Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Evaluation of effective parameters on lateral buckling of subsea pipelines on a rigid seabed
1891
1906
EN
Mohammad
Vaghefi
Civil Engineering Department, Persian Gulf University, Shahid Mahini Street, P.O. Box: 7516913817, Bushehr, Iran.
vaghefi@pgu.ac.ir
Marjan
Keshavarzi
Vocational Department, Alzahra University, Qods Square, P.O. Box: 751351673, Bushehr, Iran
Maryam
Akbari
Civil Engineering Department, Persian Gulf University, Shahid Mahini Street, P.O. Box: 7516913817, Bushehr, Iran.
m.akbari@pgu.ac.ir
10.24200/sci.2017.4610
In this study, the lateral buckling of pipelines on a rigid seabed under temperature and internal pressure is discussed regardless of the effects of waves and currents. The analytical results in some cases are compared with the numerical results obtained from ABAQUS software. Then the influence of effective parameters (such as: internal pressure, friction, initial imperfection, diameter and thickness of the pipe and the pipe material) on the lateral buckling of pipelines on a rigid seabed is evaluated in order to determine the level of importance. The most important results indicate a reduced possibility of lateral buckling with an increased coefficient of friction between the pipe and seabed, reduction of the internal pressure, and reduction of the amplitude of the initial imperfection in the pipeline. For example, compared to the models with coefficients of friction equal to 0.5 and 0.3, the safety temperature in the model with a coefficient of friction equal to 0.7 has increased 13.6% and 50% respectively. Compared to the models with initial imperfections equal to 0.3, 0.5, and 0.7 m, the safety temperature in the model with an initial imperfection of 0.1 m has increased 4.49%, 15.32%, and 40.65% respectively.
Subsea pipeline,Lateral buckling,Initial imperfection,Internal pressure,Temperature
http://scientiairanica.sharif.edu/article_4610.html
http://scientiairanica.sharif.edu/article_4610_71d831e82f6efed92581cbec8b82b447.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
A numerical investigation of the effect of the temperature on the seepage calculation
1907
1915
EN
Alireza
Tabarsa
Golestan University, Faculty of Engineering, Gorgan, Iran
a.tabarsa@gu.ac.ir
Mohsen
Lashkarbolok
Golestan University, Faculty of Engineering, Gorgan, Iran
m.lbolok@gu.ac.ir
10.24200/sci.2018.20421
Temperature difference in the soil and its environments is a common phenomenon. The permeability of the soil changes with the temperature mostly because of the variation of the viscosity of water in different temperatures. More realistic estimation of the seepage value through and beneath hydraulic structures leads to more efficient design of them. In this paper, the heat conduction equation is solved by a least squares based meshfree method to calculate the distribution of the temperature in a soil. The distribution of the permeability coefficients can be varied irregularly that may make some difficulties in the meshbased methods. In these methods the permeability changes in each mesh and finer mesh or some kinds of interpolation are required in the solution procedure. Since there is no need to form elements or grids in a meshfree method, it can handle this irregular variation simply. Here, the seepage equation is solved by the same least squares based meshfree method. The method is integral free, simple and efficient in calculation thanks to its sparse and positive definite matrices. The scheme is validated by solving a simplified version of the governing equations. More complicated problems are dealt with to investigate the phenomenon numerically.
temperature distribution,meshfree method,seepage,Permeability,least squares
http://scientiairanica.sharif.edu/article_20421.html
http://scientiairanica.sharif.edu/article_20421_834af46b531bbaa6bbc7b01cccec3d61.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Robust model and solution algorithm for the railroad blocking problem under uncertainty
1916
1930
EN
Reza
Mohammad Hasany
Department of
Civil Engineering, Sharif University of Technology, Azadi Avenue, P.O. Box 11155

8639, Tehran, Iran
rmhasany@gmail.com
Yousef
Shafahi
Department of Civil Engineering, Sharif University of Technology, Azadi Ave., P.O.Box: 111559313, Tehran, Iran
shafahi@sharif.edu
10.24200/sci.2017.4199
The railroad blocking problem emerges as an important issue at the tactical level of planning in freight rail transportation. This problem consists of determining the optimal paths for freight cars in a rail network. Often, demand and supply resource indicators are assumed to be certain, so the solution obtained from a certain model might not be optimal or even feasible in practice because of the stochastic nature of these parameters. To address this issue, this paper develops a robust model for this problem with uncertain demand and uncertain travel time as supply resource indicators. Since the model combines integer variables and nonlinear functions, a branchandcut algorithm is used to solve the linearized version of the robust model. The performance of the proposed algorithm in several instances is discussed. A comparison with a wellknown solver shows the high efficiency and effectiveness of the proposed algorithm. Finally, this algorithm is applied to a blocking problem of the railways of Iran. The results show that, by ignoring approximately 10% of the optimal value of the deterministic model, we have an optimal solution that remains unchanged with a probability of more than 0.98.
Railroad blocking problem,robust optimization,branchandcut algorithm,uncertainty,railway planning
http://scientiairanica.sharif.edu/article_4199.html
http://scientiairanica.sharif.edu/article_4199_cc6e5e8def3a9db33c8caec1a2f043ba.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Reservoir's geometry impact of three dimensions on peak discharge of damfailure flash flood
1931
1942
EN
Ahmad
Tahershamsi
Faculty of Civil and Environment Engineering, Amirkabir University of Technology, Tehran, Iran.
Farhad
Hooshyaripor
Faculty of Civil and Environment Engineering, Amirkabir University of Technology, Tehran, Iran
Sahand
Razi
Department of Civil Engineering, Islamshahr Branch, Islamic Azad University, Tehran. Iran
10.24200/sci.2017.4467
Once a dam fails, large amount of water at rest in the reservoir releases to downstream river and can cause extensive inundation areas, damage to properties, and loss of lives. The outflow hydrograph influences from variety of factors; e.g. dam’s properties, failure mode, and reservoir specification. This paper aims to analyze the effect of two latter factors on the peak outflow discharge focusing on the relative size of the failed part employing failure ratio (<em>a/A<sub>0</sub></em>) and shape of the reservoir employing shape factor (<em>S<sub>f</sub></em>) and cross section index (λ). Doing so, instantaneous experimental dam break and historical gradual failure were considered and separate analyses were carried out. Results showed that a higher peakdischarge is expected when <em>S<sub>f</sub></em> decreases or <em>a/A<sub>0</sub></em> and λ increase. Based on the experimental and historical dam failure data two distinct regression equations were developed and verified for peakdischarge estimation. The sensitivity analysis demonstrated that peakdischarge is highly sensitive to changes of the failure ratio and shape factor and it to some extend affects from cross section index.
Dam failure,Failure ratio,Peakdischarge,Reservoir shape,cross section index
http://scientiairanica.sharif.edu/article_4467.html
http://scientiairanica.sharif.edu/article_4467_c6ec34eb9ea4addc93f6afeb9ad392f2.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Predicting shear wave velocity of soil using multiple linear regression analysis and artificial neural networks
1943
1955
EN
OMOLBANIN
ATAEE
Dept. of geology, Ferdowsi University of
Mashhad, Mashhad, Iran
NASER
HAFEZI MOGHADDAS
Dept. of geology, Ferdowsi University of Mashhad, Mashhad, Iran
GHOLAM REZA
LASHKARI POUR
Dept. of geology,
Ferdowsi University of Mashhad, Mashhad, Iran
MEHDI J
ABBARI NOOGHABI
Dept. of Statistics, Ferdowsi University of Mashhad, Mashhad, Iran
10.24200/sci.2017.4263
In this paper, the correlation between shear wave velocity and some of the index parameters of soils including standard penetration test blow counts (<em>SPT</em>), finecontent (<em>FC</em>), soil moisture (<em>W</em>), liquid limit (<em>LL</em>) and depth (<em>D</em>) is investigated. The study attempts to show the application of artificial neural networks and multiple regression analysis in the prediction of the shear wave velocity (<em>V<sub>S</sub></em>) value of soils.<br /> New predicting equations are suggested to correlate <em>V<sub>S</sub></em> and mentioned parameters based on a dataset collected from Mashhad city in the north east of Iran. The results suggest that better and more exact correlations in the estimation of <em>V<sub>S</sub></em> are acquired when <em>ANN</em> method is used. The predicted values using <em>ANN</em> method are checked against the real values of <em>V<sub>S</sub></em> to evaluate the performance of this method. The minimum correlation coefficient obtained in <em>ANN</em> method is higher than the maximum correlation coefficient obtained from the <em>MLR</em>. In addition, the value of estimation error in the <em>ANN</em> method is much less than the <em>MLR</em> method indicating the higher confidence coefficient of the <em>ANN</em> in estimating the <em>V<sub>S</sub></em> of soil.
Shear wave velocity,SPT,depth,Finecontent,artificial neural network,Multiple Linear Regression,and Mashhad
http://scientiairanica.sharif.edu/article_4263.html
http://scientiairanica.sharif.edu/article_4263_57852cf72ee0384832b234269900f3bf.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Importance of bed roughness in transversal variability of the flow patterns and bed shear stress due to secondary currents
1956
1967
EN
Seyed Hossein
Mohajeri
Department of Civil Engineering, Faculty of Engineering, Science and Research Branch Islamic Azad University, Tehran, Iran
mohajeri@srbiau.ac.ir
Akbar
Safarzadeh
Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
safarzadeh@uma.ac.ir
Seyed Ali Akbar
Salehi Neyshabouri
Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran
salehi@modares.ac.ir
10.24200/sci.2017.4204
Laboratory experiments were carried out in order to study the influence of the bed roughness on secondary circulations and lateral flow variability in a straight open channel. Flow field and bed shear stress were measured using an acoustic doppler velocimeter and a particular type of the Preston tube, respectively. All experiments attest presence of noticeable lateral variations of the flow characteristics due to the secondary currents. The observations also reveal that the lateral variations in the experiments with larger bed roughness are more intense. This implies the formation of a more stable mechanism for the maintenance of the cellular pattern in the experiments with larger bed roughness elements. Regarding formation of the secondary currents, application of double averaging method (averaging of the time averaged turbulence parameters within a thin spatial slab parallel to the bed) is also discussed. It was found that, to properly consider the lateral variations of the flow characteristics, spatial averaging should be implemented among the measured data at different spanwise locations. As such secondary current enhancements can also affect more complex and natural flow like river flows, it can also be recommended to examine the importance of such phenomenon in those areas respecting double averaging method.
Rough bed,turbulent flow,Flow variability,Openchannel,Secondary
http://scientiairanica.sharif.edu/article_4204.html
http://scientiairanica.sharif.edu/article_4204_0d25389dd9e362a044a6d453fe93a63e.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Behavioral analysis of vehiclepedestrian interactions in Iran
1968
1976
EN
Abbas
Sheykhfard
Civil Engineering Department of Babol Noshirvani University of Technology
a.sheykhfard@stu.nit.ac.ir
Farshidreza
Haghighi
Civil Engineering Department of Babol Noshirvani University of Technology, Babol, Iran
haghighi@nit.ac.ir
10.24200/sci.2017.4201
Statistics upon injured and killed pedestrian accidents in recent years expresses a high vulnerability of this group of road users. By identifying influential factors on the interactions of pedestriansvehicles and representing appropriate solutions to reduce the impact of these factors, the possibility of such interactions and consequently, the relative accidents can be reduced. In present research, based on naturalistic driving studies (NDS), the driving behavior of 29 drivers of vehicles was investigated. 289 vehiclepedestrian interactions in the local urban routes of Babol City in Mazandaran, Iran at the traffic peak hours were determined. By analyzing the interactions using the DREAM method (Driving Reliability and Error Analysis Method), the risk factors were identified and two causal patterns were determined for pedestrian crossings and places lacking pedestrian crossings. Drivers talking to passengers and listening to music were among the factors influencing occurrence of interactions at pedestrian crossings. Unexpected behaviors by pedestrians while crossing (such as sudden running, crossing careless of the traffic flow, and crossing without obtaining the permission from the vehicle driver) played a substantial role in occurrence of interactions in places without pedestrian crossings. Finally, some solutions were proposed for reducing the chances of occurrence of interactions.<br />
Pedestrian accidents,Vehiclepedestrian interaction,Vehicle driver behavior,Pedestrian behavior,DREAM method
http://scientiairanica.sharif.edu/article_4201.html
http://scientiairanica.sharif.edu/article_4201_f1a87f8a9cb273014ce2937b455370a1.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Experimental and numerical study of a proposed momentresisting connection for precast concrete frames
1977
1986
EN
Mojtaba
Fathi
Department of Civil
Engineering, Razi University, Kermanshah, Iran
fathim@razi.ac.ir
Mahdi
Parvizi
Department of Civil Engineering, Razi University, Kermanshah, Iran
parvizi.mahdi@razi.ac.ir
Javad
Karimi
Department of Civil Engineering, Razi University, Kermanshah, Iran
j.karimi@razi.ac.ir
M.Hossein
Afreidoun
Department of Civil Engineering, Razi University, Kermanshah, Iran
afreidoun.mohammadhoseein@razi.ac.ir
10.24200/sci.2017.4200
This paper presents the test results of a proposed ductile momentresisting beamcolumn connection for precast concrete frames and a developed3D nonlinear finite element model of this connection in several different details of connection, to predict its behavior under cyclic loading, based on the loading of the ACI T1.101. In this connection, precast concrete beam and column are connected to each other by steel linkage element. This method is able to create concrete structures with higher quality through minimizing <em>insitu</em> concreting and maximizing the speed of construction as well as usage of ductile and exchangeable elements in sensible locations of the connection. Two types of bolted and welded connections were compared to monolithic connection in terms of stiffness, strength, energy dissipation capacity and ductility factor. All specimens satisfied all criteria of ACI T1.101.To investigate the behavior of these connections a 3D nonlinear finite element model has been simulated. Numerical results showed a good agreementwith experimental results. The initial stiffness of monolithic connectionspecimen wasgreater thanboltedconnection and welded connectionspecimens.Even though, the beam moment capacity factors for two welded and bolted samples were a little more than monolithic sample; but the ductility factors of these samples were a little less than that of monolithic sample.
Experimental Study,Precast Concrete Frame,MomentResisting Connection,cyclic loading,Finite Elements Analysis
http://scientiairanica.sharif.edu/article_4200.html
http://scientiairanica.sharif.edu/article_4200_134c8a8b6c8e1c2c25473d247e3f5010.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Nearfault ground motion effects on the responses of tall reinforced concrete walls with bucklingrestrained brace outriggers
1987
1999
EN
Hamid
Beiraghi
Department of Civil Engineering, Mahdishahr Branch, Islamic Azad University, Mah
dishahr, Iran.
+98
9122093893
h.beiraghi@mshiau.ac.ir
10.24200/sci.2017.4205
In this paper, responses of reinforced concrete corewall structures connected to the outside columns by bucklingrestrained brace (BRB) outriggers in tall buildings were investigated. These buildings are subjected to forward directivity near fault (NF) and ordinary farfault (FF) ground motions. According to the current codes for the DBE level, the response spectrum analysis procedure was applied to analyze and design the structures. The nonlinear fiber element approach was used to simulate the reinforced concrete corewalls. Nonlinear time history analysis was implemented using 14 NF as well as 14 FF records at MCE level. In the corewall, the results show that the mean moment demand envelope as well as the mean shear demand envelope obtained from the NF records are approximately similar to the corresponding demand envelope from FF records. The reason has to do with extending plasticity all over the RC corewall which is subjected to both sets of records. The overall responses of the reinforced concrete corewall with BRB outrigger system is in acceptable range both for NF and FF earthquakes. In this study, the largest curvature ductility demand in the reinforced concrete corewall took place at levels just above the outriggers.<br /> <strong> </strong>
Reinforced concrete,corewall,plastic hinge,BRB,outrigger,NLTHA,nearfault
http://scientiairanica.sharif.edu/article_4205.html
http://scientiairanica.sharif.edu/article_4205_e80a45a71a5fb39088c2898416c68381.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Collocated Mixed Discrete Least Squares Meshless (CMDLSM) method for solving quadratic partial differential equations
2000
2011
EN
Saeb
Faraji
Department of
Civil &
Environmental Engineeri
ng, Amirkabir university of technology
saebfaraji@aut.ac.ir
M.
Kolahdoozan
Department of Civil & Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
mklhdzan@aut.ac.ir
M.H.
Afshar
School of Civil Engineering, Iran University of Science and Technology Narmak, Tehran, P.O. Box 16765163, Iran
mhafshar@iust.ac.ir
10.24200/sci.2017.4203
In this paper, a Collocated Mixed Discrete Least Squares Meshfree (MDLSM) method is proposed and used for efficient solution of engineering problems. Background mesh is not required in the MDLSM method; hence the method is a truly meshfree method. Nodal points are used in the MDLSM methods to construct the shape functions while collocated points are used to form the least squares functional. In the original MDLSM method, the location of the nodal points and collocated points are the same. In the proposed Collocated Mixed Discrete Least Squares Meshfree (CMDLSM) method, a set of additional collocated points is introduced. It is expected that the accuracy of results is improved by using the additional collocated points. It is noted that the size of coefficient matrix is not increased in the proposed CMDLSM method compared with the MDLSM method. The required computational effort for solving the linear algebraic system of equations, therefore, is the same as that of MDLSM method. A set of benchmark numerical examples, cited in the literature, is used to evaluate the performance of proposed method. The results indicate that the accuracy of solutions is improved by using additional collocated points in the proposed CMDLSM method.
Meshfree,PDEs,DLSM,MDLSM,Collocated points,CMDLSM
http://scientiairanica.sharif.edu/article_4203.html
http://scientiairanica.sharif.edu/article_4203_6f92c0efb8788f8cf01aa3a39f2f8b84.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Flexural and shear strengthening of RC beams with NSM technique and manually made CFRP bars
2012
2025
EN
Mohammad Kazem
Sharbatdar
Faculty of Civil Engineering, Semnan University, Semnan, Iran
,
Postal Code: 3513119111
msharbatdar@semnan.ac.ir
M.
Jaberi
Faculty of Civil Engineering, Semnan University, Semnan, Iran
2005.mostafa@gmail.com
10.24200/sci.2017.4207
In this paper, the efficiency of NSM method for both flexural and shear strengthening of RC beams were examined by applying an innovative manually made CFRP bar (MMFRP) as an alternative reinforcement composite material through experimental and numerical investigation. Experimental program was consisted of three inverted Tsection RC flexuraldominated beams and three rectangular section RC sheardominated beams with parameters of the length and anchoring of MMFRP bars and their inclination to the longitudinal axis of the beams. The structural performance of the tested beams and the Finite Element (FE) modeling approach including modes of failure, loaddeflection response and ultimate load capacity are presented and discussed. Test results indicated that using proposed MMFRP bars significantly improved the flexural resistance and shear capacity of deficient concrete beams. Furthermore reduction of the crack width and increase in the quantity and propagation of new cracks was observed in strengthened beams compared to control beam.
Beams,Shear,Flexural strengthening,Composite Materials,numerical,NSM
http://scientiairanica.sharif.edu/article_4207.html
http://scientiairanica.sharif.edu/article_4207_e016ef7b57c3a66d1a2e9083405649db.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Estimation of van Genuchten SWCC model for unsaturated sands by means of the genetic programming
2026
2038
EN
A.
Taban
000000022913581X
Department of Civil Engineering Isfahan (Khorasgan) Branch, Islamic Azad
University,
Isfahan, Iran
am.taban@gmail.com
M . Mirmohammad
Sadeghi
Department of water and Natural Environment, Laboratory of Soil Mechanics, Isfahan
Higher Education and Research Institute (IHEARI)
M.A.
Rowshanzamir
Department of Civil Engineering, Isfahan University of Technology (IUT), Isfahan, Iran
mohamali@cc.iut.ac.ir
10.24200/sci.2017.4206
The van Genuchten Model (1980) is widelyused for the description of the SoilWater Characteristic Curve (SWCC) of a variety of soils. This study uses the Genetic Programming (GP) for the presentation of equations estimating the van Genuchten (vG) Model fitting parameters for unsaturated clean sand soils. Moreover, this study uses the data derived from the valid dataset of Benson et al. (2014), including 95 measured SWCCs in both drying and wetting phases. The data on the particle size distributions includes the finegrain percentage (Fines %), <em>d</em><sub>60</sub>, <em>d</em><sub>10</sub>, besides the residual and saturated volumetric water content and ), as the GP model inputs of set of terminal. As for the model outputs of set of terminal, the fitting parameters for the vG model include <strong><em>a</em></strong> and <strong><em>n</em></strong>. The functions used in the GP training were 'plus', 'minus', 'times', taken from the MATLAB default functions, 'mydivide' proposed by Silva (2007), and some other new power functions included by this study. Accordingly, new equations were presented for the estimation of vG Model fitting parameters for both forms of wetting and drying. Finally, to evaluate the accuracy of the proposed estimation equations, the GP results were evaluated and verified in different procedures.
SWCC,van Genuchten Model,Unsaturated soils,Genetic programming,Fitting Parameters
http://scientiairanica.sharif.edu/article_4206.html
http://scientiairanica.sharif.edu/article_4206_941a3b4ae8ad623078c06dc2c5d32da0.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Probabilistic model of unsaturated slope stability considering the uncertainties of soilwater characteristic curve
2039
2050
EN
A.
Johari
Department of Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran
johari@sutech.ac.ir
A.
Hooshmand Nejad
Department of
Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran
a.hooshmandnejad@sutech.ac.ir
S.
Mousavi
Department of
Civil and Environmental Engineering, Shiraz University of Technology, Shiraz, Iran
s.mousavi@sutech.ac.ir
10.24200/sci.2017.4202
Many soil slopes are unsaturated and failure of them can be a major cause of damage to structures. Apart from soil properties, the SoilWater Characteristic Curve (SWCC) is the backbone of any unsaturated slope analysis. Uncertainties of these effective parameters of unsaturated slopes cause the probabilistic analysis to be more realistic rather than deterministic. In this research, the stochastic analysis of unsaturated slope stability is carried out based on simplified Bishop’s method. The stochastic parameters are the input parameters of SWCC in addition to effective internal angle of friction, effective cohesion and unit weight of soil. Based on the collected results from hundreds of stochastic analyses, the probability of failure is presented as a three dimensional surface. Finally, probabilistic model is developed to model this surface and evaluate the probability of failure as function of safety factor and its correlation of variation. <strong></strong>
Unsaturated soils,Slope stability,Soilwater characteristic curve,Artificial intelligence,Probabilistic model
http://scientiairanica.sharif.edu/article_4202.html
http://scientiairanica.sharif.edu/article_4202_0b160133988f58a644442ca7c6c43767.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Efficient multiobjective optimization algorithms for construction site layout problem
2051
2062
EN
A.
Kaveh
Centre of Excellence for Fundamental Studies in Structural Engineering, Iran University of Science and Technology, Narmak, Tehran, P.O. Box 1684613114, Iran
alikaveh@iust.ac.ir
M.
Rastegar Moghaddam
School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran,
b
P.O. Bo
x 16846

13114, Iran
M.
Khanzadi
School of Civil Engineering, Iran University of Science and Technology, Narmak, Tehran,
b
P.O. Bo
x 16846

13114, Iran
khanzadi@iust.ac.ir
10.24200/sci.2017.4216
Construction site layout planning is one of the managerial aspects of the construction industry and has significant impacts on performance of the sites. Since in real site layout optimization, many objectives are involved, therefore multiobjective algorithms are needed. In this study, multiobjective version of two metaheuristics, CBO and ECBO, are developed and their applicability and performance are checked on a case study. The quality of the results obtained, verify the ability of these algorithms in finding optimal pareto front on this problem. Another tool that is utilized in this study is data envelopment analysis (DEA) which by calculating the efficiency of optimal pareto front layouts, can help decision makers to select the final layout among the candidates. It should be mentioned that the DEA has previously been used in models with multiple inputs and outputs.<strong></strong>
site construction layout problems,multiobjective optimization,colliding bodies optimization,Data envelopment analysis,optimal pareto front
http://scientiairanica.sharif.edu/article_4216.html
http://scientiairanica.sharif.edu/article_4216_32853e6bc8b6176c321a748f76555129.pdf
Sharif University of Technology
Scientia Iranica
10263098
23453605
25
4
2018
08
01
Improving shallow foundations resting on saturated loose sand by a zeolitecement mixture: A laboratory study
2063
2076
EN
Sina
Salamatpoor
Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
s_salamatpoor@sci.iaun.ac.ir
Yaser
Jafarian
International Institute of Earthquake Engineering and Seismology (IIEES)
yjafarianm@iiees.ac.ir
Alborz
Hajiannia
Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
alborzhajian@pci.iaun.ac.ir
10.24200/sci.2018.50153.1567
Improvement of sands is frequently carried out by cement together with several other additives. The common additives have high manufacturing costs and negative environmental impacts during their manufacturing process and recycling in nature. Zeolite as a mineral substance for cement replacement can improve the strength parameters of a treated sand, without the negative deficiencies of the common additives. In this study, unconfined compression strength (UCS) and smallscale 1g model tests were conducted to evaluate the mechanical features of zeolitetreated sand and to study the behavior of shallow foundations rested on zeolite pad, respectively. The results of this study demonstrate that the UCS of the cemented sand samples increase when the cement is replaced by zeolite at an optimum proportion of 40% with 14 and 28 days curing times. Adding this amount of zeolite to cemented sand mixture causes an increase in terms of the improvement rate between 40% and 125% and increases the bearing capacity ratio (BCR) of the strip foundation treated by zeolite pad in the range of 11% and 420%. In addition, zeolite pad leads to decline the settlement of the treated strip footing from 16% to 86% in terms of the settlement reduction ratio (SRR).
Stabilized sand,Shallow footing,Zeolite,Unconfined compression strength,Smallscale 1g test
http://scientiairanica.sharif.edu/article_20208.html
http://scientiairanica.sharif.edu/article_20208_728e2d7f57b68449e3f7265021687a8f.pdf