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Practices of Minimizing Steel Reinforcement Bars’ Waste During the Design Phase of Sustainable Projects
, M.Sc. Thesis Sharif University of Technology ; Mortaheb, Mohammad Mehdi (Supervisor)
Abstract
Nowadays, every society tries to adjust its development’s orientation towards sustainable development. Construction projects have a significant share of every country’s economy. Construction waste management is one of the most important issues affecting sustainability. Construction waste management and waste minimization programs in construction projects not only can save resources and help the economy, but also can enhance a country’s development toward sustainable development. Designing process can be an effective phase in waste management among different stages of a project life cycle. Considering the significant number of concrete building constructions in Iran, the aim of this research...
Reduction of Residual Displacement of Concrete Structures by use of High Strength Rebars
, M.Sc. Thesis Sharif University of Technology ; Khalu, Alireza (Supervisor)
Abstract
Reinforced concrete bridge columns located in regions of high seismicity are designed with large ductility capacity for adequate protection against collapse. This type of design tends to result in large permanent displacements. To maximize post-event operability and to minimize repair costs, new design strategies to reduce these residual displacements are necessary. Even though seismic codes ensure life safety for bridges, large residual displacement after severe earthquake may make the bridge useless. For example, after 1995 Hyogo-ken Nanbu earthquake (Japan), more than 100 reinforced concrete bridge columns experienced a tilt angle of more than 1 degree (1.75% drift). These columns had to...
Study of behavior of reinforced concrete beams with smart rebars using finite element modeling
, Article International Journal of Civil Engineering ; Volume 8, Issue 3 , September , 2010 , Pages 221-231 ; 17350522 (ISSN) ; Eshghi, I ; Piran Aghl, P ; Sharif University of Technology
2010
Abstract
In this paper the response of cantilevered reinforced concrete (RC) beams with smart rebars under static lateral loading has been numerically studied, using Finite Element Method. The material used in this study is SuperelasticShape Memory Alloys (SE SMAs) which contains nickel and titanium elements. The SE SMA is a unique alloy that has the ability to undergo large deformations and return to their undeformed shape by removal of stresses. In this study, different quantities of steel and smart rebars have been used for reinforcement andthe behavior of these models under lateral loading, including their load-displacement curves, residual displacements, and stiffness, were discussed. During...
An Investigation on Concrete Frames Reinforced with Shape Memory Alloys in Plastic Hinge Zones
, M.Sc. Thesis Sharif University of Technology ; Khalu, Alireza (Supervisor)
Abstract
In this paper, the response of a concrete one-story frame with smart rebars under static lateral loading has been numerically studied, using Finite Element Method. The material used in this study is Shape Memory Alloy (SMA) which contains nickel and titanium elements. During lateral loading, rebars yield or concrete crushes in compression zone in some parts of the RC frames and also residual deflections are created in the structure. The SMA exhibits little residual strains under cycles of loading and unloading even after passing the yielding zone. In addition, SMAs have a good energy dissipation capacity that helps reduce damage while increasing structural capacity. In this study, SMA rebars...
Protection of Steel Rebar in Concrete with Zinc Based Coatings in Persian Gulf
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Reinforced concrete is one of the most important structural materials used in the construction industry worldwide. Nevertheless, certain physical and chemical factors in the service environment can contribute to its deterioration and failure. One of the most significant factors is the reinforcing steel bar (rebar) corrosion. In order to minimize the rebars corrosion, different kinds of coatings were investigated and evaluated by scientists. In this investigation comparative studies were performed on two different kinds of coated rebars (zinc-rich epoxy and polyamide epoxy coated rebars) and uncoated rebar. In order to evaluate these reinforced concretes, the adhesion, durability, thickness...
Investigation the behavior of Low-Rise Shear Walls with Smart Rebars
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
In this paper, the response of low-rise shear walls with smart rebars under static lateral loading has been numerically studied, using Finite Element Method. The material used in this study is Shape Memory Alloys (SMAs) which contains nickel and titanium elements. During lateral loading, rebars yield or concrete crushes in compression zone in some parts of the RC shear walls and also residual deflections are created in the structure. The SMA exhibits little residual strains under cycles of loading and unloading even after passing the yielding zone. In addition, SMAs have a good energy dissipation capacity that helps reduce damage while increasing structural capacity. In this study, SMA...
Numerical Analysis on Flexural Behavior of Concrete Beams Reinforced with FRP bars
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
The main problem of steel-reinforced concrete structures is corrosion of steel reinforcements which leads to premature failure of the concrete structures. This problem costs a lot annually to rehabilitate and repair these structures. In order to improve the longterm performance of reinforced concrete structures and for preventing this corrosion problem, Fiber Reinforced Polymer (FRP) bars can be substituted of conventional steel bars for reinforcing concrete structures. This study is a numerical study to evaluate structural behavior of the simply supported concrete beams reinforced with FRP bars in comparison with steel-reinforced concrete beams. The commercial Finite Element Modeling...
Response of reinforced concrete structures to macrocell corrosion of reinforcements. Part I: Before propagation of microcracks via an analytical approach
, Article Nuclear Engineering and Design ; Volume 241, Issue 12 , 2011 , Pages 4874-4892 ; 00295493 (ISSN) ; Shodja, H. M ; Sharif University of Technology
2011
Abstract
Assessment of the macrocell corrosion which deteriorates reinforced concrete (RC) structures have attracted the attention of many researchers during recent years. In this type of rebar corrosion, the reduction in cross-section of the rebar is significantly accelerated due to the large ratio of the cathode's area to the anode's area. In order to examine the problem, an analytical solution is proposed for prediction of the response of the RC structure from the time of steel depassivation to the stage just prior to the onset of microcrack propagation. To this end, a circular cylindrical RC member under axisymmetric macrocell corrosion of the reinforcement is considered. Both cases of the...
Shake table test of a masonry building retrofitted with shotcrete
, Article Engineering Structures ; Volume 219 , 2020 ; Beyer, K ; Mohtasham Dolatshahi, K ; Yekrangnia, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This paper presents the results of a series of shake table tests carried out on a half-scale single-story unreinforced masonry building with asymmetric openings. First, the unretrofitted building is subjected to seven increasing steps of bidirectional seismic excitation. The damaged building is then rehabilitated using steel mesh and shotcrete layer with two walls retrofitted from the exterior face and the other two from the interior face. Afterward, the shake table test is again conducted on the retrofitted specimen in nine increasing excitation levels. Three cases of interior-to-interior, interior-to-exterior, and exterior-to-exterior shotcrete connections are considered at the...
Prediction of the degree of steel corrosion damage in reinforced concrete using field-based data by multi-gene genetic programming approach
, Article Soft Computing ; Volume 26, Issue 18 , 2022 , Pages 9481-9496 ; 14327643 (ISSN) ; Eftekhari, M ; Ghorbani, M ; Ehteshamzadeh, M ; Beirami, H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Unanticipated failure of reinforced concrete structures due to corrosion of steel rebar embedded in concrete causes to increase the demand for finding methods to forecast the service life of concrete structures. In this field, the success of machine learning-based methods leads to the use of multi-gene genetic programming (MGGP) method for classifying the degree of corrosion destruction of steel in reinforced concrete in this paper. Despite the common application of MGGP that is the symbolic regression, in this research, MGGP was adapted to use in classification tasks. Accordingly, a large field database has been collected from different regions in the Persian Gulf for modeling of MGGP and...
Corrosion resistance evaluation of rebars with various primers and coatings in concrete modified with different additives
, Article Construction and Building Materials ; Volume 262 , 2020 ; Jahandari, S ; Rasekh, H ; Shariati, M ; Afshar, A ; Shokrgozar, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Corrosion of steel rebars in concrete can reduce the durability of concrete structures in coastal environments. The corrosion rate of these concrete structures can be reduced by using suitable concrete additives and coating on rebars. This paper investigates the corrosion resistance of steel rebars by the addition of pozzolanic materials including fly ash, silica fume, polypropylene fibers, and industrial 2-dimethylaminoethanol (FerroGard 901) inhibitors to the concrete mixture. Three different types of rebars including mild steel rebar st37, and two stainless steel reinforcements, AISI 304 and AISI 316, were used. Various types of primer and coating including alkyd based primer, hot-dip...