Numerical Simulation of Effect of Drain Pipe in Uplift Force, Exit Hydraulic Gradient and Seepage in Gravity Dams
Farzin
Salmasi
Tabriz University, Agricultural faculty, Irrigation department
author
Hadi
Arvanaghi
Water Engineering Department, Faculty of Agriculture, University of Tabriz, Tabriz, Iran
author
Ali
Taheri aghdam
Water and Science Enginreering, tabriz,tabriz,iran
author
text
article
2021
per
In this study, the effects of diameter and location of drain pipes in uplift force, exit hydraulic gradient and seepage in the foundation of gravity dams are investigated. For this purpose, the SEEP/W software as a subgroup of Geo-Studio software is implemented and the foundation of a gravity dam is simulated. The results showed that the existence of drain pipes under the gravity dam reduce 4, 6, and 9 times of uplift force, exit hydraulic gradient and seepage, respectively. Installation of two drain pipes with 0.25L distance from each other and in the depth of 0.26D near the dam heel presents a more suitable position with respect to uplift force reduction (D is the pervious foundation depth). Also, by defining the best position for the location of drain pipes, it was observed that drainage pipes in these situations reduce 41-67% in the volume of the studied dam and increase the safety factor up to 2 to 3 times against the dam overturning. It is also found that the drainage pipe diameter has less effect on the uplift force, exit hydraulic gradient and seepage and is controlled by the rules of the executive. For validation, the numerical method used in this study was compared with the laboratory method by others and a suitable match was observed.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2209
2230
https://ceej.aut.ac.ir/article_3704_b2d39157833dffd03e7b360a63e601a0.pdf
dx.doi.org/10.22060/ceej.2019.17183.6489
Numerical Simulation of Three-Dimensional Flow of Sudden Dam-Break over the Porous Bed
Akbar
Safarzadeh
Department of Civil engineering,Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
author
Peyman
Mohsen zadeh
M.Sc., Graduated of Civil-Hydraulic Structures Eng., Faculty of Eng., Univ. of Mohaghegh Ardabili, Ardabil, Iran
author
salim
abbasi
M.Sc., Graduated of Civil-Hydraulic Structures Eng., Faculty of Eng., Univ. of Mohaghegh Ardabili, Ardabil, Iran
author
text
article
2021
per
Dam break is a very important problem due to its effects on the economy, security, human casualties and environmental consequences. In this study, 3D flow due to dam break over the porous substrate is numerically simulated and the effect of porosity, permeability and thickness of the porous bed and the water depth in the porous substrate are investigated. Classic models of dam break over a rigid bed and water infiltration through porous media were studied and results of the numerical simulations are compared with existing laboratory data. Validation of the results is performed by comparing the water surface profiles and wave front position with dam break on the rigid and porous bed. Results showed that, due to the effect of dynamic wave in the initial stage of dam break, a local peak occurs in the flood hydrograph. The presence of porous bed reduces the acceleration of the flood wave relative to the flow over the solid bed and it decreases with the increase of the permeability of the bed. By increasing the permeability of the bed, the slope of the ascending limb of the flood hydrograph and the peak discharge drops. Furthermore, if the depth and permeability of the bed are such that the intrusive flow reaches the rigid substrate under the porous bed, saturation of the porous bed, results in a sharp increase in the slope of the flood hydrograph. The maximum values of the peak discharge at the end of the channel with porous bed occurred in saturated porous bed conditions.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2231
2248
https://ceej.aut.ac.ir/article_4012_a1a7219290806734bf17c68b1c6d2572.pdf
dx.doi.org/10.22060/ceej.2020.17329.6530
Estimating Structural Collapse Responses Considering Modeling Uncertainties using Artificial Neural Networks and Response Surface Method
Mohammad Amin
Bayari
Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
author
Esmaeel
Izadi Zaman Abadi
Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
author
Naser
Shabakhty
School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
author
text
article
2021
per
This research investigates the collapse responses of a concrete moment frame considering modeling uncertainties. These modeling uncertainties are considered for evaluating a collapse response related to the modified Ibarra-Krawinkler moment-rotation parameters for beam and column elements of a given structure. To analyze these uncertainties, the correlations between the model parameters in one component and between two structural components were considered. Latin Hypercube Sampling (LHS) method was employed to produce independent random variables. Moreover, Cholesky decomposition was adopted to produce correlated random variables. Performing 281 simulations for the uncertainties involved considering their inter-correlations, incremental dynamic analysis (IDA) was done using 44 far-field accelerograms to determine structural collapse responses. Collapse responses of each simulation, including mean collapse capacity, mean collapse drift and mean annual frequency, were obtained. Then, the collapse responses were predicted using the response surface method and artificial neural network. The results show that the Correlation coefficients (R) between the target data resulted from incremental dynamic analysis (IDA), output data resulted from response surface method (RSM), and artificial neural network (ANN) were obtained for the collapse responses above 0.98. The maximum prediction errors for mean collapse capacity and mean collapse drift are less than 5% and for mean annual frequency less than 10% under the response surface method (RSM) and artificial neural network (ANN).
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2249
2276
https://ceej.aut.ac.ir/article_3795_f87c87b33a2dcd4feff390128fe2b6fc.pdf
dx.doi.org/10.22060/ceej.2020.17312.6539
Effect of seawater in grout on the mechanical behavior of cement stabilized marine sand
mojgan
geravand
Department of civil engineering, university of Qom
author
hamed
bayesteh
Department of civil engineering, university of Qom
author
mahdi
sharifi
Department of civil engineering, university of Qom
author
text
article
2021
per
One of the challenges in the field of geotechnical engineering is the sustainable development of soil improvement methods in marine environments due to severe environmental conditions such as high salinity. Implementation of soil-cement columns using deep mixing method and jet-grouting methods is an effective way to deal with problems caused by low resistance of coastal problematic soils. What is common in the implementation of these columns in the engineering community is the need to use fresh water to make the grout used in these columns. This, both from the point of view of its supply and transportation costs and from the lack of fresh water in many areas, imposes high costs on projects and time delays. However, prior to the final cement retention, the saline water present in the environments of the columns was mixed with the fresh water in the grout as they were built deep in the soil. Investigating the feasibility of using seawater in mixing these columns and evaluating the behavior of soil-cement samples in marine conditions has received little attention. In this study, it has been attempted to investigate the effective factors in the grout mixing scheme, including water salinity, cement percentage, water-cement ratio and processing time on uniaxial compressive strength and sand-cement tensile strength. SEM images were also microstructurally evaluated for sample behavior. The results show that in the 15% to 25% cement content, the use of seawater in grout production does not decrease the strength of sand-cement samples in the marine environment. The obtained compressive strength range for sand-cement samples made with seawater is approximately (1.5 to 6) MPa and the tensile to compressive strength ratio of these samples is in the range (0.15 to 0.3).
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2277
2296
https://ceej.aut.ac.ir/article_3895_0af0170e29b52243103cc15217f36ba4.pdf
dx.doi.org/10.22060/ceej.2020.17372.6540
Damage Detection of Single Tapered Poles Using APSO Algorithm
Hamed
Ghohani Arab
Civil Engineering Department, University of Sistan and Baluchestan, Zahedan, Iran
author
Ali
Mahallati Rayeni
Civil Engineering department, University of Sistan and Baluchestan, Zahedan, Iran
author
Arash
Naderi
Civil Engineering department, University of Sistan and Baluchestan, Zahedan, Iran
author
Mohammad Reza
Sohrabi
Civil Engineering department, University of Sistan and Baluchestan, Zahedan, Iran
author
Mohammad Reza
Ghasemi
Civil Engineering department, University of Sistan and Baluchestan, Zahedan, Iran
author
text
article
2021
per
In this paper, the damage detection of single tapered poles is studied. Structural damage is identified using an optimization-based method. In this method, the APSO is used to detect the location and severity of the damage. The objective function for detecting the damage is a correlation coefficient based on natural frequencies. In order to accelerate the calculation of the natural frequencies of the structure, the iterative method is used. In this paper, the damage induced into the structure is simulated as reduction of the stiffness matrix of the element in a finite element modeling of the structure and also in order to match the real situation, damages. To evaluate the efficiency and robustness of the proposed method in detecting damage of tapered poles, two numerical examples, including a police surveillance camera pole and a water storage pole under different damaged scenarios with considering measurement noise, are examined. In the first and second examples, structures are divided by 15 and 25 elements, respectively, with the uniform moment of inertia. The results show that the proposed method is capable of detecting both the location and severity of the damage properly, despite the complexity of some damage scenarios. Therefore, the algorithm can be used to detect the damage of other structures.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2297
2314
https://ceej.aut.ac.ir/article_3903_efb316e0b4cd775e323887333fa53306.pdf
dx.doi.org/10.22060/ceej.2020.17377.6542
Evaluation of the Correlation Between Performance Parameters of Asphalt Binder and Mixture in the RAP-Containing Asphalt Mixtures
Daryoosh
Daryaee
School of civil engineering, Malayer university, Malayer, Iran
author
Mahmood
Ameri
School of Civil Engineering, Iran University of Science and Technology (IUST).
author
text
article
2021
per
In asphalt pavement hot recycling, reclaimed asphalt pavements called "RAP" and aged bitumen extracted from them are known as reclaimed asphalt binder (RAB). In this study, the performance of RAB-containing binder compounds with different percentages of recycled bitumen (0, 25%and 50%) and RAP-containing asphalt mixtures with varying contents of the RAP (0, 25% and 50%) were compared in two conditions (with and without a rejuvenating agent). The main purpose of this study was to evaluate the relationship between bitumen’s performance parameters and asphalt mixture’s performance parameters. Therefore, the correlation between the parameters obtained from the fatigue and the rutting tests of binder compounds (linear amplitude sweep test and multiple stress creep and recovery test, respectively) and parameters obtained from the fatigue and rutting tests of asphalt mixtures (four-point beam fatigue test and dynamic creep test, respectively) were investigated for the first time in RAP-containing asphalt mixtures. The results indicated that the behavior of asphalt mixtures in fatigue and rutting resistance was agreed with the behavior of the binder compounds in the linear amplitude sweep and multiple stress creep and recovery tests. Besides, there were statistically good correlations between the binder's fatigue life and asphalt mixtures' fatigue life and relatively good statistical correlations between binder's rutting resistance and asphalt mixtures' rutting resistance in the RAP-containing asphalt mixtures.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2315
2334
https://ceej.aut.ac.ir/article_3884_b36ac8f4a041272db592c23688d4c140.pdf
dx.doi.org/10.22060/ceej.2020.17386.6546
Comparative Comparison of Contractors' Evaluation Criteria, Sub-Criteria and Indicators in Water Industry Tender Using Questionnaire and Text Mining
Majid
Parchami Jalal
دانشگاه تهران، دانشکده معماری
author
hadi
shakiba zahed
PhD student, Architecture Department, the University of Tehran, Tehran, Iran
author
Mohammad Amin
Ghaaderi
project management and construction department, architecture faculty, university of tehran, tehran, iran
author
text
article
2021
per
The efficiency of contractors selection in infrastructure projects is always one of the main concerns of employers. The purpose of this study is to propose a new method for the specification of evaluation criteria, according to the type of project under assignment and prioritization, and to determine the proposed score of the evaluation criteria of the contractors using two different methods. The first involves statistical analysis of the questionnaires, and the second involves the text mining of the interviews. For this purpose, after library studies, fieldwork, and questionnaire design, questionnaires were given to experts in the industry, and their statistical analysis identified important criteria and sub-criteria and then interviewed another group of experts. Using the text mining and clustering of interview texts, the criteria and indices of contractors' evaluation were identified, and the results of these two methods were compared with the bidding law implementing regulations in Iran. SPSS software was used to analyze the interviews, and the K-means algorithm was used for interviews text mining. The findings of the study indicate that the results of the text mining and questionnaire are in agreement, and It can be concluded that the identified criteria have acceptable accuracy and generalization capability, and organizations can use these criteria and evaluation indicators to select the most suitable contractor in the tenders. Identified Criteria, in addition to covering all the criteria introduced in the Bidding Law Implementing Regulations, also include two new criteria, namely Claim Management and Safety Management & Quality Control.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2335
2352
https://ceej.aut.ac.ir/article_3848_1d985255db5241c9f119452c32040c52.pdf
dx.doi.org/10.22060/ceej.2020.17388.6547
Synthesis of Fe3O4@SiO2@CS magnetic bio-nanocomposite by silica extracted from wheat straw for removal of Basic Red 46 dye from aqueous solutions
Elham
najafi
shahid beheshti university
author
afsaneh
shahbazi
Prof., Environmental Sciences Research Institute, Shahid Beheshti University, G.C., Tehran, Iran
author
soran
kamari
Shahid Behesti university
author
text
article
2021
per
In the present study, amorphous silica was successfully extracted from wheat straw by acid leaching technique using various acids including HCl, HNO3, H2SO4 and H3PO4 and was used in the synthesis of Fe3O4@SiO2 nanocomposite. Then, the synthesized nanocomposite were functionalized by chitosan functional group (CS) to obtain Fe3O4@SiO2@CS bionanocomposite. The percentages of the constituents, the crystallization state, the identification of the functional groups and the surface morphology of the produced materials were investigated using XRF, XRD, FT–IR, VSM, BET, SEM and zeta potential analyzes. Finally, the synthesized Fe3O4@SiO2@CS bionanocomposite was used for removal of Basic Red 46 dye from aqueous solutions as an efficient and effective adsorbent. The results showed that pure and active silica with purity of 96.52% was extracted from wheat straw using acid leaching with HNO3 acid. Also, the results of VSM analysis showed the superparamagnetic properties of Fe3O4@SiO2@CS bionanocomposite with magnetic properties of 17.55 emu g–1.In addition, the results of dye removal showed that the Basic Red 46 dye removal efficiency using synthesized Fe3O4@SiO2@CS bionanocomposite was 97% and adsorption capacity of it was 1700 mg g–1, which is much higher and desirable than many other adsorbents.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2353
2370
https://ceej.aut.ac.ir/article_3855_be0eca72fb4a2cfa6c2e9466e96373f0.pdf
dx.doi.org/10.22060/ceej.2020.17391.6548
Evaluation of the seismic sensitivity of steel frame with converging bracing to random variables
majid
moradi
babol university
author
Hamidreza
Tavakoli
Civil Engineering, Babol Noshirvani University of Technology
author
text
article
2021
per
Structural response to seismic load is one of the tasks of structural and earthquake engineers. Many factors affect the response of structures to seismic load. Seismic load, structural system, geometric characteristics and materials are examples that affect the response of structures to seismic load. The effect of each of these cases can be determined by sensitivity analysis. The purpose of this study was to evaluate the sensitivity of steel frame with converging braid compared to random variables under a seismic load. 10-story frame types with the convergent bracing system (four types) are analyzed after design and modeling using Monte Carlo and FOSM methods. Then the sensitivity of their response to random variables is evaluated. In this study, two-dimensional frames for sensitivity analysis were used. Also, the sensitivity analysis of the FOSM method is compared to the Monte Carlo analysis. The steel yield stress, the steel elastic modulus, the dead load, the live load, the damping coefficient and the length of the span are considered as random variables and their impact on the period of the structures, the maximum displacement of the roof and the maximum base shear have been investigated. The results show that the effect of random variables on the maximum Roof displacement is higher. The maximum sensitivity of the base shear to the random variables in the X convergent brace is more than the other structural systems, and the FOSM method has the least error in estimating the periodicity of the structures with the lowest error compared to the maximum roof displacement and the maximum base shear. The general results of the analysis show that steel yield stress, dead load, and damping ratio have the most effect on the response of steel bracing frames, so they should be carefully considered in structural calculations. This sensitivity is lower in live load, span length, and elasticity modulus of steel.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2371
2388
https://ceej.aut.ac.ir/article_3905_1580173b8664acc555eb8f842100f37c.pdf
dx.doi.org/10.22060/ceej.2020.17402.6550
Optimal Design and Performance Assessment of Viscous Dampers in Steel Frames Based on Life Cycle Cost
Narjes
Ahadzadeh kolour
Faculty of Civil Engineering, Sahand University of Technology, Tabriz, Iran
author
Mohammad
Charkhtab Basim
Faculty of Civil Engineering, Sahand University of Technology, Tabriz, Iran
author
MohammadReza
Chenaghlou
Faculty of Civil Engineering, Sahand University of Technology, Tabriz, Iran
author
text
article
2021
per
In recent years, it is tried to express the expected performance of structures as financial and social measures. In this study, an algorithm for the optimal design of viscous dampers with the goal of achieving minimum total cost is presented. For this purpose, an appropriate cost model to determine the initial cost of equipping structures with viscous dampers has been presented and the expected costs of the structure due to possible earthquakes over its life cycle have been estimated using life cycle cost analysis (LCCA). The results of this analysis have been used in an optimization algorithm with the aim of achieving the minimum total cost of structures. To evaluate the seismic behavior of structures, the Endurance Time (ET) method is used as a dynamic analysis method which requires much less computation effort than conventional time history methods. In this regard, three-moment frames with 3,7 and 15 stories having weakness in initial design are modeled nonlinearly, and then, using a genetic algorithm, the optimum arrangement of linear and nonlinear viscous dampers along with the damping exponent (Alpha) is acquired. Two closed-form methods have also been used for the design of viscous dampers, namely energy-based damping design and displacement-based design. Finally, the performance of the structures has been evaluated and compared under 12 far-field and 12 near-fault ground motion records.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2389
2414
https://ceej.aut.ac.ir/article_3840_c823379ce3cc74ad9029d9ff8323c4bd.pdf
dx.doi.org/10.22060/ceej.2020.17403.6551
Shearing behavior of Carbonate Sand of Khark Island Cemented by a Pseudo-natural Method
Mohammad Reza
Arvin
Civil Engineering Department, Faculty of Engineering, Fasa University, Fasa, Iran.
author
Ali
Masoomi
Civil Engineering Department, Fasa University
author
Mohsen
Ajdari
Civil Engineering Department, Fasa University
author
text
article
2021
per
In the present study, the effect of natural cementation on the shearing behavior of carbonate sand of Khark Island, south of Iran, has been investigated. To do so, a pseudo-natural cementation method was employed. The importance of this technique lies in its suitability as a substitute for undisturbed samples of cemented carbonate soil that are hard and costly to prepare. Uncemented and cemented samples provided by this method were tested using direct shear apparatus and the results were analyzed and compared to one another. Furthermore, the effects of factors such as curing time and relative compaction on the shearing behavior of the Khark sand were studied. It was observed that cementation results in the rise of the shearing resistance, in particular at high vertical stresses, and leads to a decline in the tendency of soil to dilation. While cementation led to growth in the internal friction angle of soil, it may cause an increase, a decrease, or no change in the cohesion of the Khark sand. The increase in curing time led to a considerable rise in the cohesion and a minor change in the internal friction angle of the cemented soil. Furthermore, results showed that as the relative compaction of the investigated cemented carbonate soil goes up, the cohesion of the soil might increase, decline, or stay unchanged while the internal friction angle always increases. Factors that are likely to contribute to the development of the behavior stated earlier were introduced and their effects were discussed thoroughly.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2415
2434
https://ceej.aut.ac.ir/article_3834_03639c142d2770cd7dc585b042c8717b.pdf
dx.doi.org/10.22060/ceej.2020.17405.6552
Sediment transport modeling in circular smooth and rough rainwater transport pipes using factorial analysis, intelligence and empirical methods
roghayeh
ghasempour
Water resource engineering and management, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran
author
Kiyoumars
Roushangar
Civil Engineering Department, Tabriz University, Tabriz, Iran.
author
text
article
2021
per
Sedimentation is one of the serious problems in water and urban wastewater transport pipes, which disturbs the transport of water flow. In this study, the capability of the intelligence Gaussian Process Regression (GPR) approach was investigated in predicting sediment transport in circular rainwater transport pipes with smooth and rough beds. In this regard, at first, the hydraulic and sediment parameters which had the most correlation with sediment transport were determined using factorial analysis. Then, different models were developed using these parameters and were investigated via three experimental data series. Also, the accuracy of the obtained results was compared with the traditional techniques. The results showed the high efficiency of the intelligent GPR model in the prediction of sediment transport in rainwater transport pipes compared to the empirical methods based on non-linear regression techniques. For the two-mentioned hydraulic conditions of pipes, the model with input parameters λs, Fm, Dgr, d50/y, which are relative sediment size, non-dimensional sediment size, Froude number of sediments, and total roughness coefficient, respectively, was obtained as a superior model. The factorial and omitted sensitivity analysis showed that d50/y was the most effective parameter in the estimation of sediment transport in both smooth and rough pipes.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2435
2450
https://ceej.aut.ac.ir/article_3914_c1d3365b249a60803e1b7394d7a264f5.pdf
dx.doi.org/10.22060/ceej.2020.17406.6553
An Analytical Study of Seismic Performance of a New Type of Reduced Length Buckling Restrained Brace (RLBRB) with S-shaped Core
Reza
Tahmasebi
Faculty of Civil Engineering, Shahrood University of Technology
author
Jalil
Shafaei
Faculty of Civil engineering, Shahrood University of Technology, Shahrood, Semnan, Iran
author
text
article
2021
per
The use of steel braces in buildings with a system of seismicity in the moment frame can significantly control the lateral displacement of the structure. One of the problems with the conventional bracing system is their buckling in compressive loads, which reduces the amount of energy absorbed by the structure. The buckling restrained braces (BRBs) have been removed by the removal of buckling bracing at the pressure of common bracing, but such cases as overweight, high prices and rigorous implementations have led to the introduction of a new type of buckling brace called Reduced Length Buckling Restrained Brace (RLBRB). However, in RLBRB, due to the low cyclic fatigue phenomenon, the length of bracing cannot be over-reduced so that it can be replaced as an inactive system after an earthquake. In this research, a new and innovative idea called Reduced Length Buckling Restrained Brace with S-shaped Core is introduced, which, despite its very short length, can overcome all the problems with the RLBRB and BRB system while also serving as a passive control system. Therefore, the analytical model in the ABAQUS finite element software was validated with the experimental results of RLBRB and BRBs of previous research work. Then, according to the results of the analysis, the profile of the longitudinal buckling curves with the S-shaped core is compared with the RLBRB and BRB braces. The results from the comparison of the proposed pattern with conventional buckling braces indicate that, despite the smaller and lighter ones, these braces have the same behavior as the BRB braces.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2451
2474
https://ceej.aut.ac.ir/article_3892_18ada073273d300fe169f6216edb02eb.pdf
dx.doi.org/10.22060/ceej.2020.17407.6554
Effect of Foundation Flexibility on the Capacity of Concrete Moment Frames with Shear Wall
Elham
Rajabi
Department of Civil Engineering/ Tafresh University/ Tafresh/ Ian.
author
text
article
2021
per
Considering the soil-foundation-structure interaction (SFSI) in the structural modeling procedure can change the seismic structural response. However, the SFSI effects are mostly ignored in the analysis procedure of structures, as a general engineering belief regarding its conservative effects. This conservation is not always the case, although the period and the damping of structures change by considering SFSI effects and consequently, the seismic demand decreases. The aim of this paper is to evaluate the influence of foundation flexibility on the capacity of concrete moment frames with the shear wall. For this purpose, the beam on nonlinear Winkler foundation approach is used, which is a simple and efficient method. First, a collection of 3, 6 and 10 storied reinforced concrete moment resisting frames founded on soft, medium and hard soils are designed based on FEMA450. After the implementation of frames in Opensees software, a set of seismic scenarios are selected. In the following, each frame that has been founded on the soft, medium and hard soil is analyzed for the case of fixed-base and the flexible-base assumption by incremental dynamic analysis (IDA). A comparison is made between the results of each frame in the flexible-base and fixed-base conditions. The results show that the consideration of the SFSI effects can significantly influence the IDA curves and decrease the structural capacity of frames. So that dynamic instability will occur before the expected capacity corresponding to fixed-base assumptions has been achieved. This instability increases with increasing shear wave velocity of soils and height of frames. For example, 3 and 6 storied frames with the flexible base, which have been founded on soft soil, reach ultimate capacity in 52% and 45% of spectral acceleration corresponding to fixed base, respectively.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2475
2496
https://ceej.aut.ac.ir/article_3841_e498d99d6ac22795d8f4c8a8f06d3318.pdf
dx.doi.org/10.22060/ceej.2020.17410.6555
Global Sensitivity Analysis in the Surface Settlement Prediction Caused by Mechanized Tunneling
leila
nikakhtar
Faculty of Mining, Petroleum & Geophysics Engineering, Shahrood University of Technology, Shahrood, Iran
author
S.
Zare
Department of Petrol um, Mining and Geo physic, Shahrood University of Technology
author
Hossein
Mirzaei Nasirabad
Department of Mining Engineering, Sahand University of Technology, Tabriz, Iran
author
text
article
2021
per
Global sensitivity analysis is one of the beneficial and useful tools to identify the uncertainty of input variables that has been extremely investigated in different science such as simulations. Sensitivity analysis is an essential step in the production of a meta-model, which by identifying effective parameters in tunneling, reduces the time and computations required. In this paper, sensitivity analysis was carried out on geotechnical and operational parameters of EPB mechanized tunneling in soft soil. So, the tunneling processes were modeled using a finite difference method in FLAC 3D software, and the numerical model was validated by the monitoring data obtained from the East-West route of the Tehran metro 7 line. The sensitivity analysis by using the elementary effect Morris method was performed on the 6 input parameters and three parameters (face pressure, specific gravity and cohesion of the soil layer in which the tunnel was excavated) were selected as effective and sensitive parameters in the maximum surface settlement. Then to construct the meta-model, 100 samples were generated from effective parameters using the Latin Hypercube method. After numerical simulation for each sample, the simulation results were used for surface settlement prediction by using an artificial neural network. The results showed that the prediction of the meta-model based on the artificial neural network and the numerical model for the data in the design phase corresponded about 98%.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2497
2514
https://ceej.aut.ac.ir/article_3838_9942f979639bfc8a22fb59f25a5a6ccb.pdf
dx.doi.org/10.22060/ceej.2020.17432.6558
Shear Capacity of High-Strength Concrete Slender Beams without Transverse Reinforcement
Masoud
Ahmadi
Department of Civil Engineering, Ayatollah Boroujerdi University, Boroujerd, Iran.
author
Mehdi
Ebadi Jamkhaneh
Department of Civil Engineering, Damghan University, Damghan, Iran
author
text
article
2021
per
In the present study, a new model is derived to estimate the shear capacity of high-strength concrete slender beams without transverse reinforcement using a hybrid adaptive neuro-fuzzy inference system (ANFIS) and particle swarm optimization (PSO) based on the wide range of experimental results. The proposed model relates the shear capacity of the beam to effective depth, the compressive strength of concrete, percent of longitudinal reinforcement, the ratio of shear span to effective depth, and the nominal maximum size of coarse aggregate. The experimental data are randomly categorized into two subsets of the training set and test set. After establishing the proposed model, a sensitivity analysis was carried out to assess the validity of the proposed ANFIS-PSO model. For this purpose, the results of the proposed model are calculated by considering the variation of the two selected input parameters, whereas the values of other parameters are fixed at the corresponding median values. To check the reliability of the proposed model more accurately, the predicted values are compared with the codes and standards such as ACI 318-14, Eurocode-2, CEB-FIP Model Code, AS 3600-2009, and JSCE Guidelines against the whole experimental specimens based on the three well-known statistical measures; correlation coefficient (R2), root mean squared error (RMSE), and mean absolute percentage error (MAPE). It can be found that the proposed ANFIS-PSO model passed desired conditions and could estimate the shear capacity of the high-strength concrete slender beams without transverse reinforcement with a good degree of accuracy.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2515
2534
https://ceej.aut.ac.ir/article_3843_61a653b7232687e253c4a2f87e4e1f4d.pdf
dx.doi.org/10.22060/ceej.2020.17435.6560
Seismic evaluation of low and mid-rise steel moment-resisting frames equipped with viscous dampers based on FEMA P-695 collapse capacity
Amir
Abbaszadeh Shaha-naghi
M.Sc. , School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran.
author
Gholamreza
Ghodrati Amiri
Professor, Center of Excellence for Fundamental Studies in Structural Engineering, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran.
author
Morteza
Raissi Dehkordi
Assistant Professor, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran
author
Mahdi
Eghbali
Assistant Professor, Department of Civil Engineering, Faculty of Engineering, University of Zanjan, Zanjan, Iran.
author
text
article
2021
per
In this study, the seismic performance of steel special moment-resisting frames was analyzed under far-field records with and without viscous dampers using FEMA P-695. 4, 8, and 12-story frames were loaded, analyzed, and designed with and without viscous dampers based on ASCE 7-10 and AISC360. Furthermore, characteristics of viscous dampers are considered for the specific damping ratio of 15% (4,8-story), and 20% (12-story). The frames with and without dampers were modeled in OpenSees by lumped plasticity with Bilin Material. These frames were analyzed and calculated by Incremental Dynamic Analysis (IDA) under 44 far-field records with “Hunt & Fill” algorithm. The seismic performance of studied frames is presented as the collapse probability based on seismic fragility and collapse safety margin. The results demonstrate that the collapse capacity of 4, 8, and 12- story moment-resisting frames with viscous dampers have improved by 28%, 88%, and 74%, corresponding to the median collapse capacity. Moreover, the design of buildings with 75% of design base shear using viscous dampers has a significant effect on the optimal weight of building and construction costs and improvement of seismic performance and technical criteria.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2535
2560
https://ceej.aut.ac.ir/article_4046_2628976c78c458608c362974eed55546.pdf
dx.doi.org/10.22060/ceej.2020.17438.6561
Investigation of Performance and Determination of Optimal Dimensions of Surface Runoff Collection Network Using SWMM Model
Majid
Omidi Arjenaki
Civil Engineering, Water Tendency and Hydraulic Structures, Sharekord University, Iran
author
Hamed Reza
Zarif Sanayei
Assistant Professor of Civil Engineering, Faculty of Engineering, Sharekord University, Iran
author
Heisam
Heidarzadeh
Assistant Professor of Civil Engineering, Faculty of Engineering, Sharekord University, Iran
author
text
article
2021
per
Road flooding has always caused many problems in cities due to inadequate networks of the runoff collection. Therefore, it is essential to identify flood-prone areas and canals that have been flooded. In this study, the sufficiency of the Surface Runoff Collection Network in Shahrekord was investigated during 2, 5, and 10-year rainfall returns using the SWMM model. It should be noted that no studies have been conducted on the issue of urban runoff in this area until now. In this simulation, model calibration has been performed based on the discharge index at three and the depth index at two rainfall events. The error coefficients of NSE, RMSE, and BIAS% have been applied to compare the simulated model error with the observed values. The equivalent width index has been found as the most sensitive index of the model by sensitivity analyses. The validation has been performed on two discharge parameters and runoff depth, each in 2 separate rainfall events, in several random canals and nodes. The acceptable values for the error coefficients showed a high accuracy of the simulation. After the validation phase, the model has been run for 2, 5, and 10-year rainfall return periods, and it was found that flooding occurs in 19.4%, 20.68%, and 21.52% of canals, respectively. The locations of the flooded canals indicate that the southwestern part of the city will be flooded. The optimal dimensions of the canals to prevent flooding have been determined during the 10-year rainfall return period, and the volume of concrete needed to modify the dimensions of each canal has also been estimated.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2561
2580
https://ceej.aut.ac.ir/article_3844_f213a1403514758dfb95acb0b258d889.pdf
dx.doi.org/10.22060/ceej.2020.17452.6565
Investigation of Soil-Structure Interaction Effects on Damage Detection of Wind Turbine Tower with Biorthogonal Wavelets
Mohsen
Mehr Motlagh
Department of Civil Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran.
author
Arash
Bahar
Civil Engineering Group, Faculty of Engineering, University of Guilan, Rasht, Iran
author
omid
bahar
Faculty/International Institute of Earthquake Engineering & Seismology (IIEES)
author
text
article
2021
per
The wind has been one of the cleanest sources of energy. The tendency to use wind turbines has been a growing trend in the world in recent decades. The size and capacity of wind turbines are increasing rapidly in order to obtain more wind energy. Statistics show that more giant turbines are more broken down and require more maintenance. Wind farm owners' goal is to monitor work to reduce downtime and increase the efficiency of each wind turbine. The wind turbine tower carries the entire wind turbine and is the second-largest cost of the wind turbine. Damage to the tower can endanger the entire wind turbine and cause extensive damage. However, the background to the study of the wind turbine tower’s health monitoring against its mechanical installations is insignificant. Besides, no comprehensive research has been conducted on the tower’s health monitoring with soil-structure interaction included. In this study, biorthogonal wavelets were used to process the mode shape of the damaged tower. The foundation is a square concrete foundation 20 m × 20 m and 1 m in depth. Two different soils, normally consolidated clay and dense sand, are considered. Eighteen failure scenarios were defined. This study indicates that the use of side-to-side mode shapes of the tower has a tangible advantage over its fore-aft mode shapes for detecting failure. Considering the desirable effect of soil-structure interaction on damage detection, it is necessary to examine this analysis’s effect.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2581
2600
https://ceej.aut.ac.ir/article_4301_22faa663ba6932ebc0a2d05f3acdced3.pdf
dx.doi.org/10.22060/ceej.2021.17394.6566
A Relationship between the Energy Demands of MDOF and Equivalent SDOF Systems under Pulse-Type Near-Fault Earthquakes
Seyed Abdonnabi
Razavi
Department of Civil Engineering, Islamic Azad University, Ahvaz branch, Ahvaz, Iran
author
Navid
Siahpolo
Assistant professor, ACECR Institute for higher education, Khuzestan branch, Ahvaz, Iran
author
Mehdi
Mahdavi Adeli
Assistant Professor, Department of Civil Engineering, Islamic Azad University, Ahvaz branch, Ahvaz, Iran
author
text
article
2021
per
The purpose of paper is qualitative and quantitative study of the relationship between the energy demand of multi-degree-of-freedom systems, MDOF, and equivalent-single-degree-of-freedom systems to calculate the total energy demand of the MDOF system using the ESDOF energy demand. For this purpose, multi-story special steel moment frames designed and analyzed under 10 near-fault earthquake with forward-directivity effects. Moreover, the process done for the ESDOF system considering specified values of R (degree of nonlinearity). Accordingly, linear and nonlinear total dissipated energy (TDE), hysteretic energy (HE), and damping energy (DE) ratios were introduced to estimate the relationship of the ESDOF and MDOF energy. Results shows that ratio of nonlinear to linear TDE and HE/TDE is affected by period and R in ESDOF system. However, as the period and R increase, the ratio converges to one. The same result was observed between the nonlinear TDE of the MDOF system and the linear TDE of the ESDOF system. In other words, ESDOF linear TDE can be used instead of MDOF for long periods. In addition, the nonlinear TDE of the MDOF system to the nonlinear TDE of the ESDOF system ratio is affected by higher modes and period, by increasing the period the ratio is generally greater than one for the constant R. Also the effect of higher modes on the ratio of total story dissipated energy to total structure dissipated energy was significant for low R values. With increasing R, the structure tends to damp all the dissipated energy in the first mode.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2601
2624
https://ceej.aut.ac.ir/article_3800_5958e9c92c0ba59c73faa0210997a5a5.pdf
dx.doi.org/10.22060/ceej.2020.17466.6569
Effect of copper slag on the mechanical properties and fracture energy of fiber reinforced cementitious composite
Moosa
Mazloom
تهران - لویزان - دانشگاه شهید رجایی - دانشکده عمران
author
Mohammad
Akbari Jamkarani
Master of Science in Structural Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran
author
text
article
2021
per
One of the most important weakness points of concrete is its drawback in tension and cracking. The use of fibers in concrete greatly reduces this disadvantage. Fiber-reinforced cementitious composite (FRCC) is a type of fiber-reinforced concrete (FRC) that does not contain coarse aggregate and only has fine aggregate. In fact, the high level of cement in FRCC is a problem for the environment. This problem can be solved by using different cement replacement materials as a part of cement. In this study, the effect of copper slag on the mechanical properties and fracture energy of fiber-reinforced cementitious composite (FRCC) containing polypropylene fiber is investigated. Silica fume and copper slag were replaced as a part of cement. For this purpose, a control mix without silica fume and copper slag, 4 mixes containing 5%, 7%, 10% and 15% silica fume, and 4 mixtures with 5%, 10%, 20% and 30% copper slag was casted. In specimens containing silica fume, the ones with 15% of it had the highest quantity of fracture energy, compressive, tensile, and flexural strengths. Among the samples having copper slag, the ones containing 10% and 20% of it had the highest values above. It is worth noting that some binary mixtures containing both copper slag and silica fume were prepared too. Comparing the results of all the mentioned mixtures, it is concluded that the best results belong to the binary mixture containing both 15 % copper slag and 15 % silica fume.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2625
2638
https://ceej.aut.ac.ir/article_3993_763299a3a0b7d9e5c2a2db2265dc2976.pdf
dx.doi.org/10.22060/ceej.2020.17458.6573
Investigation of Some Performance Indices in Design of Water Distribution Network Based on Hydraulic and Mechanical Reliability Criteria
Mahdi
Taji Elyatoo
Shahid Beheshti University
author
Jafar
Yazdi
Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University
author
text
article
2021
per
Due to the high costs of running a water distribution network, the design of the least cost and most reliable networks is of great engineering importance. One issue that has been the focus of recent years' research is the comparison of indices and their relative success in measuring the reliability of water distribution networks. Many studies have been conducted to date on the reliability of water distribution networks. In the present study, the performance of various hydraulic and mechanical parameters was compared to each other under pipe failure conditions. This study provides more performance indices than previous studies. In this paper, The investigation on the nodal pressure performance index, velocity, pressure difference, combined velocity and nodal pressure index, network flexibility performance index (NRI), minimum head surplus index (MSH) and entropy performance index (ERI) on the Hanoi and Pescara water distribution network were performed using NSGA-II optimization algorithm and Epanet software. The results showed that in the design of a small water distribution network (Hanoi), the network flexibility index (NRI) performs best and in the design of a medium water network (Pescara), at low-cost level, node pressure performance index (PIP) and at high-cost level, the Network Flexibility Index (NRI) performed the best among the other indices; the two indices have, on average, created more pressure than other indices on the network and increased surplus energy in the network. Also, in case of accidental failure of several pipes, the nodal demands of the network are more than other indices.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2639
2656
https://ceej.aut.ac.ir/article_4011_5b2ac31a3d528d80064b3b38486df569.pdf
dx.doi.org/10.22060/ceej.2020.17480.6574
Experimental and numerical investigation of the effect of steel fiber on fiber reinforced concrete under multiaxial compression
Gholamreza
Baghban Golpasand
Department of Structural Engineering, University of Tabriz, Tabriz, Iran
author
غلامرضا
Farzam
Department of Structural Engineering, University of Tabriz, Tabriz, Iran
author
Siamak
Soleymani Shishvan
Department of Structural Engineering, University of Tabriz, Tabriz, Iran
author
text
article
2021
per
Concrete is one of the most widely used building materials in the world and the use of fiber-reinforced concrete (FRC) in structures to increase its tensile strength and improve its behavior has been extensively developed in recent decades. It is necessary to determine the constitutive equations of FRCs when the numerical investigation of their behavior is running. These equations should be including relations to handle the effect of steel fibers on the behavior of FRC. In this study, the behavior of FRCs with a different percent of steel fiber under triaxial compression, with different values of confining pressure, is experimentally and numerically investigated. Hoek cell is used in triaxial tests. In the numerical simulation, five-parametric constitutive equations with Willam-Warnke (W-W) failure criterion, isotropic hardening/softening function and non-associated plasticity were used and substepping integration method was carried out for integration of constitutive equations. For applying the effect of steel fibers on the failure surface, Kt coefficient was determined from the results of biaxial experimental tests on SFRCs. The constitutive equations are implemented with UMAT subroutine in ABAQUS and specimens are simulated in ABAQUS. By the comparison of the experimental (maximum strength) results and the numerical (stress-strain curve) results, an acceptable agreement was seen between them. Finally, based on the consistency between experimental and numerical results, it was concluded that the numerical model could be used, with enough confidence, to predict the behavior of SFRCs specimens.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2657
2678
https://ceej.aut.ac.ir/article_3996_51711a7d113473bc9d897e3ef94afeeb.pdf
dx.doi.org/10.22060/ceej.2020.17462.6576
Estimation of vertical exchange velocity through the sediment-water interface (Case study: Ziarat River in Golestan province)
Jaefar
Khandoozi
Gorgan University of Agricultural Sciences and Natural Resources
author
Amir Ahmad
Dehghani
Water Engineering, Gorgan University of Agricultural Sciences and Natural Resources
author
Mehdi
Meftah
Water Engineering, Gorgan University of Agricultural Sciences and Natural Resources
author
Abdolreza
Zahiri
Associate professor in Water Engineering, Gorgan University of Agricultural Sciences and Natural, Golestan, Iran.
author
Khalil
Ghorbani
Gorgan University
author
text
article
2021
per
Precise estimation of water exchange between surface and subsurface flow in the hyporheic zone which is the habitat of microorganisms, is vital. The temperature can be used as a tracer for the estimation of water exchange through sediment-water interphase. In this study, an instrument was designed and constructed to make the measurement and recording of sediment temperature in the depth of the hyporheic zone possible. In this regard, measurements were made in the Ziarat River of Golestan Province by the aforementioned instrument, and vertical exchange velocity through the sediment-water interface was calculated using an extended conceptual model of heat transfer. For this purpose, in a 40 m interval of the river, 10 cross-sections were selected at 4 m intervals, and at each cross-section, the temperature of four different depths of the riverbed (just below the bed, 0.25, 0.50, 0.75 m) was recorded during July and December 2018. The results showed that in all seasons, there is a continuous vertical exchange through the sediment-water interface, which can be obtained from the difference of thermal potential between the surface and subsurface of the river flow. The average of vertical exchange velocity for July and December was 59.3 mm/day and 284.3 mm/day, respectively.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2679
2694
https://ceej.aut.ac.ir/article_3845_3dbd5eab7f3b82ddf98283cc433d9e54.pdf
dx.doi.org/10.22060/ceej.2020.17495.6579
Pavement maintenance planning of large-scale transportation networks considering energy consumption
Amir
Golroo
Transportation group, Civil dept, AUT
author
Amirhossein
Fani
Transportation Engineering, Department of Civil Engineering, Amirkabir University of Technology, Tehran, Iran
author
Hamed
Naseri
Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran.
author
text
article
2021
per
Maintenance and rehabilitation scheduling optimization are some of the most critical parts of the pavement management system. Pavement agencies usually face large-scale pavement networks. The complexity of network management is exponentially increased in the circumstances that the dimension of the network is extended. Hence, meta-heuristic algorithms and decomposition techniques are usually applied to solve these problems. In this investigation, energy consumption optimization is taken into account as an essential environmental criterion. Furthermore, a recently developed meta-heuristic algorithm called the Soccer league competition algorithm is utilized to solve the problem. This robust algorithm is inspired by the competitions of players and teams in soccer leagues. A real network containing 84 segments is the case study of this investigation. According to the results, the Soccer league competition algorithm is competent to solve a large-scale network problem in a short time. Moreover, the comparison of different strategies outcomes indicates that considering energy consumption as the second objective function reduces the energy consumption and total cost 13% and 10%, respectively, and increases the average international roughness index by 9%.
Amirkabir Journal of Civil Engineering
Amirkabir University of Technology
2588-297X
53
v.
6
no.
2021
2695
2712
https://ceej.aut.ac.ir/article_3835_9ef83768624f97312c0e07aaad4342b0.pdf
dx.doi.org/10.22060/ceej.2020.17500.6582