Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Comparison of the effect of using mineral nanomaterials on the performance of HMA and glasphalt agaiants the moisture damage
2965
2986
FA
Davud
Saedi
Faculty of Engineering, Urmia University, Urmia, Iran
st_d.saedi@urmia.ac.ir
Hamid
shirmohammadi
Faculty of Civil Engineering, Urmia University, Urmia
h.shirmohammadi@urmia.ac.ir
Gholam Hossein
Hamedi
0000-0003-4421-3721
Department of Civil Engineering, Faculty of Engineering, University of Guilan, Rasht, Iran
hamedi@guilan.ac.ir
Yunes
Azaryun
Faculty of Engineering, Urmia University, Urmia, Iran
yones.azarion.99@gmail.com
10.22060/ceej.2019.16413.6214
Pavement response to a variety of damages is affected by the bond between bitumen and aggregate (adhesion) which is strongly affected by moisture and moisture entering from the surface or substrates of asphalt pavement causing the aggregate to stripped. The result of moisture damage is commonly called stripping because the bitumen is separated from the aggregates and the aggregates remain uncoated. Various factors affect the moisture sensitivity of asphalt mixtures, which are generally divided into two categories: The first one is of internal origin and is directly related to the properties of the asphalt mixing constituents. In contrast, the second category is of external origin and is dependent on conditions outside the asphalt mixing system. Today, glasphalt technology is considered as an efficient way to reduce asphalt production costs, reduce fuel consumption, and reduce environmental pollution caused by the production of this type of waste. Despite the advantages of glasphalt, moisture damage is a weak point for these types of mixtures. The present study evaluated the moisture sensitivities of glasphalt and HMA and compared the performance of these two types of mixtures, along with the effects of two types of additives, nano hydrated lime and nano calcium carbonate on moisture damage. The moisture sensitivity of both types of mixtures was evaluated using a modified Lotttman test and a thermodynamic test of Wilhelm plate based on surface free energy methods. The results of the indirect tensile strngth test showed that the resistance of glasphalt in dry conditions was higher than that of HMA. However, glasphalt are exposed to wet conditions with a higher resistance to HMA. The results obtained from the thermodynamic test also showed that the modification of both types of asphalt binder (AC 60-70 and AC 85-100) using nano hydrated lime and nano calcium carbonate increases the total surface free energy and adhesion of the bonding of both types of base asphat binders. This increase improves the strength of mixtures made with this type of asphat binders against moisture damage of cohesion type, which is a positive effect in reducing the moisture damage.
Glasphalt,Hot mix asphalt,Moisture sensitivity,Nanomaterials,Modified Lottman Test
https://ceej.aut.ac.ir/article_3561.html
https://ceej.aut.ac.ir/article_3561_2c445e32f1b3546240a4f9c8d3793289.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
The Effect of High Temperatures on the Mechanical and Microstructural Properties of Geopolymer Concrete
2987
3002
FA
Mohammad
Amiri
0000-0002-3751-0261
Assistant Professor, Faculty of Engineering, Hormozgan University, Bandar Abbas, Iran.
eng.amirii.mohammad@gmail.com
marziyeh
aryanpoor
Master Student, Islamic Azad University of Bandar Abbas, Faculty of Engineering
marziyeh_aryanpoor@yahoo.com
10.22060/ceej.2019.16419.6219
The concrete structures used in various applications including iron and aluminum foundries and hazardous waste disposal lose performance when subjected to heat. As aluminum silicate materials however, geopolymers behave in a much more stable manner than normal concrete when exposed to high temperatures. Calcium silicate hydrate (C-S-H) and calcium-aluminum-silicate-hydrate nanostructures, which are products of the geopolymerization process that strengthens geopolymer concrete, undergo many changes when exposed to heat. The study therefore investigates the effect of high temperatures on geopolymer concrete’s strength parameters from a microstructural perspective and according to nanostructural changes of C-S-H and C-A-S-H. In this regard, about 300 samples were cured in the humidity bath for 1, 3, 7, 14, and 28 days. All samples were then put in of 25, 50, 100, 200, 300, 500, 700, and 900°C temperatures for 2 hours. Length and weight change percentages, compressive strength, and ultrasonic and cracking behavior tests were performed on all samples. Images from the scanning electron microscope (SEM) and the energy-dispersive X-ray (EDX) analysis were also used to evaluate the microstructural behavior of samples in various temperatures. According to the results, sample weight and length changes and compressive strength depended on the behavioral nature of C-S-H and C-A-S-H nanostructures. Nanostructural analysis of C-A-S-H points to high temperatures reducing compressive strength and weight as well as causing more cracks. The compressive strength of the 28 samples in 900°C temperature also decreased from 604 kg/cm2 to 75 kg/cm2. The complete disintegration of the C-S-H and C-A-S-H nanostructures and the decomposition of water from the chemical bond and the OH hydroxyl group are the reasons for this reduction.
High Temperatures,Geopolymer Concrete,Compressive Strengths,C-A-S-H,SEM
https://ceej.aut.ac.ir/article_3658.html
https://ceej.aut.ac.ir/article_3658_0d8ab4428002b9264d18568923407852.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Topology evaluation of Tehran subway network utilizing a bi-level mixed index for subway networks ranking
3003
3014
FA
Amir Reza
Mahdavi
0000-0001-7309-5002
Transportation Planning Department, Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran
armahdavi1992@outlook.com
AmirReza
Mamdoohi
0000-0002-5339-9807
Transportation Planning Dept., Civil & Envi. Eng. Faculty, Tarbiat Modares University
armamdoohi@modares.ac.ir
Mahdieh
Allahviranloo
Groove School of Engineering, City College of New York, United States of America
mallahviranloo@ccny.cuny.edu
10.22060/ceej.2019.16436.6226
As an essential infrastructure of cities, public transit networks have special importance in decreasing traffic congestion and air pollution and subway system is considered as the most efficient mode of public transit due to being green and mass transit. In this study, a mixed evaluation index composed of two components of shape and service points is proposed. The shape point is calculated utilizing network length, topology characteristics, station density, and average edge length (integer value between zero and ten). Annual passenger and passenger per unit length are used to calculate the service point (between zero and one). The study evaluated and compared subway networks for 52 cities around the world where according to this analysis New York city subway system is ranked 1, with a score of 8.506, and Tehran is ranked 29, with the score of 4.39. We also classified subway networks into three groups based on their connectivity and complexity indices using fuzzy c-means (FCM) clustering method and Tehran’s subway system is classified as partially accessibility network. Results of proposed classification based on network complexity and connectivity using fuzzy c-means methods indicate that the Tehran subway is the developed subway system but London, Tokyo, and New York are the more developed subway system. Results of regression models based on the world trend for primary predicting of the needed number of stations and length of a network show that currently, length and number of stations of the Tehran subway network should be equal to 206.3 km (31.1 km deficiency) and 147 (8 stations deficiency), respectively.
Bi-level mixed index,Evaluation of subway networks,Subway networks classification,Subway,Tehran
https://ceej.aut.ac.ir/article_3646.html
https://ceej.aut.ac.ir/article_3646_5d32351613adcebb47692e3feb4794b9.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Application of Multiquadric Radial Basis Function method for Helmholtz equation in seismic wave analysis for reservoir of rigid dams
3015
3030
FA
Reza
Babaee
University of Qom
r.babaee@stu.qom.ac.ir
Ehsan
Jabbari
0000-0002-6345-8567
University of Qom
ehsan.jabbari@gmail.com
Morteza
Eskandari-Ghadi
University of Tehran
ghadi@ut.ac.ir
10.22060/ceej.2019.16443.6230
The high costs of mesh generation in mesh-dependent solution, weakness in capturing <br />singularities, the need of modeling all over the domain, the need of problem dependent fundamental <br />solutions, etc. are some of weaknesses in the common numerical mesh-dependent methods for solving <br />continuum mechanics boundary value problems. In this study, aiming for eliminating some of these <br />shortcomings, one of the well-known Radial Basis Functions (RBF) methods, Multiquadric (MQ), is <br />developed for dynamic analysis of 2D reservoirs of rigid dams in frequency-domain. To this end, the <br />Helmholtz equation and the governing complex boundary conditions are reproduced using MQ function <br />in the frequency domain. The results show that with the use of real and complex forms of the MQ <br />function, the computational time will be respectively optimized for frequencies smaller and larger than <br />the natural frequency of the reservoir. Also, to determine the most important factors affecting both the <br />accuracy and convergence of MQ method, first the inefficiency of some of the previously introduced <br />methods is proved, and then a new high-speed algorithm is presented. It is shown that the optimal <br />shape parameter for MQ method can be formulated in terms of the frequencies of seismic records. <br />This advantage simplifies the application of MQ method in this particular problem and reduces the <br />computational time, considerably. The high accuracy of the present method is shown in two different <br />examples, where the effects of sediment absorption may either be considered or not. The high accuracy <br />compared to the exact solutions achieved in this paper is due to a continuous estimation function defined <br />all over the domain and also due to the simple algorithm used for finding the optimal shape parameter.
Multiquadric Radial Basis Function (MQ-RBF),Concrete Gravity Dam,Shape parameter,Frequency Domain,hydrodynamic pressure
https://ceej.aut.ac.ir/article_3580.html
https://ceej.aut.ac.ir/article_3580_ffd59b086b2249200e985288f6bd73ff.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Effect of Opening on the Lateral Stiffness of Masonry Walls with and without Ties
3031
3042
FA
Masood
Shafiei Varzane
Senior structural engineer, Isfahan, Iran.
masoodshafiei@ymail.com
Farhad
Behnamfar
0000-0002-9365-8295
Isfahan University of Technology
farhad@cc.iut.ac.ir
10.22060/ceej.2019.16157.6144
In this study, lateral response of masonry walls with openings is studied. The numerical modeling and analysis is followed and the developed models are validated using available experimental results. Samples selected for validation analysis include two masonry walls confined with reinforced concrete perimeter ties and one masonry wall with no ties. Validity of the numerical models has been established against the experimental samples within Abaqus software using nonlinear static analysis. Variation in the size, location and aspect ratio of the opening are taken into account and the lateral stiffness and strength of the walls are calculated. In addition, a series of equations have been developed based on strength of materials for simple calculation of lateral stiffness, strength and ductility of masonry walls with opening. This has the important advantage of avoiding complex and time consuming 3D nonlinear finite element analysis for the same purpose. To do this task, three different cases of failure are accounted for the walls including: when presence of the opening is not effective, when behavior of the two piers besides the opening is governing, and when the overhead lintel governs the lateral behavior of wall. Each of the mentioned cases are in turn divided into other sub-cases and several nonlinear finite element analyses have been undertaken. Results of the developed analytical equations are compared and calibrated with those of the finite element analysis and desirable accuracy of the relations developed in this study is confirmed.
Masonry wall,opening, lateral stiffness,Finite Elements,concrete tie
https://ceej.aut.ac.ir/article_3731.html
https://ceej.aut.ac.ir/article_3731_61d1e6d8bce4482bd9053f1d0cee2b71.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Optimal operation of reservoirs with increasing water use efficiency: Climate change adaptation approach (case study: Jareh Dam)
3043
3058
FA
seyed majid
mosavi
Department of civil engineering, Jundi-Shapur university of Technology, Dezful
s_majid_m0692@jsu.ac.ir
hesam
seyed kaboli
department of civil engineering, Jundi-Shapur university of technology, Dezful
hkaboli@jsu.ac.ir
10.22060/ceej.2019.16494.6252
Impacts of climate change on water resources will force decision-makers to adopt climate change adaptation policies in order to reduce social-economic problems and difficulties resulting from it and water resource sustainable development. One of the adaptation methods is to increase water use efficiency in agriculture that will adjust climate change impacts include decreasing runoff and increasing water demands. In this study, the impact of water use efficiency as a climate change adaptation approach is assessed in the optimal operation of JAREH dam. Fifteen climate change scenarios were generated by using downscaling technique on CMIP5 data for the near (2020-2044) and far (2070-2094) future. Based on these scenarios, time series of reservoir inflow and downstream water demand were projected for both future periods. An optimization model is developed considering the water efficiency coefficient parameter in order to define four water use efficiency scenarios (0-S1, 0.1-S2, 0.3-S3, 0.5-S4). Results show that reservoir inflow decreases up to 18.8% and water agriculture demand increases up to 29%. The amount of water allocation would increase up to 18.7% in the future periods than in the baseline period under S1 scenario to supply the increased water demand, which may decrease reliability of reservoir system for water allocation. Increasing water use efficiency coefficient up to 0.5 in the future periods would increase system reliability up to 20% that will reduce social-economic problems caused by climate change impact in this study area.
Efficiency Coefficient,optimization,climate change,Reservoir,Adaptation
https://ceej.aut.ac.ir/article_3541.html
https://ceej.aut.ac.ir/article_3541_354b3a1c17a33705fbd35fa7479dcc3d.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Experimental study of Energy Dissipation at Vertical Drops Equipped to Vertical Screen with Gradually Expanding at the Downstream
3059
3072
FA
Behnam
Nayebzadeh
Civil Engineering Faculty, University of Tabriz, Tabriz, Iran
bnayebzadeh@yahoo.com
Mohammad ali
Lotfollahi-yaghin
Professor, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran
lotfollahi@tabrizu.ac.ir
Rasoul
Daneshfaraz
0000-0003-1012-8342
Associate Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.
daneshfaraz@yahoo.com
10.22060/ceej.2019.16493.6265
In the present study, the effect of vertical drop, gradually expanding and vertical screens are investigated to increase the energy dissipation efficiency of the flow. The experiments were carried out in a horizontal laboratory flume with a rectangular cross section, two vertical drop heights, and the wall expanding ratios of 0.5 to 1, the porosity ratio of the screens of 40% and 50%, and the range of Froude number of 0.86-0.92. The results showed that the use of screens and the expansion of the walls would increase energy dissipation and decrease the pool and downstream depths. The application of expanding wall, screens and the effect of simultaneous use of screens and expanding walls increases the efficiency of energy dissipation by 25, 44 and 48 percent, respectively. The porosity ratio of the screens is not much efficient in energy dissipation, but it reduces the pool depth and increases the downstream depth. Under the same hydraulic conditions, with increasing drop height, the energy dissipation rate due to the higher impact intensity of the jet passing through the drop or its downstream floor increases and the pool depth decreases. By increasing the discharge, the hydraulic jump formed in the upstream of the screens with a porosity ratio of 40% is submerged and moves upstream. However, in screens, 50% of the jump is free and moves downstream.
Vertical drop,Energy dissipation efficiency,Gradually Expanding,Screens,Pool depth
https://ceej.aut.ac.ir/article_3560.html
https://ceej.aut.ac.ir/article_3560_8974fcbd6d560220b9e9c8ca5862ccf9.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Decentralized control of tall shear structures against sensor failures and uncertainty in earthquake excitations
3073
3090
FA
Roya
Raji
Structure, Civil engineering faculty, Tabriz university, Tabriz, Iran
r.raji@tabrizu.ac.ir
Hosein
Ghaffarzadeh
Tabriz, Tabriz university, civil engineering faculty
ghaffar@tabrizu.ac.ir
Ali
Hadidi
structure, civil engineering faculty, tabriz university, Tabriz, Iran
a_hadidi@tabrizu.ac.ir
10.22060/ceej.2019.16541.6266
This paper uses centralized and decentralized H∞ controllers with static output feedback and linear matrix inequality theory (LMI) as well as a number of changes in LMI variables to retrofit shear structures against a variety of uncertainties. The robustness of this method is evaluated both in centralized and decentralized controls against dynamic forces such as earthquake, uncertainty in earthquake excitation and sensor failure, then structural responses are compared. Finally, the responses of the used control algorithm are compared with the results of the linear quadratic regulator controller (LQR). There are two structural models, including 5 and 20 stories shear structures. The results indicate good robustness of the used control algorithm to the failure of the sensors, the clear difference in response values of the applied algorithm compared to the LQR method, and near results in centralized and decentralized controllers. Although the earthquake excitations uncertainty changes the responses but still controlled responses are clearly less than the uncontrolled responses.
Active control؛ Decentralized control؛ Sensor failure,Uncertainty,Earthquake excitation
https://ceej.aut.ac.ir/article_3578.html
https://ceej.aut.ac.ir/article_3578_8861681603a0d753fed83209c86cb206.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Environmental risk assessment of Alborz Dam using Topsis and Fuzzy Topsis methods
3091
3108
FA
leila
moradi
Department of Civil Engineering, Faculty of Engineering, Qom University, Qom, Iran
leilamoradi.ce@gmail.com
Taher
Rajaee
Department of Civil Engineering, Faculty of Engineering, Qom University, Qom, Iran
trajaee@qom.ac.ir
Maedeh
Sadeghpoor
Department of Civil Engineering, Faculty of Engineering, Islamic Azad University, Qaemshahr Branch, Iran
maedeh_sadeghpoor@yahoo.com
10.22060/ceej.2019.16556.6270
The purpose of this study was to evaluate the environmental risks of Alborz Dam on Bababrood River in Babol city, using multi-criteria decision making methods. Initially, environmental identification of the study area was carried out, Then a list of environmental risks identified in the construction and exploitation phase was prepared and presented to environmental experts familiar with the Alborz dam area in the form of a questionnaire. environmental risks scored by environmental experts based on three indicators, Severity of occurrence, Probability of occurrence, Then environmental risks ranking was performed using TOPSIS and Fuzzy TOPSIS methods. The most important risks of Alborz dam using TOPSIS method in the construction phase, respectively: Was Obtained, Destruction of forest within the dam with a score of 0.926, Displacement of reservoir residents with a score of 0.837 And in the phase of operation: Thermal stratification of dam reservoir with a score of 0.847, Landslide with a score of 0.751. Also, the most important risks of the Alborz dam using the Fuzzy Topsis method in the construction phase, respectively: Was Obtained, Displacement of reservoir residents with a score of 0.682, Demolition of forest within the dam with a score of 0.677, And in the phase of operation, respectively: Thermal stratification of dam reservoir with a score of 0.645, Landslide with a score of 0.630. Finally, one method of integration (average rating method) was used to resolve the conflict between the results.
Environmental risk assessment,multi-criteria decision-making,Topsis,Fuzzy TOPSIS,Alborz Dam
https://ceej.aut.ac.ir/article_3652.html
https://ceej.aut.ac.ir/article_3652_86dfb45b6ea471871c9d4dfb807fab60.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Numerical Analysis of Geogrid Reinforcement on the Ultimate Bearing Capacity of Strip Footing Under Eccentric Loads and Determination of Optimum Layout
3109
3124
FA
Masoud
Rabeti Moghadam
Engineering Faculty, Yasouj University, Yasuj, Iran
rabeti@yu.ac.ir
Jahanpour
Monfared
Faculty of Engineering, Yasouj University, Yasouj, Iran
jahan.m2011@gmail.com
Mansour
Parvizi
Faculty of Engineering, Yasouj University, Yasouj, Iran
parvizi@yu.ac.ir
10.22060/ceej.2019.16233.6162
In this study, the effect of geogrid on the ultimate bearing capacity of strip footing, which was imbedded on sandy soil and under eccentric loads (VM) was investigated by using PLAXIS 2D finite element software. After numerical verification, the effect of parameters, such as the amount of eccentricity, applied vertical load, the number of reinforced layers and layout of the geogrid layers on the ultimate bearing capacity of strip footing was studied. The results of analyzes were presented in the form of dimensionless graphs. Based on the analyses result, the optimum depth of first geogrid layer from foundation (u), the vertical intervals of the layers (h), the number (N) and layout of the geogrid layers have been determined. The results of the analysis show that by adding the geogrid layers, the bearing capacity of footing under the eccentric load increases significantly. The amount of the effectivity is related to the layout of layers and the amount of the eccentricity. In the optimum layout of the layers, the position of geogrid layers depends on the number of layers. Also, the optimum number of layers for obtaining the maximum bearing capacity at eccentric load condition was obtained to be four layers in the present study. The optimum depth for the first, second, third and fourth layers, at the optimal layout, was 0.5, 0.7, 0.3 and 0.9 meters from the base of the footing, respectively.
Bearing Capacity,Strip Footing,Geogrid,Eccentric Loading,Optimum Layout
https://ceej.aut.ac.ir/article_3566.html
https://ceej.aut.ac.ir/article_3566_1930381bbff4688de6c969ce62878139.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Continuous Wavelet and Fourier Transform Methods for the Evaluation of the Properties of Critical Excitation
3125
3144
FA
Reza
Kamgar
0000-0002-6575-7122
Office No. 57, Department of Civil Engineering, Shahrekord University, Shahrekord, Iran.
kamgar@sku.ac.ir
Noorollah
Majidi
Shahrekord University, Shahrekord, Iran
noorollahmajidi1373@gmail.com
Ali
Heidari
0000-0001-8229-4978
Associate Professor, Department of Civil Engineering, Shahrekord University, Shahrekord, Iran
heidari@sku.ac.ir
10.22060/ceej.2019.16575.6271
A designer needs to design a structure with the aim of obtaining the maximum possible load expected for the structure during its lifetime. In this paper, considering the information obtained from the earthquakes, the critical earthquakes were computed for a shear frame building equipped with a belt truss system and subjected to two constraint scenarios. For this purpose, a nonlinear optimization problem has been solved in which the objective function was the maximization of the roof displacement. In the first constraint scenario, the computed critical earthquake was known as the first state critical earthquake. In addition, for the second constraint scenario, the earthquake was named as the second state critical earthquake. In the first scenario, the energy, the duration of strong ground motion, and peak ground acceleration were considered as the constraints, while in the second scenario, the upper bound Fourier spectrum was added to these constraints. Finally, the properties of the initial and critical earthquakes were investigated using the Fourier analysis method and continuous wavelet transform. The numerical results showed that the Fourier spectrum of the first critical earthquake was 6.86 times higher than the maximum values for the same parameter in case of other earthquakes at a frequency near the first natural frequency of the structure. Also, using the time-frequency curve, it was shown that duration of the strong ground motion of all earthquake places within the dominant duration of the frequencies of the same earthquake was more than 10 sec.
Critical excitation,shear frame,Wavelet transform,Fourier frequency,optimization
https://ceej.aut.ac.ir/article_3579.html
https://ceej.aut.ac.ir/article_3579_293007321ef569017f5d0180afd36d3e.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Sensitivity Analysis of Response of a Cable Bridge with Base Isolation to Material Variation under Near Earthquake
3145
3160
FA
Hamidreza
Tavakoli
0000-0001-5298-6199
Civil Engineering, Babol Noshirvani University of Technology
tavakoli@nit.ac.ir
majid
moradi
0000-0002-8470-6160
Babol Noshirvani University of Technology
majid_moradi68@yahoo.com
10.22060/ceej.2019.16617.6280
Several factors can influence the response of structures under seismic loading. The specifications of the materials used may differ from the parameters required in the design of structures. This difference can affect the response of structures. In this study, we have tried to investigate the sensitivity analysis of the effects of changing the properties of materials on the seismic response of a suspended cable bridge equipped with RNC isolator. A cable bridge with and without the RNC isolation has been dynamically analyzed after initial modeling under a Sanfernado earthquake record. Then, the effect of random variables on the response of these structures is investigated using Monte Carlo and first order second moment sensitivity methods. Finally, the accuracy of FOSM analysis compared to Monte Carlo method. Two parameters of base shear and maximum deck displacement are considered as structural responses. The results show that among the material characteristics, final strength properties of concrete, reinforcement yield stress and modulus of elasticity of cables have the most influence on the seismic response of these structures. Also, the sensitivity of these parameters in the isolated bridge is lower than that of the non-separated bridge.
Cable bridge,RNC isolator,Sensitivity analysis,Random Variation,Near Reacord
https://ceej.aut.ac.ir/article_3664.html
https://ceej.aut.ac.ir/article_3664_3e1304dca5070f4bc0dfdfe2d2bf6a20.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Analytical study of seismic performance of retrofitted unreinforced masonry walls using steel plates
3161
3182
FA
Delaram
Ostad
Faculty of Civil Engineering, Shahrood University of Technology, Shahrood, Iran
delarmostad@gmail.com
Jalil
Shafaei
0000-0002-7590-4042
Faculty of Civil engineering, Shahrood University of Technology, Shahrood, Semnan, Iran
jshafaei@shahroodut.ac.ir
10.22060/ceej.2019.16570.6281
In recent earthquakes, masonry structures experienced a lot of damage due to high weight and low ductility and low shear strength. Retrofitting of masonry wall is challenges in urban construction. The unreinforced masonry walls cannot resistant to the earthquake and their basic weakness is in ductility. The wall ductility is reduced when the aspect ratio of wall decrease in comparison to the wall strength. The purpose of this study is to investigate the seismic performance of unreinforced masonry walls with two aspect ratio of 0.5 and 0.7 with scale 1:2 and retrofitting of masonry walls using different layouts of steel ties. The analytical evaluation of seismic behavior of unreinforced masonry wall has been done using ABAQUS finite element software. The force-displacement curve of specimen was bilinearized FEMA356 method. Analytical results were compared in terms of ultimate strength, effective stiffness and ductility. The ultimate strength, effective stiffness and ductility of retrofitted specimens using steel tie increased in comparison to the referenced specimen.
Unreinforced Masonry Wall,Seismic Retrofit,seismic performance,Steel Tie,Finite element analysis
https://ceej.aut.ac.ir/article_3672.html
https://ceej.aut.ac.ir/article_3672_970b9cb8d46b065a74399ddd862660c3.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Evaluation of Shear Strength Behaviour of Anzali Port Sand Reinforced with Polyethylene terephthalate (PET)
3183
3202
FA
Zahra
Hajiannejad
shahrood university of technology
zahra.hajian71@yahoo.com
Mohsen
Keramati
Civil Engineering, Shahrood University of technology
keramati@shahroodut.ac.ir
Morteza
Alinejad
Department of Civil Engineering, Shahrood University of Technology,
alinejad1993@gmail.com
reza
naderi
civil engineering, shahrood univeristy of technology, shahrood, iran
r_naderi@shahroodut.ac.ir
10.22060/ceej.2019.16281.6181
Due to the increasing production of plastic materials, there is an international concern about disposal or recycling of plastic waste in the world. One of the ways to reuse plastic waste is to use it in the engineering works to modify mechanical properties of loose soils. The purpose of this research is to find a way to reuse a particular kind of plastics (bottles of dough, soft drinks, mineral water, etc.) in geotechnical works to improve soil. In this paper, the mechanical behavior of Anzali Port sand, reinforced with 1×1 cm polyethylene terephthalate crumbs and 1×5cm strips, to 0, 0.1 , 0.5 , 1 and 2% and polyethylene terephthalate fibers to 0 and 0.1 and 0.5% of the dry weight of the soil which were arranged separately, was evaluated. Samples were prepared at the relative density of 75%. The effects of parameters such as dimensions, the weight percentage of reinforcers in the soil and vertical stress were investigated. The results of the experiments showed that although the polyethylene terephthalate crumbs and strips improve the mechanical behavior of sandy soil, but the effect of fiber reinforcers on soil mechanical properties has been much higher. Also, the optimum percentage of polyethylene terephthalate crumbs and strips reinforcers was 1% of sand dry weight. The comparison between reinforced and unreinforced samples showed that reinforced specimens had more ductility and resistance.
Sand,Polyethilen Terphetelate,Large scale direct shear test,Reinforcement,Mechanical Behavior
https://ceej.aut.ac.ir/article_3648.html
https://ceej.aut.ac.ir/article_3648_da7c149eb35e7ff325e8bb5d50786ffd.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Numerical Simulation for Determination of Sliding Type and Stability Factor of Safety in Finite Slopes with Limit Equilibrium Method
3203
3220
FA
Farzin
Salmasi
0000-0002-1627-8598
Associate Professor, Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz-Iran
ferzin.salmasi@gmail.com
Bahram
Nourani
PhD candidate, Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz-Iran
nourani.t_bahram@yahoo.com
Hosein
Hakimi Khansar
PhD candidate, Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz-Iran
hakimi1904@yahoo.com
10.22060/ceej.2019.16332.6190
In this study, the effect of soil material parameters including soil specific weight (γ), cohesion (C) and angle of internal friction (∅) and geometric parameters of slope including angle with the horizontal (β) and slope height (H) on factor of safety (Fs) are investigated. Slope factor of safety is considered in two scenarios: (i) slope with dry condition and (ii) slope with steady-state saturated condition that comprises water level drawdown circumstances. In addition, the type of slip circle investigated. For this purpose, the limit of equilibrium method (LEM) is implemented. Results indicated that, decreasing of water level and omitting the hydrostatic pressure on the slope, would result in safety factor decrement such a way that with drawdown of 5.5 m water level, the factor of safety decreases about 41.42 % and also the type of slip circle is changed. Comparison of the plane and circular failure surfaces showed that plane failure method has good results for near-vertical slopes only. Determination of clip type showed that for β<60o each of the three types of slip (toe circle, midpoint circle and slope circle) occur, but for β>60o only toe circle can happen. Application of the LEM in Bishop’s method resulted the values of R2 and RMSE equal to 0.93 and 0.121, respectively that the error of this method is 1.3% respect to other methods, which can be neglected in comparison with the complex and accurate methods.
Earthen slope,hydrostatic pressure,safety factor against sliding,slope failure,water surface draw down
https://ceej.aut.ac.ir/article_3546.html
https://ceej.aut.ac.ir/article_3546_17696c2e1d371fe08b136168edcd10ab.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
A comparison of the applicability of the theoretical VART, Gaussian, and ADZ models for pollution source identification in the rivers
3221
3236
FA
Jafar
Chabokpour
Civil engineering department, university of Maragheh
j.chabokpour@maragheh.ac.ir
10.22060/ceej.2019.16629.6285
A series of experimental data and two series of field data which have been extracted by USGS in the MONOCACY River and ANTIETAM creek have been utilized to compare source identification accuracy of the Gaussian, ADZ, and VART models. To achieve the object of the study, the theoretical solution of the VART model for sudden release, and the second-order central moment equation of the Gaussian and ADZ models have been operated For all of the experimental and field data series, firstly, all of the model parameters have been computed and then by operation of the extracted parameters and the mentioned relationships, the accuracy of them have been calculated. The results showed that the accuracy of the VART model for experimental and field data is 25% and 4.8% respectively. Also, the average relative errors of the Gaussian and ADZ models are 1.65% and 14%, respectively, which confirms the desirable accuracy of the Gaussian model. The results of the present study have been revealed that the Gaussian model in both of the model parameter numbers and the calculation accuracy is superior to the others. Also, to assess the goodness of fit between experimental and field data series and the theoretical Breakthrough curves, the average Nash-Sutcliffe parameters have been calculated about 0.97, which exhibits the favorable goodness in the fits.
Tracer,Location of the Pollution Source,VART Model,Gaussian Model,ADZ model
https://ceej.aut.ac.ir/article_3576.html
https://ceej.aut.ac.ir/article_3576_a0f2b28524efe933e3e3c3e321a46c9d.pdf
Amirkabir University of Technology
Amirkabir Journal of Civil Engineering
2588-297X
2588-2988
52
12
2021
02
19
Soil Stabilization by Nano Polymer Polylatice (Case Study: Hossein Abad Area of Qom Province
3237
3248
FA
Mohammad Mehdi
Bakhshi
Tarbiat Modares Univ., Civil & Environmental Eng. Faculty, Env. Eng. Div.
P.O. Box 14115-397
Tehran, Iran
mdibakhshi@gmail.com
Bita
Ayati
0000-0001-7720-9863
Tarbiat Modares Univ., Civil &amp; Environmental Eng. Faculty, Env. Eng. Div.
P.O. Box 14115-397
Tehran, Iran
ayati_bi@modares.ac.ir
Hossein
Ganjidoust
Tarbiat Modares Univ., Civil & Environmental Eng. Faculty, Env. Eng. Div.
P.O. Box 14115-397
Tehran, Iran
h-ganji@modares.ac.ir
10.22060/ceej.2019.16402.6211
Today, wind erosion and the dust caused by it, as an environmental problem, affects not only the desert regions of Iran, but also the entire country. The beginning of haze crisis in Iran originates in the last two decades. At first, the haze entered the country through the west and southwest of the country and gradually reached the central areas. The dust can be caused by various natural and artificial factors. There are different methods for soil stabilization, such as using windbreak, planting and use of mulch. The use of new soil stabilization methods, due to reduced environmental impacts, is a suitable alternative for oil mulch. Soil stabilization by using Nano polymer polylatice creates a uniformly coherent cortex that is resistant to high wind speed and has less environmental degradation effects. In this research, the soil of the Hossein Abad area, near the salt lake of Qom, has been used for wind erosion test to verify the stabilization with the use of nano polymer polylatice. After passing through a 2 mm sieve, the soils were stabilized with concentrations of 1, 1.5 and 2 L/m2 of polylatice in trays with dimensions of 80*80*3 cm. These specimens were exposed to wind by three different velocities, including 10, 15 and 20 m/s, during 7 and 30 days and their stabilities were analyzed against wind. The concentration of dust of the Hossein Abad area in the 7 and 30-day stabilization decreased by 60 and 50 times at a wind speed of 20 m/s, respectively and as time passed by after adding mulch, the amount of particles deposited along the channel were also decreased significantly.
Soil Stabilization؛ Wind Erosion؛ Mulch,Nano Polymer Polylatice؛ Hossein Abad Qom
https://ceej.aut.ac.ir/article_3653.html
https://ceej.aut.ac.ir/article_3653_7694e584ff10c7697dd7ed582f9f88e6.pdf