2018-05-22T03:18:31Z
http://ijstc.shirazu.ac.ir/?_action=export&rf=summon&issue=400
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
OPTIMIZATION OF SKELETAL STRUCTURES USING A HYBRIDIZED ANT COLONY-HARMONY SEARCH- GENETIC ALGORITHM
Ant Colony Optimization (ACO) has been used as one of the popular meta-heuristicalgorithms in structural optimization. In this algorithm, the selected cross sections are chosenaccording to a parameter called “probability ratio”. This parameter and the way to choose the crosssections from a list of cross sections, are the most important points in the optimization process.Though the Ant Colony algorithm has a special ability in achieving the optimal point, in somecases in order to avoid local optima, the utilization of special techniques is needed. In the presentpaper, the first aim is to use Harmony Search (HS) algorithm to increase the local search ability ofthe ACO. In this way a combined algorithm, denoted by HACOHS, is obtained with specialabilities to achieve a global optimum. For this purpose, optimal design of skeletal structures suchas trusses and steel frames is considered using the HACOHS. However, in the process ofoptimization by HACOHS method, several GA selections are employed at the cross sectionselection stage. Utilizing the Tournament (HACOHS-T), Roulette wheel (HACOHS-Ro), andRank (HACOHS-Ra) methods it is found that the HACOHS-T is the most efficient of thesealgorithms for optimal design of skeletal structures.
Optimization
ant colony algorithm
harmony search
Genetic algorithm
skeletal structures
2014
02
01
1
20
http://ijstc.shirazu.ac.ir/article_1840_ad8eb554563ff7b30715cd9d974537ec.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
SEMI-ACTIVE SEISMIC CONTROL OF MID-RISE STRUCTURES USING MAGNETO-RHEOLOGICAL DAMPERS AND TWO PROPOSED IMPROVING MECHANISMS
This research examines performance of semi-active control of structures usingMagneto-Rheological (MR) dampers. Mechanical specifications of this smart fluid damper changeby falling into the magnetic field, so by increasing intensity of magnetic field the resulting damperpower consequently increases. In this paper, two models of 9 and 20-story buildings were firstselected as case studies and respective specifications of these structures (mass, stiffness anddamping matrices) were calculated using valid sources as well as analysis of structures ignoringaxial deformations against imposed loads. Then, sample structures were simulated in a Simulinkenvironment. Consequently, optimum force determination processor, control system and MRdamper were modeled in Simulink environment and were installed on a structural system. Finally,the obtained results from damper equipped structure were compared with non-controlled structure.In semi-active control case, clipped optimal algorithm was considered as control algorithm andoptimal classic linear control method was used to determine control power. Based on the obtainedresults, it is observed that using this control method will significantly decrease structure response,such that MR damper can be about 12% to 36% effective in reducing maximum lateral drift and upto 21% in reducing maximum acceleration. Two mechanisms are eventually offered to improve thefunction of dampers and their performance. The proposed mechanism is shown to be effective inreducing the capacity and number of dampers required.
Smart fluid dampers
magneto-rheological (MR) dampers
clipped optimal algorithm
linear optimal
control algorithm
simulink modeling
mid–rise structures
2014
02
01
21
36
http://ijstc.shirazu.ac.ir/article_1841_4b941151f1a70e762b59c337efa2735d.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
SEISMIC STABILITY ANALYSIS OF THREE DIMENSIONAL SLOPES USING ACCEPTABLE STRESS FIELDS
Presented is a method of three-dimensional stability analysis of slopes due toearthquake forces based on the Lower-bound theorem of the limit analysis approach. The method’saim is to determine the factor of safety of such slopes using numerical linear finite element andlower bound limit analysis to produce seismic stability charts for three dimensional (3D)homogeneous slopes. The rigorous limit analysis results in this paper together with results of otherresearchers were found to bracket the slope stability number and therefore can be used tobenchmark for solutions from other methods. It was found that using a two dimensional (2D)analysis to analyze a 3D problem will lead to a significant difference in the factors of safetydepending on the slope geometries. Numerical 3D seismic results of the proposed algorithm arepresented in the form of some dimensionless graphs which can be a convenient tool to be used bypracticing engineers to estimate the initial stability for excavated or man-made slopes.
Three-dimensional slope
Slope stability
limit analysis
Lower-bound
limit equilibrium
1. INTRODUCTION
2014
02
01
37
50
http://ijstc.shirazu.ac.ir/article_1842_21aa554aca84cee9dedf3d12b7fa3b1b.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
EFFECT OF QUARRY DUST AND BILLET SCALE ADDITIONS ON THE PROPERTIES OF FLY ASH BRICKS
This paper reports the effect of addition of quarry dust and billet scale on the propertiesof fly ash bricks. Bricks were made with fly ash and cement and varying percentages of quarrydust and billet scale. All the mixtures were made to be flowable in fresh state. The bricks werethen tested for strength, modulus of rupture, ultrasonic pulse velocity, initial rate of suction, waterabsorption, and efflorescence. The strength of bricks ranged from 0.8 MPa to 18.9 MPa, modulusof rupture ranged from 0.13 MPa to 3.7 MPa, water absorption from 15 to 32 %, and initial rate ofsuction between 0.27 and 2.21 kg/m2.min. All the bricks were categorised as non-efflorescent. Itis concluded that the optimum ratio of fly ash and billet scale and quarry dust and billet scale is 1:1to get improved strength. Furthermore, it is shown that fly ash bricks incorporating 25% of quarrydust and billet scale gives reduction in the various properties observed.
Fly ash brick
quarry dust
billet scale
strength
water absorption
2014
02
01
51
60
http://ijstc.shirazu.ac.ir/article_1843_fb8a0f61ae935a2042885ff5114d27eb.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
A RELIABILITY ALLOCATION MODEL AND APPLICATION IN DESIGNING A MINE VENTILATION SYSTEM
A mine ventilation system is an important component of an underground miningsystem. It provides a sufficient quantity of air to maintain a suitable working environment.Therefore, the mine ventilation system should be kept at a highly reliable level and also bemaintained at a very reliable level during the whole service time of the coal mine. However, inreality, failures of a mine ventilation system do occasionally happen. Most of such failures canresult in potential risk for the workers. For example, the insufficient quantity of fresh air to theunderground mine working face may lead to the increased concentration of coal gas to the lowerflammable limit. Once an ignition source exists, a gas explosion can take place. Hence, somefailures become an immediate cause of a mine accident and can cause fatalities and/or propertydamage. By an in-depth analysis, one of the reasons contributing to the mine ventilation failure isthat most systems lack enough technical considerations when they were initially designed.Underestimating the components can substantially lead to a poor quality system. In order toimprove coal mine safety, in this paper, a model scientifically allocating the reliability practice isintroduced into the mine ventilation systems design process. Such a model can well consider theindeterminate problems in both the decision-making process and the system itself, to achieve theoptimum reliability allocation. In detail, first, based on previous research findings, the hierarchicalstructure of a mine ventilation system is identified by the analytic hierarchy process (AHP)method. Second, the proposed reliability allocation model using the fuzzy mathematics calculationis applied to complete and optimize the reliability allocation works. Application of this model isalso demonstrated at the end of this paper.
Reliability allocation
design
mine ventilation system
2014
02
01
61
73
http://ijstc.shirazu.ac.ir/article_1844_e570c45939992e545502e48e7ab14e8b.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
INFLUENCE OF THE SCALE EFFECT ON THE MECHANICAL PARAMETERS OF COARSE-GRAINED SOILS
The mechanical parameters of coarse-grained soils are often obtained via indoor orfield tests. In these tests, it is necessary to reduce the particle size of the original graded soils dueto the size limitation of the testing apparatus. Therefore, several scale methods (e.g., the equivalentsubstitute method and parallel gradation method) have been proposed to reduce the size of theoriginal graded soils to the proper testing size. However, the mechanical parameters will bedifferent if different scale methods are adopted, a phenomenon that has been termed the “scaleeffect”. In this research, a group of large-scale oedometer tests were conducted with specimensthat were downsized using different scale methods. The results show that (1) when adopting thesame scale methods, the compression modulus increases with the increase in the nominalmaximum particle size. (2) For the same nominal maximum particle size, samples that aredownsized using the equivalent substitute method have a higher compression modulus and degreeof particle breakage than those adopting the parallel gradation method. (3) Then Duncan-Chang EBmodel parameters were back calculated from oedometer tests using an immune geneticalgorithm (IGA). These mechanical parameters were also used in a three-dimensional (3D) finiteelement method analysis of the Pankou Rock-fill Dam. The manner in which the scale methodinfluences rock-fill dam deformation is also discussed.
Oedometer test
Scale effect
scale method
nominal maximum particle size
IgA
2014
02
01
75
84
http://ijstc.shirazu.ac.ir/article_1845_765899b6bbab8d30ac8c00497fb243d5.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
AN EXPERIMENTAL AND NUMERICAL STUDY OF FLOW PATTERNS AT A 30 DEGREE WATER INTAKE FROM TRAPEZOIDAL AND RECTANGULAR CHANNELS
Knowing flow pattern, especially stream tube dimensions at the vicinity of a lateralintake is important to study flow discharge and sediment rate entering to the intake as well as tobetter design a measure for controlling sediment entry into the intake. Previous studies have beenfocused on intake from rectangular channels. In the present study, however, different experimentaltests were carried out at a 30 degree water intake installed at bank of a trapezoidal channel tomeasure the three components of flow velocities; these data were then applied to calibrate thenumerical SSIIM2 model; by running the SSIIM2 model for different flow conditions, more datawere obtained. From the analysis of both experimental and numerical data the flow patternsupstream of intake were plotted and the stream tube dimensions were obtained for all flowconditions. It was found that the dividing stream width for intake from trapezoidal canal at thebottom is less than it is for intake from rectangular canal for the same flow conditions; the width atany elevation was found to depend directly on the diversion flow ratio. Relations for predictingdividing stream width as a function of diversion flow ratio have been presented for intake fromboth rectangular and trapezoidal cross sections. Also, computed secondary current strength at theintake entrance, which is an effective parameter in transporting sediment to the intake, showed thatit is a function of flow diversion ratio and for intake from trapezoidal channel it is less than fromrectangular channel.
Dividing stream width
trapezoidal channel
secondary current
2014
02
01
85
97
http://ijstc.shirazu.ac.ir/article_1846_2531c52f5bcf00a9ea207da41ded4323.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
TWO PHASE FLOW MODELING IN SHAFT-SPILLWAYS USING VOLUME OF FLUID (VOF) METHOD
In this paper, the optimum inlet shape of morning-glory spillway is discussed. Theeffect of some parameters including maximum discharge coefficient and minimum possibilityof cavitation (cavitation index) are investigated. For this purpose, using computational fluiddynamics (CFD) in the form of finite volume method, 3D Navier-Stokes equations of flow atdifferent inlet shapes are solved. Free water surface is modeled by water-air two phase flowand equations are solved by volume of fluid (VOF) method. Flow turbulence is modeled by“K-Є model”. Based on experimental results, models are verified and discharge, velocity,pressure and cavitation index for different inlet shapes are computed and compared with eachother. The morning-glory spillway inlet is modeled using different types of equationsincluding WAGNER equation (Y=aX^3.88), CREAGER equation (Y=aX^1.87) and circularform for their funnel profile shapes. In each model changing the head (h) versus discharge (Q)diagram is drawn and results are compared.
Morning glory spillway
cavitation
VOF method
CFD
2014
02
01
99
109
http://ijstc.shirazu.ac.ir/article_1847_d1e62f9e428f421656379b4ae279b57f.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
HYDRAULIC JUMP IN A DIVERGING CHANNEL WITH AN ADVERSE SLOPE
In this research, the adverse hydraulic jump formed in a gradually expanding stillingbasin of rectangular cross section is investigated both theoretically and experimentally. Theexperiments were conducted in a specially designed model for a wide range of bed slopes anddiverging angles of the basin walls in addition to classic jump for a wide range of Froude numbers.A momentum-based theory is presented to determine the sequent depth ratio. The results show thatthere is good agreement between theoretical and experimental data. Comparison of importantparameters of a diverging hydraulic jump on the adverse slope, such as length, sequent depth andenergy loss, with those in the classic jumps indicated that any increase in the adverse bed slopeand the diverging angle of basin wall would cause a reduction of the sequent depth and relativelength of jump and increase in the relative energy loss in comparison to the classical hydraulicjump.
Hydraulic jump
gradually diverging stilling basin
adverse bed slope
sequent depth
Energy loss
2014
02
01
111
121
http://ijstc.shirazu.ac.ir/article_1848_72dd87bba4ff166acf99762fcf0ab71c.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
APPLICATION OF THE HBMO APPROACH TO PREDICT THE TOTAL SEDIMENT DISCHARGE
River sediment discharge estimation is a very important process for the water resourcemanagement. Sediment discharge is usually calculated either from the direct measurements ofsediment concentration or sediment transport empirical equations. Due to several difficulties inapplying empirical equations and direct measurements, in this study a general equation isdeveloped to estimate the total sediment load with a good accuracy. An artificial intelligent modelbased on Honey Bee Mating Optimization (HBMO) is used to estimate the parameters of theproposed equation. The set of variables in the model is based on evaluating some of the existingempirical equations and also the prior researches to find the dominant parameters in the sedimenttransport formulas. Based on these investigations some parameters such as average flow velocity,water surface slope, average flow depth, median particle diameter, water temperature and width ofthe rivers are more effective and have been selected as the dominant variables in this research.With consideration of the mentioned variables, this model tries to determine the coefficients andpowers of the general equation. Three data sets of different rivers have been chosen to demonstratethe model. The model has been calibrated by 75% of the data and validated by the remaining 25%.To calculate the proposed model efficiency and validity, the results have been compared with twocommon models. Therefore, the Sediment Rating Curve (SRC) and Non Linear Regression (NLR)models have been applied and the statistical results have been proposed to show the modelefficiency.
HBMO
total sediment
prediction
Mathematical modeling
2014
02
01
123
135
http://ijstc.shirazu.ac.ir/article_1849_7871a9232935828741d4f1ccd8b07e16.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
MAGNETIC NANO-BIOSORPTION OF HEAVY METAL FROM AQUEOUS SOLUTIONS USING SUGARCANE BAGASSE
Uranium in the environment is hazardous to human health and requires better methodsfor detection and remediation. Bioadsorbent coated on nanocrystalline iron oxides offers a numberof advantages as sorbents for water purification and environmental remediation. In this study, firsthighly uniform and crystalline iron oxide nanocrystals (nMAG) were prepared using iron salts inpresence of NaOH by co- precipitation process and then sugarcane bagasse coated on synthesizediron oxide nanocrystals has been used as a bioadsorbent for uranium solution with lowconcentration. The effect of different parameters on optimum function of this process has beenanalyzed. The results showed that maximum uranium absorption occurs at pH levels of about 3.Optimum amounts of biomass, uranium concentration and contact time are 0.1 gr, 50 ppm and 120min, respectively. Thus, the uranium biosorption by magnetic biosorbent can be considered apotential technology of treatment process for uranium removal in which the adsorbents and theadsorbed pollutant can be quickly recycled by simply applying a magnet.
Sugarcane bagasse
Uranium
nano biosorbent
biosorbtion
2014
02
01
137
146
http://ijstc.shirazu.ac.ir/article_1850_e46949749e61d4b20b23207396a82566.pdf
Iranian Journal of Science and Technology Transactions of Civil Engineering
2228-6160
2228-6160
2014
38
C1
ADSORPTION OF REMAZOL BLACK RL AND REACTIVE YELLOW 145 FROM AQUEOUS SOLUTIONS BY PINE NEEDLES
Adsorption of Reactive Yellow 145 (RY145) and Remazol Black RL (RBRL) onto pineneedles (PN) was investigated with respect to initial dye concentrations, adsorbent dosage, and pHin a batch manner. The obtained data in the study were described according to the Langmuir andFreundlich isotherm models and the Langmuir model describes the experimental data very wellwith a qmax value of 13.831 and 7.225 for RBRL and RY145 respectively. As the pH decreased,adsorption density increased gradually and the highest adsorption density was obtained at pH 2 forboth adsorbents (91.57 and 64.77% for RBRL and RY145 respectively). Equilibrium adsorptionrates of 70.15% with RY145 and 86.72% with RBRL onto PN were observed at 90 min. In orderto better model the kinetics of adsorption, first order, pseudo second order and second ordermodels were applied. Among these models, the pseudo-second order kinetic model provided agood correlation for the adsorption of RY145 and RBRL by PN with a R2> 0.999. Results showedthat pine needles have great potential to remove Reactive Yellow 145 (RY145) and RemazolBlack RL from aqueous solutions.
Adsorption
reactive yellow 145
Remazol Black RL
pine needles
2014
02
01
147
155
http://ijstc.shirazu.ac.ir/article_1851_20caefe8413f879707681124210ef166.pdf