Download or read book Defining Structurally Acceptable Mechanical Properties of High strength Reinforcing Steel Bars Through Low cycle Fatigue Testing written by Graham Stephen Hogsett and published by . This book was released on 2017 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-cycle fatigue tests were performed on high-strength reinforcing bars currently being developed in the United States, to quantify mechanical properties and fatigue life under simulated seismic conditions. Reinforcing bars with yield strengths ranging for about 60ksi to over 100ksi were tested. The high-strength bars with yield strengths exceeding 80ksi were obtained from three manufacturers that produce high-strength bars using the main three manufacturing techniques in use in the United States. Primary variables considered also include chemical composition, geometric deformations, bar grade, clear gripping span, loading protocol, and manufacturing process. The results of monotonic and cyclic tests are presented and comparisons are made based on the variables listed. A previously proposed fatigue model is considered and recalibrated for the new testing data.
Download or read book Defining Structurally Acceptable Properties of High strength Steel Bars Through Material Testing written by Chase Meany Slavin and published by . This book was released on 2015 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-cycle fatigue tests were performed on reinforcing bars in order to assess the acceptability of newly developed high-strength reinforcing bars in seismic applications. The steels tested are classified as grade 60 A706, grade 80 A706, grade 80 A615, and grade 100. The high-strength reinforcing bars tested represent the two most common manufacturing processes used today: microalloying and quenching-and-tempering. The results of these tests are presented along with comparisons between the fatigue life of bars based on steel grade and other bar properties. A statistical analysis of the test results is presented in order to assess the impact of many parameters on the low-cycle fatigue performance of grade 60 A706 and higher-strength reinforcing bars
Download or read book ACI Materials Journal written by and published by . This book was released on 2004 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plastic Buckling Fatigue Testing of Large Diameter Steel Reinforcing Bars written by David Elias Duck Rodriguez and published by . This book was released on 2019 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: Critical regions of reinforced concrete elements designed for ductility and energy dissipation are required to sustain many large-amplitude strain cycles during rare and strong intensity earthquakes. Steel reinforcing bars in such critical regions often end up buckling and then fracturing in a mode of failure that defines the collapse prevention limit-state. While this failure mode is commonly misnamed low-cycle fatigue, it does not meet ASTM Manual on Low-Cycle Fatigue (1969) guidelines which require to avoid buckling or bending. Instead, the term Plastic Buckling-Straightening Fatigue (PBSF) is used to describe the fatigue testing where the effects of plastic buckling are included. Historically, the longitudinal reinforcement used for ordinary large-diameter RC bridge columns has been limited to No. 11 and smaller bars. The combination of such longitudinal reinforcement and the closely spaced transverse reinforcement at the plastic hinge region results in result in heavily congested column cages that prove challenging to build and require large amounts of labor and materials. To help reduce the congestion, larger sized bars could be used to reduce the number of bars needed to provide the same longitudinal reinforcement ratio. This would reduce the amount of material, construction time, and amount of labor needed. Furthermore, in some particular cases, the use of mechanical splices for these large diameter bars would further accelerate bridge construction by allowing the use of precast concrete techniques. However, the PBSF life of large diameter bars and their mechanical splices has not been investigated. To date, research to investigate the effects of buckling in strain-controlled fatigue testing of longitudinal steel reinforcement have focused on No. 11 and smaller bar sizes. The experimental results presented here provide the first successful PBSF data for large diameter bars and are used to implement a Damage Index to quantify the fatigue life of a reinforcing steel bar. The innovative design and implementation of a loading apparatus used to test large-diameter reinforcing bars and their mechanical splices for PBSF is described. Main features of the loading apparatus are the high rotational stiffness and the gripping method, which was successfully achieved by exploiting the thermoplastic properties of sulfur concrete.
Download or read book High Strength Bars as Concrete Reinforcement Part 6 written by James F. Pfister and published by . This book was released on 1964 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Corrosion on Low cycle Fatigue seismic Behaviour of High strength Steel Reinforcing Bars Rusteel written by and published by . This book was released on 2014 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dissipative capacity of modern r.c. and composite steel/concrete structures is directly related to the rotational capacity of the elements in which plastic hinges are located: it strictly depends on the geometrical and mechanical characteristics of the sections and, moreover, on the ductile capacity of the steel reinforcing bars (deformation and dissipated energy). Nowadays the lowcycle fatigue/seismic behaviour of steel reinforcing bars is not well known and, at European level, no production control tests are prescribed for the mechanical characterisation of the seismic performance of reinforcing steels. This situation is well reflected in the framework of the revision of European standard EN10080 and in Mandate M115 which tends to harmonise production control for reinforcing steels also introducing low-cycle fatigue tests. Full knowledge about the effective ductility requirements imposed on bars by real seismic events is necessary: a detailed analysis of the ductility demand on reinforcements, considering both r.c. and composite steel/concrete structures, is consequently necessary and deeply analysed in the project. At the same time, the ductility capacity of steel reinforcing bars has been investigated considering also the detrimental effects due to aggressive environmental conditions, generally resulting in a progressive decrease of the mechanical characteristics of deformation, strength and dissipative capacity. The evaluation of the ability of corroded steel bars to still sustain the ductile requirements due to seismic action has been analysed, finally providing practical indications for the protection of bars from corrosion, in addition to what was already suggested by Eurocode 2.
Download or read book A Pilot Experimental Study on the Low Cycle Fatigue Behavior of Stainless Steel Rebars for Earthquake Engineering Applications written by Yihui Zhou and published by . This book was released on 2008 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic application of stainless steel rebar (SSR) recently has attracted much attention in the civil engineering due to its superior material properties, including high corrosion resistance and high specific strength. However, as to all new materials, a number of shortcomings are unavoidable, such as high initial costs, unknown low-cycle fatigue behavior and uncertain ductility property. In this study, a series of tests on selected SSR were carried out. For the purpose of comparison, one type of traditional carbon steel (A706 G60) rebar and a new material (MMFX II) were also tested. A706 G60 has been promoted in the recent design specification of reinforced concrete, particularly in the seismic design. MMFX II is high strength steel appeared in the market recently. The specific objective of this study is to investigate the low-cycle fatigue and ductility properties of the selected SSR. The test specimens, both for the low fatigue and the monotonic loading conditions, were designed according to the ASTM specifications and fabricated from #8 rebars. The tests were strain controlled. An electronic hydraulic loading system manufactured by MTS at the Structural Engineering & Earthquake Simulation Laboratory (SEESL) at the University at Buffalo was used, and MTS displacement extensometers were used to measure the elongations. For the low-cycle fatigue tests, specimens were subjected to constant amplitude strain of various magnitudes. Strain based strain-life formulae were obtained by regression analysis of the experimental results. Compared to results of the traditional carbon steel rebar, SSR has shown higher ductility and longer fatigue life.
Download or read book Fatigue Strength of High yield Reinforcing Bars written by Thorsteinn Helgason and published by Transportation Research Board National Research. This book was released on 1976 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The stress range to which a reinforcing bar is subjected is the primary factor determining its fatigue life. For design purposes, there is a limiting stress range, the fatigue limit, above which a reinforcing bar will have a finite fatigue life and is certain to fracture. At stress ranges below the fatigue limit, a reinforcing bar will have a long fatigue life and may be able to sustain a virtually unlimited number of stress cycles. The magnitude of the fatigue limit depends on the minimum stress during each stress cycle and on the shape of the deformatins rolled onto the bar surface.
Download or read book Analysis of Bar Grip Spliced Reinforcing Steel Bars written by M. T. Peabody and published by . This book was released on 1983 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Mechanical Properties of Reinforcing Steel Bars at Low Temperature written by Yun-Miew Pang and published by . This book was released on 1972 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ACI 318 19 Building Code Requirements for Structural Concrete ACI 318 19 and Commentary ACI 318R 19 written by ACI Committee 318 and published by . This book was released on 2019-05 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abstract Journal in Earthquake Engineering written by and published by . This book was released on 1995 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low cycle Fatigue Behavior of Modern and Historic Grade 40 Reinforcing Steel Bars written by Zach John Quesnel and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research evaluated the predictability of the fatigue behavior of modern and historic grade 40 reinforcement when subjected to different strain histories and to characterize differences observed. While several previous studies have investigated the low-cycle fatigue behavior of grade 40 reinforcing steel using constant amplitude cycles with zero mean strain, existing research was minimal for tests with variable amplitude loading and strain histories with positive mean strain that would be characteristic of the strain history for reinforcement bars in reinforced concrete columns subjected to cyclic loads. First, sixteen constant amplitude cyclic tests were conducted to calibrate the parameters of the Koh-Stephens fatigue relationship. The calibrated M and n parameters were calculated to be 0.15 and -0.38 for the modern grade 40 reinforcement, respectively, and 0.07 and -0.45 for the historic grade 40 reinforcement, respectively. Then, twelve variable amplitude cyclic tests were conducted. The damage accumulated over the variable amplitude strain history was tracked using the Miner rule to predict fatigue fracture. Results showed high variability, with coefficient of variations above 0.25 for almost all specimen sets, and high sensitivity to model parameters. Electron backscatter diffraction scans were taken of both the modern and historic grade 40 reinforcement to determine if differences in metallurgy could explain the variability. The electron scans determined that the historic reinforcement, recovered through demolition of 70-year-old in-service bridges, had greater previous strain deformation than the modern virgin-steel bars. It was also found that the grain size of the virgin steel bars was more consistent than the historic bars. These two findings together help explain some of the high variability in the testing data. In conclusion, this study determined that modern reinforcement likely has between 50% and 100% more elongation at fracture and greater cyclic fatigue life than historic bars. This should be considered when evaluating older in-service bridges for retrofit and comparing retrofit strategies using modern experimental tests, as the reinforcement in modern tests likely has greater fatigue life. Additionally, the study identified additional research questions aimed at increasing the predictability of fatigue fracture of reinforcement subjected to variable strain histories generated from earthquake ground motions.
Download or read book Metals Abstracts written by and published by . This book was released on 1999 with total page 1014 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimisation of Ductility of Welded Steel Bars Ribbed Coils and Mesh Fabric for Reinforced Concrete Elements Under Severe Seismic Loads written by and published by . This book was released on 2002 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book HRIS Abstracts written by National Research Council (U.S.). Highway Research Board and published by . This book was released on 1985 with total page 1254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Strength of Deformed Reinforcing Bars written by I. C. Jhamb and published by . This book was released on 1969 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:
