2019-05-25T16:14:29Z
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-heuristic<br />algorithms in structural optimization. In this algorithm, the selected cross sections are chosen<br />according to a parameter called “probability ratio”. This parameter and the way to choose the cross<br />sections from a list of cross sections, are the most important points in the optimization process.<br />Though the Ant Colony algorithm has a special ability in achieving the optimal point, in some<br />cases in order to avoid local optima, the utilization of special techniques is needed. In the present<br />paper, the first aim is to use Harmony Search (HS) algorithm to increase the local search ability of<br />the ACO. In this way a combined algorithm, denoted by HACOHS, is obtained with special<br />abilities to achieve a global optimum. For this purpose, optimal design of skeletal structures such<br />as trusses and steel frames is considered using the HACOHS. However, in the process of<br />optimization by HACOHS method, several GA selections are employed at the cross section<br />selection stage. Utilizing the Tournament (HACOHS-T), Roulette wheel (HACOHS-Ro), and<br />Rank (HACOHS-Ra) methods it is found that the HACOHS-T is the most efficient of these<br />algorithms 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 using<br />Magneto-Rheological (MR) dampers. Mechanical specifications of this smart fluid damper change<br />by falling into the magnetic field, so by increasing intensity of magnetic field the resulting damper<br />power consequently increases. In this paper, two models of 9 and 20-story buildings were first<br />selected as case studies and respective specifications of these structures (mass, stiffness and<br />damping matrices) were calculated using valid sources as well as analysis of structures ignoring<br />axial deformations against imposed loads. Then, sample structures were simulated in a Simulink<br />environment. Consequently, optimum force determination processor, control system and MR<br />damper were modeled in Simulink environment and were installed on a structural system. Finally,<br />the obtained results from damper equipped structure were compared with non-controlled structure.<br />In semi-active control case, clipped optimal algorithm was considered as control algorithm and<br />optimal classic linear control method was used to determine control power. Based on the obtained<br />results, it is observed that using this control method will significantly decrease structure response,<br />such that MR damper can be about 12% to 36% effective in reducing maximum lateral drift and up<br />to 21% in reducing maximum acceleration. Two mechanisms are eventually offered to improve the<br />function of dampers and their performance. The proposed mechanism is shown to be effective in<br />reducing 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 to<br />earthquake forces based on the Lower-bound theorem of the limit analysis approach. The method’s<br />aim is to determine the factor of safety of such slopes using numerical linear finite element and<br />lower bound limit analysis to produce seismic stability charts for three dimensional (3D)<br />homogeneous slopes. The rigorous limit analysis results in this paper together with results of other<br />researchers were found to bracket the slope stability number and therefore can be used to<br />benchmark for solutions from other methods. It was found that using a two dimensional (2D)<br />analysis to analyze a 3D problem will lead to a significant difference in the factors of safety<br />depending on the slope geometries. Numerical 3D seismic results of the proposed algorithm are<br />presented in the form of some dimensionless graphs which can be a convenient tool to be used by<br />practicing 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 properties<br />of fly ash bricks. Bricks were made with fly ash and cement and varying percentages of quarry<br />dust and billet scale. All the mixtures were made to be flowable in fresh state. The bricks were<br />then tested for strength, modulus of rupture, ultrasonic pulse velocity, initial rate of suction, water<br />absorption, and efflorescence. The strength of bricks ranged from 0.8 MPa to 18.9 MPa, modulus<br />of rupture ranged from 0.13 MPa to 3.7 MPa, water absorption from 15 to 32 %, and initial rate of<br />suction between 0.27 and 2.21 kg/m2.min. All the bricks were categorised as non-efflorescent. It<br />is concluded that the optimum ratio of fly ash and billet scale and quarry dust and billet scale is 1:1<br />to get improved strength. Furthermore, it is shown that fly ash bricks incorporating 25% of quarry<br />dust 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 mining<br />system. It provides a sufficient quantity of air to maintain a suitable working environment.<br />Therefore, the mine ventilation system should be kept at a highly reliable level and also be<br />maintained at a very reliable level during the whole service time of the coal mine. However, in<br />reality, failures of a mine ventilation system do occasionally happen. Most of such failures can<br />result in potential risk for the workers. For example, the insufficient quantity of fresh air to the<br />underground mine working face may lead to the increased concentration of coal gas to the lower<br />flammable limit. Once an ignition source exists, a gas explosion can take place. Hence, some<br />failures become an immediate cause of a mine accident and can cause fatalities and/or property<br />damage. By an in-depth analysis, one of the reasons contributing to the mine ventilation failure is<br />that most systems lack enough technical considerations when they were initially designed.<br />Underestimating the components can substantially lead to a poor quality system. In order to<br />improve coal mine safety, in this paper, a model scientifically allocating the reliability practice is<br />introduced into the mine ventilation systems design process. Such a model can well consider the<br />indeterminate problems in both the decision-making process and the system itself, to achieve the<br />optimum reliability allocation. In detail, first, based on previous research findings, the hierarchical<br />structure of a mine ventilation system is identified by the analytic hierarchy process (AHP)<br />method. Second, the proposed reliability allocation model using the fuzzy mathematics calculation<br />is applied to complete and optimize the reliability allocation works. Application of this model is<br />also 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 or<br />field tests. In these tests, it is necessary to reduce the particle size of the original graded soils due<br />to the size limitation of the testing apparatus. Therefore, several scale methods (e.g., the equivalent<br />substitute method and parallel gradation method) have been proposed to reduce the size of the<br />original graded soils to the proper testing size. However, the mechanical parameters will be<br />different if different scale methods are adopted, a phenomenon that has been termed the “scale<br />effect”. In this research, a group of large-scale oedometer tests were conducted with specimens<br />that were downsized using different scale methods. The results show that (1) when adopting the<br />same scale methods, the compression modulus increases with the increase in the nominal<br />maximum particle size. (2) For the same nominal maximum particle size, samples that are<br />downsized using the equivalent substitute method have a higher compression modulus and degree<br />of particle breakage than those adopting the parallel gradation method. (3) Then Duncan-Chang EB<br />model parameters were back calculated from oedometer tests using an immune genetic<br />algorithm (IGA). These mechanical parameters were also used in a three-dimensional (3D) finite<br />element method analysis of the Pankou Rock-fill Dam. The manner in which the scale method<br />influences 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 lateral<br />intake is important to study flow discharge and sediment rate entering to the intake as well as to<br />better design a measure for controlling sediment entry into the intake. Previous studies have been<br />focused on intake from rectangular channels. In the present study, however, different experimental<br />tests were carried out at a 30 degree water intake installed at bank of a trapezoidal channel to<br />measure the three components of flow velocities; these data were then applied to calibrate the<br />numerical SSIIM2 model; by running the SSIIM2 model for different flow conditions, more data<br />were obtained. From the analysis of both experimental and numerical data the flow patterns<br />upstream of intake were plotted and the stream tube dimensions were obtained for all flow<br />conditions. It was found that the dividing stream width for intake from trapezoidal canal at the<br />bottom is less than it is for intake from rectangular canal for the same flow conditions; the width at<br />any elevation was found to depend directly on the diversion flow ratio. Relations for predicting<br />dividing stream width as a function of diversion flow ratio have been presented for intake from<br />both rectangular and trapezoidal cross sections. Also, computed secondary current strength at the<br />intake entrance, which is an effective parameter in transporting sediment to the intake, showed that<br />it is a function of flow diversion ratio and for intake from trapezoidal channel it is less than from<br />rectangular 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. The<br />effect of some parameters including maximum discharge coefficient and minimum possibility<br />of cavitation (cavitation index) are investigated. For this purpose, using computational fluid<br />dynamics (CFD) in the form of finite volume method, 3D Navier-Stokes equations of flow at<br />different inlet shapes are solved. Free water surface is modeled by water-air two phase flow<br />and equations are solved by volume of fluid (VOF) method. Flow turbulence is modeled by<br />“K-Є model”. Based on experimental results, models are verified and discharge, velocity,<br />pressure and cavitation index for different inlet shapes are computed and compared with each<br />other. The morning-glory spillway inlet is modeled using different types of equations<br />including WAGNER equation (Y=aX^3.88), CREAGER equation (Y=aX^1.87) and circular<br />form for their funnel profile shapes. In each model changing the head (h) versus discharge (Q)<br />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 stilling<br />basin of rectangular cross section is investigated both theoretically and experimentally. The<br />experiments were conducted in a specially designed model for a wide range of bed slopes and<br />diverging angles of the basin walls in addition to classic jump for a wide range of Froude numbers.<br />A momentum-based theory is presented to determine the sequent depth ratio. The results show that<br />there is good agreement between theoretical and experimental data. Comparison of important<br />parameters of a diverging hydraulic jump on the adverse slope, such as length, sequent depth and<br />energy loss, with those in the classic jumps indicated that any increase in the adverse bed slope<br />and the diverging angle of basin wall would cause a reduction of the sequent depth and relative<br />length of jump and increase in the relative energy loss in comparison to the classical hydraulic<br />jump.
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 resource<br />management. Sediment discharge is usually calculated either from the direct measurements of<br />sediment concentration or sediment transport empirical equations. Due to several difficulties in<br />applying empirical equations and direct measurements, in this study a general equation is<br />developed to estimate the total sediment load with a good accuracy. An artificial intelligent model<br />based on Honey Bee Mating Optimization (HBMO) is used to estimate the parameters of the<br />proposed equation. The set of variables in the model is based on evaluating some of the existing<br />empirical equations and also the prior researches to find the dominant parameters in the sediment<br />transport formulas. Based on these investigations some parameters such as average flow velocity,<br />water surface slope, average flow depth, median particle diameter, water temperature and width of<br />the rivers are more effective and have been selected as the dominant variables in this research.<br />With consideration of the mentioned variables, this model tries to determine the coefficients and<br />powers of the general equation. Three data sets of different rivers have been chosen to demonstrate<br />the model. The model has been calibrated by 75% of the data and validated by the remaining 25%.<br />To calculate the proposed model efficiency and validity, the results have been compared with two<br />common models. Therefore, the Sediment Rating Curve (SRC) and Non Linear Regression (NLR)<br />models have been applied and the statistical results have been proposed to show the model<br />efficiency.
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 methods<br />for detection and remediation. Bioadsorbent coated on nanocrystalline iron oxides offers a number<br />of advantages as sorbents for water purification and environmental remediation. In this study, first<br />highly uniform and crystalline iron oxide nanocrystals (nMAG) were prepared using iron salts in<br />presence of NaOH by co- precipitation process and then sugarcane bagasse coated on synthesized<br />iron oxide nanocrystals has been used as a bioadsorbent for uranium solution with low<br />concentration. The effect of different parameters on optimum function of this process has been<br />analyzed. The results showed that maximum uranium absorption occurs at pH levels of about 3.<br />Optimum amounts of biomass, uranium concentration and contact time are 0.1 gr, 50 ppm and 120<br />min, respectively. Thus, the uranium biosorption by magnetic biosorbent can be considered a<br />potential technology of treatment process for uranium removal in which the adsorbents and the<br />adsorbed 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 pine<br />needles (PN) was investigated with respect to initial dye concentrations, adsorbent dosage, and pH<br />in a batch manner. The obtained data in the study were described according to the Langmuir and<br />Freundlich isotherm models and the Langmuir model describes the experimental data very well<br />with a qmax value of 13.831 and 7.225 for RBRL and RY145 respectively. As the pH decreased,<br />adsorption density increased gradually and the highest adsorption density was obtained at pH 2 for<br />both adsorbents (91.57 and 64.77% for RBRL and RY145 respectively). Equilibrium adsorption<br />rates of 70.15% with RY145 and 86.72% with RBRL onto PN were observed at 90 min. In order<br />to better model the kinetics of adsorption, first order, pseudo second order and second order<br />models were applied. Among these models, the pseudo-second order kinetic model provided a<br />good correlation for the adsorption of RY145 and RBRL by PN with a R2> 0.999. Results showed<br />that pine needles have great potential to remove Reactive Yellow 145 (RY145) and Remazol<br />Black 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