro Happold UK, Laboratory for Steel. Because these tests are very expensive, and because of the large number of parameters regarding the RHS to be investigated (steel grade, wall thickness, load distribution, boundary conditions), a number of finite element models for these specimens are made. By modeling the specimens with different types of finite elements (shells, solids) and taking into account some types of loading distributions and boundary conditions, the obtained results (stresses, strains, displacements) from a static analysis are compared with those obtained from the real 4-points bending tests. In this way, the obtained conclusions would lead to decrease of the number of the specimens that need to be tested as well as the costs of the project. Furthermore, by using finite element analysis, many factors with direct influence on the fatigue resistance can be considered. منبع دانلود JSEG131329597000.pdf
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    An Investigation on the Behavior of Retaining Structure of Excavation Wall Using Obtained Result from Numerical Modeling and Monitoring Approach. (A Case Study of International "Narges Razavi 2 Hotel", Mashhad) Soheil Ghareh 1 ; Mehdi Saidi2 With the growing population and density in metropolitan areas, higher tendency to live in high-rise buildings, and increasing demand for parking lots, it seems necessary to excavate soil to construct underground spaces. During excavation work, as the height of the wall increases, special care should be taken to the wall stabilization to avoid any consequent damage including extensive property damage or loss of life. Different methods such as performing steel or concrete pile, sheet piling, reciprocal anchorage, diaphragm wall, soil nailing, and soil anchorage can be utilized to stabilize excavation wall. As all of these methods have their own advantages and disadvantages, it is important to know the limitations and differences of each method. Besides providing more work space in the wall, using novel methods of stabilization may lead to considerable savings in cost and time. By examining the behavior of retaining structure and also predicting the value of wall displacement, resulting from existing loads such as adjacent structures of the wall, service loads, and vehicle live load, a big step can be taken to prevent any probable damage. Currently, due to the development of high speed digital computers, finite element method (FEM) can be applied to predict the behavior of retaining structure. In this paper, as a case study, the behavior of retaining structure of excavation wall of Narges Razavi 2 International Hotel, Mashhad, stabilized using steel pile and soil anchorage, has been investigated. For this purpose, the results obtained from finite difference software, FLAC2D, and finite element software, PLAXIS2D, have been compared with those obtained from the monitoring of excavation wall. It was found that there is a good consistency between the results. منبع دانلود JSEG121329597000.pdf
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    Structural Damage Identification of Plate Structures based on Frequency Response Function and Natural Frequencies A Esfandiari In this paper, a structural damage identification method (SDIM) is developed for plate-like structures. This method is derived using dynamic equation of undamaged/damaged plate, in which local change in flexural rigidity is characterized utilizing a damage distribution function. The SDIM requires to modal data in the intact state and frequency response of damage state where most of vibration based damage identification techniques requires to modal data in both states. Change of mode shapes of damaged plate are approximated as a linear combination of mode shapes of intact plate and are considered in dynamic equation of damaged plate. Constant Coefficients of linear combination have been evaluated using perturbed equation of motion and the damage distribution function. Two strategies for making the inverse problem damage identification are introduced in connection with damage the present SDIM: (1) by using sensitivity of natural frequencies and (2) by using FRF-data, a sufficient number of equations can be derived to detect magnitude and location of damage. The feasibility of presented method is validated through some numerically simulated damage identification test taking into account random noise in FRF-data. منبع دانلود JSEG111329597000.pdf
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    The Stability Assessment of Dasht-e-Abbas Pressure Intake Tunnel Subjected to Ground Strength Reduction-Iran S. M Mir Mohammad Hosseini 1 ; P Malek Mohammadi2 ; M Kargar3 The hydraulic pressure is one of the most important factors in the design of pressure intake tunnels. Since the surrounding media cannot usually resist the high internal pressure of these tunnels, they are usually finished with an adequate lining mostly of reinforced concrete, which is an interaction problem between water, soil or rock and concrete lining. Although reinforcing the concrete lining may reduce the width and number of the developed cracks in the lining, the penetration of water into the surrounding media can still happen due to high water pressure in the tunnel. Thus, it may lead to the development of hydro pressure on the external surface of the lining. There are some theoretical methods that are developed for the design of tunnel lining in this condition. When the tunnel is located above the underground water table, the seeping water may lead to strength reduction of the adjacent soils, particularly when the ground, like the mudstone layers existing in Dasht-e-Abbas region, south-west of Iran, is cohesive and consists of soils that are susceptible to water. In this paper, the hydrostatic interaction between soil and concrete lining of Dasht-e-Abbas pressure intake tunnel has been investigated when the shear strength parameters of the mudstone layers decrease due to the seepage of water to the surrounding media. To evaluate the stability of the tunnel, a two dimensional numerical simulation is developed using the finite element code called PLAXIS and interaction analyses are carried out. The analyses are done in stages to assess the maximum internal forces induced in the lining. The structural stability of the tunnel is evaluated and discussed in this condition. Based on the obtained results, it is noted that for more realistic understanding of the behavior of infrastructures like pressure intake tunnels under various conditions, numerical analyses should also accompany experimental and analytical approaches such as Schleiss method which is described in this paper, especially for tunneling in media that is susceptible to water and ground strength reduction. The numerical analysis results show a considerable increase in the lining internal forces when subjected to the reduction of ground strength. However, the tunnel structure is still stable under the effect of surrounding ground degradation with the constructed lining specifications. منبع دانلود JSEG101329597000.pdf
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    Modified Linear Approximation for Assessment of Rigid Block Dynamics Vahid Sharif This study proposes a new linear approximation for solving the dynamic response equations of a rocking rigid block. Linearization assumptions which have already been used by Hounser and other researchers cannot be valid for all rocking blocks with various slenderness ratios and dimensions; hence, developing new methods which can result in better approximation of governing equations while keeping simplicity is necessary. In this paper, a new linear approximation is derived for solving the deferential equations of a rocking block in order to include wider range of blocks with various slenderness. The proposed method is verified by numerical solutions of the governing equations utilizing two methods of: average acceleration and fourth order Runge-Kutta. Verifications revealed more reasonable accuracy of the proposed method in comparison with the current linearization assumptions منبع دانلود JSEG91313868600.pdf
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    A Mathematical Modeling for Plastic Analysis of Planar Frames by Linear Programming and Genetic Algorithm Leila Shahryari In this paper, a mathematical modeling is developed for plastic analysis of planar frames. To this end, the researcher tried to design an optimization model in linear format in order to solve large scale samples. The computational result of CPU time requirement is shown for different samples to prove efficiency of this method for large scale models. The fundamental concept of this model is obtained from moment distribution method which is a safe theorem based method, so in this mathematical modeling, the objective is finding the largest load which ensures equilibrium and yield conditions. Contrary to moment distribution method, calculation of load factor and the value of moments in the elements are completely automatic and not to need user decision. As the objective function and constraints of this model are linear so it can be solved by linear programming (LP) software such as LINGO that is shown in this paper and also the model is solved by genetic algorithm (GA) to compare two solutions منبع دانلود JSEG81313868600.pdf
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    A Comparison of Seismic Safety of Steel MRF Designed According to Different Editions of Iranian Seismic Code kiarash Nasserasadi In this paper, efforts are made to compare the safety of steel moment resistant frames designed according to different editions of the Iranian code of Practice for seismic resistant design of buildings. Also, failure risk of a low and medium height frame which designed for high and low seismicity regions according to three editions of the code are evaluated. First, the testing cases were designed and based on a simplified method the fragility functions of frames were evaluated. The probability of failure of frames was calculated by multiplying the fragility function and hazard curves in probabilistic manner. The results indicate that, apart from some exceptions, every edition of new code provides better safety for structures. However, within a single version of the code, the consistency of safety has not been maintained. The structures designed for low seismicity regions are more reliable than those which designed for high seismicity regions. Further research should address this issue and fix the possible. منبع دانلود JSEG71313868600.pdf
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    Comparison Study on Neural Networks in Damage Detection of Steel Truss Bridge Hassan Aghabarati 1 ; Mohsen Tabrizizadeh2 This paper presents the application of three main Artificial Neural Networks (ANNs) in damage detection of steel bridges. This method has the ability to indicate damage in structural elements due to a localized change of stiffness called damage zone. The changes in structural response is used to identify the states of structural damage. To circumvent the difficulty arising from the non-linear nature of the inverse problem, three neural networks, Multi-Layer Perceptron Neural Network (MLPNN), Radial Basis Function Neural Network (RBFNN) and General Regression Neural Network (GRNN) are employed to simulate damage states of steel bridges. It was observed that the performance of all three networks is well and they have good agreement with actual results performed with Finite Element analysis. The efficiency of GRNN in structural identification is so good, although RBFNN has results close to GRNN and MLPNN results are satisfactory. All networks have good results while there is a little damage in structural members. Generally, results would have more error when damages in structural members extend. The engineering importance of the whole exercise can be appreciated once we realize that the measured input at only a few locations in the structure is needed in the identification process using neural networks. منبع دانلود JSEG61313868600.pdf
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    Development of Fiber Reinforced SCM for Sustainable Construction Iman Mehdipour 1 ; Nicolas Ali Libre2 ; Mohammad Shekarchia1 The sustainability of the built environment is increasingly coming to the forefront of infrastructure design and maintenance decisions. To address this, development of a new class of more sustainable cement-based materials is needed. Fiber reinforced self-consolidating mortar (FRSCM) was developed by optimizing the micromechanical parameters, which control composite properties in the hardened state, and the processing parameters, which control the rheological properties in the fresh state. The addition of fibers may take advantage of its high performance in the fresh state to achieve a more uniform dispersion of fibers, which can help to mitigate the shrinkage of the self-consolidating composite. In other words, fibers can have rheological and mechanical synergistic effects and that optimized fiber combinations can better increase mechanical performance while maintaining adequate flow properties for fiber reinforced self-consolidating mortar. In this study, effects of aspect ratio (l/d) and volume fraction (Vf) of polypropylene (PP) fiber on the free shrinkage and mechanical properties of FRSCM were investigated. Besides, the rheological properties of fiber reinforced SCMs are investigated by mini-slump and mini V-funnel tests. Nine mortar mixtures are prepared containing 0 to 0.7 percent of 6 and 12 mm length polypropylene fibers. The shrinkages of hardened mortar were measured since removing the molds and the measurements were continued up to six months. The results show that, the optimum volume fraction of polypropylene fiber content in SCMs to achieve appropriate rheological and mechanical properties is about 0.3% of the mixture volume. On the other hand, increasing the volume fraction and aspect ratio of PP fibers to about 0.7% causes the mechanical properties to drop considerably. This could be due to balling of fibers or fibers coagulation in the mixtures which decreases the mechanical properties. منبع دانلود JSEG41313868600.pdf
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    Lifelines Performance of the Mw 8.8 Offshore BIOBÍO,Chile Earthquake Alex Tang The paper will provide a summary of all lifelines performance in this strong earthquake. The paper will discuss the damage, emergency response, and recovery of electric power, telecommunication, transportation (roads and bridges), seaports, airports, water and wastewater, and their facilities. The impact as a result of the lifelines service interruption will be discussed; most important is the discussion of lifelines interdependence. Each lifeline will be separated into its own section that presents the failure modes, emergency response, and recovery of service. Each section will end with observations and recommendations. منبع دانلود JSEG31313868600.pdf
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    Assessment of the Drain Conditions on Variations of the Pore Pressure in Surrounding Soil of the Tunnel Mohammad Azadi Azadi ; S.M Mir Mohammad Hosseinib ; S.M. Nasimifar ; M Pouranian Excess pore pressure under seismic loadings has always been a main concern in geotechnical engineering practices. The phenomenon in soil can cause an effective stress and hence cause the shear strength of the soil to decrease considerably and large deformations to occur in the area. Generally, increases in pore pressure occur in un-drained conditions. If it is formed, its consequences decrease seriously. There are several reports on devastations caused by excess pore pressure in the surrounding soil of the underground structures. As stresses and deformations of the tunnel lining increase, the surrounding soil of the tunnel is liquefied and large deformations become observable. If an increase in the pore pressure occurs in the surrounding soil of the tunnel, which is an improvement of the surrounding area of the tunnel, then stresses and deformations should be set on the allowable limit. Therefore, evaluation of excessive pore pressure effects on the tunnel lining can be regarded as an important issue and this paper is designed to focus on precisely this topic. منبع دانلود JSEG21313868600.pdf
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    تلفات ۸۰۰ هزار نفری با یک زلزله ۷ ریشتری در تهران/ ایجاد شبکه لرزه‌نگاری زلزله‌های کشور با ۱۱۰۰ دستگاه شتاب‌نگار/ ۲۰۰ هزار از یک میلیون پلاک ثبتی تهران در بافت فرسوده هستندمنبع: [Hidden Content] رئیس مرکز تحقیقات راه، مسکن و شهرسازی با بیان این‌که چهار منطقه حاد از نظر فرسودگی و ناپایداری در تهران وجود دارد گفت: اگر در این چهار منطقه زلزله‌ای به بزرگای ۷.۲ تا ۷.۳ ریشتر رخ دهد بالغ بر ۸۰۰ هزار نفر تلفات خواهیم داشت. به گزارش خبرنگار پایگاه خبری وزارت راه و شهرسازی محمد شکرچی زاده در پنجمین نشست زلزله تهران که صبح امروز چهارشنبه ۲۲ اردیبهشت ماه با عنوان زلزله تهران و بافت فرسوده در مرکز تحقیقات راه، مسکن و شهرسازی برگزار شد گفت: مرکز تحقیقات ۴۰ سال قبل با هدف تهیه آیین‌نامه دستورالعمل ساخت‌وسازهای مقاوم در برابر زلزله و پس از زلزله‌های مرگبار دهه ۵۰ در جنوب خراسان تاسیس شد. بنابراین فلسفه وجودی مرکز تحقیقات تهیه آیین‌نامه ساختمان‌های ضد زلزله است و بعدها وظایف دیگری به عهده این مرکز گذاشته شد. رئیس مرکز تحقیقات راه، مسکن و شهرسازی با اشاره به تهیه مباحث مختلف مقررات ملی ساختمان افزود: بیشتر مباحث مقررات ملی ساختمان به توضیح درباره مقاوم‌سازی ساختمان در برابر زلزله می‌پردازد که تدوین این مباحث بر عهده مرکز تحقیقات است. وی ایجاد شبکه لرزه‌نگاری و شتاب‌نگاری در مرکز تحقیقات را یادآور شد و ادامه داد: این شبکه با بیش از ۱۱۰۰ دستگاه شتاب‌نگار در سراسر کشور مرتبط است و لرزه‌ها را ثبت می‌کند. همچنین در این مرکز در زمینه ژئوتکنیک لرزه‌ای و معماری و شهرسازی بر اساس مقاومت در برابر زلزله پژوهش‌های خوبی انجام شده است. شکرچی زاده با بیان اینکه ما در مرکز تحقیقات راه، مسکن و شهرسازی کارگروه زلزله تهران را به عنوان یکی از زیرمجموعه‌های سازمان مدیریت بحران تشکیل داده‌ایم تصریح کرد: تهران به عنوان مرکز سیاسی و اقتصادی کشور و یکی از مهمترین پایتخت‌های اثرگذار در رویدادهای منطقه از نظر ژئوتکنیکی ناآرام است و هرازچندگاهی زلزله‌هایی به بزرگای حدود ۳ ریشتر را شاهدیم که نشان می‌دهد باید زلزله تهران به صورت خاص و جداگانه بررسی شود. تحقیقات در خصوص زلزله تهران می‌تواند الگوی دیگر کلانشهرها خصوصا تبریز قرار گیرد که وضعیت بدتری از تهران دارد. وی با اشاره به آیین‌نامه ۲۸۰۰ که در خصوص دستورالعمل‌های ساختمان‌سازی تدوین شده افزود: در این آیین‌نامه نیز به مبحث زلزله اشاره شده که براساس آن شهرداری تهران باید درباره ساختمان‌های بسیار بزرگ که قرار است در مناطق گسل‌خیز تهران ساخته شوند تحقیق کند تا روی گسل بودن یا نبودن محل ساخت و ساز ساختمان‌های بزرگ مشخص شود. در جلساتی که با شورای شهر تهران، سازمان زمین‌شناسی و شهرداری تهران داشتیم محدوده گسل‌های تهران مشخص شده و شهرداری براساس آیین‌نامه ۲۸۰۰ موظف است به ساختمان‌هایی که در محدوده گسل‌ها هستند مجوز ساخت ندهد. تاکید مقاوم‌سازی ساختمان‌های نوسازی شده در برابر زلزله در سند بازآفرینی معاون وزیر راه و شهرسازی افزود: اگر در تهران زلزله‌ای رخ دهد آنچه خسارت‌بارتر از خود زلزله است آتش‌سوزی‌های در اثر ترکیدگی شبکه گازرسانی است. این موضوع در کنفرانس آتش هفته آینده بررسی خواهد شد. سند ملی بازآفرینی بافت‌های ناکارآمد به تصویب هیئت دولت رسیده که در آن بر مقوله مقاوم‌سازی ساختمان‌های نوسازی شده در برابر زلزله تاکید فراوانی شده است. این سند مورد توجه مقامات عالی نظام و هیئت دولت در هفته‌های اخیر واقع شد. وی یادآور شد: در زمانی که مسکن‌سازی مطرح بود این بحث نیز مطرح شد که به جای ساخت مسکن مهر در خارج شهرها بافت‌های ناکارآمد داخل شهرها که از نظر تاسیسات زیربنایی آمده هستند بازسازی شوند اما به این موضوع توجه نشد و ما این فرصت را از دست دادیم. وی خاطرنشان کرد: امروز در تهران بیش از یک میلیون نفر و در سراسر کشور ۱۹ میلیون نفر در بافت‌های ناکارآمد زندگی می‌کنند. در برخی شهرها از جمله بندرعباس تا ۴۰ درصد محدوده شهری بافت ناکارآمد است اما به جای بهسازی این بافت‌ها مسکن مهر را در بیرون شهر ساختیم. بنابراین لازم است تا به کمک بخش خصوصی بافت‌های فرسوده بهسازی و زندگی‌پذیر شوند. البته لزوم رعایت مقاوم‌سازی در برابر زلزله و کاهش ریسک‌پذیری در برابر مخاطرات در بهسازی این بافت‌ها از اهمیت بالایی برخوردار است. عضو هیئت علمی دانشگاه تهران وجود چهار منطقه حاد از نظر فرسودگی و ناپایداری را یادآور شد و اظهار کرد: اگر در این چهار منطقه زلزله‌ای به بزرگای ۷.۲ تا ۷.۳ ریشتر رخ دهد بالغ بر ۸۰۰ هزار نفر تلفات خواهیم داشت به خصوص مناطقی که در نزدیکی گسل شمال تهران و گسل کهریزک قرار دارند، بنابراین وقوع زلزله و فعال شدن گسل‌ها در تهران اجتناب‌ناپذیر است اما زمان آن مشخص نیست. در تهران یک میلیون پلاک رسمی به ثیت رسیده که ۲۰۰ هزار پلاک آن در بافت‌های فرسوده قرار دارند و از ۷۰ هزار هکتار مساحت شهر تهران ۶ درصد در بافت ناکارآمد و ۳۰ درصد در بافت ناپایدار واقع شده است./
  22. admin
    بیطرف مطرح کرد؛ معرفی مهندسان ناظر از سوی سازمان نظام مهندسی ساختمان تهران به شهرداری/ پایان اختلاف‌های سازمان نظام مهندسی و شهرداری منبع: [Hidden Content] رئیس سازمان نظام مهندسی ساختمان استان تهران با اعلام توافق شهرداری تهران و نظام مهندسی ساختمان گفت: با توافقات انجام شده، بار دیگر مهندسان ناظر از سوی نظام مهندسی به شهرداری تهران معرفی می‌شوند. به گزارش پایگاه خبری وزارت راه و شهرسازی، حبیب‌الله بیطرف رئیس سازمان نظام مهندسی استان تهران امروز ۲۲ اردیبهشت ماه در گفت و گو با خبرنگاران گفت: سرانجام بعد از یک و نیم ماه و در نتیجه ۱۶ جلسه که هشت جلسه آن بین شهرداری، نظام مهندسی، شورای شهر و وزارت راه و شهرسازی برگزار شد و هشت جلسه نیز به صورت دوجانبه بین دو سازمان نظام مهندسی و شهرداری انجام پذیرفت، در نهایت موارد اختلافی حل شد و صورت جلسه‌ای در ۶بند به امضا رسید که ارجاع مهندس ناظر، کنترل نقشه‌ها، شناسنامه فنی – ملکی ساختمان‌ها، مطالعات ژئوتکنیک و زیرسطحی، موارد مربوط به سازندگان و مجریان ذیصلاح و نیز پرونده‌های ارجاع شده در طول یک و نیم ماه گذشته از بندهای این توافق‌نامه محسوب می‌شوند. وی همچنین از امضای موافقت‌نامه بین سازمان نظام مهندسی و شرکت آب و فاضلاب استان تهران خبر داد که در نتیجه این توافق‌نامه باید استاندارد‌های چهارگانه در تجهیزات مربوط به لوله‌کشی ساختمان‌ها رعایت شود. رییس سازمان نظام مهندسی در خصوص جزییات این موافقت‌نامه با شرکت آب و فاضلاب گفت:‌ موضوع اول مربوط به لوله‌کشی آب سرد و گرم ساختمان‌هاست که از این پس باید کلیه استاندارد‌ها اعم از جنس لوله، نوع شیرآلات، نحوه اتصال لوله‌ها و مجموعا ۳۷ مورد که در تکنیک مشخص شده در ساختمان‌ها باید رعایت شود. بی‌طرف مبحث دوم را رعایت موارد مربوط به لوازم بهداشتی دانست که باید ۱۲ مورد جزییات فنی را رعایت کنند. لوله‌کشی آب باران و و فاضلاب دیگر بند تفاهم‌نامه با شرکت فاضلاب است که رییس سازمان نظام مهندسی به رعایت موارد ۱۸ گانه آن تاکید کرد. رعایت موارد هشت‌گانه تجهیزات بهینه‌سازی مصرف آب مورد آخر است که با توجه به محدودیت منابع آبی کشور، بی‌طرف آن را بسیار مهم عنوان کرد. رییس سازمان نظام مهندسی درباره‌ی تفاهم‌نامه با شهرداری گفت: با این تفاهم‌نامه فرآیند‌های صدور پروانه ساختمان تسهیل می‌شود همچنین موارد قانونی سازمان نظام مهندسی مورد توجه قرار گرفت. بی‌طرف اظهار امیدواری کرد که از این پس همه به قوانین و مقررات طی وظایف خود پایبند باشند. وی همچنین درباره‌ی پایبندی مجریان ذیصلاح به استاندارد‌های ساخت‌وساز گفت: اصلی‌ترین ضامن رعایت مقررات ساختمان وجود پیمانکار متعهد به ضوابط است که اگر کارش را درست انجام دهد دنیا گلستان می‌شود. گفتنی است، از اول فروردین ماه لزوم معرفی مهندسان ناظر از فرایند صدور پروانه ساختمان توسط شهرداری تهران حذف شده بود که این اختلافات در سلسله جلساتی که برگزار شد تا حد قابل توجهی حل شده است./
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    دانلود کتاب سال تاسیسات

    admin پاسخی ارسال کرد برای یک موضوع در جزوات آموزشی غیرتخصصی

    دانلود کتاب سال تاسیسات راهنمای جامع صنعت تهویه و تاسیسات کشور جلد اول و دوم در 282 صفحه گردآوری توسط نشریه فنی مهندسی تهویه تاسیسات این کتاب برای استفاده مهندسین تاسیسات مناسب است سال انتشار :1390 منبع : [Hidden Content] دانلود از پیوست Ketab_Sal_Tasisat_Vol_2.part2.rar Ketab_Sal_Tasisat_Vol_2.part3.rar Ketab_Sal_Tasisat_Vol_2.part1.rar Ketab_Sal_Tasisat_Vol_1.part1.rar Ketab_Sal_Tasisat_Vol_1.part2.rar Ketab_Sal_Tasisat_Vol_1.part3.rar Ketab_Sal_Tasisat_Vol_1.part4.rar
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    Reinforced Concrete Design Project Five Story Office Building

    admin پاسخی ارسال کرد برای یک موضوع در پروژه های بتن

    Reinforced Concrete Design Project : Five Story Office Building Andrew Bartolini | December 7, 2012 Designer 1 | Partner: Shannon Warchol CE 40270: Reinforced Concrete Design یک فایل پی دی اف انگلیسی در مورد مراحل طراحی یک سازه 5 طبقه بتنی با کاربری اداری میباشد. فایل مربوط به سال 2012 میباشد. طراحی بر اساس آیین نامه ACI 318-11 میباشد. سقف با سیستم دال میباشد. از دیوار برشی استفاده نشده است. Table of Contents Abstract ...............................................................................................................................3 Introduction ..........................................................................................................................4 Design .................................................................................................................................5 i. Slab Thickness ............................................................................................................6 ii. Loads ..........................................................................................................................6 iii. Estimation of Column Sizes .....................................................................................6 iv. Slab Design ..............................................................................................................7 v. T-beam Design for Flexure ......................................................................................10 vi. T-beam Design for Shear ........................................................................................14 viii. Crack Control .......................................................................................................16 ix. T-beam deflection control .......................................................................................17 x. Column Design ........................................................................................................18 Summary and Conclusion .................................................................................................21 Recommendations ..............................................................................................................22 Appendix A: Design Figures ..................................................................................................24 B: Load Estimate Calculations ...............................................................................39 C: Slab Design Calculations ..................................................................................40 D: T-Beam Flexure Calculations ...........................................................................42 E: T-Beam Shear Calculations ...............................................................................48 F: Crack Control Calculations ...............................................................................54 G: Deflection Calculations .....................................................................................56 H: Column Design Calculations ............................................................................68 blog206309.zip
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    عکسهایی از تقویت سازه بتنی با ورق فولادی (ژاکت فولادی) منبع: [Hidden Content]

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