Experimental investigation of the effect of relative densities and type of loading on sand liquefaction under irregular earthquake loading
bahareh
katebi
Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Navid
Ganjian
Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
author
Mehdi
Derakhshandi
Assistant, Professor, Department of Civil Engineering, Science and Research Branch, Islamic Azad University
author
abas
ghalandarzadeh
School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran
author
text
article
2022
per
The cyclic triaxial test has been widely used to evaluate the liquefaction potential of soil over the past few decades. When a specimen is subjected to repeated shear loading, the sand particles tend to rearrange their stacking into a denser state. While drainage is prevented, pore pressure generation and loss of effective stress have resulted. This paper presents a systematic experimental investigation into the liquefaction behavior of saturated sand subject to seismic loading with various relative densities such as 30, 50 and 70 percent. Dynamic triaxial tests were run on saturated firozkooh sand using irregular time history loads that were recorded during the 1999 Chi-Chi earthquake in Taiwan. The records could be classified as shock and vibration type waveforms. The effect of each type of waveform and relative densities of sand samples on the liquefaction potential of sand was also evaluated in order to compare these results with previous studies, some cyclic tests have been done with various relative densities 30, 50 and 70 percent. The triaxial test results indicate that the pore pressure generation and liquefaction resistance of sand are influenced by the relative densities and the type of irregular loadings. Also, with the increasing duration of the records in the same PGA, the vibration waveform have more liquefaction potential than the shock waveform.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
3
20
https://ceej.aut.ac.ir/article_3502_51ea1cca6e2e8c79ebb383bc9d02df73.pdf
dx.doi.org/10.22060/ceej.2019.16278.6175
Operation of the non-linear Muskingum model in the prediction of the pollution breakthrough curves through the river reaches
Jafar
Chabokpour
Civil engineering department, university of Maragheh
author
text
article
2022
per
The Muskingum model in both types of the linear and non-linear is one the most common models in the flood routing through the river reaches. The simplicity and being stepwise in calculating the exit flood hydrographs are the advantages of this model. Because of the similarity between the shape of the flood hydrograph and pollution breakthrough curves, it is tried to examine the applicability of the non-linear Muskingum model in the prediction of the contaminant concentration in downstream of the river reaches. The field data series of the MONOCACY and ANTIETAM Creek Rivers which were gathered by USGS have been used. During the tests, Rhodamine was used and the concentration pollute graphs were acquired in the four and eight cross-sections of the mentioned rivers, respectively. The triple sets of the model parameters have been extracted in each reach, then the BC curves have been simulated in each position using them. It is observed that this model can rebuild the dimensions of the exit BC curve properly but, it also has some limitations in the modeling of the convection term of the pollution using average flow velocity. For its solution, the extracted BC curves have been transported along the time axis with the magnitude of in which L is the reach length and u is the average flow velocity. Also, for a better understanding of the effects of the model parameters in the simulated concentrations, the sensitivity analysis has been performed and it is found that the parameters of the , and are the most to less effective parameters in the concentration calculation, respectively. It was also found that the power parameter of this model (m) for pollution transport fluctuates in the range (0.1-1.4) and has an average value of 0.85. The value of the weighted coefficient (x) was also obtained in the range (-1 to +1), but the frequency of values greater than zero was greater and its average value was reduced to 0.91.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
21
34
https://ceej.aut.ac.ir/article_4471_f08b551c68db6b8cd97e92d529033840.pdf
dx.doi.org/10.22060/ceej.2021.17413.6556
Experimental study of uplift of buried pipe liquefiable soil at different depths by shaking table
Sima
Bahram Ghannad
Department of Geotechnical Engineering, Faculty of Civil Engineering, University of Tabriz
author
Masoud
Hajialilue Bonab
Departement of Geotechnical Engineering, Faculty of civil engineering, University of Tabriz
author
Maral
Ghorbani Barazin
Department of Geotechnical Engineering, Faculty of Civil Engineering, University of Tabriz
author
text
article
2022
per
Many buried structures, including tunnels and lifelines, have been severely damaged in recent earthquakes. It is noteworthy that the phenomenon of soil liquefaction has played a significant role in the occurrence of these damages. Damage caused by the uplift of lifelines has motivated the study of the uplift of buried structures. Therefore, in this study, an attempt has been made to the experimental study of the uplift of buried pipes in liquefiable soils by physical modeling at different depths. The soil used in this study is Gum Tape sand and shaking table has been used to simulate seismic load. Also, due to the importance of the deformation mechanism in this process, the particle image velocimetry method has been used to find out how the soil around the pipe moves during liquefaction. Buried pipe at three depths: 1.5, 2.5 and 5 times the diameter of the pipe has been subjected to seismic load and the degree of elevation and deformation mechanism have been investigated. The results show that with decreasing the buried depth of the pipe, due to the relatively high pore water pressure in the lower depth of the soil, the overpressure created after dynamic loading tends to be wasted and flows towards the low-pressure points (surface part). And because in the surface areas, the flow is upward, so the uplift continues to some extent. Also, the displacement vectors on the sides of the pipe are in the form of circular rings that try to raise the pipe.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
35
52
https://ceej.aut.ac.ir/article_4497_90ea7bf546ba30bccf9750b00c47c933.pdf
dx.doi.org/10.22060/ceej.2021.17581.6609
Numerical Simulation of Sand Production Using Coupled DEM-LBM
siavosh
Hohari
Faculty of Engineering, Ferdowsi University of Mashhad
author
Ehsan
Seyedi Hosseininia
Civil Eng. Department, Faculty of engineering, Ferdowsi University of Mashhad
author
text
article
2022
per
Sand production imposes a considerable cost on the oil industry. In the current study, this phenomenon is studied numerically to better understand the particulate mechanism of sanding in unconsolidated sandstones and study the effect of confining stress and pressure drawdown on sand production. The discrete element method (DEM) is used to simulate the particulate media, and the lattice-Boltzmann method (LBM) is adopted to model the fluid flow through it. The two methods are coupled, and the fluid-solid interaction is modeled using the immersed moving boundary (IMB) method. An in-house computer program is developed based on these methods to simulate the 2D sanding procedure under radial fluid flow and isotropic stress in the absence of particle cementation. The results show that the number of produced particles and the sanding rate increase with the increase of confining stress. Also, after the sand initiation, the sanding rate in all models decreases due to the formation of sand arches around the model’s inner cavity. These arches are prone to instability, and new larger arches replace them after their collapse. After examining the effect of fluid pressure difference on sand production, it is concluded that the pressure difference has little influence on sand production at relatively low-stress levels. However, at higher stress levels, the pressure difference has a considerable impact on sanding results as it increases the number of produced particles more than twice with a 50% increase in pressure difference. This study confirms that the 2D coupled DEM-LBM model can properly capture the mechanism of the sand production phenomenon.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
53
74
https://ceej.aut.ac.ir/article_4417_9c701a641d8b9c281b5297fc09d0b657.pdf
dx.doi.org/10.22060/ceej.2021.18019.6739
Numerical study on the end rotation effect of elastomeric bearings on their mechanical behavior in flexible bridges
touraj
taghikhany
Associate Prof.
author
Vahid
Garoosi
MSc, Dept. of Civill Engg, Amirkabir University Tehran, Iran
author
text
article
2022
per
When elastomeric bearings support the deck of long-spans or tall pier bridges, they experience end rotation and it can change the seismic performance of the whole isolated system. So far, the behavior of these bearings has been numerically modeled under individual actions (compression, shear, or bending) or combined compression and shear load. However, the effect of end rotation on the response of elastomeric bearings and its numerical model in combination with different load actions have not been considered well. In the current study, we used a two-dimensional mechanical model of elastomeric bearings that simulate the effect of end rotation in the combined action of pressure, shear and end rotation. The test results indicate that bearing rotational stiffness increases with the increasing vertical load but decreases with increasing shear deformation. Further, end rotation does not affect the critical displacement appreciably, but it significantly influences the critical shear force.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
75
94
https://ceej.aut.ac.ir/article_4406_1cf73be8e1bf03966125f4ed16df24db.pdf
dx.doi.org/10.22060/ceej.2021.18061.6752
Comparison between the Interface Interaction of Sand and Clayey Sand with PET Geogrid in Pullout Test Based on Active Length
Ali
Mahigir
Civil Engineering Department, Imam Khomeini International University
author
Alireza
Ardakani
Department of civil engineering, Imam Khomeini International University, Qazvin, Iran.
author
Mahmood
Hassanlou Rad
Assistant Professor, Faculty of Technical and Engineering, Imam Khomeini International University, Qazvin, Iran
author
text
article
2022
per
Large pullout test is used to investigate the geogrid pullout behavior in the anchorage zone. When the pullout load is applied to the geogrid, this force is gradually transmitted along with the sample until it reaches the end of the geogrid. In order to more accurately investigate the soil-geogrid interaction mechanism, the pullout behavior of geogrid should be evaluated based on the active length. In this study, by performing a series of large-scale pullout tests, the distribution of shear stress and pullout interaction coefficient of a PET geogrid embedded in clean sand and 20% clayey sand were investigated based on active length. The results showed that the value of the pullout force to start the movement of the last geogrid transverse member increased with increasing vertical effective stress in both geogrid embedded in two soil. In all pullout tests, minimum active interaction coefficient was obtained at the conversion of transfer force stage to pullout stage.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
95
112
https://ceej.aut.ac.ir/article_4427_dec678ff65abaa2f1aee4eee74076874.pdf
dx.doi.org/10.22060/ceej.2021.18191.6800
Investigating the influencing factors on the frequency of speeding violations: A case study of citizens of Tehran
Ali
Movahed
Department of Civil and Environmental Engineering, Amirkabir University of
Technology, Tehran, Iran
author
Ali
Shafaat
Assistant Professor at Shahid Beheshti University, Faculty of Architecture and Urban Design, Tehran, Iran
author
Meeghat
Habibian
Assistant Professor, Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
author
text
article
2022
per
As the most frequent driving violation, speeding has been the cause of 21% of accidents in the first three months of 1398 in Tehran. Speeding behavior has roots in drivers’ attributes and attitudes toward driving, which has not been studied enough for drivers in Tehran. This study examined the association between speeding violation frequency and drivers' attributes, including socioeconomic characteristics and attitudes toward driving. A Zero-inflated negative binomial regression model developed using a cohort of 470 adult drivers. Results show that the hours of physical activity and exercise per week, some perceptions such as "other drivers move slowly" and "Traffic violations are an immoral act" affect the occurrence and the frequency of speeding. Besides, having delays in most trips that the person is driving, driving experience of less than five years, and having vehicle body insurance directly affect the frequency of speeding. Based on the results, it can be concluded that reviewing the rules can be helpful in reducing speeding violations, for instance, adding some penalties in body insurance contracts for the number of speeding violations. Also, education courses for raising public awareness toward violations can be practical, especially for drivers with more experience and speeding violations.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
113
124
https://ceej.aut.ac.ir/article_4415_5ebd3e6008363a30fe59835e7610f0ba.pdf
dx.doi.org/10.22060/ceej.2021.18279.6817
Undular Flow Conditions and Discharge Coefficients in Rectangular Broad-Crested Weirs
Bahram
Nourani
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
author
Farzin
Salmasi
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
author
Hadi
Arvanaghi
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
author
Faezeh
Rezaei
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
author
text
article
2022
per
Weirs are common hydraulic structures that can be used in conveyance water canals for increasing the water depth upstream of turnouts or measurement of flow discharge. In this study, the effect of hydraulic parameters and creation conditions of undular flow in the broad-crested weirs were investigated numerically using the finite volume method and the results were evaluated by the experimental method of other researchers. Results indicated that discharge coefficients (Cd) for experimental data are between 0.321-0.332, whereas the Cd for numerical simulation (using ANSYS FLUENT) is between 0.301-0.354. Over the crest where the minimum water depth (dmin) happens, when Fr1 is less than 1.5 (Fr1<1.5), the creation of waves was observed. This type of flow is known as the undular flow. In this situation, measuring water depth over the broad crested weir is not easy and can introduce error for discharge estimation. For preventing of the undular flow, the flow depth cannot be less than a specified value. In this study, this limitation was observed for H/L > 0.1. Thus it can result that long broad-crested weirs (H/L<0.1) are more susceptible than the broad-crested weirs (0.1≤H/L<0.4) in the creation of the undular flows. Additionally, a regression equation for estimation of the Cd in the broad-crested weirs is proposed with reasonable accuracy.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
125
140
https://ceej.aut.ac.ir/article_4512_9308ce79d389d4864f9eb1c427cb5512.pdf
dx.doi.org/10.22060/ceej.2021.18314.6830
Effect of Temperature and Number of Heating–Cooling Cycles on the Mode I, Mode II and the Mixed-Mode I-II Fracture Toughness of concrete
Shima
Latifi
Imam Khomeini International University
author
M.
Hosseini
گروه مهندسی معدن، دانشگاه بین المللی امام خمینی (ره)، قزوین، ایران
author
Mahdi
Mahdikhani
Imam Khomeini international university
author
text
article
2022
per
In this research, the effects of temperature and number of heating-cooling cycles on mode I, mode II and the effective value of the mixed-mode I-II fracture toughness of concrete were investigated through two series of tests. In the first series of tests, the effect of temperature was studied in a heating-cooling cycle at ambient temperature (25 °C) and 60, 150, 200, 300, 500, and 700 °C. The highest and lowest mode I, mode II and the effective value of the mixed-mode I-II fracture toughness were, respectively, observed at 150 and 700°C. In the second series of tests, the effect of the number of heating-cooling cycles was investigated on mode I, mode II and the effective value of the mixed-mode I-II fracture toughness of concrete specimens at 150°C and a crack inclination angle of 45°. According to the results, mode I, mode II and the effective value of the mixed-mode I-II fracture toughness increased in the first cycle and decreased with increasing the number of heating-cooling cycles. As the crack inclination increased, the effective value of the mixed-mode I-II fracture toughness of the concrete specimens increased. The mode II fracture toughness increased up to a crack inclination angle of 45° and then decreased. Moreover, with increasing the crack inclination angle, the mode I fracture at the inclination angle of 0° was changed into the mixed-mode (tension–shear) fracture at inclination angles smaller than 28.8°. The mixed-mode tension–shear fracture was changed into the mixed-mode compressive–shear fracture at crack inclination angles larger than 28.8°.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
141
164
https://ceej.aut.ac.ir/article_4413_bd5b365cc177ceb7596a1ef38434bcc1.pdf
dx.doi.org/10.22060/ceej.2021.18363.6850
Experimental and Numerical Study on the Seismic Performance of MSE/Soil Nail Hybrid Walls
Nabiallah
Ahmadi
Department of Civil Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran.
author
Majid
Yazdandoust
Department of Civil Engineering, Tafresh University, Tafresh, Iran.
author
text
article
2022
per
In this study, a series of 1-g shaking table tests using variable-amplitude harmonic excitations were performed on 0.8 m high MSE/Soil nail hybrid wall models to investigate the seismic behavior of this innovative retaining system. Ten finite element models were also prepared with different wall heights and nail lengths to carry out a parametric study. Findings showed that in models with constant length of steel strip, the deformation mode of MSE/Soil nail hybrid walls highly depends on the length of nails and the combination of a base sliding and overturning deformation mode was observed as the predominant mode of deformation. Irrespective of different nail lengths, the pattern of the observed failure mechanisms included a moving block and a combination of a reverse curve and flat failure surface with certain intersection point. Also, a range of ∆x/H = 0.55 - 1.10 % as a transitional level from quasi-elastic to plastic state and based on starting the development of active wedge failure, a range of ∆x/H = 5.0% - 5.6 % as a transitional level from plastic to failure state were determined. On the other hand, according to the significant increase in wall displacements by decreasing the L/H ratio of 0.7, L/H= 0.7 was presented as the critical ratio in seismic conditions.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
165
190
https://ceej.aut.ac.ir/article_4420_d5b8560041572923609a3910134459f2.pdf
dx.doi.org/10.22060/ceej.2021.18379.6862
Vibration control of stiffness irregular structures under near and far-field earthquakes by MR dampers and fuzzy controllers
mohammadreza
zamanian
Department of Civil Engineering, Semnan Branch, Islamic Azad University, Semnan, Iran.
author
ali
kheyroddin
Faculty of Civil Engineering, Semnan University, Semnan, Iran.
author
alireza
mortezaei
Seismic Geotechnical and High Performance Concrete Research Centre, Department of Civil Engineering, Semnan Branch, Islamic Azad University, Semnan, Iran.
author
text
article
2022
per
With the increase in the population of cities and the lack of spaces for construction, the creation of diverse uses, architecture and beauty of structures, the need for irregular structures is increasing. One way to reduce the construction hazards is to use vibration control tools in them. In the present study, the performance of a magnetic damper with a fuzzy controller to reduce the vibrations of an irregular hard structure under near and near earthquakes has been investigated. In the present study, the performance of a magnetic damper with the fuzzy controller to reduce the vibrations of an irregular stiffness structure under near and far field earthquakes has been investigated. The capacity of the introduced magnetic damper is equal to 1000kN, which is installed in the first floor between the floor level and the ceiling level of the first floor. The fuzzy system is designed based on the relative speed of the two ends of the damper to determine the relative speed of the amount of voltage and, consequently the control force that enters the structure. Three different types of irregularities in height, including hardness irregularities with a coefficient of 60%, are used in a 10-story structure and are modeled in the OpenSees software. These irregularities have been investigated in three different elevation locations including the lower half of the structure height (floors 1 to 5), the lowest floor (1st floor) and the middle floor of the structure (5th floor). Based on the numerical analyzes performed for these structures under the excitation of near and far field earthquakes, the residual displacement is reduced by an average of 23.15% and 45.64%, respectively. In addition to the improvement of criteria such as maximum displacement, base shear and moment in both types of earthquakes, the most improvement occurred in the irregular structure of the first floor and the least for the middle floor. In addition to improving criteria such as maximum displacement, base shear, and moment in both types of earthquakes, the most improvement occurred for the irregular structure on the first floor and the least for the irregular structure in the middle floor.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
191
208
https://ceej.aut.ac.ir/article_4480_0ae6014bc5ef869a364f744d88adc9e4.pdf
dx.doi.org/10.22060/ceej.2021.18497.6880
Evaluation of the dual additive effect of rubber powder and PET numerically and laboratory in Hot asphalt mixture
amirhossain
ameri
graduated from civil engineering department , Iran university of science and technology
author
M.
Ameri
دانشکده عمران، دانشگاه علم و صنعت ایران، تهران، ایران
author
Hamid
Shaker
Department of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
author
Faezeh
jafari
Department of Civil Engineering, Malayer University, Malayer, Iran
author
Baitollah
Badarloo
Assistant professor in structural Eng., Department of Civil Engineering, Qom University of Technology (QUT), Qom, Iran
author
text
article
2022
per
Utilizing Polyethylene Terephthalate (PET) and Crumb Rubber (CR) together in asphalt mixtures may result in the omission of these two materials from the environment and the formation of more resilient asphalt, enjoying the simultaneous softening quality of crumb rubber (CR) and hardening quality of polyethylene terephthalate (PET). Therefore, the two additives were combined in (0 and 100) %, (25 and 75) %, (50 and 50) %, (75 and 25) %, and (100 and 0) %, and the mixture was formed. Two additives were added to the mixture in 10% and 15% by weight of bitumen. Resilient Modulus Testing, Dynamic Creep Test, Moisture Sensitivity, and ITS Method were used to assess the modified mixture. Results revealed that the recommended material had the desired characteristics so that the use of every 15% Dual-use Additives of Crumb Rubber (CR) and Polyethylene Terephthalate (PET) to bitumen used leads to a 1.5% increase in Resilient Modulus and Dynamic Creep. Moreover, Indirect Tension in the dry state will be 1.14 times of the control sample (Crumb Rubber (CR): 25% and Polyethylene Terephthalate (PET): 75%). For the Moisture sensitivity test, the sample including 10 % of Crumb Rubber (CR) alone can cause an increase in the moisture sensitivity by 11%. Finally, the neural network method is used to estimate the lab results and evaluate the model's accuracy.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
209
228
https://ceej.aut.ac.ir/article_4394_df2925a105e7da02b24411bcab61b6d2.pdf
dx.doi.org/10.22060/ceej.2021.18530.6887
A new method for determining natural modes and their frequencies with the concept of node in vibrations of M-DOFs
Aliasghar
Safavi
Lecturer at Engineering Department of Golestan University
author
text
article
2022
per
This paper evaluates the vibration of M-DOF systems by calculating the natural frequencies and mode shapes. The introduced method is established on the base of the node concept, which is the point of a mode shape with zero displacement. In this method, a system with two or more degrees of freedom is transformed into two or more isolated systems with one- DOF. Those systems are isolated in node places and vibrate with the same frequencies in every mode. Each spring located between two adjacent lumped masses will be converted to series combination of two separated springs. The stiffness of the first spring is equal to the effective stiffness of the two series separated springs. The proposed method provides a good physical understanding about the concept of vibration modes. Besides, this method is accurate and sometimes is simpler and quicker than the common method.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
229
246
https://ceej.aut.ac.ir/article_4360_1734f908a188773e757949573af468dc.pdf
dx.doi.org/10.22060/ceej.2021.18638.6913
Simulation of soil stress in earth dams using artificial intelligence models and determination of effective features
Arvand
Hakimi Khansar
PhD candidate, Department of Science and Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
author
Javad
Parsa
Tabriz University
author
Ali
Hoseinzadeh dalir
29th Boulevard
University Sq
author
Jalal
Shiri
Associate Professor, Water Engineering Department, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
author
text
article
2022
per
The general purpose of this paper is to select effective features and model soil stress in earth dams during construction. Five features, including fill level, duration of construction, reservoir level (impoundment), impounding rate and fill rate, were selected as hybrid model inputs. By performing hybrid algorithm and sensitivity analysis and feature selection method, fill level and duration of construction were recognized as the most effective features in modeling the total stress in selected cells, because concurrent mean square error values for the fill level and duration of construction in TPC25.1, TPC25.3 and TPC25.4 cells were 1.523, 2.747 and 0.750, respectively. In TPC25.2 cell, three features including fill level, duration of construction and impoundment level, had the greatest effect in modeling the total soil stress based on the mean square error value of 5.245. Comparison of the results of the ANN model with ANFIS and GEP showed that although the difference in the accuracy of the models is very small, all three models had acceptable results in the test step, the ANFIS model results indicated that the statistical error measures of , RMSE, MAE and NS in TPC25.4 cell were 0.9955, 0.0227, 0.0185 and 0.9666, respectively. It showed that how much the input data are more scattered, the ANFIS model had more capability than ANN and GEP models to simulate the soil stress in the studied earth dam.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
247
262
https://ceej.aut.ac.ir/article_4354_a6f4e026c305f9ffd6eeb1ddb6bc21cc.pdf
dx.doi.org/10.22060/ceej.2021.18682.6925
Introducing a Novel Diagram-Based Method for Shear Design of Steel Plates at High Temperatures
Abbas
Ghadami
Assistant Professor, Dept. of Civil Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran
author
Ghazaleh
Pourmoosavi
Post Doc. Researcher, School of Civil Engineering, University of Tabriz, Tabriz, Iran
author
Ali
Ghamari
Post Doc. Researcher, Dept. of Civil Engineering, Sharif University of Technology, Tehran, Iran
author
text
article
2022
per
It seems necessary to develop a simplified design approach in order to evaluate the shear strength of web panels under fire condition as the size of furnaces is limited, the cost of experiments aimed at testing the fire resistance of structures is quite high and access to simulation software packages such as ANSYS and ABAQUS is not always guaranteed. In this paper, web panel shear design relationships of AISC360-16 and AASHTO-14 specifications are exploited to be used in fire conditions. To this end, the stress-strain reduction factors provided in EN 1993-1-2 are directly applied. Afterward, the design curves are proposed for the prediction of the ultimate shear strength and limiting temperature of steel plate girders under fire by taking into account the strength degradation caused by high temperatures and the effects due to sectional instability. According to the results, the proposed curves are more accurate in compact plates with plastic shear buckling at both ambient and high temperatures. However, by increasing the web slenderness, the difference is increased. At ambient temperatures, the maximum difference for compact, non-compact, and slender web plates is about 1.1%, 23%, and 28%, respectively. The difference at 400ºC reaches almost 3% and 7% for non-compact and slender web panels, respectively. In addition, at 600ºC, especially for slender plates, proposed curves yield values that are nonconservative for ultimate shear strength, such that the difference is about 11%. Also, the maximum difference for existing experimental and numerical studies is about 20% and 4%, respectively.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
263
282
https://ceej.aut.ac.ir/article_4355_f518922f47d064a967dc56975b58e532.pdf
dx.doi.org/10.22060/ceej.2021.18741.6945
Determination of Groundwater Quality Using a GIS-AHP Based System and Compared with Wilcox Diagram (Case Study: Rafsanjan Plain)
Somayeh
Salehi
Ph.D Student of Hydraulic Structure, Department of Civil Engineering, Shahid Bahonar University of Kerman, Iran
author
Ali
Esmaeily
Assistant Professor, Department of Surveying Engineering, Faculty of civil and surveying Engineering, Graduate University of Advanced Technology, Kerman
author
Hadi
Farhadi
Ph.D. Student in Remote Sensing, Faculty of Geodesy and Geomatics Engineering, K.N Toosi University of Technology, Tehran, Iran
author
text
article
2022
per
Determining the quality of groundwater is one of the key elements of water usage in drinking, agriculture and industry sectors. Rafsanjan plain is one of the most economical plains in the country due to the existence of pistachio orchards. Therefore, proper management and careful study of groundwater in this plain is an essential need. The present study was conducted to evaluate the groundwater quality of the Rafsanjan plain with agricultural applications. In the first stage, after selecting the effective parameters for water quality assessment, weighting was performed by Analytic Hierarchy Process (AHP) method and then the groundwater quality of the study area was determined using GIS software and bases on water quality standard provided by the University of California. According to the results of the final zoning of groundwater quality, about 1.6% of the study area has very good quality, 20% has medium quality, 52.7 has poor quality and 25.7 has very poor quality. In addition, based on the statistical analysis of the Wilcox diagram, 1.5%, 16.2%, and 60.2% of the wells in the study area had good, medium and poor quality, respectively. Moreover, 22.1% of the wells are not included in the diagram due to very poor quality. This research revealed that a GIS-AHP-based method could analyze these kinds of data spatially and consistent results could be obtained.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
283
298
https://ceej.aut.ac.ir/article_4486_159175700c7855c6e878b99869fbfa76.pdf
dx.doi.org/10.22060/ceej.2021.18764.6954
Investigation of seismic behavior of drilled flange connection with inclined arrangement of holes
Peyman
Shadman
Civil engineering department,Islamic azad university, science and research branch, Tehran, Iran
author
Armin
Aziminejad
Civil engineering department,Islamic azad university, science and research branch, Tehran, Iran
author
abdolreza
sarvghad moghadam
IIEES,Tehran,Iran
author
Mohammad Ali
Jafari
Faculty of Niroo Research Institute (NRI)
author
text
article
2022
per
Since unreinforced welded connections were brittle and prematurely fractured in the connections of the beam-to-column penetration welds in the 1994 Northridge earthquake, the researchers proposed radius-cut flange reduction connections to improve the seismic behavior of rigid connections. The brittle failure of the weld in the beam-to-column connection and the lateral buckling of the beam flange in the reduced sections of the beam flange led to propose the modified forms of this type of connection. The new type of connection includes drilled flange connection with parallel rows of holes. In order to improve the performance of these drilled flange connections, in this study, beam flange drilling arrangements were used with an inclined arrangement of holes with different hole diameters. The study showed that in the inclined arrangement of a hole, the amount of plastic rotation is 0.059 radians, which is 7.3% more than the plastic rotation of the same radius-cut flange reduction connection. Also, in the best connection sample with the most suitable oblique drilling arrangement, the equivalent plastic strain index in the center and corner of the complete joint penetration weld line decreased to 92.3% and 87.7%, respectively, compared to conventional radius-cut flange reduction connections. Mises index in this connection in the center and corner of the complete joint penetration weld line decreased to 45.5% and 39.9% compared to radius-cut flange reduction connections, respectively. This indicates better performance and less sensitivity of this type of connection to the problems of the complete joint penetration weld line of the beam-to-column connection compared with conventional radius-cut flange reduction connections and these drilled flange connections with the parallel arrangement.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
299
322
https://ceej.aut.ac.ir/article_4470_f4835a052a772d7ddc6f4d2bec37bcfa.pdf
dx.doi.org/10.22060/ceej.2021.18755.6955
The Graph Decision Model for Risk Allocation in Design-Build Contracts; Game Theory approach
garshasb
khazaeni
Assistant Professor, Islamic Azad University West Tehran branch
author
Ali
khazaeni
Islamic Azad University, South Tehran
author
text
article
2022
per
Risk allocation, the definition and division of responsibility associated with a possible future loss or gain, seeks to assign responsibility for a variety of hypothetical circumstances should a project not proceed as planned. The result of improper risk allocation is increased costs, project delays and services, which cause loss of value-for-money for the public interest. This paper introduced a decision support system based on the graph model for systematically resolving construction risk allocation. In this model mainly assumed success of a contract needs to agreement on how risks are allocated by parties. The graph analysis process considers the decision-makers, their decision options, and their relative preferences when modeling risk allocation negotiation as a game theory problem. Owners could also use the model to perform an in-depth stability analysis in order to ascertain the possible compromise resolutions or equilibrium. The model predicts the sequence of decisions that took place in the dispute and furnishes an array of useful strategic insights about the risk allocation renegotiation. Moreover, the model to determine how changes in preferences can affect the equilibrium results executes a sensitivity analysis. This risk allocation procedure is useful for both researchers and practitioners to better deal with the dispute-prone nature of construction contracts.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
323
342
https://ceej.aut.ac.ir/article_4508_c24ef7ab17b6d7c2b34d9370498d026c.pdf
dx.doi.org/10.22060/ceej.2021.18789.6963
The effect of mineralogy and grain size of fine aggregate and different macro textures on the durability of the RCCP surface under abrasion conditions
mostafa
adresi
Assistant Professor, Department of Geotechnical and Water Engineering, Faculty of Civil Engineering, Shahid Rajaee Teacher Training University
author
text
article
2022
per
The roller-compacted concrete pavement (RCCP) surface is almost smooth and without texture due to the vibrating rollers in the construction process. The lack of texturing causes a decrease in skid resistance in RCCP. For this purpose, different scenarios were proposed to create surface texture at micro and macro levels and provide the necessary friction. To provide friction at micro-scale, siliceous and calcareous sand and a combination of 50-50 of them with broken and natural aggregate shape was used in the construction of 8 RCCP mixing designs. In addition, in order to provide macro-texture, each of the eight mixing designs was textured by methods such as seeding (three cases), stamping (two cases), and brooming (two cases). The purpose of this paper is to investigate the durability of various micro and macro textures created on RCCP surfaces by the simulation method proposed in the ASTM C 944 standard. The results showed that different textures have almost the same abrasion resistance. Among these, the seeding texture with a grain size of 4.75-9.5 mm has the weakest, and the stamp texture of 4 x 4 cm has the most durable abrasion resistance. Changes in abrasion resistance were associated with more changes in the mixing design. This means that crushed silica sand had the highest and natural lime sand had the lowest abrasion resistance. The results demonstrated that the combination of calcareous and siliceous materials improves abrasion resistance. In this regard, the higher the fracture rates of combined sand, the better the abrasion resistance.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
343
362
https://ceej.aut.ac.ir/article_4374_d2e9a5452b318e433fc39a059c7bee50.pdf
dx.doi.org/10.22060/ceej.2021.18816.6967
The Study of Characteristics of High-Performance Cement Base Material Reinforced with Dramix Steel Fiber
Seyyed Amir Hossein
Madani
Department of Civil Engineering, Arak Branch, Islamic Azad University, Arak, Iran
author
S.Mohammad
Mirhosseini
Department of, civil Engineering Arak Branch, Islamic Azad University, Arak, Iran.
author
Ehsanollah
Zeighamie
Department of Civil Engineering, Arak Branch, Islamic Azad University, Arak, Iran
author
Alireza
Nezamabadi
Assistant Prof, Department of Mechanical engineering, Arak Branch, Islamic Azad University, Arak, Iran.
author
text
article
2022
per
Concrete can resist high tension stress. The low tensile strength and high fragility have made it unconsidered in designing Code. Using steel fiber in the concrete matrix decreases the fragility and brittleness of the material. Improvement of mechanical characteristics will cause the steel fiber reinforced with concrete matrix to be an efficient material for construction. In this paper, the mechanical properties of cement-based composites reinforced with various percentages of fiber (1 wt% and 2 wt%) have been studied. The matrix of cement-based, with DRAMIX fiber, in three types of 3D, 4D, and 5D, had compressive strength up to 64 MPa. In this study, to evaluate flexural strength, 4-point bending test was done on the reinforced flexural elements with various percentages of steel fiber. Flexural properties, including load-displacement graph, crack line, energy absorption, and bending tension stress have been evaluated and compared. The results show that in some specimens, strain-hardening behavior until before concentrating of cracks and failure and after strain-softening happens. Strain-hardening behavior improves the mechanical properties of the materials. In this case, failure occurred at various critical matrix cracks.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
54
v.
1
no.
2022
363
376
https://ceej.aut.ac.ir/article_4551_b20967ce59c7784378a3ae63d31816b0.pdf
dx.doi.org/10.22060/ceej.2021.18287.6970