Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Performance of Bucket Foundation Resting on Sand Subjected To Vertical Load
139
148
EN
Abdolhosein
Haddad
Civil Engineering faculty, Semnan University
haddad@semnan.ac.ir
Reza
Amini
Civil Engineering faculty, Semnan University
r.amini@semnan.ac.ir
10.22060/ajce.2018.14812.5498
In comparison with the monopile foundation, bucket foundation is an economical option to reduce the construction costs of offshore wind turbines. It is similar to a suction caisson, which is driven into the soil like an upside-down bucket. Various available scientific researches have stated that how the length of skirt affects the ultimate capacity (qult) of bucket foundations that are utilized for different kinds of offshore applications. The experiments and 3D FE analyses have been performed to assess the ultimate vertical load capacity (Vult) of bucket foundations. The experiments were conducted on loose sand and it shows that as the length of the skirt increases, the qult enhances. A conceptual relationship as a depth factor was suggested to estimate the Vult of bucket foundations on the sand with regard to embedment ratio and soil friction angle. The FE analysis results have shown that the inner soil in the bucket foundation approximately behaves as a rigid body under the vertical loading. Therefore, it might be supposed that with similar dimension, the qult of embedded and bucket foundation is close. Moreover, it was found that due to the increase in the slip line length of bucket foundation, the foundation failed in greater settlement than surface footing.
Skirted foundation,failure mechanism,embedment ratio,skirt length
https://ajce.aut.ac.ir/article_3166.html
https://ajce.aut.ac.ir/article_3166_f839dd55c1747b243d98dba77be05834.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Intelligent Mathematical Modeling of Discharge Coefficient of Nonlinear Weirs with Triangular Plan
149
156
EN
AmirHamzeh
Haghiabi
Professor, Water Engineering Department, Lorestan University, Khorramabad, Iran.
ahaghiabi@gmail.com
Abbas
Parsaie
0000-0001-7312-0634
Water Engineering Department
abbas_parsaie@yahoo.com
Zahra
Shamsi
Department of Water and Soil Conservation, Ministry of Agriculture Jihad, Kerman, Iran
azm.shams@gmail.com
10.22060/ajce.2018.14833.5500
In this study, the discharge coefficient (Cd) of non-linear weirs with a triangular plan was mathematically modeled using a group of method data handling (GMDH), genetic programming (GP) and multivariate adaptive regression splines (MARS) techniques. For this purpose, related datasets including parameters on Cd were collected from literature. These methods were selected since they are classified as smart function fitting (SFF) methods. The main advantages of SFF methods compared to other artificial intelligence methods are defining the most effective parameters on output and assigning more weights to them in mathematical expression process. Results of MARS indicated that this method with fifteen basic functions could achieve good accuracy for modeling and predicting Cd (R2= 0.98 and RMSE=0.024). Results of GMDH showed that this model includes two hidden layers and that there are five and four neurons at the first and second hidden layers, receptivity. Results of developed GP model declared that this model consists of three genes and has acceptable performance for modeling Cd. Evaluation of proficiency of utilized models with each other indicated that the best accuracy is related to MARS model. Calculating the discrepancy ratio index (DDR) shows that the minimum range of DDR is related to MARS model.
DDR Index,Nonlinear Weir,Flow Measurement,discharge capacity
https://ajce.aut.ac.ir/article_3164.html
https://ajce.aut.ac.ir/article_3164_d113348404665432e6b3ccc873872908.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Determining Bearing Failure Modes of Jointed Rock Foundations Subjected to the Load of Strip Footings
157
166
EN
Meysam
Imani
0000000314495262
Geotechnical Engineering Group, Amirkabir University of Technology, Garmsar Campus, Garmsar, Iran
imani@aut.ac.ir
ahmad
fahimifar
Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
fahim@aut.ac.ir
10.22060/ajce.2019.14836.5502
The main prerequisite for choosing the best method of obtaining the ultimate bearing capacity of soils or rock masses is determining the probable failure mode that can occur beneath the footing. Most available methods for determining the bearing capacity of rock masses are based on general shear failure of the rock mass. But depending on the properties of the intact rock and the joint sets, other types of failure modes including local or punching shear failure may occur. In such conditions, using relations which are based on the general shear failure is not sufficiently precise. In this study, distinct element method was applied for performing wide sensitivity analyses on different intact rock and the joint sets characteristics; the range of occurrence of failure modes was investigated. Three types of failure modes including general shear failure, local shear failure, and punching shear failure were considered under the vertical load of a strip footing. Two perpendicular joint sets were considered for the jointed rock mass and different orientation angles and spacing were also taken into account for the joint sets. The obtained results showed that the shear strength properties of the intact rock and the joint sets, the elastic modulus of the intact rock and the orientation angle and spacing of the joints have a considerable effect on the mode of failure, while the normal and shear stiffness of the joint sets do not play an important role in the failure mode.
Rock foundations,Bearing Capacity,Failure mode,Numerical Analysis,distinct element method
https://ajce.aut.ac.ir/article_3228.html
https://ajce.aut.ac.ir/article_3228_8f187dd96628b174031df806cbc41c5d.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Analysis of Chloride Diffusivity in Green Concrete Based on Fick’s Second Law
167
178
EN
Hakime
Abbaslou
civil engineering department, Sirjan university of technology, Sirjan, Iran
abaslou@gmail.com
Ehsan
Delnavaz
Civil engineering department, Sirjan University of Technology, Sirjan, Iran
e.delnavaz@stusirjantech.ac.ir
Ali Reza
Ghanizadeh
Civil engineering department, Sirjan University of Technology, Sirjan, Iran
ghanizadeha@sirjantech.ac.ir
10.22060/ajce.2018.14893.5504
The important factor that plays a significant role in preventing the entry of destructive elements into concrete is the cementitious composition of concrete. Moreover, reuse of agricultural wastes in concrete which called green concrete can replace materials used in the manufacturing of concrete and also reduce the negative effects on the environment, such as reduction of waste disposal and CO<sub>2 </sub>emissions. In this study, green concrete was produced with ash of Horsetail plant and Rice Husk residues containing a large amount of silicon as an additive with 0, 5, 10, 15, 20 and 25%, replacing Portland cement in four different concrete mix designs. In order to investigate chloride penetration after concrete curing, the specimens were exposed to salinity levels of 0.7, 15 and 35 dS/m from one surface for 150 days with a 10 cm water head. In terms of concrete strength, the optimum percentage of plant ash was 15%. The results showed the trend diffusion coefficient of conventional concrete > green concrete- Horse-tail ash> green concrete-rice husk ash. Thus, green concrete, in addition to the appropriate strength specifications and reduction of environmental problems, also has a major role in the reduction of chloride ion penetration into areas exposed to solutions containing chloride ions.
Concrete,Plant Ash,Chloride,Diffusion Coefficient
https://ajce.aut.ac.ir/article_3115.html
https://ajce.aut.ac.ir/article_3115_b76c25f2b0e7cf0c3619f1dd31b3ef21.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Artificial Neural Network and Optimization Algorithm to Improve Soil Resistance by Means of Aggregation Size Variation
179
186
EN
Ahmadreza
Mazaheri
Department of Civil Engineering, Engineering Faculty, Ayatollah Borujerdi University, Borujerd, Iran
armazaheri@yahoo.com
Farshid
Jafarian
Faculty of Engineering, Mahallat Institute of Higher Education, Mahallat, Iran
fjafarian@mahallat.ac.ir
10.22060/ajce.2018.14988.5512
Nowadays, extensive researches are conducted on soil improvement and most of them are focused on the enhancement of soil strength properties. In this study, the aggregation of soil particles including Gravel, Sand, and Clay was investigated on soil resistance. To do this, the number of 25 different testing experiments were experimentally performed according to the Design of Experiment (DOE). The soil strength parameter was determined by means of direct shear tests on large samples. Based on the experimental results, the effect of aggregation size on shear strength was extensively investigated. To do this, Artificial Neural Network (ANN) was employed to evaluate the effect of different combinations of soil particles on bearing capacity. To provide more precise predictive model, the ANN was trained using the Genetic Algorithm (GA). After that, the optimal condition of mix design with optimal load-bearing capacity was found by a hybrid strategy of EOA-ANN. It was obtained 1091.94 (KPa) that had not been reported using the experiments. To evaluate the reliability of the proposed method, a new experimental test was conducted based on the optimal parameters found by hybrid strategy and it was verified with corresponding estimated ones. At the end, very good agreement was reported between the new experiment and the optimal results. It shows that the employed intelligent method in this paper can be successfully used for the enhancement of soil properties in other investigations.
Soil strength,neural networks,direct shear tests,aggregation size
https://ajce.aut.ac.ir/article_3168.html
https://ajce.aut.ac.ir/article_3168_7650f0b4bf3e07a37c1b5cd6a665b5f5.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Investigation of the Rheological Behavior and Properties of Modified Asphalt Binder with Nano Hydrated Lime
187
192
EN
Alireza
Azarhoosh
Department of Civil Engineering, University of Bojnord, Bojnord, Iran
a.r.azarhoosh@aut.ac.ir
gholam hossein
hamedi
Department of Civil Engineering, University of Guilan, Rasht, Iran
hamedi@guilan.ac.ir
10.22060/ajce.2018.15083.5520
The common types of pavement distresses include: fatigue cracking and rutting. Some of the typical causes of pavement deterioration include: traffic loading; environment or climate influences; drainage deficiencies; materials quality problems; construction deficiencies; and external contributors, such as utility cuts. The most common method for decreasing these types of distress in asphalt mixtures is using suitable additives. Nanomaterials, in recent years, have been widely used to improve rheological properties of asphalt binder. This study is aimed to investigate the effect of nano hydrated lime, which is prepared from hydrated lime in a low-cost method using a planetary ball mill, on rheological behavior of asphalt binder. Therefore, in this research, the dynamic shear rheometer (DSR) test was used to determine the characteristics of control and modified asphalt binder at moderate and high temperatures. The bending beam rheometer (BBR) test was also used to determine their characteristics at low temperatures. The results indicated that the use of nano hydrated lime, especially in the amount of 10% (by weight of asphalt binder), increases the resistance to rutting fatigue cracking. Also, Modified asphalt binder at low temperatures based on the two creep stiffness parameter and m-value has a better performance than control asphalt binder.
Asphalt Binder Rheology,Nano Hydrated Lime,Rutting,Fatigue Cracking,Thermal Cracking
https://ajce.aut.ac.ir/article_3167.html
https://ajce.aut.ac.ir/article_3167_438792eb5458dd614671e144fcef096a.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Assessment of Data-driven Models in Downscaling of the Daily Temperature in Birjand Synoptic Station
193
200
EN
Mehdi
Amirabadizadeh
Water Engineering Department, Faculty of Agricultural, Birjand University. Iran
amirabady_m200@yahoo.com
Yousef
Ramezani
Water Engineering Department, Faculty of Agricultural, Birjand University. Iran
ramezani.yy@gmail.com
mohammad
nazeri tahroudi
0000-0002-6871-2771
Ph.D Student, Department sciences and water engineering, University of Birjand, Birjand, Iran
m_nazeri2007@yahoo.com
Mohammad Javad
Zeynali
Water Engineering Department, Faculty of Agricultural, Birjand University. Iran
mj.zeynali@yahoo.com
10.22060/ajce.2018.15115.5522
In this study, seven models such as multivariate regression, Contemporaneous Autoregressive-Moving Average (CARMA), CARMA-ARCH (Autoregressive Conditional Heteroskedasticity), Support Vector Regression (SVR), Adaptive Neuro-Fuzzy Inference System (ANFIS), Support Vector Machine (SVM) and Genetic Programming (GP) were investigated to downscaling the maximum daily temperature of Birjand synoptic station using 26 predictor’s parameters that resulting from the fifth Intergovernmental Panel on Climate Change (IPCC) report and compared. The max daily temperature values measured from 12/03/1961 until 20/12/2005. In all mentioned methods from 26 predictive parameters using the Pearson correlation test, 15 parameters were selected that have a high correlation with the max daily temperature values. The results of evaluating the accuracy and model indicated that from the same models such as GP, ANFIS and SVM, the GP model has the least amount of errors (about 4 °C) and in the regression models (multivariate regression and SVR), SVR have been lowest error rate (about 1 °C) and the highest accuracy in simulated max daily temperature values. The results of the investigation the error rate of the mentioned models indicated that after the SVR model, two CARMA and CARMA-ARCH stochastic models have high and acceptable accuracy about 97 percentages. In general, the results of the simulation the max daily temperature indicates the best accuracy of regression toward another methods. One of the reasons for the results of the SVR model is to optimize the parameters of the model using the ant colony algorithm for estimating the maximum temperature values of the Birjand synoptic station.
Down Scaling,genetic algorithm,Neural Network,Support Vector Regression,Temperature
https://ajce.aut.ac.ir/article_3169.html
https://ajce.aut.ac.ir/article_3169_d01d77cabf2113f35d6c6958bff065ec.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Proposed List of Significant Indicators for Iran Airport Construction Projects
201
212
EN
Abouzar
Sharifi Arkami
Semnan University
arkami@airport.ir
mohammad kazem
sharbatdar
Semnan University
msharbatdar@semnan.ac.ir
10.22060/ajce.2019.15185.5524
Airports are vital national resources that play a prominent role in the transportation of passengers and freight in domestic and international commerce. Airports authorities are vying to capture the lion’s share of the regional and global market while air travel is growing in popularity all over the globe, and mammoth projects are underway to keep up, new and expanded airports need to meet that rampant demand. The available sustainability tools and rating systems need to better incorporate the broader socioeconomic settings associated with the built environment, In other words, due to the lack of indigenous indicators, it is necessary to identify the significant indicators in this industry. This paper introduces significant assessment indicators (SAIs) for evaluating the sustainability performance of airport projects. A questionnaire survey among practitioners across the nation confirmed the necessity and identified priority Indicators of sustainability. Data for analyzing the significance of the assessment indicators collected through a questionnaire survey that given to three groups of experts, encompass government officials, professionals, and clients and Delphi method and Cronbach’s alpha coefficient method has used in this study to evaluate the data reliability. This paper demonstrates the importance of sustainability knowledge, indicators, as a positive step towards meeting Sustainability in airport projects. Finally, the authors presented 52 SAIs of airport construction projects according to Iran conditions that are consistent with the principles of sustainable development.
Sustainable Development,Indicators,Rating Systems,Infrastructure,Assessment Frameworks
https://ajce.aut.ac.ir/article_3242.html
https://ajce.aut.ac.ir/article_3242_00fa311ef15e5a25128ac704030b304a.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
An EvolutionaryAlgorithm for Deriving Optimal Operating Policy Under Uncertainties for Tehran Multi-reservoir System
213
224
EN
Farzane
Karami
K.N. Toosi University of Technology
farzane_krm@yahoo.com
Alireza
Borhani
Dariane
K.N. Toosi University of Technology
borhania@kntu.ac.ir
10.22060/ajce.2019.15254.5528
Projecting future inflows under climate change and rapidly growing population has large uncertainty and requires serious attention for proper utilization of limited water resources. Existing algorithms can only optimize the operation policy for a specified scenario (e.g., drought, wet, or normal year; decreased or increased demands) and when established, the system would face serious operational difficulty if the expected scenario does not occur. On the other hand, most of water resources systems involve more than three objectives and demand proper techniques to handle computational complexities in so-called many-objective problems. This paper aims at providing a many-objective optimization algorithm using social choice (SC) and melody search (MeS) algorithms that is able to efficiently derive general system operation rules suitable for all possible future scenarios. In other words, the proposed algorithm overcomes uncertainties in the occurrence of future scenarios and works optimally regardless of future conditions; whether it be variable streamflows and/or increased water demands. To evaluate the performance of the proposed algorithm, a system consisting of five reservoirs in the Tehran region with four objective functions. It is shown that in all cases the general multi-scenario rule derived by the proposed method performs as good as each of the operation rules derived for every specific scenario assuming the occurrence of that scenario. Moreover, the proposed many-objective algorithm is able to handle as many objectives as needed without any computational burden and/or algorithm complexity.
Many-Objective,Uncertainty,Scenarios,Melody Search,Social Choice
https://ajce.aut.ac.ir/article_3247.html
https://ajce.aut.ac.ir/article_3247_3d1e170a5b7cfe3a711e05a4ce4e072d.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
The Effect of Dimensional Change of Boundary Elements on the Response Modification Factor of the Steel Plate Shear Wall
225
232
EN
Farzad
hatami
0000-0002-4860-4298
Amir Kabir University of Technology
hatami@aut.ac.ir
Nima
Paslar
M. Sc. of Civil Engineering, Gheshm Unite, Azad Islamic University
nima.paslar91@gmail.com
10.22060/ajce.2018.15303.5532
During the past few decades, steel plate shear wall (SPSW) has been used as a lateral load-bearing system in building construction; however, the wall boundary conditions have been considered symmetric and identical in most of the performed projects and researches. In this paper, the Response Modification Factor of this system, when the columns are non-identical, and the effect of changing the dimensions of each boundary element have been investigated. These wall models could be seen when architectural and facility limitations are governing in the design or in the seismic retrofitting of existing structures when boundary elements especially the columns are of non-identical dimensions. Moreover, the necessity of this investigation would be important concerning the role of the Response Modification Factor in seismic design of structures. In this study, the effect of changing the dimensions of boundary elements on the Response Modification Factor of steel plate shear wall was calculated using Uang’s method and Newmark & Hall’s method. The same study has also been performed on ductility, energy absorption, and ultimate strength.
Steel Plate Shear Wall,Response Modification Factor,Boundary Elements,Ductility,Energy Absorption,Non-Identical
https://ajce.aut.ac.ir/article_3143.html
https://ajce.aut.ac.ir/article_3143_63c3a03144c0b664e5fb33bd8ab0c2a1.pdf
Amirkabir University of Technology
AUT Journal of Civil Engineering
2588-2899
2588-2902
3
2
2019
12
01
Experimental Investigation of the Effect of Hybrid fibers on Lightweight Concrete Beams Reinforced with GFRP Bars
233
242
EN
seyedehsan
vakili
PhD Student, Department of Civil Engineering, Kharazmi University, Tehran, Iran
std_seyedehsanvakili@khu.ac.ir
peyman
homami
Kharazmi University
homami@khu.ac.ir
M. Reza
esfahani
Ferdowsi University of Mashhad
esfahani@um.ac.ir
10.22060/ajce.2019.15474.5542
The main purpose of this study investigated the effects of hybrid use of micro glass fiber (GF), micro polypropylene fiber (PF) and macro steel fiber (SF) on the flexural capacity, energy absorption, ultimate load carrying, failure mode and ductility behavior of lightweight aggregate concrete (LWC) beams reinforced with glass fiber reinforced polymer (GFRP) bars. A total of eight beams with a rectangular cross-section and 100 mm wide × 200 mm deep × 1500 mm long, were cast and tested up to failure under four-point bending. The correction factor (φ) calculated compared with American design codes of ACI 440.1R-06 and ISIS design manual No. 3. The φ factor for beams made of hybrid PF, SF into the LWC mixes (PSLWC) and reinforced with 0.9 ρfb; where ρfb is the balanced reinforcement ratio of the GFRP bars is approximately 1.38 times to the φ factor for beams made of hybrid GF, PF into the LWC mixes (GPLWC) and hybrid GF, SF added into the LWC mixes (GSLWC) that reinforced with 0.9 ρfb. The results experimental showed the ultimate load-carrying capacity increased 5% to 49%, with increasing reinforcement ratio from 0.9 ρfb to 1.4 ρfb. According to experimental observations, failure modes in the beams made of GPLWC, GSLWC and PSLWC also reinforced with 0.9 ρfb failure modes coincides with the failure modes ACI 440.1R-06. The results indicate that the use of GPLWC, GSLWC and PSLWC at beams reinforced with GFRP bars improves the flexural capacity, ultimate load carrying, energy absorption and ductility.
Hybrid fibers,Macro steel fiber,Micro polypropylene and glass fiber,Lightweight aggregate concrete (LWC),GFRP bars
https://ajce.aut.ac.ir/article_3252.html
https://ajce.aut.ac.ir/article_3252_a6dc076bb3393bb12682c44d450c4c37.pdf