Journal articles on the topic 'Steel bars Testing'
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1
Maropoulos, S., D. Fasnakis, Ch Voulgaraki, S. Papanikolaou, A. Maropoulos, and A. Antonatos. "Fatigue testing of reinforced-concrete steel bars." IOP Conference Series: Materials Science and Engineering 161 (November 2016): 012067. http://dx.doi.org/10.1088/1757-899x/161/1/012067.
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Amer, Osama. "Quasi‑static Cyclic In‑plane Testing of Slender GFRP-Reinforced Concrete Shear Walls." Civil Engineering Beyond Limits 3, no. 3 (November 6, 2022): 1–14. http://dx.doi.org/10.36937/cebel.2022.1737.
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Using Glass fiber-reinforced polymer (GFRP) bars as a replacement for conventional steel bars is one of the most potential solutions to steel-corrosion-related problems in concrete. Their durability and high strength-to-weight ratio make them a cost-effective and applicable alternative to conventional steel bars. This study investigates the characteristic behavior of concrete shear walls reinforced with steel, GFRP, and a hybrid scheme of steel and GFRP bars under seismic loading. Six full-scale RC shear walls with an aspect ratio of 3.25 were tested under pseudo-static reversed-cyclic lateral load to investigate the potential of a hybrid reinforcement scheme of steel-GFRP to improve the seismic behavior of slender RC shear walls. The overall performance of each tested wall was characterized by investigating the hysteretic response, crack propagation, lateral load capacity, and energy dissipation behavior.
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Kida, Katsuyuki, Koretoko Okamoto, Masayuki Ishida, Koshiro Mizobe, and Takuya Shibukawa. "Observation of Corrosion Resistance of 13Cr-2Ni-2Mo Stainless Steel Quenched by Induction Heating." Applied Mechanics and Materials 597 (July 2014): 140–43. http://dx.doi.org/10.4028/www.scientific.net/amm.597.140.
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13%-Cr martensitic stainless steels are widely used in the production of many mechanical components that require high hardness and good corrosion resistance. In the present work, 20mm-diameter 13Cr-2Ni-2Mo steel bars were quenched by induction heating (IH) method and after that tempered in a farness. 240 hours corrosion test of the bars was carried out using a salt spray testing method (JIS Z 2371:2000). The results were compared to two stainless steels, SUS304 and SUS440C. Their inner hardness distributions were measured. It was found that the hardness of IH-quenched and farness-tempered 13Cr-2Ni-2Mo stainless steel is almost the same as that of the SUS440C. The 13Cr-2Ni-2Mo steel has the same corrosion resistance as the SUS304 steel.
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Rafi, Muhammad Masood, Abdul Basit Dahar, Tariq Aziz, and Sarosh Hashmat Lodi. "Elevated Temperature Testing of Thermomechanically Treated Steel Bars." Journal of Materials in Civil Engineering 32, no. 6 (June 2020): 04020145. http://dx.doi.org/10.1061/(asce)mt.1943-5533.0003202.
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Német, Miroslav, Mária Mihaliková, Alexandra Kovalčíkova, and Anna Lišková. "Changing the Hardness Automotive Steels at Different Strain Rate." Key Engineering Materials 635 (December 2014): 41–44. http://dx.doi.org/10.4028/www.scientific.net/kem.635.41.
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Currently, the automotive industry used sheets of different qualities. The most common include IF (inter Interstitial Free) steel and alloyed steel. Use the sheet quality depends on the point of application in the production car. Testing and product testing is a standard part of the process of innovation and production itself. Testing of automotive steels under dynamic conditions is increasingly important. Changing the hardness HV 1 was performed on the fractured bars on the static and dynamic loading conditions. Tests were made on steel IF and S 460.
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Wang, Wei, Jie Chen, Bo Diao, Xuefei Guan, Jingjing He, and Min Huang. "Bayesian Fatigue Life Prediction of Corroded Steel Reinforcing Bars." Advances in Civil Engineering 2021 (December 28, 2021): 1–15. http://dx.doi.org/10.1155/2021/4632152.
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This paper presents a general method for fatigue life prediction of corroded steel reinforcing bars. A fatigue testing on standard specimens with pitting corrosion is carried out to obtain corrosion fatigue data. The maximum corrosion degree (MCD), characterizing the most severe site of the corrosion pit, is identified to have a log-linear relationship with the fatigue life. A fatigue life model incorporating the MCD and the stress range for corroded steel reinforcing bars is proposed. The model parameters are identified using the testing data, and the model is considered as the baseline model. To utilize the proposed model for life prediction of corroded steel reinforcing bars with different geometries and working conditions, the Bayesian method is employed to update the baseline model. The effectiveness of the overall method is demonstrated using independent datasets of realistic steel reinforcing bars.
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Rhim, Hong Chul, Dae You Kim, Chang Shik Cho, and Do Hyun Kim. "Effect of Steel Plates on Estimation of the Compressive Strength of Concrete via Ultrasonic Testing." Materials 13, no. 4 (February 17, 2020): 887. http://dx.doi.org/10.3390/ma13040887.
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The presence of embedded steel affects the estimates obtained for the compressive strength of concrete during ultrasonic testing, as it increases the ultrasonic wave velocity. Thus, if the presence of steel in concrete is inevitable, then a correction factor is required for an accurate estimation of the concrete strength. While previous studies focused on the effect of steel reinforcing bars on the speed of ultrasonic waves in concrete, this work expands on the significance of embedded steel from steel bars to include steel plates. The wave velocity was measured for varying dimensions of embedded steel plates from 15 mm to 150 mm using 54-kHz ultrasonic testing equipment. Through experiments, the effect of steel plates on the ultrasonic testing of concrete was quantified to derive proper correction factors. It was found that the thickness, depth, and height of the steel plates significantly affected the test results. These findings can be applied to ultrasonic testing to estimate the compressive strength of concrete consisting of a significant volume of steel, such as in steel-reinforced concrete structures.
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Fan, Liang, Yi Bao, and Genda Chen. "Feasibility of Distributed Fiber Optic Sensor for Corrosion Monitoring of Steel Bars in Reinforced Concrete." Sensors 18, no. 11 (November 1, 2018): 3722. http://dx.doi.org/10.3390/s18113722.
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This study investigates the feasibility of distributed fiber optic sensor for corrosion monitoring of steel bars embedded in concrete. Two sensor installation methods are compared: (1) attaching the sensor along the bar and (2) winding the sensor on the bar. For the second method, optical fibers were winded spirally on steel bars with different spacings: 0 mm, 2 mm, 5 mm, and 10 mm. Steel bar pull-out testing was conducted to evaluate the effect of presence of distributed sensor on the bond strength of steel–concrete interface. Electrochemical testing was carried out to assess the influence of the installation methods on the corrosion resistance of the reinforced concrete. Winding the optical fiber on steel bars with a 10-mm spacing does not affect the bond strength and corrosion resistance and allows real-time corrosion monitoring. The distributed sensor data can be used to estimate the corrosion induced steel loss and predict concrete cracking.
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Basaran, Bogachan, Harun Yaka, and Ilker Kalkan. "Engineering plastic gripping mechanism for tension testing of FRP bars." Journal of Composite Materials 54, no. 28 (June 17, 2020): 4427–40. http://dx.doi.org/10.1177/0021998320933658.
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A new grip adaptor, made of an engineering plastic Cast Polyamide 6 (PA6G), was developed for tension testing of FRP reinforcing bars. The new adaptor offers several advantages over conventional anchors, including the ease of application and reuse, being economical, no need for skilled labor, smaller difference between the hardness of the adaptors and sample. Bars with three different diameters (6, 8 and 12 mm), three types of fiber (Carbon, Glass and Basalt) and four types of surface texture (ribbed, wound, fine-sand coated and coarse-sand coated with widely-spaced wrapping) were tested to failure under uniaxial tension. Two identical bars were tested for each combination of parameters (fiber type, surface texture and bar diameter), one with PA6G and the other with grout-filled steel anchors. The tests indicated that the proposed method was able to ensure FRP bars to reach their tensile capacities and fail by rupture without crushing in the gripping regions and pull-out from the jaws of the testing machine. The modulus of elasticity, tensile strength and ultimate strain values of the bars with PA6G anchors were in rather close agreement with the respective values of specimens with conventional steel anchors. This close agreement, i.e. mostly a difference below 5%, implies the success of the proposed method. Among all tested bars, only the ribbed ones failed in the gripping regions in the presence of both anchors as a result of the limited contact surface (rib area), pointing out the need for the use of longer anchors for ribbed bars.
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Zhao, Qingyuan, Jianting Zhou, Qianwen Xia, Senhua Zhang, and Hong Zhang. "Non-Destructive Testing of Steel Corrosion Fluctuation Parameters Based on Spontaneous Magnetic Flux Leakage and Its Relationship with Steel Bar Diameter." Materials 12, no. 24 (December 9, 2019): 4116. http://dx.doi.org/10.3390/ma12244116.
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In an actual structure, the arrangement of steel bars is complicated, there are many factors affecting the corrosion of steel bars, and these factors affect each other. However, accurately reflecting the corrosion of steel bars in actual engineering through theoretical calculations is difficult. Besides, it is impossible to detect and evaluate steel bars rust completely and accurately. This article is based on spontaneous magnetic leakage detection technology and adopts the method of stage corrosion and scanning along the reinforcing bar. Based on spontaneous magnetic flux leakage detection technology, the linear change rate of the tangential component curve of the magnetic flux leakage signal generated after the corrosion of a steel bar is studied, and a comparison is made between the steel bar coated concrete samples with different steel bar diameters. In this paper, the “origin of magnetic flux leakage signal” is defined as a reference point, which is convenient for effectively comparing the magnetic signal curves under all operating conditions. Besides, the “rust-magnetic fluctuation parameter” is proposed to accurately reflect the sudden change of leakage magnetic field caused by disconnection due to the corrosion of a steel bar. A new data processing method is provided for the non-destructive testing of steel corrosion using the spontaneous magnetic flux leakage effect, which can effectively reduce the influence of steel bar diameter on magnetic flux leakage signal and improve the precision of non-destructive testing technology of steel bar corrosion using the metal magnetic memory effect.
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Lollini, Federica, Maddalena Carsana, Matteo Gastaldi, and Elena Redaelli. "Corrosion behaviour of stainless steel reinforcement in concrete." Corrosion Reviews 37, no. 1 (January 28, 2019): 3–19. http://dx.doi.org/10.1515/corrrev-2017-0088.
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AbstractIn Europe, stainless steel rebars have been used since the mid-80s, whilst in North America, their use has been progressively growing only since the mid-90s. Due to their higher resistance to corrosion in comparison to ordinary black steel bars, they have been employed in a wide number of applications worldwide to achieve the durability performance of reinforced concrete structures, especially in extremely corrosive marine environments or when long service lives are required. In this paper, a state of the art on the corrosion resistance of stainless steel bars is reported. In particular, the contribution of Professor Luca Bertolini in this research field is considered. Initially, different testing methods are presented to point out their advantages and limitations and then the results on corrosion behaviour of different grades of stainless steel bars (i.e. austenitic, ferritic and duplex), obtained especially with tests in concrete, are analysed. Afterwards, some of the recent applications of stainless steel bars are illustrated.
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Cadoni, Ezio, Matteo Dotta, Daniele Forni, and Nicoletta Tesio. "Dynamic Behaviour of Reinforcing Steel Bars in Tension." Applied Mechanics and Materials 82 (July 2011): 86–91. http://dx.doi.org/10.4028/www.scientific.net/amm.82.86.
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In this paper the preliminary results of the tensile behavior of reinforced steel in a large range of strain rates are presented. Tensile testing at several strain rates, using different experimental set-ups, was carried out. For the quasi-static tests a universal electromechanical testing machine with the maximum load-bearing capacity of 50 kN was used, while for the intermediate and high-strain rate regimes a hydro-pneumatic apparatus and a JRC-Split Hopkinson Tensile Bar respectively were used. The target strain rates were set at the following five levels: 10-3, 30, 250, 500, and 1000 1/s. The specimens used in this research were round samples having 3mm in diameter and 5mm of gauge length obtained from reinforcing bars. Finally, the material parameters for Cowper-Symonds and Johnson-Cook models were determined.
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Yang, Hui, Zhengxing Guo, Hang Yin, Dongzhi Guan, and Sen Yang. "Development and testing of precast concrete beam-to-column connections with high-strength hooked bars under cyclic loading." Advances in Structural Engineering 22, no. 14 (June 19, 2019): 3042–54. http://dx.doi.org/10.1177/1369433219857855.
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A traditional reinforcing detail—hooked bars anchored in the joint core—for the bottom bars in precast beams was improved by using small-diameter high-strength bars to reduce the steel congestion in the cast-in-place connection zone. Five full-scale beam-to-column connections, including a monolithic specimen, were tested under reversed cyclic loading. The primary test variables were the type of beam longitudinal bars, manner of roughening the inner surface of the precast U-shell, presence or absence of the small-diameter stirrups inside the U-shell, and height of the precast columns. An analysis of the strength, ductility, stiffness, and energy dissipation showed that the proposed connection exhibited a comparable, although slightly inferior, seismic performance relative to the monolithic connection. Among the precast specimens, the existence of additional stirrups slightly improved the total performance. The use of high-strength steel bars as beam top longitudinal bars further decreased the loading capacity and energy dissipation. The air bubble film technique used to roughen the interfaces ensured the structural integrity.
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Olaseinde, Oluwatoyin, O. Ajanaku, O. M. Ojo, and S. O. Seidu. "COMPARATIVE STUDY OF THE REINFORCED STEEL BARS OBTAINED FROM A FAILED RESIDENTIAL BUILDING AND THE SHELVES." FUTA JOURNAL OF ENGINEERING AND ENGINEERING TECHNOLOGY 15, no. 2 (November 29, 2021): 128–38. http://dx.doi.org/10.51459/futajeet.2021.15.2.383.
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Nigeria is a developing nation, the need to build structures is on high rise. The rate of structure failure and building collapse is also on the rise. This paper presents a comparative study on Mechanical Properties of Reinforced steel bars obtained from the shelves, and that obtained from the failed structure of a residential building which is then compared to International standard NO-432 . Steels are main reinforcing materials for most structural buildings, but when the integrity is compromised, it leads to devastating consequences. The quality of concrete and steel reinforcement must be such that has appropriate yield strength so that the structure can sustain the require load within the required time interval. The Ultimate Tensile Strength and percentage elongation of the steel bars obtained from the two sources were investigated. One of the sources was a reinforcing bar used in Millennium Estate, Mary Land, Lagos State, Nigeria. The steel bar samples of sizes 10mm and 16mm diameter were subjected to mechanical testing using a universal testing machine. The percentage elongation met with the standards while the 16mm samples are below the standards for both the failed structure and shelves.
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Ahmed, Ehab A., Christian Dulude, and Brahim Benmokrane. "Concrete bridge barriers reinforced with glass fibre-reinforced polymer: static tests and pendulum impacts." Canadian Journal of Civil Engineering 40, no. 11 (November 2013): 1050–59. http://dx.doi.org/10.1139/cjce-2013-0019.
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The behaviour of concrete bridge barriers reinforced with glass fibre-reinforced polymer (GFRP) bars has been investigated at the University of Sherbrooke in collaboration with the Ministry of Transportation of Quebec (MTQ) through a two-phase research project. This paper presents the test results of MTQ Type 311 barrier prototypes under static (Phase I) and pendulum impact (Phase II) loading conditions. The test program included two full-scale 2.6 m long barrier prototypes for laboratory testing under static loads (Phase I) and four full-scale 11 m long barrier prototypes for field impact tests (Phase II). The laboratory static tests included one prototype totally reinforced with GFRP bars and one totally reinforced with steel bars for comparison, whereas the pendulum impact tests included two replicas totally reinforced with GFRP bars and another two totally reinforced with conventional steel bars. The barrier walls of the six prototypes were provided with the same reinforcement amount of GFRP and steel bars (No. 20 GFRP @ 200 mm and 20M steel bars @ 200 mm). The performance of the GFRP-reinforced concrete (GFRP-RC) barriers was evaluated and compared with that of their steel-RC counterparts. The results of this investigation revealed that the behaviour of the GFRP-RC concrete bridge barriers of MTQ Type 311 is similar to their steel-RC counterparts.
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Liu, Hanbing, Xiang Lyu, Yuwei Zhang, Guobao Luo, and Wenjun Li. "Steel Corrosion Evaluation of Basalt Fiber RPC Affected by Crack and Steel-Concrete Interface Damage Using Electrochemical Methods." Sensors 20, no. 18 (September 4, 2020): 5027. http://dx.doi.org/10.3390/s20185027.
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Basalt fiber (BF) is a new anti-corrosion and environmentally friendly material, which is expected to delay the corrosion process of steel bars and improve the durability of reinforced reactive powder concrete (RPC). The electrochemical method is a nondestructive testing and real-time monitoring technique used to characterize the corrosion behaviors of steel bars embedded in concrete structures. In this paper, the electrochemical technique was employed to evaluate the corrosion of steel bars embedded in basalt fiber modified reactive powder concrete (BFRPC). Besides, crack and steel-concrete interface damage (SCID) were considered as typical factors that affect steel corrosion in concrete. Thus, both reinforced fiber-free RPC and BFRPC specimens with crack and SCID were prepared for evaluating the steel corrosion behaviors by electrochemical methods. The results revealed that both crack and SCID would aggravate the steel corrosion, and the crack was the major factor that affects the corrosion process. Moreover, the excellent compactness of BFRPC and the bridging action of BF could effectively prevent the concrete cracking and steel corrosion process of concrete. Using reinforced BFRPC instead of ordinary concrete in practical projects could greatly extend the service life of steel bars.
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Cui, Yifei, Shihao Qu, Jiuwen Bao, and Peng Zhang. "Bond Performance of Steel Bar and Fly Ash-Based Geopolymer Concrete in Beam End Tests." Polymers 14, no. 10 (May 14, 2022): 2012. http://dx.doi.org/10.3390/polym14102012.
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This paper presents a comprehensive investigation of the bond characteristics of steel bar reinforced geopolymer concrete (GPC). The ASTM A944 beam end tests were conducted on GPC beams reinforced with plain or ribbed bars. The bond–slip curves and the bond strength of GPC beams were obtained. The relationship between the bond stress and relative slip in plain and ribbed bar reinforced GPC has been represented by empirical formulae. The bond testing results were compared with those of corresponding ordinary Portland cement concrete (OPC) using statistical hypothesis tests. The results of hypothesis testing showed that GPC was significantly superior to OPC in terms of bond capability with plain bars and bond stiffness with ribbed bars. The statistical analysis indicated that the bond–slip relations derived for OPC are inapplicable to GPC; thus, new bond–slip relations are suggested to estimate the development of bond stress and relative slip between GPC and steel bars.
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Cable, James K. "Changing the Shape and Location of Pavement Load Transfer Devices." Transportation Research Record: Journal of the Transportation Research Board 1907, no. 1 (January 2005): 95–101. http://dx.doi.org/10.1177/0361198105190700111.
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Load transfer is an important aspect of portland cement concrete joint design. To date, aggregate interlock and round steel dowels have been used to accomplish load transfer. Research was done to examine the use of steel dowels of alternative shapes to provide load transfer. A field research project in Iowa has used two elliptical bars of different sizes at three spacings and numbers of bars per joint. Test sections included bars across the entire joint and sections using bars only in the wheelpaths. The impact of cut, fill, and transition sections was also factored into the experimental design. This paper documents the construction of the project, testing that is being done, and the initial results of the work.
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Shahidi, F., L. D. Wegner, and B. F. Sparling. "Investigation of bond between fibre-reinforced polymer bars and concrete under sustained loads." Canadian Journal of Civil Engineering 33, no. 11 (November 1, 2006): 1426–37. http://dx.doi.org/10.1139/l06-070.
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Although the use of fibre-reinforced polymer (FRP) bars to replace steel in reinforced concrete is becoming more common, uncertainty remains concerning the long-term performance of FRP, including the effect of a sustained load on the bond between the FRP bars and the concrete. An experimental study was therefore undertaken to investigate the long-term durability of the bond for various types of bars embedded in concrete: one type of glass FRP, two types of carbon FRP, and conventional steel reinforcing bars. Pullout specimens were tested both statically to failure and under sustained loads for periods of up to 1 year while free-end slip was monitored. Results revealed lower short-term bond strengths for FRP bars relative to steel and significant variability in long-term bond-slip performance among FRP bars of different types. Post-testing investigations revealed damage to bar surfaces at the macroscopic level, as well as broken longitudinal fibres and damage to the surface coatings at the microscopic level.Key words: reinforced concrete, fibre-reinforced polymer (FRP), bond, creep, pullout, sustained loads.
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Caprili, Silvia, Jörg Moersch, and Walter Salvatore. "Mechanical Performance versus Corrosion Damage Indicators for Corroded Steel Reinforcing Bars." Advances in Materials Science and Engineering 2015 (2015): 1–19. http://dx.doi.org/10.1155/2015/739625.
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The experimental results of a testing campaign including tensile and low-cycle fatigue tests on different reinforcing steel bar types in the as-delivered and corroded condition are presented. Experimental data were statistically analyzed adopting ANOVA technique; Performance Indicators (PIs), describing the mechanical performance characteristics of reinforcements, and Corrosion Damage Indicators (CDIs), describing the detrimental effects of corrosion phenomena, were determined and correlated in order to evaluate the influence of corrosion on the behaviour of reinforcing steels, providing useful information for designers in addition to what is presented in current standards.
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Fillmore, Brandon, and Pedram Sadeghian. "Contribution of longitudinal glass fiber-reinforced polymer bars in concrete cylinders under axial compression." Canadian Journal of Civil Engineering 45, no. 6 (June 2018): 458–68. http://dx.doi.org/10.1139/cjce-2017-0481.
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Contribution of longitudinal glass fiber-reinforced polymer (GFRP) bars in concrete columns under compression has been ignored by current design guidelines. This paper challenges this convention by testing 21 concrete cylinders (150 mm × 300 mm) reinforced with longitudinal GFRP and steel bars in compression. It was observed that GFRP bars could sustain high level of compressive strains long after the peak load of the specimens without any premature crushing. The results of a new coupon test method showed that the elastic modulus of GFRP bars in compression is slightly higher than that of in tension, however the compressive strength was obtained 67% of tensile strength. An analytical model was successfully implemented to predict the axial capacity of the tests specimens and it was found that the contribution of the bars in the load capacity of the specimens was within 4.5–18.4% proportional to the bars reinforcement ratio normalized to the elastic modulus of steel bars.
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Habeeb Askandar, Nasih, and Abdulkareem Darweesh Mahmood. "Torsional Strengthening of RC Beams with Near-Surface Mounted Steel Bars." Advances in Materials Science and Engineering 2020 (March 18, 2020): 1–11. http://dx.doi.org/10.1155/2020/1492980.
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The strength of reinforced concrete members can be enhanced by using the externally bonded reinforcement (EBR) and near-surface mounted (NSM) methods. However, very few studies have adopted the NSM method for torsional strengthening. Although previous studies have reported the efficacy of using epoxy-resin-bonded NSM steel bars in increasing the flexural and shear strength of RC beams, no study has examined the use of steel bars and epoxy adhesives for torsional strengthening. Therefore, this study investigates the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with NSM steel bars (Ø10 mm) in different configurations. The practical part of this investigation consisted of seven cast and tested beams of 150 × 250 × 2000 mm dimensions. One beam was reference, which is not strengthened; meanwhile, all the other beams were strengthened with two U-shape-welded NSM steel bars. During the testing process, the twist angle at the torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional beam were compared with those of the strengthened beams. The torsional performance of the RC beams was significantly improved by using NSM steel bars, whereas in various NSM configurations, the 90° NSM beams outperformed the 45° NSM beams.
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Zhou, Yingwu, Li Zhuang, Zhiheng Hu, Biao Hu, Xiaoxu Huang, and Zhongfeng Zhu. "Perforated steel for realizing extraordinary ductility under compression: Testing and finite element modeling." REVIEWS ON ADVANCED MATERIALS SCIENCE 61, no. 1 (January 1, 2022): 195–207. http://dx.doi.org/10.1515/rams-2022-0021.
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Abstract One key obstacle restricting the application of fiber-reinforced polymer (FRP) bars from being used as reinforcement in structural concrete is the significantly reduced ductility because FRP under tension is linear elastic up to brittle rupture at small strain. Recently, a new structural concept, compression yielding (CY), has been proposed as a way to overcome the insufficient ductility of concrete structures reinforced with FRP bars or other non-ductile materials. In the CY structural system, the compression-zone of normal concrete is replaced by a ductile material within the plastic hinge. This enables the flexural deformation to be achieved by the compressive deformation of CY material rather than a tensile deformation of longitudinal reinforcing bars. To this end, an ideal CY material requires strength to be maintained during the extraordinarily large deformation process. This study tries to identify methods for developing this kind of CY material by designing and optimizing perforations inside a mild steel block. The effects of key parameters, including ratio, diameter, and arrangement of perforations on the stiffness, strength, and ductility of CY materials were experimentally investigated. In addition, a finite element (FE) model was developed to predict the behavior of the proposed CY material.
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Bernardo, Hector, Miguel Ángel Vicente, Dorys Carmen González, and Juan Fernando Martínez. "Cyclic Bond Testing of Steel Bars in High-Performance Underwater Concrete." Structural Engineering International 24, no. 1 (February 2014): 37–44. http://dx.doi.org/10.2749/101686614x13830788505513.
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Huo, Bao Rong, and Xiang Dong Zhang. "Experiment Study of BFRP Bars’ Mechanical Properties." Applied Mechanics and Materials 174-177 (May 2012): 830–33. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.830.
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The testing rule of mechanical properties of material can be established and the mechanical performance can be found by studying the basic mechanical properties of BFRP bars. Using the opressive sleeve anchor developed by the researchers,tensile tests of BFRP bars are carried out according to the national standards of “GFRP bar tensile test methods”.The BFRP bar’s force-deformation curve is linear before the force-deformation relationship is destroyed,therefore,referring to steel wire or steel cable,the BFRP bar’s reliable strength is suggested to be approximately 80% of its ultimate tensile strength. The BFRP bar’s tensile elastic modulus is related to the content of basalt fiber.The tensile elastic modulus increases with the increase of the basalt fiber’s content and the content increases when the BFRP bar’s diameter becomes longer, so the tensile elastic modulus increases with the increase of its diameter. Compared with steel, the BFRP bar is obviously superior in the aspects of tensile strength, corrosion resistance ,etc,therefore to use the BFRP bar in reinforced concrete structures insead of steel is feasible.
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Lee, Jung Yoon. "Surface Interaction Studies on Glass Fiber Reinforced Polymer Bars." Key Engineering Materials 345-346 (August 2007): 1217–20. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1217.
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The use of fiber reinforced polymer (FRP) bars has been gaining increasing popularity in the civil engineering community due to their favorable properties such as high-strength-to-weight ratio and good corrosion resistance. In order for concrete to be FRP reinforced, there must be interfacial bond between FRP bars and concrete. The interfacial bond behavior of FRP bars to concrete is expected to vary from that of conventional steel bars, since various key parameters that influence bond performance are different. This paper presents the results of an experimental and analytical study on the interfacial surface interaction of glass fiber reinforced polymer (GFRP) bars in high strength concrete cube. The experimental program consisted of testing 54 concrete cubes prepared according to CSA S802-02 standard 1). The split specimens showed that interfacial bond failure of the steel bar occurred due to concrete crushing in front of the bar deformations, while interfacial bond failure of the GFRP bars occurred partly on the surface of the bar and partly in the concrete by peeling of the surface layer of the bar.
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Lei, Bin. "Bond Behaviour between Recycled Aggregate Concrete and Corroded Steel Rebars." Applied Mechanics and Materials 166-169 (May 2012): 1391–94. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.1391.
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In this paper, corrosion percentages ranged from 0 to 7.62% of steel rebar for pulling out specimens was controlled by the accelerated method of electrochemistry. According to the RILEM standard, pulling out test with dimensions of 200×200×200mm3 and recycled aggregate concrete (RAC) of C30 was carried out, and the load versus slip curves between RAC and corroded steel rebars with different corrosion percentages were recorded. Based on the experimental results, the effect of RAC and reinforcement corrosion on the bond behaviour between steel rebars was investigated. The results show that the bond strength between RAC and deformed bars increases with corrosion up to a certain amount, and then the bond strength decreases as the corrosion rate further increases, which is similar to that of normal concrete. However, the decreasing rate of the bond strength between RAC and corroded steel rebars is much faster than that between normal concrete and corroded steel bars. According to the testing results, the relationship of bond stress-slip between corroded bars and RAC was given in the end.
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Rafi, Muhammad Masood, Abdul Basit Dahar, and Tariq Aziz. "High temperature mechanical properties of steel bars available in Pakistan." Journal of Structural Fire Engineering 9, no. 3 (September 10, 2018): 203–21. http://dx.doi.org/10.1108/jsfe-06-2017-0035.
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Purpose The purpose of this paper is to present the results of experimental testing of steel rebars at elevated temperatures. Three types of bars available in the local market in Pakistan were used. These data are not available in Pakistan. Design/methodology/approach Three types of bars were used, which included cold-twisted ribbed (CTR), hot-rolled deformed (HRD) and thermo-mechanically treated (TMT) bars. The diameter of the bar of each type was 16 mm. The bars were heated in an electrical furnace at temperatures which were varied from 100°C to 900°C in increment of 100°C. Bars of each type were also tested at ambient temperature as control specimens. The change of strength, strain and modulus of elasticity of the bars at high temperatures were determined. Findings The mechanical properties of the bars were nearly unaffected by the temperatures up to 200°C. CTR bars did not show yield plateau and strain hardening both at ambient and high temperatures. The high temperature yield strength and elastic modulus for all the three types of bars were similar at all temperatures. The yield plateau of both the HRD and TMT bars disappeared at temperatures greater than 300°C. The ultimate strength at high temperature of the HRD and TMT bars was also similar. The behaviours of the HRD and TMT bars changed to brittle beyond 400°C as compared to their behaviours at ambient temperature. The CTR bars exhibited ductile characteristics at failure at all the exposure temperatures relative to their behaviour at ambient temperature. Research limitations/implications The parameters of the paper included the rebar type and heating temperature and the effects of temperature on strength and stiffness properties of the steel bars. Practical implications Building fire incidents have increased in Pakistan. As reinforced concrete (RC) buildings exist in the country in significant numbers, the data related to elevated temperature properties of steel is required. These data are not available in Pakistan presently. The presented paper aims at providing this information for the design engineers to enable them to assess and increase fire resistance of RC structural members. Originality/value The presented paper is unique in its nature in that there is no published contribution to date, to the best of authors’ knowledge, which has been carried out to assess the temperature-dependent mechanical properties of steel reinforcing bars available in Pakistan.
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Li, Xian, Heng Lin Lv, and Shu Chun Zhou. "Flexural Behavior of Innovative Hybrid GFRP-Reinforced Concrete Beams." Key Engineering Materials 517 (June 2012): 850–57. http://dx.doi.org/10.4028/www.scientific.net/kem.517.850.
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Fiber-reinforced polymer (FRP) bars are emerging as a competitive option for replacing steel bars as reinforcement in various concrete structures exposed to aggressive environments. However, the low elastic modulus and brittleness of FRP bars significantly reduce the stiffness and the ductility of FRP-reinforced concrete (FRP-RC) members. In order to improve the flexural behavior of FRP-RC members and meanwhile ensure their satisfactory corrosion-resistant performance, an innovative FRP-reinforced concrete encased steel composite (FRP-RCS) member, which consists of ductile structural steel shapes in combination with corrosion-resistant FRP-reinforced concrete, was conceived and studied. An experimental investigation on the flexural behavior of the proposed FRP-RCS beams was conducted by testing a total of five large-scale simply supported beam specimens subjected to four-point bending loads. The test specimens included one FRP-RC beam reinforced with GFRP bars only and four FRP-RCS beams reinforced with both GFRP bars and encased structural steel shapes. The main parameters considered in this study were concrete compressive strength and amounts of GFRP reinforcement. The test results indicated that using encased steel shapes provided a significant enhancement in load carrying capacity, stiffness, ductility and energy absorption capacity of test beams. The tested FRP-RC beam suffered a brittle failure caused by sudden fracture of tensile GFRP bars whereas the proposed FRP-RCS beams behaved in a ductile manner due to the beneficial residual strength of encased steel shapes following concrete crushing. In addition, the experimental results also demonstrated that the concrete compressive strength had little effect on load carrying capacity of FRP-RCS beams whereas the load carrying capacity can be enhanced by increasing the reinforcement ratio. Analytical methods were also constructed using OpenSEES2.2.2 to simulate the load-deflection response of tested beams..
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Dabiri, Hamed, Visar Farhangi, Mohammad Javad Moradi, Mehdi Zadehmohamad, and Moses Karakouzian. "Applications of Decision Tree and Random Forest as Tree-Based Machine Learning Techniques for Analyzing the Ultimate Strain of Spliced and Non-Spliced Reinforcement Bars." Applied Sciences 12, no. 10 (May 11, 2022): 4851. http://dx.doi.org/10.3390/app12104851.
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The performance of both non-spliced and spliced steel bars significantly affects the overall performance of structural reinforced concrete elements. In this context, the mechanical properties of reinforcement bars (i.e., their ultimate strength and strain) should be determined in order to evaluate their reliability prior to the construction procedure. In this study, the application of Tree-Based machine learning techniques is implemented to analyze the ultimate strain of non-spliced and spliced steel reinforcements. In this regard, a database containing the results of 225 experimental tests was collected based on the research investigations available in peer-reviewed international publications. The database included the mechanical properties of both non-spliced and mechanically spliced bars. For better accuracy, the databases of other splicing methods such as lap and welded-spliced methods were excluded from this research. The database was categorized as two sub-databases: training (85%) and testing (15%) of the developed models. Various effective parameters such as splice technique, steel grade of the bar, diameter of the steel bar, coupler geometry—including length and outer diameter along with the testing temperatures—were defined as the input variables for analyzing the ultimate strain using tree-based approaches including Decision Trees and Random Forest. The predicted outcomes were compared to the actual values and the precision of the prediction models was assessed via performance metrics, along with a Taylor diagram. Based on the reported results, the reliability of the proposed ML-based methods was acceptable (with an R2 ≥ 85%) and they were time-saving and cost-effective compared to more complicated, time-consuming, and expensive experimental examinations. More importantly, the models proposed in this study can be further considered as a part of a comprehensive prediction model for estimating the stress-strain behavior of steel bars.
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Saadoon Al-Yassri, Labeeb, Alaa Mahdi Al-Khekany, and Hajer Satea Abbas. "Experimental Study of Replacement the Tension Reinforcing Bars in Concrete Beams by Steel Pipes." International Journal of Engineering & Technology 7, no. 4.20 (November 28, 2018): 229. http://dx.doi.org/10.14419/ijet.v7i4.20.25931.
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Structures designed with reinforced concrete beams are used extensively in construction projects because of their functional and economic features. In this research, tested concrete beams were cast and reinforced with small diameter steel pipes and /or steel bars as flexural reinforcement to study the effect of this configuration of reinforcement on the structural behavior of reinforced concrete beams. The idea of this research involves performing and testing of four reinforced concrete beams reinforced by small diameter steel pipes with different percentages of replacement with traditional steel bars (0%, 33%, 66% and 100%). The experimental results showed that using of steel pipes reduces the flexural capacity by (2.7, 18.3, 37.5%) if compared with traditional steel bar according to the replacement percentages of (33%, 66%, and 100%) respectively. Moreover, the stiffness of beams reinforced with steel pipes (fully or partially) decreased as a result of the difference in the mechanical properties between steel bar and the steel pipe and also, the bond strength reduction between the smooth steel pipe and surrounded concrete.
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Pająk, Małgorzata, and Grzegorz Wandzik. "Laboratory Tests of Concrete Beams Reinforced with Recycled Steel Fibres and Steel Bars." Materials 14, no. 22 (November 9, 2021): 6752. http://dx.doi.org/10.3390/ma14226752.
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This paper explores the possibility of the partial replacement of the longitudinal reinforcement in reinforced concrete (RC) beams with recycled steel fibres (RSF). Testing was focused on the contribution of two volume ratios of the RSF—0.5%, 1.0%. Basic compression and flexural tensile tests were performed to evaluate the effectiveness of the fibres following current standards. Additionally, the full-scale beams with and without conventional reinforcement were subjected to four-point bending tests. The results indicate that RSF improved the load-bearing capacity of the RC beams. Cooperation of RSF with the steel bars in carrying loads was proved. Findings from the Digital Image Correlation (DIC) revealed no impact on the cracking pattern of the RC beams.
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Kovačič, Miha, Goran Đukić, Brigita Gajšek, and Klemen Stopar. "CAD Based Electric Transporter Path Planning and Production Storage Optimization Using Genetic Algorithm – Industrial Case Study." Tehnički glasnik 14, no. 2 (June 11, 2020): 174–79. http://dx.doi.org/10.31803/tg-20200523200341.
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Štore Steel Ltd. is one of the largest flat spring steel producers in Europe. There are two production lines after rolling – one for flat bars and the other for round bars. The flat bars production generally consists of visual examination, straightening and cutting operation. In addition, heat treatment or magnetic particle testing could be conducted. On the other hand, the round bars production consists generally of straightening, automatic control line control, chamfering and cutting. In addition, heat treatment is possible. For manipulation of the material in the rolling plant, the electric transporter and several cassettes are used. In the paper path planning and production storage optimization (i.e. storage spaces for cassettes) were conducted using genetic algorithm. The production storage is actually the space between main transport passage and individual operations. In the research the universal system using CAD geometry is presented where AutoCAD environment and in-house developed AutoLISP system were used. The production storage – storage spaces for cassettes (location and orientation) with corresponding electric transporter trajectories are represented as CAD objects and thus form individual solution/organism. The organisms undergo simulated evolution. The results of the evolution are compared with actual production storage in the steel plant.
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Harrigan, John J., Bright Ahonsi, Elisavet Palamidi, and Steve R. Reid. "Experimental and numerical investigations on the use of polymer Hopkinson pressure bars." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2023 (August 28, 2014): 20130201. http://dx.doi.org/10.1098/rsta.2013.0201.
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Split Hopkinson pressure bar (SHPB) testing has traditionally been carried out using metal bars. For testing low stiffness materials such as rubbers or low strength materials such as low density cellular solids considered primarily herein, there are many advantages to replacing the metal bars with polymer bars. An investigation of a number of aspects associated with the accuracy of SHPB testing of these materials is reported. Test data are used to provide qualitative comparisons of accuracy using different bar materials and wave-separation techniques. Sample results from SHPB tests are provided for balsa, Rohacell foam and hydroxyl-terminated polybutadiene. The techniques used are verified by finite-element (FE) analysis. Experimentally, the material properties of the bars are determined from impact tests in the form of a complex elastic modulus without curve fitting to a rheological model. For the simulations, a rheological model is used to define the bar properties by curve fitting to the experimentally derived properties. Wave propagation in a polymer bar owing to axial impact of a steel bearing ball is simulated. The results indicate that the strain histories can be used to determine accurately the viscoelastic properties of polymer bars. An FE model of the full viscoelastic SHPB set-up is then used to simulate tests on hyperelastic materials.
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Ahmad, Sazzad, and Wahidur Rahman Sajal. "An Experimental Investigation of Relationship between surface Hardness and Strength of Locally produced TMT 500W bar in Bangladesh." Journal of Engineering Science 11, no. 1 (October 5, 2020): 113–22. http://dx.doi.org/10.3329/jes.v11i1.49554.
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The high-strength mild steel bars (usually low carbon steel) are widely used for structural purposes throughout the world including Bangladesh. The strength of these deformed barsis measured through a sample decimation process via Universal Testing Machine (UTM), after which the broken pieces are discarded as scrap for recycling. Therefore, measuring the hardness of steel could be a good indication of strength and will involve less sample and short time for testing. The strength–hardness relationship for steel and cast iron is well defined. However, the TMT 500W deformed bar using in Bangladesh has different structural phenomena due to its unique fabrication technique. Therefore, it is necessary to understand how the strength varies with hardness for this grade of steel. The current research aims to explore the hardness–strength relationship for TMT (Thermomechanical Treatment) 500W bar as an alternate of the tensile test to minimize the wastage, cost and time of testing. Several TMT 500W bars were collected from the local market and measured the Rockwell Hardness B (HRB), strength and other relevant macroscopic/microscopic parameters. Finally, two empirical relationships of yield and tensile strength have been established using rim hardness, core hardness, and rim thickness data. The actual strength data shows a good agreement with present findings and the result variation is found less than 2% and 3% in the case of yield strength and tensile strength respectively.
Journal of Engineering Science 11(1), 2020, 113-122
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Gajdzica, Tomáš, Jiří Kliber, and Milan Kotas. "The Microstructural Properties of Microalloyed Steel after Plastometric Testing." Materials Science Forum 567-568 (December 2007): 373–76. http://dx.doi.org/10.4028/www.scientific.net/msf.567-568.373.
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With the aid of an ASC-type finishing line (Automatic System Control) and continuous cooling of the rolled stock in water boxes, modern continuous light mills enable thermomechanical (controlled) rolling of SBQ-type rods (Special Bar Quality). During the thermomechanical forming (at different temperatures or cooling rates etc.), one can analyze the quality parameters of roundsection steel bars. In order to obtain better understanding to the forming conditions (temperature, strain and strain rate) and the possibility of cooling (related to its rate and time), an experiment involving continuous and discontinuous testing by means of a Gleeble plastometer was suggested. After its implementation, the attention was focused on the mathematical interpretation of the stressstrain characteristics of the steel and on metallographic observation of microstructural changes. The results achieved are of universal meaning and contribute to the theoretical understanding of controlled forming.
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Liu, Yong Jun, Qing Hong Zeng, Hong Ru Liu, and Shuo Xun Wang. "Experimental Study on Post Fire Tensile Properties of Reinforcing Rebars Connected by Grout-Filled Splice Sleeves." Key Engineering Materials 773 (July 2018): 305–10. http://dx.doi.org/10.4028/www.scientific.net/kem.773.305.
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This paper presents some experimental results of tensile properties of reinforcing bars spliced by grout-filled coupling sleeves after exposed to fires to identify the effect of temperature histories on tensile properties of spliced reinforcing bars, which provide a useful base for assessing structural behaviors of precast reinforced concrete buildings damaged by fires. A spliced rebar system investigated in this paper consists of two equal-diameter steel reinforcing bars with 25mm diameter and a straight coupling sleeve with 55mm outer and 42mm inner diameters. As a result, the thickness of grout between internal steel bars and outer sleeves are 8.5mm. Five test specimens are manufactured in identical technology and divided into three groups. First group is reference group consist of just one specimen which is not exposed to fire. Second and third groups consist of two specimens that are exposed to ISO 834 standard fire in furnace for 15 and 25 minutes respectively. The temperature-time curves of grout between rebars and sleeves are measured via thermocouples embedded in grout. Subsequently, a universal testing machine is used to test the ultimate load bearing capacities of five specimens. Test results demonstrate that ultimate load bearing capacities of steel rebars spliced by grout-filled sleeves are considerably reduced due to fire damaged grout.
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de Alcantara, Naasson P., Danilo C. Costa, Diego S. Guedes, Ricardo V. Sartori, and Paulo S. S. Bastos. "A Non-Destructive Testing Based on Electromagnetic Measurements and Neural Networks for the Inspection of Concrete Structures." Advanced Materials Research 301-303 (July 2011): 597–602. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.597.
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This paper presents a new non-destructive testing (NDT) for reinforced concrete structures, in order to identify the components of their reinforcement. A time varying electromagnetic field is generated close to the structure by electromagnetic devices specially designed for this purpose. The presence of ferromagnetic materials (the steel bars of the reinforcement) immersed in the concrete disturbs the magnetic field at the surface of the structure. These field alterations are detected by sensors coils placed on the concrete surface. Variations in position and cross section (the size) of steel bars immersed in concrete originate slightly different values for the induced voltages at the coils.. The values for the induced voltages were obtained in laboratory tests, and multi-layer perceptron artificial neural networks with Levemberg-Marquardt training algorithm were used to identify the location and size of the bar. Preliminary results can be considered very good.
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Miriţoiu, Cosmin Mihai, Dumitru Bolcu, Marius Marinel Stănescu, Rosca Vîlcu, and Dan Ilincioiu. "A Comparison of Composite Bars against Metallic Bars from the Mass per Unit Length Point of View." Key Engineering Materials 601 (March 2014): 58–61. http://dx.doi.org/10.4028/www.scientific.net/kem.601.58.
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There were built some new original composite sandwich bars with polypropylene honeycomb core and the exterior layers of the bars were made of epoxy resin reinforced with steel wire mesh. For these composite bars, there were determined the stiffness by using two different experimental methods: variant 1- using the Walter-Bai testing machine and variant 2- using the eigenfrequency of the first eigenmode. The errors between these two methods were determined. In the next stage of the paper, some metallic beams, equivalent from the stiffness point of view with the composite ones, were considered. Comparisons between them, from the mass per unit length point of view, were made.
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Salih Maged, Saad Frhan. "Resistance of Fiber Reinforced Concrete Plates to Dynamic Loads." Tikrit Journal of Engineering Sciences 14, no. 4 (December 31, 2007): 1–17. http://dx.doi.org/10.25130/tjes.14.4.07.
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The objective of this work is to study the effect of impact and blast dynamic loading upon concrete plates reinforced with normal deformed steel bars as well as steel or glass fibers. In order to examine the effect of using different volume and weight fractions of s skeletal bars and steel or glass fiber reinforcements on the impact and blast resistance, 24 plates and 24 prisms were manufactured as test specimens. A set consisting 0f 8 plates were tested under high velocity impact using 14.7 caliber bullets with a shooting distance of 63 m. The specimens with 1.5 % steel fiber and two layers of steel mesh (8 mm at 75 mm) have shown resistance to full perforation of the bullet. Improvements to the resistance to spalling, scabbing and crack growth have also been observed. Field blast testing was carried out on a second set of 8 specimens by using a charge of 100 gm located at the center of each specimen. All the plates were 160 mm thick and with had minimum reinforced of 0.75% glass fiber and a single layer of steel mesh (8 mm at 75 mm). Have shown resistance to full perforation of waves and have restricted the number, the width and the growth of cracks. The last set of the remaining 8 plates was subjected to a low speed impact test performed by a falling steel ball. Test results clearly show the significant effect of using steel and glass fiber besides deformed bars to enhance the impact resistance by 400 % and 20 % by using 1.5 % steel fiber and 0.75 % glass fiber resistance .Energy absorption capacity and ductility were also increased by 100 % and 600 % by using 1.5 steel fiber. Chang in compressive strength of about ±6 % and ± (20 – 30 ) % were observed by using 1.5% steel fibers and 0.75% glass fibers respectively. The inclusion of 1.5% steel fibers and 0.75% glass fibers together with deformed steel bars have improved the tensile strength by 200% and 70% respectively.
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Hopartean, George, Ted Donchev, Diana Petkova, Costas Georgopoulos, Mukesh Limbachiya, and Noel Parnada. "Experimental testing of medium scale GFRP reinforced concrete frames." MATEC Web of Conferences 289 (2019): 04004. http://dx.doi.org/10.1051/matecconf/201928904004.
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Fibre reinforced polymers (FRP) have been used as strengthening for existing RC structures for many decades. Lately, there has been a lot of interest in using FRP as internal reinforcement in beams, slabs and columns. One potential area of application could be reinforced concrete frames internally reinforced with GFRP bars. With limited research in this direction, the objective of this publication is to assess the behaviour of glass FRP (GFRP) reinforced concrete frames under reversed cyclic lateral in plane loading and to analyse the seismic performances of such elements. For the purpose of this paper, experimental testing of two 1/3 scaled down frames is conducted in displacement-controlled mode with the loading history according to ACI 374.1-05. The control sample is reinforced with conventional steel reinforcement and the results obtained are compared with the sample reinforced with GFRP bars. In summary, observations on the sample behaviour at specified drift ratio such as load-displacement behaviour, envelope curves and energy dissipation are presented.
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Razdobreev, V. G., D. G. Palamar, O. I. Leshchenko, and K. Yu Kluychnikov. "MODERN TRENDS IN THE PRODUCTION OF CORROSION-RESISTANT AND FIRE-RESISTANT PRESTRESSING REINFORCING BARS." Fundamental and applied problems of ferrous metallurgy, no. 35 (2021): 108–33. http://dx.doi.org/10.52150/2522-9117-2021-35-108-133.
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The aim of the work is to study modern methods of production in the world of corrosion-resistant and fire-resistant high-strength reinforced rolled steel, designed for pre-stressed reinforced concrete structures. The specific cost of reinforcement is determined by the ratio of its value to the design resistance and decreases with increasing strength class. In Ukraine, economically alloyed steel grades are used for the production of prestressed high-strength reinforcing steel with a diameter of 6-40 mm of periodic profile according to DSTU 3760: 2019. It is also possible to use thermal strengthening of rolled products from rolling heating in the rolling mill stream, or from special (separate) heating. Hardening, tempering and also cold deformation of smooth profiles with the subsequent drawing of a periodic profile are also applied. According to the Interstate GOST 34028-2016 for the countries of the Customs Union, high-strength reinforcing steel of periodic profile of class A600p is made in bars and skeins with a diameter of 10-40 mm, and classes A800 and A1000 only in bars with a diameter of 10-40 mm from low-alloy steel grades. Depending on the diameter of the reinforcing steel, different production methods are used. GOST 34028-2016 contains clear requirements for corrosion resistance and methods of its testing. Many foreign requirements for the production of high-strength prestressed reinforcement, depending on the diameter of the profile (6-50 mm) and the method of production use carbon steels with different maximum carbon content from 0.37 to 0.8%, maximum silicon content from 0.55 up to 2.0% and a maximum manganese content of 1.8 to 2.0%. Thermomechanical reinforcement of reinforcing steel from rolling heating in the flow of rolling mills, hardening from separate (special) heating followed by tempering and strengthening by mechanical extraction followed by low-temperature tempering are used. Corrosion is the main cause of damage and destruction of reinforced concrete structures and buildings of prestressed reinforced steel from carbon steels. This problem in the world today is solved with the use of stainless steels, which have high corrosion resistance and fire resistance. Prestressed stainless steel reinforcement has higher strength and, especially, ductility than carbon steel. Stainless steel grades are used for the production of prestressed reinforcing steel with a diameter of 5 to 75 mm. In the production of periodic profiles of stainless steel reinforcement, there are two main technological routes: hot rolling and cold rolling. A promising way is the use of controlled hot rolling and thermomechanical treatment. As the rolling temperature decreases, the hardness of the austenite phase increases. For two-phase stainless steels, this allows to achieve high strength and ductility. Examples of the use of prestressed high-strength rebar in the world are: the construction of sealed shells that prevent the release of radioactive substances into the environment in severe accidents at nuclear power plants; construction of tanks for nuclear waste; construction of offshore platforms for oil production; construction of sea and river bridges, long-span ceilings, high-rise buildings, roads and other similar facilities.
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Włodarczyk, Maria. "The strength capacity of compression members reinforced with FRP bars. The results of structural testing." AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 19, no. 12 (December 31, 2018): 715–19. http://dx.doi.org/10.24136/atest.2018.484.
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The paper describes experimental testing on compression members reinforced with FRP and steel bars. The main objective of the work was to investigate the effect of reinforcement type on the strength capacity of elements. It was observed that in most of the cases the failure of the elements happened due to concrete crushing..
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El-Mogy, Mostafa, Amr El-Ragaby, and Ehab El-Salakawy. "Experimental testing and finite element modeling on continuous concrete beams reinforced with fibre reinforced polymer bars and stirrups." Canadian Journal of Civil Engineering 40, no. 11 (November 2013): 1091–102. http://dx.doi.org/10.1139/cjce-2012-0509.
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Continuous concrete beams are common elements in structures such as parking garages and overpasses, which might be exposed to extreme weather. Using the non-corrodible fibre reinforced polymer (FRP) bars is a viable alternative to avoid steel corrosion problems. Due to the linear-elastic behaviour of FRP materials, the possibility of moment redistribution in FRP-reinforced beams is questionable. In this paper, the experimental results of ten full-scale continuous concrete beams are summarized followed by a finite element parametric study using ANSYS software. Steel, glass fibre reinforced polymer, and carbon fibre reinforced polymer bars were used in different combinations as longitudinal and transverse reinforcement. The main investigated parameters were the ratio and type of longitudinal and transverse reinforcement. Results showed that moment redistribution in such beams is possible if the reinforcement configuration is chosen properly. The developed finite element model predicted the response of tested beams with a reasonable degree of accuracy and was used to expand the range of investigated parameters.
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Puoza, Julius Caesar, Frimpong Opoku, and Bernard Aboagye. "Development and testing of a motorized cassava fufu pounding machine." International Journal of Engineering & Technology 5, no. 1 (December 10, 2015): 1. http://dx.doi.org/10.14419/ijet.v5i1.5155.
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A motorized cassava fufu pounding machine was developed and tested. The machine principal parts were hopper, throat, pounding compartment, discharge outlet, main frame, electric motor seat, auger, shaft and pulleys. Mild steel material and stainless steel sheet were used in the fabrication based on its availability, strength, appearance, cost, and corrosion resistance. The machine is powered by a 5hp electric motor; the dimension of the machine is 1010mm × 600mm × 930mm (length × breadth × height). Output capacity of 120kg/hr was obtained. The machine is affordable and easy to operate and manage. It is therefore recommended for the restaurants, chop bars and households to prepare a good and hygienic fufu thereby solving the problem of energy sapping and time wasting in manual fufu pounding.
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Rubin, Per, Richard Larker, Erik Navara, and Marta Lena Antti. "Novel Cost-Efficient Method of Producing Ausferritic Steels Displaying Excellent Combination of Mechanical Properties." Defect and Diffusion Forum 405 (November 2020): 11–18. http://dx.doi.org/10.4028/www.scientific.net/ddf.405.11.
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Round bars Ø 53 mm were hot-rolled from a 1.4 tonne ingot forged to 165 × 165 mm. The composition of the steel was 0.45 wt. % C and 3.33 wt. % Si plus alloying elements for hardenability. Microstructure after air cooling from 1010 °C on the cooling bed was predominantly ausferritic. Tensile testing of as-rolled bars resulted in yield strength 846 ± 22 MPa, ultimate tensile strength 1169 ± 99 MPa and A5-elongation of 1.7 ± 0.8 % (without prior necking). When as-rolled steel was baked in air at T = {Ms initial -30 K} for six hours, the yield stress raised to 1121 ± 4 MPa, the ultimate tensile stress raised to 1447 ± 5 MPa and the elongation raised to 22.6 ± 1.6 % (with necking > 18 %). For as-rolled bars during continuous cooling, the exposure time within the temperature range 460 – 320 °C was estimated to be about 10 minutes. The microstructure of as-rolled “semi-finished” bars is stable at room temperature. The first baking was done six months after hot-rolling. Optical and scanning electron microscopy showed that remaining areas of austenite, not transformed during continuous cooling but stable at room temperature, transforms to ausferrite when properly baked.
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Wang, Hai Chao, Xi Quan Xu, Li Jun Zhou, Hong Ying Zhang, and Feng Lian Yang. "The Experimental Study on Concrete-Filled Thin-Walled Square Steel Tube Short Columns Fixed U-Shaped Steel Bars." Applied Mechanics and Materials 94-96 (September 2011): 962–69. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.962.
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Based on the compression characteristics of the concrete-filled thin-walled square steel tube short columns, the U-shaped tie bars are designed in this paper. The U-shaped tie bars and steel pipe walls are connected with each other in T-shape in order to enhance the local stability of the walls under pressure. According to the concrete strength C30/C35/C40 and the thickness of the steel plates 1.25mm/1.75mm/2.5mm,42 short-column specimens are made, and the size of all specimens is 200mm×200mm×690mm.The bearing capacity test is done by the 500-ton electro-hydraulic serve testing machine. The strain of U-shaped tie bar and thin-walled steel are tested, and then the whole curve of compression process is obtained. The results show that the U-shaped tie bar has a very good role in bonding, and has good effects on improving buckling mode and the ductility of the components significantly. Concrete-filled thin-walled square steel tube short column fixed U-shaped tie bar has advantages on stronger post- deformability and more applicable to configuration compared with existing research achievements, and can provide a reference for engineering design.
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Budenkov, G. A., O. V. Nedzvetskaya, and T. N. Lebedeva. "Reference Blocks for Acoustic Nondestructive Testing of Small-Diameter Bars of Tool Steel." Russian Journal of Nondestructive Testing 39, no. 11 (November 2003): 828–32. http://dx.doi.org/10.1023/b:runt.0000023751.44232.38.
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Saito, T., Y. Yabe, and T. Fujimori. "An ultrasonic testing method for gas pressure welded joints of reinforcing steel bars." Ultrasonics 23, no. 3 (May 1985): 119–27. http://dx.doi.org/10.1016/0041-624x(85)90060-5.
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Ivanov, D. I., and A. A. Kozhukhov. "Increasing the service life of pellet car grate bars made of 40Х24Н12СЛ steel." Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 77, no. 10 (October 12, 2021): 1066–75. http://dx.doi.org/10.32339/0135-5910-2021-10-1066-1075.
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Intercrystallite corrosion (ICC) is the main reason to decrease service life of pellet car grate bars made of steel 40Х24Н12СЛ. In the process of the study of microstructure of pellet car grate bars manufactured according to GOST 977–88, the structure defects were established that increase the tendency to ICC. To prevent the ICC of the bars, a mode of heat treatment was elaborated, consisting of two basic operations: air hardening with preliminary exposure within 80 minutes at the temperature 1100 °С, followed by tempering within 150 minutes at the temperature 900 °С. The study of the structure of the pilot grate bar showed that the selected mode of the hardening enables to dissolve the carbide network in the structure of the detail and crash large carbides, and the subsequent tempering contributes to the growth of the carbide phase in the entire volume of metal, partially remaining in the structure after hardening. It was shown that the proposed mode of the heat treatment contributes to bringing the structure of the metal to a more “equilibrium” state, which will allow to exclude the formation of large carbides and carbide network, growth and coagulation along the grain boundary. Results of tests of a pilot batch of grate bars installed at an industrial induration machine with a working area of 768 m2 and operating temperature of 20–1310°С presented. It was established that the elaborated technology ensures absence of casting defects in the grate bars – cracks and warping, inclination of the grate bars to ICC, increased by 23.13% heat resistance compared to the reference grate bars of foreign supply due to the globular form of carbide secretions with a minimum length of borders along which the metal matrix is depleted by chrome. Industrial testing of the grate bars manufactured under the experimental technology has proved the practical significance and applicability of the performed research.