Impact Factor :
1.025
Q1(Year 2015)
ISSN : 1026-3098
e-ISSN : 2345-3605
Published Issues
Corrigendum to "Some resilient aspects of urban areas to air pollution and climate change, case study: Tehran, Iran" [Scientia Iranica 23(5) (2016) 1994-2004]
2016
Abstract :
The e ects of climate and meteorological factors on urban problems such as air pollution, heat island, and urban hydrology have increasingly become important in terms of mitigation and adaptation issues during the recent years. In the present paper, we discuss some of the climate or meteorological factors a ecting air pollution in Tehran. Tehran is a unique megacity in terms of geographic setting, being mountainous and an ever-expanding urban area that su ers from acute air pollution and heat waves episodes. Recent records of air pollutants also show increased trends with some low-frequency variability caused by chaotic atmospheric motions. Moreover, the wind speed has also decreased as a result of the aerodynamic surface roughness increase and probably the decrease in the passage of cyclones over the mid-latitudes according to the recent ndings. Mixed-layer height over the city, due to higher-surface heat fluxes (mainly due to the reduction in surface albedo, anthropogenic heat, and lower green spaces), is expected to increase; although it is favorable for reduction in some air pollutants such as CO, it is not eligible for ozone. Finally, an integrated framework for actions regarding impacts, emissions, urban climate change, and monitoring including adaptation and mitigation towards a climate-change resilient city is proposed.
Keywords :
Climate record; Air pollution; Resilient city; Urban Area; Tehran.
( 184 Visit ) ( 159 Download )

Neurocomputing in Civil Infrastructure
2016
Abstract :
This article presents a review of the recent applications of artificial neural networks (ANN) for civil infrastructure including structural system identification, structural health monitoring, structural vibration control, structural design and optimization, prediction applications, construction engineering, and geotechnical engineering. The most common ANN used in structural engineering is the backpropagation neural network followed by recurrent neural networks and radial basis function neural networks. In recent years, newer hybrid techniques have been used in structural engineering by a number of researchers such as the neuro-fuzzy inference system, time-delayed neuro-fuzzy inference system, and wavelet neural networks. Deep machine learning techniques are among the newest techniques to find applications in civil infrastructure systems.
Keywords :
Artificial Neural Networks; Civil Structures; System Identification; Structural Health Monitoring; Control; Prediction; Optimization, construction, geotechnical
( 108 Visit ) ( 32 Download )

The effects of drivers’ behavior on driver-injury severities in Iran: An application of the mixed-logit model
2016
Abstract :
It has long been established that adverse driver behavior, including behavior relating to distracted driving, propensities for risk taking, and disregarding traffic rules, have been critical determinants with regard to the likelihood of a vehicle crash and its resulting injury severity. Socio-economic/educational/cultural factors (e.g. social willingness to comply with the law) have significant positive effects on traffic related fatalities. Using crash data from Iran over a six-year period from January 1, 2006 to December 31, 2011, this paper estimates a mixed logit model (with possible outcomes of severe injury, minor injury, and no injury) to investigate the unsafe driving behavior effects on driver-injury severity in a vehicle collision on interprovincial routes. The methodological approach allows the parameters to vary across observations as opposed to a fixed parameter model. The results showed random effects of female drivers, separated bi-directional route and clear weather condition for no injury severity function, following too closely for minor injury function, and average annual daily traffic for severe injury function. Several factors were found to significantly increase the likelihood of severe injury crashes including disregarding traffic rules, exceeding the speed limit, improper overtaking/passing, and driving in an erratic and negligent manner. The results of this paper will further help decision makers to better understand the contributing factors on crash injury severity and implement treatments to reduce the crash severity and improve transportation safety. 
Keywords :
Driver-injury severity; Mixed logit model; Unsafe driving; Interprovincial routes
( 848 Visit ) ( 53 Download )

The effect of fuzzy controller on damage of steel structure considering structural uncertainties
2016
Abstract :
In this study, the effect of active and semi active fuzzy logic controllers (FLC) on the damage imposed on steel structures considering structural uncertainties are investigated. Two FLCs are designed for controlling the actuators and controllable viscous dampers, as active and semi active devices, respectively. Fragility curves are used to show the probability of damage imposed on uncontrolled and controlled structures. They are developed in consideration with three performance levels specified in FEMA 356, including Immediate Occupancy (IO), Life Safety (LS) and Collapse Prevention (CP). For investigating the effect of structural uncertainties on the damage, fragility curves are generated separately considering deterministic and probabilistic parameters for the structure. To simulate the structure including the probabilistic parameters, Latin hypercube sampling is employed. Effectiveness of the controllers are illustrated and verified using the simulated response of a 3-story nonlinear benchmark building excited by several ground motions. To compare the performance of fuzzy controllers, fragility curves are also generated for the structure controlled by LQG and clipped-optimal controllers. Results show that FLCs can reduce the probability of damage significantly. Moreover, it is observed that the uncertainty in mass and yield strength have the greatest effect on the maximum drift of structure.
Keywords :
fragility curves; fuzzy logic controller (FLC); active controller; semi active controller; structural uncertainty
( 657 Visit ) ( 15 Download )

 Fuzzy Supervisory Control of a Seismic Shake Table
2016
Abstract :
The design and implementation of a novel fuzzy supervisory control approach for the motion control of a seismic shake table is addressed in this work. For this purpose, a single degree of freedom laboratory-scale electric shake table was developed. The control scheme comprises two loops: a PI inner loop and a fuzzy outer loop as the supervisor. Three separate supervisory controllers are proposed and implemented in the shake table and their performance in tracking two real earthquakes is assessed via extensive shake table testing. The test results reveal the effectiveness of the fuzzy supervisory controller in reducing displacement and acceleration tracking errors.
Keywords :
Seismic Shake Table, Electric, Motion Control, Tracking, Fuzzy Supervisory
( 633 Visit ) ( 35 Download )

RPIM and RPIM-MLS based MDLSM method for the solution of elasticity problems
2016
Abstract :
 One of the main difficulties in the development of meshless methods using the Moving Least Squares approximation, such as Mixed Discrete Least SquaresMeshless (MDLSM) method, is the imposition of the essential boundary conditions. In this paper the RPIM shape function, which satisfies the properties of the Kronecker delta condition, is employed in the Mixed Discrete Least SquaresMeshless (MDLSM)method for solving the elasticity problems. Accordingly, two new MDLSM formulation is proposed in this article namely RPIM-based MDLSM and coupled MLS-RPIM MDLSM formulation. The essential boundary conditions can be imposed directly in both presented methods.The proposed methods are used for the solution of three benchmark elasticity problems and the results are presented and compared with the available analytical solutions and those of MLS-based MDLSM formulation. In addition, in each example different types of nodal distributions, regular and irregular configurations, are considered to test the performance of the presented methods. The numerical tests indicates higher accuracy of the suggested approaches in comparison with the MLS-based MDLSM method.
Keywords :
meshfree method, MDLSM method, radial point interpolation method (RPIM), moving least squares approximation (MLS), coupled method
( 599 Visit ) ( 43 Download )

Dispersion of surface waves in a transversely isotropic half-space underlying a liquid layer
2016
Abstract :
Surface waves dispersion is studiedin a two-layer half-space consisting of a finite liquid layer overlying a transversely isotropic solid half-space. A couple of complete potential functions are utilized to uncouple the equation of motion of the transversely isotropic solid along with the displacement potential for the liquid. The frequency equationand the dispersion curves are developed. Several solid materials are considered for the bed and phase and group velocity curves are presented. Higher modes of dispersion are also discussed and the respective graphs are plotted. Various special cases are considered by letting the liquid layer depth take zero value to form a solid half-space as well as very large values to form a full-space bi-material. Moreover, an isotropic bed material can be obtained as a reducedcase, setting the respective elastic constants.Reduced frequency equations and numerical results are derived for each case to confirm the results with existing ones.
Keywords :
Surface wave, Dispersion, Liquid, transverse isotropy, Rayleigh wave, Stoneley wave, Scholte wave, Frequency equation, Anisotropy
( 1031 Visit ) ( 73 Download )

Satellite and ground-based assessment of Middle East meteorological parameters impact on dust activities in western Iran
2016
Abstract :
In this article, the relation between meteorological parameters and dust activities in western Iran has been studied. Satellite-based data achieved from TOMS are used to investigate the dust activities within a time period of 30 years. In the rst part of this study, we examine the statistical trend of Aerosol Index (AI) and local meteorological parameters in 15 di erent stations. The same patterns of AI variations in all stations indicate that this region has always been subjected to dust storms which originate from similar sources in the neighboring countries that could be known as a sole dust transfer system. In the second part, we investigate the spatial correlation between the regional meteorological parameters in the Middle East and AI data to determine the contribution of meteorological parameters to dust levels. Broadly, results show that the precipitation in concurrent and antecedent months has a negative correlation with AI parameter of dusty months. Also, notably, we observed that the zonal wind speed in Iraq has a strong positive correlation with AI in our selected stations. This fact veri es that the zonal winds could be identi ed as the major cause of dust transfer system that was noted in the rst part of this study.
Keywords :
Dust; Meteorological parameters; Correlation analysis; TOMS/AI; Middle east.
( 46 Visit ) ( 30 Download )

Performance evaluation of curved welded flange-plate beam-to-column connections
2016
Abstract :
In this paper, curved welded flange-plate beam-to-column connections are introduced and investigated analytically. The connection is comprised of two curved flange-plates installed on beam flange to transfer bending moment and two web angles for transmission of shear forces. Theoretical relationships are established for initial sti ness, ultimate moment, and ultimate rotation to be used for calibration of a bilinear model of moment-rotation. Furthermore, nite element analyses are conducted on eighteen specimens designed based upon the results of theoretical study. Analyses are in good agreement with theories verifying modeling procedure. Block shear rupture, tension rupture, and formation of three plastic hinges in semi-circular portion of the flange-plate are identi ed as the major failure modes. The failure due to formation of three plastic hinges in the flange-plate is suggested to govern the connection design, which leads to a ductile behavior. As a result, a flow chart is suggested to design the proposed connection.
Keywords :
Curved flange-plate; Beam-to-column connections; Semi-rigid connections; Moment-rotation behavior; Theoretical approach; Finite element analysis; Plastic hinge.
( 42 Visit ) ( 11 Download )

Prediction of lightweight aggregate concrete compressive strength using ultrasonic pulse velocity test through gene expression programming
2016
Abstract :
The use of lightweight structural concreteto reduce the weight of earthquake resistant buildings is very useful, and utilizing non-destructive tests for determining the concrete strength of these structures is essential.Ultrasonic pulse velocity test is one of the main methods of non-destructive testing in the assessment of compressive strength of concrete in the service area. The aim of this study is estimation of the compressive strength of lightweight aggregate concreteby offering suitable mathematical formulations.For this purpose, many samples of three different types of lightweight aggregate concrete are made and tested by concrete breaking machine and Ultrasonic pulse velocity instrument.Then some relationships for prediction of the compressive strength of the concrete by using ultrasonic test results are presented. Two different methods of fitting exponential function and Gene Expression Programming (GEP) are utilized to find the proper relationships. The results show that the exponential function has high accuracy in estimating the compressive strength of lightweight aggregate concrete made ​​with natural pumices. But it doesn’t have good results for concrete made of expanded clay. However the GEP has high accuracy for all the materials and the experimental results are perfectly compatible with the test results.
Keywords :
Non-destructive testultrasonic pulse velocity; geneexpression programming; light weight aggregate concrete; prediction of concrete compressive strength
( 316 Visit ) ( 48 Download )

A METHODOLOGY FOR VALUE BASED SEISMIC DESIGN OF STRUCTURES by the ENDURANCE TIME METHOD
2016
Abstract :
A new design methodology based on the total value of structures is introduced. This methodology, namely Value Based Design of structures (VBD), uses the advantages of Endurance Time (ET) method. While prescriptive and earlier generations of performance based design approaches commonly try to find structures with the least initial cost, a design approach to incorporate directly the concept of value in design procedure has been formulated here. Reduced computational effort in ET analysis provides the prerequisites to practical use of optimization algorithms in seismic design. A genetic algorithm is used with the objective of minimizing total cost of the building during its life span. ET method is used to estimate the structural responses of each candidate design to probable earthquakes and the expected costs of earthquake consequences are calculated using Life Cycle Cost Analysis (LCCA). A prototype steel frame is optimally designed according to a prescriptive, performance based and the proposed value based design method and then their seismic performance and expected cost components are investigated. The results provide a pathway towards practical value based design and show that conformance to design code requirements or performance objectives do not assure achieving the best design regarding the overall design values.
Keywords :
Earthquake Engineering, Value Based Seismic Design, Life Cycle Cost Analysis, Structural Optimization, Endurance Time Method, Nonlinear Dynamic Analysis
( 620 Visit ) ( 276 Download )

Determination of the pollution control flow for drought management in a multi-reservoir system
2016
Abstract :
The pollution, changing according to various standards, is directly proportional to water quality in rivers. In this study, data and restrictions prescribed for standards of water quality such as Turkish Standards Institute (TSI), European Commission (EC), and the World Health Organization (WHO) were used to determine water pollution. For this purpose, correlation analysis was made to identify strong relationships between data. Regression analysis and Arti cial Neural Networks (ANN) models are developed based on these standards by data obtained from correlation analysis. The Lower Sakarya River is selected as application area, and measurement of the water quality values of this river is used in these models. Pollution control flows in the river are obtained by the ANN models and regression analysis. The obtained results are compared with regard to these standards.
Keywords :
Pollution control flow; Correlation and regression analyses; Arti cial neural networks; Drought management; Multi-reservoir system.
( 45 Visit ) ( 21 Download )

Comparison of five different models in predicting the shear stress distribution in straight compound channels
2016
Abstract :
The ability of five different methods to estimate the shear stress distribution in compound channels is investigated. Methods proposed by Yang and Lim (YLM), Khodasheans and Paquier (KPM), Sterling and Knight (SKM), Zarrati et al. (ZAM) and Bonakdari et al. (BAM) are compared with experimental data. YLM and KPM did not provide reliable results as they produced higher mean absolute percentage of error (MAPE) values of 25-55%. SKM performed adequately in predicting the pattern of shear stress distribution on the main channel bed, but on a floodplain bed it predicted a constant value over the entire wetted perimeter. The SKM method outperformed YLM and KPM with 2 to 20% MAPE. The ZAM and BAM methods produced the best results for shear stress distribution in compound channels with average MAPE% of 2.67 and 5.66 respectively. Although ZAM showed more accurate results than BAM, however BAM required solving much fewer equations than ZAM and presented more accurate results than other geometric methods. Among all models, BAM is proposed as a simple and accurate model for predicting the shear stress distribution in compound channels.
Keywords :
Compound channel, Floodplain, Main channel, Shear stress distribution, Traditional models, Wetted perimeter.
( 195 Visit ) ( 35 Download )

Evaluation of Safety Risks in Construction Using Fuzzy Failure Mode and Effect Analysis (FFMEA)
2016
Abstract :
The construction industry is one of the most dangerous environments within which to work. For this reason safety-related risk analysis is one of the most significant tasks that has to be undertaken when managing major construction projects. A combination of fuzzy Logic and Failure Mode and Effects Analysis (FMEA), Fault Tree Analysis (FTA), and Analytical Hierarchy Process-Data Envelopment Analysis (AHP-DEA) is applied to improve the process of managing safety risks. Two different types of large scale construction projects were also considered as case studies. It was found that the risk of falling from a height was the most significant risk for both types of project. Moreover, the factors intensifying the risk of injury from workers falling were found to be ignoring safety and lack of personal protective equipment as well as a lack of appropriate training for construction workers. It was also concluded that the framework is applicable to all construction sites, covers all safety aspects and its results are valid.
Keywords :
Risk evaluation, Construction safety, Fuzzy logic, FMEA, Fault tree analysis, AHP-DEA
( 602 Visit ) ( 85 Download )

Nano-Silica Effects on Mechanical Properties of Concretein Crude Oil Products Environment
2016
Abstract :
This investigation develops some important data on the mechanical properties, bond strength between concrete and steel rebar and microstructure of crude Oil-Soaked Concrete containing silica fume and Nano silica. Experiments were performed in eight mixes with different percentages of Nano silica and different water-cement ratios. Concrete samples were cured in the petrol, gas-oil, 2.5% solution of sulfuric acid and water. To conclude, considering the results, recommendations on optimization of Nano silica, silica fume and water-cement ratio for this type of concrete for use in the construction of concrete tanks holding petroleum products are offered. The result shows that Nano silica can improves various properties of the concrete in corrosive conditions.
Keywords :
Nano Silica; Petroleum Products; Sulfuric Acid; Compressive Strength; Bond Strength; Steel Rebar
( 451 Visit ) ( 31 Download )

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Published Issues
2017
Transactions on Civil Engineering
Transactions on Mechanical Engineering
Transactions on Industrial Engineering
2016
2015
Transactions on Civil Engineering
Transactions on Mechanical Engineering
Transactions on Chemistry and Chemical Engineering
Transactions on Computer Science & Engineering and Electrical Engineering
Transactions on Industrial Engineering
Transactions on Nanotechnology
2014
Transactions on Civil Engineering
Transactions on Mechanical Engineering
Transactions on Chemistry and Chemical Engineering
Transactions on Computer Science & Engineering and Electrical Engineering
Transactions on Industrial Engineering
Transactions on Nanotechnology
2013
Transactions on Civil Engineering
Transactions on Mechanical Engineering
Transactions on Chemistry and Chemical Engineering
Transactions on Computer Science & Engineering and Electrical Engineering
Transactions on Industrial Engineering
Transactions on Nanotechnology

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