Simulation of orientation of baffles in a longitudinal direction in chlorine contact tanks
Mahsa
Esmaeili
water engineering department, faculty of agriculture, Shahrekord University, Shahrekord, Iran
author
Mahdi
Asadi Aghbolaghi
water engineering Department, school of agriculture, Shahrekord University, Shahrekord, Iran
author
text
article
2020
per
Disinfection is a process designed to disable pathogens, thereby preventing the transmission of waterborne diseases. An important aspect of chemical disinfection is the design of chlorine contact basins. Chlorine contact systems with sufficient time (contact time) disinfect the water for chemical reactions to inactivate pathogens. Design of chlorine contact basin or chlorine contact tanks is to maximize the phenomenon of Residence time through the flow of spiral of baffles through the basin or contact tank. Historically, chlorine contact tanks have been investigated by empirical relationships, physical model studies, or tracer studies after the construction of a contact tank. Construction of laboratory samples and tracer studies are time consuming and costly. In recent years, computational fluid dynamics models have been used to investigate the flow and processes of solute transport in contact tanks, which is the best way to design contact tanks before construction. In this study, a 3D simulation of the CT-1 contact tank is performed using Multiphysics 5.3a software. Also, several 3D simulations in the CT-1 contact tank, in which the effect of the baffle orientation in a longitudinal direction with three different channel widths was performed, it was concluded that the narrow channel with a ratio of Winlet /Wch=0.68 (channel to inlet width ratio) and Lbo / Wch ratio (baffle opening length to Channel width ratio) equal to 1 has the highest baffle factor and the least amount of Morill index and therefore optimal hydraulic.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1891
1906
https://ceej.aut.ac.ir/article_3461_ffe83442d929a387885b8eb2c1eb0bad.pdf
dx.doi.org/10.22060/ceej.2019.15699.6003
Investigation of Shear Strength of Clay Soil – Geotextile by Adding the BCF Waste
Fibers
bahareh
ebrahimi alavijeh
Geotechnical engineering, Civil engineering, Yazd university, Yazd, Iran
author
رضا
پورحسینی
ACADEMIC MEMBER
author
text
article
2020
per
By placing the reinforcing elements, the shear strength of the soil improves. Several studies have been carried out on reinforcing of coarse grained soils, and less has been done on finegrained soils. Researches show that the shear strength of fine grained soil-geosynthetics is weaker than the coarse soils and should be to improve soil interaction with reinforcing elements. In this research, soil with about 80% passing the No.200 sieve and two types of non-woven geotextiles have been used. Shear strength of soil was considered by adding BCF waste polypropylene fibers with 0.2%, 0.7% and 1.2% by weight of dry soil. Shear strength of soil–geotextile determined by large direct shear machine and several tests were done in vertical loading–reloading conditions. Experimental results showed that vertical loading– reloading conditions increase interface shear strength. Addition of 0.7% fibers increase interface shear strength up to 15% and 9% in usual loading and loading-reloading conditions, respectively. Also increasing of normal stress in loading step, application of geotextile with higher tensile strength and reduction of moisture content are the factors improving shear strength of soil-geotextile in this study.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1907
1922
https://ceej.aut.ac.ir/article_3389_f24749a7e2b0387a3951875383529763.pdf
dx.doi.org/10.22060/ceej.2019.15719.6008
Experimental study of the effect of holes number and arrangement of lattice pounder
on offshore dynamic compaction
Mohammad Hossein
Taghizadeh Valdi
Department of Civil Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran
author
Mohammad Reza
Atrechian
Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran
author
Ata
Jafary Shalkoohy
Department of Civil Engineering, Bandar Anzali Branch, Islamic Azad University, Bandar Anzali, Iran
author
Seyed Ahmad
Hosseini
Department of Civil Engineering, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.
author
text
article
2020
per
In offshore dynamic compaction, the water effect on the deterioration of the pounder impact velocity on seabed and the crater depth formed in the soil is always a major challenge. In this paper, the water entry problem of lattice pounders of 9, 16, and 25 holes, with 3x3, 4x4, and 5x5 matrix arrangements respectively, the effect of the number, dimensions and arrangement of the pounder holes, on the impact velocity with simulated soil of the seabed and the crater depth formed in it was studied experimentally. The results showed that the impact velocity of the lattice pounders depends on the holes area, and the crater depth formed in the soil, the amount of energy transferred from the pounder to the soil and the improvement radius and depth of soil depend on the area of the pounder’s lattice web. Therefore, in dynamic compaction of the seabed, increasing the pounder weight without reticulating it cannot considered as a suitable solution to increase the impact velocity on seabed and the effective factor on soil settlement and compaction. Also increasing the pounder weight and its drop height over the optimum drop height lead to increasing the operating costs, and it requires the use of large barges and long cranes with a high load capacity.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1923
1934
https://ceej.aut.ac.ir/article_3470_23fa98168039be9eec0c1c5760732f22.pdf
dx.doi.org/10.22060/ceej.2019.15732.6014
The Effect of Semi-active Control on Nonlinear Response of Structures through Incremental Dynamic Analysis
Hassan
Bahar
Civil Engineering Group, Faculty of Engineering, University of Guilan, Rasht, Iran
author
Arash
Bahar
Civil Engineering Group, Faculty of Engineering, University of Guilan, Rasht, Iran
author
text
article
2020
per
It this paper, incremental dynamic analysis (IDA) of the controlled structures is presented. Nonlinear dynamic analyses for controlled structures are performed through Force Analogy Method (FAM) and State-space. IDA curves are demonstrated for un-controlled structures, under optimal control and under semi-active control. Therefore, the influence of control system for structures and changes in its behavior could be observed. Introductions for IDA, structural control, Semi-active Hydraulic Damper (SHD) and Force Analogy Method (FAM) are explained in the article. Full Static Condensation Model (FSCM) is introduced as a recent method that could consider non-linear behavior (through FAM and State-Space), static condensation and full Rayleigh damping matrix. In this article, FSCM is extended for the structures which are protected by optimal or semi-active control system. Therefore nonlinear behavior of controlled structures was considered. Numerical examples for a 5-story frame under scaled earthquakes were presented. The structure, for both controlled and un-controlled conditions, was modeled by the way that it could consider non-linear behavior. Control algorithms that have been used in the program were optimal control and SHD semi-active control. MATLAB codes were developed and IDA curves for no-control, optimal control and SHD control (with different arrangements of SHD control tools) are calculated and illustrated. At the end of the numerical section, some results and interpretations were extracted from IDA curves of controlled and un-controlled frames. They are explained in details and could give better understanding for dynamic behavior of the structures.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1935
1952
https://ceej.aut.ac.ir/article_3410_6c2d841ad0130684a3cab9b7960a2653.pdf
dx.doi.org/10.22060/ceej.2019.15710.6017
Removal of Nickel and Cadmium using Diatomite, Silt, Sunflower stem, and Cement
(Green Concrete Components)
somayeh
bakhtiari
department of civil engineering, sirjan university of technology
author
fatemeh
sotoodeh nia
departement of civil engineering, sirjan university of technology
author
meysam
shahrashoub
department of civil engineering, sirjan university of technology
author
hakimeh
abbslou
sirjan university of technology
author
tayebeh
amiri
sirjan university of technology
author
text
article
2020
per
Adsorption is one of the common treatment applied in heavy metal removal. Recently, studies of low-cost adsorbents, which usually are waste products from industrial, agricultural and food productions and are produced abundantly, gained intensively attention to the scientist.. Since most of the structures, ponds, and drainage pipelines are made of concrete, the use of adsorbent concrete can be an effective way to remove pollutants, especially heavy metals from wastewater. In this research, diatomite and sunflower stems were used as concrete additives to adsorb cadmium and nickel from wastewater as well as materials that could maintain and even increase the strength, durability, and stability of concrete in water and wastewater structures. Diatomite was replaced with part of the cement and sunflower replaced with part of aggregates used in concrete. The adsorption of nickel and cadmium by concrete components (cement, silt, diatomite and sunflower stem) was investigated. Cement was able to remove nickel and cadmium completely. Other components of the concrete also had a good ability to remove nickel and cadmium. The maximum adsorption capacities of Ni and Cd for diatomite, silt, and sunflower stem were 2.85, 1.88, 2.61, 2.82, 18.45, and 6.82 mgr/gr, respectively. Metal adsorption onto adsorbents was evaluated by Langmuir and Freundlich isotherms. Results indicate that both Langmuir and Freundlich isotherm models are suitable. Concrete pieces removed cadmium completely, but in nickel adsorption, the control sample had the best performance.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1953
1970
https://ceej.aut.ac.ir/article_3421_3839942b6ea0e8b731cd9c1eefa5b6c8.pdf
dx.doi.org/10.22060/ceej.2019.15746.6018
Investigation of the Effect of Temperature on the Undrained Shear Strength of Kaolinite
Akbar
Cheshomi
Department of Structural and Engineering Geology, School of Geology, College of Science, University of Tehran
author
Fariborz
Mohammadi
Department of Structural and Engineering Geology, School of Geology, College of Science, University of Tehran
author
Alimohammad
Rajabi
Department of Structural and Engineering Geology, School of Geology, College of Science, University of Tehran
author
text
article
2020
per
Investigation of the effect of temperature on soil strength is one of the issues which has been considered by many researchers in recent decades. In this study to investigate the effect of temperature on the undrained shear strength (Cu) of clay soils, a cell with the capability of both changing and keeping fixed the temperature of sample, was designed and constructed. After determining the index properties of samples for Kaolinite clay soil, undrained shear strength (Cu) test was carried out on saturated clay soil at 10, 20, 30, 40, 50, 60 and 70 ° C. Repeatability of the results was confirmed by repeating tests on samples with the same properties a given temperature. The results showed that by increasing the temperature, the Cu values decreased so that, as the temperature raised from 10 ° C to 70 ° C, the values Cu were reduced from 26.6 to 10.94 kPa. Accordingly, in the studied temperature range, an empirical relationship between temperature and Cu (with R2 = 0.96) was proposed. The general shape of the stress–strain curves of the samples in different temperature was the same and in strain level of 20% was linear. Increasing the temperature caused to decline in the range of elastic deformation and enhancement in the range of plastic deformation of the samples; in addition, by increasing the temperature, the angle of the failure plane was decreased. The measurement of axial expansion stress (AES) indicated enhancement of the stress by increasing the temperature.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1971
1982
https://ceej.aut.ac.ir/article_3392_55d7cf89d1336ec79595b786c282ba8d.pdf
dx.doi.org/10.22060/ceej.2019.15768.6021
RR198 and RG19 Dye Removal by using PES membrane modified with graphene
oxide nanofillers
afsaneh
shahbazi
Prof., Environmental Sciences Research Institute, Shahid Beheshti University, G.C., Tehran, Iran
author
Mahdieh
Aghaei
MSc Studentd, Environmental Science Research Institute, Shahid Beheshti University, Tehran 1983969411
author
Habib
Koulivand
Environmental science research institute, Shahid beheshti university
author
text
article
2020
per
The presence of the even very low concentration of dyes makes it undesirable due to its appearance. Most of the organic dyes have aromatic rings in their structure that, make them very toxic and non-biodegradable. So removal of this dyes from industrial effluents before discharging in natural waters is very important. In the present study, Graphene-oxide (GO) nano-sheets were first synthesized using the modified Hammer method and then magnetic graphene oxide (mGO) was prepared using a solvothermal method. The properties of nanofillers were investigated using SEM, XRD and VSM analyzes. The synthesized GO and mGO were embedded in the matrix of polyethersulfone (PES) using phase inversion technique in order to improve its hydrophilicity, permeability, antifouling properties, and rejection performance. Surface and cross-sectional morphology of the resulted bare and nanocomposite membranes were characterized by SEM images. The effect of blended nanoparticles on membrane hydrophilicity and performance were determined using water contact angle, pure water flux, BSA solution filtration, and Reactive Green 19 (RG19) and Reactive Red 198 (RR198) dye solution rejection. Cross-sectional SEM images of the prepared membranes presented an asymmetric structure with a finger like porous sub-layer and dense top-layer. The water contact angle for the bare PES, PES-GO 0.25 wt%, and PES-mGO 0.25wt% were 61.17°, 55.11°, and 51.04°, respectively. The pure water flux of the blended PES membranes was enhanced significantly compared to the bare PES due to the higher hydrophilicity. The results of antifouling properties using BSA filtration demonstrated that the PES-mGO 0.25wt% had the best antifouling properties. Values of flux recovery ratio for the bare PES, PES-GO 0.25 wt%, and PES-mGO 0.25wt% were 45.0, 67.0, and 72.7%, respectively. Dye rejection performance also was increased for the PES-GO 0.25 wt% and PES-mGO 0.25wt% compared to the bare PES. . Compared to the all fabricated membranes, PES-mGO 0.25wt% showed the highest hydrophilicity, permeability, rejection, and antifouling properties.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1983
1994
https://ceej.aut.ac.ir/article_3339_2d050eb0421336b2960c1f2baad57066.pdf
dx.doi.org/10.22060/ceej.2019.15781.6029
Effect of Concurrent Use of the Six-Legged Element and Rip-Rap for Scour Control
with Economic Considerations
Mohammad
Rashki Ghaleh Nou
Ph.D Student- Hydraulic structures- Dep. of Civil Engineering- University of Sistan and Balouchestan- Zahedan
author
Mehdi
Azhdary Moghaddam
University of Sistan and Baluchestan
author
Mahmood
Shafai Bajestan
Prof. Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz
author
Hazi Mohammad
Azamathulla
Professor of Civil & Environmental Engineering,
The University of the West Indies,
St. Augustine Campus, Trinidad
author
text
article
2020
per
The scour control downstream of the ski-jump spillways is one of the most important issues encountered by hydraulic engineers. In this paper, an experimental investigation was performed to evaluate the reduction in the maximum volume of the scour hole due to the concurrent use of the six-legged concrete elements (A-Jacks) and rip-rap materials in different hydraulic conditions. These elements were placed in the downstream of the ski-jump spillway. The experiments included a single size of concrete element and two sizes of rip-rap with five flow discharges and three tail-water depths. The change in tail-water depth resulted in the spillway having free, semi-submerged and submerged conditions. The results were showed that as scour depth increased, the scouring rate is significantly reduced. By simultaneous usage of concrete elements and rip-rap materials, the maximum scour volume decreased up to 100% in different hydraulic conditions as compared to the control tests. In addition, the results showed that the use of a rip-rap layer is about 80% cheaper than the coating with six-legged elements, which this difference is reduced by increasing the thickness of rip-rap layer.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
1995
2010
https://ceej.aut.ac.ir/article_3419_4a45002552e9744f3e264cf1a9871a8b.pdf
dx.doi.org/10.22060/ceej.2019.15793.6032
Compression of novel meta-heuristic algorithms for multi-objective optimization of
water resources system (case study: Sistan’s Chah Nimeh)
Abolfazl
Akbarpour
Faculty of Engineering, University of Birjand
author
mohsen
Mohsen Pourreza Bilondi
university of birjand
author
mohammad javad
zeynali
Ph. D. Student, Dep. of Sciences and Water Engineering, Birjand University, Iran.
author
text
article
2020
per
In this research, two conflicting objective functions used to solve the problem of optimization operation of Sistan’s Chah Nimeh reservoirs. The first objective function defined minimizing the total of second power of difference between agricultural demand and release and the second objective function defined maximizing the reliability index. In this study, to compare the studied algorithms, the criteria of the algorithm’s run time, the number of solutions in the optimal Pareto front, and distance, dispersion, convergence and generation distance were taken. The results of the study of Meta-Heuristic algorithms indicated that among MOPSO, MOGOA and MOALO algorithms, MOALO and MOGOA algorithms were more efficient than MOPSO algorithm. According to the performance criteria of the algorithm’s run time and the dispersion criteria, the MOPSO algorithm showed high efficiency and according to the performance criteria of the distance, convergence and generation distance criteria, the MOGOA showed high efficiency. According to the performance criteria of the number of solutions on the optimal Pareto front MOALO algorithm showed high efficiency. Also, MOALO and MOGOA algorithms effectively covered optimal pareto front. It can be said, the solutions of these algorithms find in themselves optimal pareto front, create a rich set of optimal solutions that not only effectively cover the optimal Pareto front, but also dominate the solutions of the other two algorithms. Therefore, it seems that none of these performance criteria can alone determine the superiority of an algorithm than other algorithms in solving an optimization problem.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2011
2024
https://ceej.aut.ac.ir/article_3394_dded6a2c6ebc5e0cc5f72f5246eb88c7.pdf
dx.doi.org/10.22060/ceej.2019.15818.6039
Free vibration analysis of FGM plates with opening and stiffener
Mojtaba
Shahraki
Civil Structural Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad.
author
farzad
shahabian
Civil Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad,Mashhad, Iran
author
reza
jome manzari
Master of Civil Structural Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
author
text
article
2020
per
Functionally Graded Materials (FGMs) are kinds of composite materials that due to the continuity of mixture of constituent materials as Functionally Graded, have more effective mechanical properties than multilayered composite materials. The most common use of these materials is in thin[1]walled structures such as plates and shells. Due to some executive needs, make opening and stiffener in plates might be necessary. Free vibration of a system is performed only under the influence of initial conditions and without any external excitation. A system under free vibration situation vibrates with one or more its natural frequencies. If the frequency of vibration caused by the effect of external excitation is equal to the one of the natural frequencies of the system, resonance state occurs. In this case, there will be a large amplitude fluctuation that can cause fracture of huge structures such as bridges and wings of aircrafts. Therefore, in the present study, the effective parameters on free vibration of FGM plates with opening and stiffener have been studied.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2025
2042
https://ceej.aut.ac.ir/article_3411_528ea1a1b43ef7c1188be9b3dfca4697.pdf
dx.doi.org/10.22060/ceej.2019.15832.6047
Numerical and experimental study of pitched steps effects in stepped spillway on the
hydraulic parameters and energy dissipation in the skimming flow
samira
akhgar
2- Ph.D. of Hydraulic Structures, Water Engineering Department, Faculty of Civil Engineering, Tabriz University, Tabriz, Iran. samira.akhgar66@yahoo.com
author
Kiyoumars
Roushangar
Civil Engineering Department, Tabriz University, Tabriz, Iran.
author
text
article
2020
per
One of the most prominent features of the stepped spillway performance is the considerable loss of energy during it compared with other types of spillway. Considering this feature, obtaining a more detailed view on the energy dissipation parameter and, finally, increasing its amount has been the focus of most studies related to this type of spillway. For this purpose, using a Flow-3D model, the effect of pitched steps (steps with hole) on the velocity and pressure variations, water height at downstream and energy dissipation has been investigated. As well as the appropriate model of the most energy dissipation in the laboratory was developed and studied. Numerical and experimental results show that pitched steps reduces the velocity to about (82-69%) and reduces the water height at the downstream by up to 33%, and the energy dissipation is increased to about 4 times. According to the pressure distribution profiles at the vertical edge of the step, it was observed that the amount of negative pressure in the vertical wall decreased by about 82%, and the positive pressure was approximately increased by 3 and 4 times. The negative pressure on the floor of the steps is turned into positive and the positive pressure near the edge is increased due to the presence of the hole. Also, the results showed that the error rate of the studied parameters in the numerical and experimental models was very low and acceptable, indicating a good fit between numerical and experimental data.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2043
2058
https://ceej.aut.ac.ir/article_3387_2e6eaafab9766cfec67ac4c1e1da9220.pdf
dx.doi.org/10.22060/ceej.2019.15856.6057
Comparison of Hyporheic Exchanges in 2D and 3D Riffle-Pool bed form structures
Neshat
Movahedi
PhD Student/Water and Soil Department, Gorgan University of Agricultural Sciences and Natural Resources,Gorgan, Iran
author
Amir Ahmad
Dehghani
Water Engineering, Gorgan University of Agricultural Sciences and Natural Resources
author
Christian
Schmidt
Researcher, Helmholtz Center for Environmental Research (UFZ), Department of Hydrogeology, Leipzig, Germany
author
Nico
Trauth
Researcher/Department of Hydrogeology, Helmholtz Center for Environmental Research, Leipzig, Germany
author
Mehdi
Meftah Halaghi
Associate Professor/Water and Soil Department, Gorgan University of Agricultural Sciences and Natural Resources,Gorgan, Iran
author
text
article
2020
per
Exchanges of water and solute between stream flow and flow through river bed porous media are known as hyporheic exchanges. Hyporheic exchanges transfer water and nutrient to the organism lived in the hyporheic zone, so affect ecological conditions and food cycle. One of the important driving factors of these exchanges are pressure gradients along the bed form. Riffle-pools are geomorphic features of river beds which induce strong pressure gradient along the streambed, which control hyporheic exchanges and are therefore considered in river restoration projects. The goal of this study is to compare the hyporheic flux and residence time of flow within sediment bed underneath 2D and 3D riffle-pool structures. For reaching this goal, in a first step, the surface water flow is simulated by the CFD-software OpenFAOM, resulting in a detailed pressure distribution at the stream bed. In a second step, these pressure fields are then set as a top boundary condition of a groundwater model (MODFLOW software), for simulating the flow in porous media. The results show that, by increasing bed form amplitude, hyporheic exchanges flux increases by 26 % for both 2D and 3D models, and residence time decreases by 36 %for 2D and 41 % for 3D structures. Also, comparison of 3D riffle-pool with equal 2D model shows that hyporheic exchange flux and residence time increase by 2.9 % and 3.67 %, respectively.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2059
2072
https://ceej.aut.ac.ir/article_3393_2bb76933d8eb82db1c922e50b6fa8d8a.pdf
dx.doi.org/10.22060/ceej.2019.15864.6058
Seismic Control of a 10-Storey Shear Frame Using Active Tuned Mass Dampers and
Particle Swarm Optimization Algorithm
Mazyar
Fahimi Farzam
Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
author
Babak
Alinejad
Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
author
Seyyed Ali
Mousavi Gavgani
Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
author
text
article
2020
per
Due to structural safety and residential comfort, the vibration control of buildings under earthquake and wind excitations has always been one of the important issues in the structural engineering context. One of the well-established approaches for controlling the structural vibration is the use of Tuned Mass Dampers (TMDs) employed with different methods in structures. In this paper, a 10-storey shear building with linear behavior is studied under 28 Far-Fault (FF) and Near-Fault (NF) earthquakes in MATLAB. Active Tuned Mass Damper (ATMD) is used to control the structural vibration. According to the random nature of earthquake excitation, Fuzzy Logic controller (FLC) and Mamdani Inference System are applied to determine the control force. In addition, the Particle Swarm Optimization (PSO) algorithm is used to determine the optimum TMD actuator power, and in this study, the effect of the actuator saturation is also considered. Furthermore, a method is introduced for robust optimum design of the suggested controller. Using the proposed control system and the optimum actuator power, structural responses decline about 44 pct. Additionally, due to the existence of uncertainty in earthquake records, applying a controller with average actuator power generally results in 33 pct. structural response reduction, and the performance of the active controlled system always outperforms the passive controlled system with utmost 16 pct. structural response reduction.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2073
2092
https://ceej.aut.ac.ir/article_3423_c42ffe8c6c8c85ec72c0eec34f7d7930.pdf
dx.doi.org/10.22060/ceej.2019.15883.6064
Relation between microstructure and physical and engineering properties of sandstones with emphasis on quartz content
Ali
Lakirouhani
Civil Engineering Department, Faculty of Engineering, University of Zanjan
author
Majid
Bakhshi
Department of Civil Engineering, University of Zanjan, Zanjan, Iran
author
Afshin
Zohdi
Assistant Professor, Department of Geology, University of Zanjan, Zanjan, Iran
author
text
article
2020
per
The composition, texture and microstructure of rocks affect their physical and mechanical properties such as dry unit weight, porosity, p-wave velocity and Brazilian tensile strength. The aim of this study was to investigate the effect of mineralogy sandstone characteristics on physical and mechanical properties of sandstone in three groups with low mean quartz (less than 65%), moderate (65 to 80%) and high (more than 80% ) and 26 samples were collected from southern province of Zanjan city Then, a comprehensive program of rock mechanic tests are planned and mineralogical properties and engineering parameters such as dry unit weight, porosity, P-wave velocity and Brazilian tensile strength were determined and their relationship was investigated using linear regression analysis. The results show that the mineral composition is effective on the strength properties and increasing the quartz mineral content in the samples, two physical parameters of dry unit weight and P-wave velocity and a mechanical parameter Brazilian tensile strength increase. Also, due to the correlation between physical parameters, P-wave velocity can be predicted with appropriate approximation using porosity parameter for sandstone in studied regions and the results can be used in geomechanical studies.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2093
2108
https://ceej.aut.ac.ir/article_3469_f1d901f7ba747330e10ff346efb11947.pdf
dx.doi.org/10.22060/ceej.2019.15896.6066
Investigating the Effect of Characteristics of Aggregates and SFE components of
Asphalt Binder-Aggregate on the Moisture Sensitivity of Asphalt Mixtures Modified
with Anti-Stripping Agents
Yunes
Azaryun
Faculty of Engineering, Urmia University, Urmia, Iran
author
Hamid
shirmohammadi
Faculty of Civil Engineering, Urmia University, Urmia
author
Gholam Hossein
Hamedi
Department of Civil Engineering, Faculty of Engineering, University of Guilan, Rasht, Iran
author
Davud
Saedi
Faculty of Engineering, Urmia University, Urmia, Iran
author
text
article
2020
per
One of the most common failures that occur during the life of asphalt pavements is moisture damage. The penetration of water between asphalt binder and aggregate causes the gradual separation of asphalt binder from aggregates and the weakening of the bonding force between asphalt binder and aggregates. With the expansion of this type of failure, the durability and asphalt mix resistance decreases. Moisture damage is defined as loss of strength and durability in asphalt mixtures. Many studies have been done on the use of anti-stripping additives to improve the quality of asphalt mixtures against the moisture damage in asphalt mixtures using surface free energy and mechanical test. One of the ways to improve the performance of asphalt mixes against moisture damage is the use of anti-stripping materials, which are usually used with hydrated lime or liquid anti-stripping agents. The use of these materials with a number of technical problems. In this research, it has been tried to investigate the effect of nanomaterials and liquid anti-stripping materials on the basis of mechanical and thermodynamic methods. 24 different types of asphalt mixtures have been investigated using three types of aggregates, two types of base asphalt binder and three types of additives. Asphalt binder and aggregate surface free energy components are measured by Sessile drop method and Universal sorption device and the ratio of fatigue life of asphalt mixtures through indirect tensile strength test. The results of this study indicate that the use of nanomaterials and liquid anti-stripping improves strength of asphalt mixtures against the moisture. Also, using these additives will increase the fatigue life and tensile strength of the asphalt mixture. Increasing in the fatigue life ratio was between 2-9%. The increase in fatigue life in wet conditions has been between 10-22%. Additionally, nanomaterial additives have a positive effect on the surface free energy components of asphalt binder, the surface free energy of aggregates, the free energy of adhesion between asphalt binder-aggregate, the debonding energy of asphalt binder and aggregates, and the cohesion free energy of asphalt binders, and improve the performance of these structures against moisture damage.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2109
2128
https://ceej.aut.ac.ir/article_3427_80d048ef5bdfdce9c2cbb8d5379c6330.pdf
dx.doi.org/10.22060/ceej.2019.15894.6076
Experimental investigation on the seismic behavior of adobe walls retrofitted with
palm meshes
hadi
meybodian
graduate student/yazd university
author
reza
morshed
Yazd University / member of Scientific Board
author
abolfazl
Eslami
assistant professor /yazd university
author
text
article
2020
per
Use of adobe materials is considered as a common construction practice in rural and historic cities of developing countries including Iran. Compared to other conventional building materials, adobe offers some advantages such as eco-friendly features, local availability, easy application, cost[1]efficiency, and high thermal and sound insulation. However, the weak seismic performance of adobe buildings under past earthquakes has led to extensive economic losses and casualties. Therefore, retrofitting of such buildings and development of guidelines for their seismic design seem vital if they are intended to resist strong ground motions. In addition, retrofitting of adobe buildings with natural and traditional materials would be more desirable. Due to the critical role of walls as the main load bearing element in adobe buildings, their retrofitting would be of high priority. Towards this, the current study was aimed at utilizing palm fibers as a natural and sustainable material in lateral retrofitting of adobe walls. In total, six adobe wall panels, with dimensions of 1000×900×200 mm, including one control and five retrofitted specimens were tested under the combination of a constant vertical load and incremental lateral displacement reversals. The retrofitting technique involved external application of palm meshes plastered with a straw-mud mortar. The experimental parameters comprise dimensions of meshes, number of anchors on both sides of the walls, and arrangement of meshes. The results indicated that using externally bonded fiber meshes can lead to retaining the overall integrity and change the shear failure mode to a rocking/toe crushing. Further, the lateral strength, ductility factor, and energy dissipation capacity of walls were improved remarkably.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
52
v.
8
no.
2020
2129
2142
https://ceej.aut.ac.ir/article_3414_e4432a0a959a3afc28a4a9fae2a008d8.pdf
dx.doi.org/10.22060/ceej.2019.15927.6079