University of TehranCivil Engineering Infrastructures Journal2322-209350120170601Using Different Methods of Nanofabrication as a New Way to Activate Supplementary Cementitious Materials; a Review1196181710.7508/ceij.2017.01.001ENAzadehAskarinejadRoad, Housing and Urban Development Research Center (BHRC)Journal Article20160612Reducing the consumption of cement with simultaneous utilizing waste materials as cement replacement is preferred for reasons of environmental protection. Blended cements consist of different supplementary cementitious materials (SCMs), such as fly ash, silica fume, Ground Granulated Blast Furnace Slag (GGBFS), natural pozzolans, etc. These materials should be chemically activated to show effective cementitious properties. The present review article reports three different methods of nanofabrication, using ultrasound irradiation, solvothermal/hydrothermal process and microwave irradiation, that were used for activation of two types of SCMs. Based on the obtained results, these methods are suggested as effective methods for nanomodification of supplementary cementing materials.https://ceij.ut.ac.ir/article_61817_7d75012da568b1849826a1b88b1bacd9.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Performance-Based Plastic Design of Moment Frame-Steel Plate Shear Wall as a Dual System21346171010.7508/ceij.2017.01.002ENGholamrezaAbdollahzadehFaculty of Civil Engineering, Babol University of TechnologyHamedKuchakzadehBabol University of TechnologyAlirezaMirzagoltabarBabol University of TechnologyJournal Article20150301Steel Plate Shear Wall (SPSW) is an emerging seismic load-resistant system that, compared to other systems, enjoys the advantages of stable ductile behavior, fewer detailing requirements, rapid constructability, and economy. American seismic provisions decree that a SPSW should be designed as a moment frame with a web infill plate. Specifically, in case of buildings taller than 160 ft, it decrees that a dual system must be used. This paper presents a method of Performance-Based Plastic Design (PBPD) to design steel moment frame-SPSW as a dual lateral load-resisting system. PBPD method uses pre-selected target drift and yield mechanism as its main criteria. For a specified hazard level, the design base shear is calculated based on energy work balance method, employing pre-selected target drift. Plastic design of dual frame system has been performed to meet the pre-selected yield mechanism. As presented in the paper, design procedure involves solving a system of five equations with five variables to determine the proportion of SPSW and moment frame shear, shear wall thickness, and beam/ column sections. It has been considered that a four-story structure is designed with the proposed method. Seismic performance of this dual frame system, designed with the proposed method, is evaluated by nonlinear static and dynamic analysis for both Design Basis Earthquake (DBE) and Maximum Credible Earthquake (MCE). Result analysis is in accord with the assumptions, satisfying all the performance objectives. PBPD is a direct design method in which no iteration is needed to achieve the performance objectives. Determining the proportion of SPSW and moment frame shear is an exclusive capability of this procedure.https://ceij.ut.ac.ir/article_61710_7f542b7348c3589326a257c0306dd53d.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Bearing Capacity of Shallow Foundations on Cohesionless Soils: A Random Forest Based Approach35496181810.7508/ceij.2017.01.003ENVahid RezaKohestaniDepartment of Faculty Engineering, Imam Khomeini International University, Qazvin, IranMaryamVosoghiImam Khomeini international universityMahmoudHassanlouradDepartment of Faculty Engineering, Imam Khomeini International University, Qazvin, Iran0000-0002-7236-0756MahsaFallahniaDepartment of Architecture and Energy, Faculty of Architecture and Urbanism, University of ArtJournal Article20150603Determining the ultimate bearing capacity (UBC) is vital for design of shallow foundations. Recently, soft computing methods (i.e. artificial neural networks and support vector machines) have been used for this purpose. In this paper, Random Forest (RF) is utilized as a tree-based ensemble classifier for predicting the UBC of shallow foundations on cohesionless soils. The inputs of model are width of footing (B), depth of footing (D), footing geometry (L/B), unit weight of sand (γ) and internal friction angle (ϕ). A set of 112 load tests data were used to calibrate and test the developed RF-based model. The used data set consists of 47 full-scale observations and 65 small-scale laboratory footing load tests. To demonstrate the efficiency of proposed RF-based model, the results are compared with some popular classical formulas that are most commonly used for determining the UBC. The results show the efficiency and capabilities of the proposed RF-based model as a practical tool in evaluating the UBC of shallow foundations in a fast and accurate way.https://ceij.ut.ac.ir/article_61818_39c5a71e5cacae93633a8136eaf94e94.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601A Road Map for Civil Engineers towards Bridge Engineering Through Academic Education and Professional Training51736181910.7508/ceij.2017.01.004ENRezaAkbariPhD in Structural Eng., Senior Bridge and Structural Engineer,
Road Maintenance and Transportation Org. (RMTO)ShahrokhMaalekSchool of Civil Engineering, University of Tehran, Tehran, IranJournal Article20160523It is common in many countries that engineers having an academic degree in Civil Engineering are appointed responsible for different tasks related to Bridge Engineering. However, there are serious questions about whether formal university courses in civil engineering could cover the needs of a bridge engineer to fulfill his or her job successfully. Regarding the recent significant advances in the theory and practice of bridge engineering, the answer is clearly negative. Indeed, there is a huge gap between the knowledge of a typical graduate -having a Bachelor’s degree in civil engineering or a Master’s degree in structural engineering- and the knowledge expected to be acquired by an engineer involved in various bridge engineering activities. This paper attempts to bridge this gap by introducing a road map through a proposed program of academic education and professional training. The proposed program has been dealt with in some details in the hope of opening a chapter for further scientific discussions and researches, as well as actual implementation, evaluation and improvement. The suggested programs contain a series of lessons defined within a number of modules. Universities across the world are encouraged to present such courses. Industrialized countries can play a paramount role in this process by presenting Master’s courses not only for their Native students, but also for students from developing countries. They can also contribute to training courses to be organized by authorities in developing countries.https://ceij.ut.ac.ir/article_61819_77be27b7bfb3edf6764c9f75d37eecb5.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Investigating the Performance Characteristics of Asphaltic Concrete Containing Nano-Silica75936182010.7508/ceij.2017.01.005ENHasanTaherkhaniassistant professor, civil engineering department, university of zanjan, zanjan, Iran0000-0003-1817-9494SiamakAfroozigraduate in highway and transportation engineering, university of zanjanJournal Article20160604Using nano-technology materials in the asphalt pavement industry is new compared with Portland cement concrete. The main objective of this study is to investigate the effects of nano-silica modification on some properties of a penetration grade asphalt cement and a typical asphalt concrete. 60/70 penetration grade bitumen was modified with different percentages of nano-silica (i.e. 1, 3 and 5%, by weight) and was used for making the asphalt concrete specimens. After evaluating the basic properties of the modified binder, the asphalt concrete specimens were evaluated based on the stiffness and resistance against fatigue cracking, moisture damage and permanent deformation. The fatigue life of the modified mixtures was also calculated using an already developed regression model. The results showed that penetration grade and ductility increase and softening point decreases with increasing nano-silica content. Furthermore, results showed that the addition of nano-silica results in the increase of stiffness, tensile strength, resilient modulus, fatigue life and resistance against permanent deformation and moisture damage. The reduction of indirect tensile strength in wet the condition decreases with increasing nano-silica content. Dynamic creep test results showed that, the flow number of the control mixture and the mixture containing 1% of nano-silica is much lower than 10000 loading cycles. However, the mixtures containing 3 and 5% of nano-silica do not reach to the tertiary creep region after 10000 loading cycles.https://ceij.ut.ac.ir/article_61820_85667f7fede9e9cf67683584bf01fab3.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Coupled BE-FE Scheme for Three-Dimensional Dynamic Interaction of a Transversely Isotropic Half-Space with a Flexible Structure951186182110.7508/ceij.2017.01.006ENAliMorshedifardUniversity of TehranMortezaEskandari-GhadiSchool of Civil Engineering, College of Engineering, University of Tehran, I.R. Iran.Journal Article20160802The response of structures bonded to the surface of a transversely isotropic half-space (TIHS) under the effect of time-harmonic forces is investigated using a coupled FE-BE scheme. To achieve this end, a Finite Element program has been developed for frequency domain analysis of 3D structures, as the first step. The half-space underlying the structure is taken into consideration using a Boundary Element technique that incorporates half-space surface load Green’s functions for a transversely isotropic medium. Next, the two programs are combined using a direct coupling algorithm and the final program is obtained. To validate the results, some benchmark problems are solved with the FE and the BE programs, separately and then the coupled technique is checked with the results of some special cases for which the solutions are available in the literature. At the end, a parametric study is carried out on several common types of structures to study the effects of the degree of anisotropy of transversely isotropic soil medium on the dynamic behavior of the structure. Moreover, the effect of soil-structure interaction (SSI) on the natural vibration frequency of the structures is also studied.https://ceij.ut.ac.ir/article_61821_314a07f9848eeff2f90ae29152999894.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Cyclic Loading Tests for Cold-Formed Steel Wall Frames with Lightweight Concrete1191336182210.7508/ceij.2017.01.007ENAmirHoseinpoorDepartment of Civil Engineering, Taft Branch, Islamic Azad University, Taft, IranMohammad RezaJavaheri-TaftiDepartment of Civil Engineering, Taft Branch, Islamic Azad University, Taft, Iran0000-0001-6860-0705Journal Article20160829Lightweight steel framing is a method in housing and construction that have been widely used in lightweight steel construction. In this method, the structure is built by cold formed steel elements. They are cost-effective, light, and easy to assemble. However, the performance of lateral load resisting systems in cold-formed steel structures specially the behavior of cold-formed steel shear walls filled with lightweight structural concrete under seismic loads has not been studied in detail. In this study, an experimental investigation on cold-formed steel frames filled with lightweight structural concrete has been conducted and the results are presented. Six full-scale cold-formed steel frames filled with lightweight structural concrete with two different configurations were studied. The test was performed under a standard cyclic loading regime. This study is focused on the ultimate lateral load capacity and seismic response modification factor of cold-formed steel walls filled with lightweight concrete subjected to cyclic loads. Based on the test observation, detailed discussions on the failure modes of cold-formed steel wall specimens are given. Finally, shear load resistance, seismic response modification factor, failure modes, energy dissipation and stiffness of tested shear walls are proposed and discussed. The results show that although lower height to width ratio leads to a greater shear load resistant, energy dissipation, and stiffness for shear wall filled with lightweight concrete, its seismic modification factor is lower than those shear walls, which have higher height to width ratio.https://ceij.ut.ac.ir/article_61822_e5db66bba654d252799d032161b7ccf5.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Study on Fundamental Frequencies of Cylindrical Storage Tanks Obtained from Codes and Finite Element Method1351496182310.7508/ceij.2017.01.008ENMohsenYazdanianAhvazSadeghGhasemiNISOCJournal Article20160918In the case of study on the seismic behavior of tanks, one of the most important subjects is selection of convective and impulsive frequencies for storage tanks. These two frequencies are defined by Housner. The major utility of these frequencies is for Rayleigh damping which is a must for time history analysis. API 650, EUROCODE 8 have suggested some analytical solutions for finding convective and impulsive frequencies and other parameters. In addition, these frequencies can be obtained from modal analysis by finite element software. In current study, these frequencies are obtained using Finite Element (FE) software and performing modal analysis. In the next stage, these modes are compared with analytical methods from standards. To compare tanks with different (H/R) ratios, all these tanks are modeled with the same volume and weight. This study showed that there is a good agreement between convective frequencies extracted from Finite Element method and those from standards. Furthermore, an increase in liquid level led to a rise and dip in convective and impulsive frequencies, respectively. In addition, results show that a 1.47 times increase in the viscosity leads to a 17 percent decrease in the values of impulsive frequencies.https://ceij.ut.ac.ir/article_61823_14aa26e12fd66950f0e5d6f17885b86f.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Impact of Tamper Shape on the Efficiency and Vibrations Induced During Dynamic Compaction of Dry Sands by 3D Finite Element Modeling1511636182410.7508/ceij.2017.01.009ENSaharMehdipourSchool of Engineering, Kharazmi university, Tehran, Iran.AmirHamidiSchool of Engineering, Kharazmi University, Tehran, Iran0000-0002-1662-7516Journal Article20160929Dynamic compaction is a soil improvement method which has been widely used for the increase of bearing capacity through stress wave propagation during heavy tamping. The cost and time of project implementation can be effectively curtailed by developing a model that can be used in the design of dynamic compaction operations. The numerical models offered so far are mostly one or two-dimensional, incapable of examining the total effect of wave emission in the soil. This paper involved the three-dimensional finite element program ABAQUS employing Mohr-Coulomb failure criterion for the analysis of dynamic compaction operation. Modeling of impact on soil surface involved an initial velocity applied to the tamper nodes. Flat section and conical shape tampers with various cone angles were modeled and their effects on the efficiency of dynamic compaction for soils with different initial relative densities were investigated. Moreover, variations of peak particle velocity (PPV) induced by flat or conical tamper at different radial distances and soil densities were evaluated. The analyses were done individually for each mode over five consecutive blow counts. Comparison of the results of PPV, crater depth and crater volume for different tampers revealed the effect of tamper shape on efficiency and vibrations induced during dynamic compaction. Increasing the cone angle of conical tampers increased improvement depth and velocity of particles in all radial directions.https://ceij.ut.ac.ir/article_61824_2740ea70c23933dcf8bde5b2bf8c1fae.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Concrete Filled Tubular Bracing Subjected to Cyclic Loading1651776182510.7508/ceij.2017.01.010ENMehdiGhassemiehProfessor, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.0000-0003-3566-538XZahraSaneeiniaSchool of Civil Engineering
University of TehranMahmoudBaeiSchool of Civil Engineering
University of TehranJournal Article20160420The energy absorption of concrete filled, hollow-steel bracing was analyzed respect to geometric and mechanical parameters including the width-to-thickness section ratio, slenderness level, and strength of the steel and concrete. Local buckling and ductility were also investigated with respect to variation in the cross-section. The infill increased the compression resistance, even after multiple, inelastic load reversals. This resulted in improved ductility capacity by limiting local buckling and in some cases preventing the local buckling. The energy absorption of such braces is appraised with respect to earthquake design presented in different international standards. The overall system effectiveness was assessed by comparing infilled bracing to an existing state-of-the-art, buckling restraint bracing system. The results showed the energy dissipation in buckling restraint bracing systems is more of in comparison with tubular bracing system designed by European and American codes in higher cycles.https://ceij.ut.ac.ir/article_61825_920ea24d1de8b8f9254a79e28d437056.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601GIS-Based Multi Criteria Evaluation for Thermal Power Plant Site Selection in Kahnuj County, SE Iran1791896182610.7508/ceij.2017.01.011ENSadriSiefiDepartment of Natural Resources, Isfahan University of Technology, Isfahan 83111-84156, IranHazhirKarimiIsfahan University of TechnologyAlirezaSoffianianDepartment of Natural Resources, Isfahan University of Technology, Isfahan 83111-84156, IranSaiedPourmanafiSoffianianJournal Article20160627Choosing a location for a power plant site is a complex task that involves evaluation of multiple factors, which should satisfy a number of economic and environmental requirements. The main aim of this study is to determine the best possible candidates for thermal power plant sites using Multi-criteria Evaluation and Geographic Information System (GIS) in Kahnuj County in the southeast of Iran. First, the affecting factors to find the best sites for power plant establishment were identified including socio-economic and environmental factors. Each criterion was mapped in the GIS environment. Then, the layers were standardized and the relative weights of these layers were determined. Finally, weighted information layers were consolidated by Weighed Linear Combination approaches in GIS environment and the suitable locations were selected and ranked accordingly. The final index maps were grouped in five categories ranging from “no suitability” to “high stability” with an equal interval classification method. As a result the most suitable sites were patches located in the north-west parts of the study area.https://ceij.ut.ac.ir/article_61826_2b3d9da7d8304d3ec4c59aaae9f61fb0.pdfUniversity of TehranCivil Engineering Infrastructures Journal2322-209350120170601Estimation and Evaluation of Greenhouse Gas Emissions during the Life-Cycle of Wastewater Pipelines: Case Study of Tehran, Iran1912066182710.7508/ceij.2017.01.012ENBardiaRoghaniPhD candidate, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.MassoudTabeshProfessor, Centre of Excellence for Engineering and Management of Civil Infrastructure, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran.0000-0002-8982-8941Mohammad SadeghAmrollahiM.Sc. Graduate Student, School of Civil Engineering, College of Engineering, University of Tehran, Tehran, IranGovindarajanVenkateshSenior Lecturer, Department of Engineering and Chemical Sciences, Faculty of Health, Science and Technology, Karlstad University, Karlstad, Sweden.Journal Article20160917Climate change occasioned by the accumulation of greenhouse gases (GHGs) is now widely accepted as an issue which mankind needs to address. The starting point is necessarily the determination of all the sources of emissions during the life-cycles of the studied components. Post-calculation, the results ought to be presented to decision-makers in a clear manner so as to provide the basis on which corrective actions could be considered. This paper calculates the GHGs emissions during the life-cycle of wastewater pipelines and introduces a different approach to communicate information about GHGs released, to decision-makers. Different diameters of concrete and high-density polyethylene (HDPE) wastewater pipes are compared in a case study. Results show that the total CO<sub>2</sub>-equivalent (CO<sub>2</sub>-eq) emissions attributed to concrete pipes are greater than HDPE pipes. Hence, the equivalent bio-productive area of forest required to sequester the CO<sub>2</sub> (the major GHG) and its corresponding costs will be greater for the former.https://ceij.ut.ac.ir/article_61827_9a44cb53d85a6a5d614dbe4d1e16b035.pdf