Download or read book Development Length of Large Diameter Reinforcing Bars Under Cyclic Loads written by Chi-Hung Cheng and published by . This book was released on 1995 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bond Slip Behavior and Development of Bridge Column Longitudinal Reinforcing Bars in Enlarged Pile Shafts written by Juan Murcia-Delso and published by . This book was released on 2013 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enlarged (Type II) pile shaft foundations are used frequently in reinforced concrete bridges because of the convenience in construction and efficiency in post-earthquake inspection and repair. According to the specifications of the California Department of Transportation (Caltrans), the diameter of a Type II shaft should be at least 610 mm (2 ft) larger than that of the column. Hence, the column reinforcement extended into the pile shaft can be perceived as forming a non-contact splice with the pile shaft reinforcement. Because of the lack of data, the seismic design specifications of Caltrans on the embedment length of column reinforcement in Type II shafts are very conservative for large-diameter columns, which could complicate the construction work and entail high construction costs. This dissertation presents an experimental and analytical investigation to characterize the bond between concrete and reinforcing steel when a reinforced concrete member is subjected to severe cyclic loading, and determine the minimum embedment length required for column longitudinal reinforcement extended into a Type II shaft. Experiments were carried out to investigate the bond strength and cyclic bond deterioration of large-diameter bars (No. 11, 14, and 18) commonly used in large-diameter bridge columns and piles. The experimental results have been used to develop, calibrate, and validate a phenomenological bond-slip model for bars embedded in well-confined concrete. The model successfully reproduces bond deterioration caused by cyclic bar-slip reversals and tensile yielding of the bar, and has been implemented in an interface element in a finite element program. A physics-based dilatant interface model formulated with a multi-surface plasticity concept has also been developed and implemented in the finite element program to simulate bond-slip under a broad range of confinement situations. With the phenomenological bond-slip model, nonlinear finite element analysis has been conducted to extrapolate results of development length tests conducted on large-diameter bars, and assess the reliability of the development lengths required in the AASHTO LRFD Bridge Design Specifications. Finally, two large-scale tests on column-pile shaft assemblies were conducted. The tests were combined with finite element analysis to evaluate the conservatism of the current Caltrans specifications, and provide new design recommendations that can significantly reduce the embedment length required for column reinforcement, while ensuring an appropriate performance of the column-pile shaft connections under severe seismic loads.

Download or read book Report on Steel Reinforcing Bars Under Cyclic Loads written by and published by . This book was released on 2012-01-01 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Anchorage of Large diameter Reinforcing Bars Grouted Into Ducts written by and published by . This book was released on 2008 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of a few large-diameter reinforcing bars for the construction of precast concrete bridge bents allows simplified construction by reducing the number of alignments to be made in the field. These bars are grouted into ducts in a precast concrete cap beam. In the proposed precast concrete substructure system, the grouted bars carry tensile forces across the joint between the column and cap beam. This joint is the yielding element in the structural system, and it is crucial to the performance of the structure that the bars yield before other failure mechanisms, including bond failure, occur. However, the cap beam is typically insufficient to anchor the bar, as the depth of the beam is substantially less than the American Association of State Highway and Transportation Officials (AASHTO) bridge code allows. For this project, 17 pullout tests were conducted to determine the bond characteristics and development length of large-diameter bars grouted into ducts. The bars tested ranged in size from #8 to #18. Pullout tests conducted with embedment lengths of at least six bar diameters yielded the reinforcing bar, while the test conducted with an embedment length of 14 bar diameters resulted in bar fracture. The tests and subsequent analysis showed that the bond of these grouted connections is significantly better than the bond of bars cast directly into concrete. The development lengths needed to fully anchor the bar are therefore within the depth available in the cap beam.

Download or read book Local Bond Between a Reinforcing Bar and Concrete Under High Intensity Cyclic Load written by Siripong Hungspreug and published by . This book was released on 1981 with total page 960 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transfer Development and Splice Length for Strand reinforcement in High strength Concrete written by Julio A. Ramirez and published by Transportation Research Board. This book was released on 2008 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This report documents research performed to develop recommended revisions to the AASHTO LRFD Bridge Design Specifications to extend the applicability of the transfer, development, and splice length provisions for prestressed and non-prestressed concrete members to concrete strengths greater than 10 ksi. The report details the research performed and includes recommended revisions to the AASHTO LRFD Bridge Design Specifications. The material in this report will be of immediate interest to bridge designers."--Foreword.

Download or read book Concrete Structures in Earthquake written by Thomas T. C. Hsu and published by Springer. This book was released on 2019-01-21 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers 23 papers by top experts from 11 countries, presented at the 3rd Houston International Forum: Concrete Structures in Earthquake. Designing infrastructures to resist earthquakes has always been the focus and mission of scientists and engineers located in tectonically active regions, especially around the “Pacific Rim of Fire” including China, Japan, and the USA. The pace of research and innovation has accelerated in the past three decades, reflecting the need to mitigate the risk of severe damage to interconnected infrastructures, and to facilitate the incorporation of high-speed computers and the internet. The respective papers focus on the design and analysis of concrete structures subjected to earthquakes, advance the state of knowledge in disaster mitigation, and address the safety of infrastructures in general.

Download or read book American Environmentalism written by J. Michael Martinez and published by CRC Press. This book was released on 2013-06-20 with total page 1227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Protecting the natural environment and promoting sustainability have become important objectives, but achieving such goals presents myriad challenges for even the most committed environmentalist. American Environmentalism: Philosophy, History, and Public Policy examines whether competing interests can be reconciled while developing consistent, coherent, effective public policy to regulate uses and protection of the natural environment without destroying the national economy. It then reviews a range of possible solutions. The book delves into key normative concepts that undergird American perspectives on nature by providing an overview of philosophical concepts found in the western intellectual tradition, the presuppositions inherent in neoclassical economics, and anthropocentric (human-centered) and biocentric (earth-centered) positions on sustainability. It traces the evolution of attitudes about nature from the time of the Ancient Greeks through Europeans in the Middle Ages and the Renaissance, the Enlightenment and the American Founders, the nineteenth and twentieth centuries, and up to the present. Building on this foundation, the author examines the political landscape as non-governmental organizations (NGOs), industry leaders, and government officials struggle to balance industrial development with environmental concerns. Outrageous claims, silly misrepresentations, bogus arguments, absurd contentions, and overblown prophesies of impending calamities are bandied about by many parties on all sides of the debate—industry spokespeople, elected representatives, unelected regulators, concerned citizens, and environmental NGOs alike. In lieu of descending into this morass, the author circumvents the silliness to explore the crucial issues through a more focused, disciplined approach. Rather than engage in acrimonious debate over minutiae, as so often occurs in the context of "green" claims, he recasts the issue in a way that provides a cohesive look at all sides. This effort may be quixotic, but how else to cut the Gordian knot?

Download or read book Seismic Design of Reinforced Concrete Buildings written by Jack Moehle and published by McGraw Hill Professional. This book was released on 2014-10-06 with total page 783 pages. Available in PDF, EPUB and Kindle. Book excerpt: Complete coverage of earthquake-resistant concrete building design Written by a renowned seismic engineering expert, this authoritative resource discusses the theory and practice for the design and evaluation of earthquakeresisting reinforced concrete buildings. The book addresses the behavior of reinforced concrete materials, components, and systems subjected to routine and extreme loads, with an emphasis on response to earthquake loading. Design methods, both at a basic level as required by current building codes and at an advanced level needed for special problems such as seismic performance assessment, are described. Data and models useful for analyzing reinforced concrete structures as well as numerous illustrations, tables, and equations are included in this detailed reference. Seismic Design of Reinforced Concrete Buildings covers: Seismic design and performance verification Steel reinforcement Concrete Confined concrete Axially loaded members Moment and axial force Shear in beams, columns, and walls Development and anchorage Beam-column connections Slab-column and slab-wall connections Seismic design overview Special moment frames Special structural walls Gravity framing Diaphragms and collectors Foundations

Download or read book Compression and Tension Lap Splices in Reinforced Concrete Members Subjected to Inelastic Cyclic Loading written by Nader Panahshahi and published by . This book was released on 1987 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Large Diameter Reinforcement Under Large Strain Cyclic Reversals written by Rodrigo Carreno Vallejos and published by . This book was released on 2018 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: To resist strong intensity earthquakes, the design of reinforced concrete members often relies on well-detailed plastic hinge regions for a ductile response. Within these plastic hinges, large strain deformations are expected in both the concrete and steel reinforcement. In the case of ordinary bridge columns, experimental testing of full-scale specimens has shown that fracture of longitudinal reinforcement, following visible plastic buckling is a common failure mode in the plastic hinge of columns designed according Caltrans' Seismic Design Criteria (SDC). This type of failure is defined herein as "Plastic Buckling-Straightening Fatigue" (PBSF), as the name "Low-cycle fatigue" commonly used for it is inconsistent with limitations set forth by ASTM standards for this phenomenon. The mechanism under which the PBSF type of failure occurs starts with micro-cracks developing at the root of bar deformations, in the concave side of a buckled bar, which start to propagate for an abrupt fracture when the bar stretches. Knowing the process under which the fracture occurs, the buckling behavior of the longitudinal reinforcement, considering the effect of material properties and the configuration of transverse hoops is studied, evaluating the fatigue life of the bars. Based on the regression of multiple Finite Element Model results, a simple design and verification procedure is proposed to control the PBSF limit state in ordinary bridge columns, recommended for inclusion in Caltrans SDC specifications. The use of large diameter reinforcement has proven an effective method to expedite the construction process of reinforced concrete bridges (Marsh, et al., 2011). The fatigue life of large bars however, has not been well documented yet, with the use of large diameter reinforcement in seismic regions limited to #11 bars vertical members in most ordinary bridges. For this research work, a series of Grade 60 #18 bars were tested under large amplitude cyclic strain histories, evaluating the fatigue life of the reinforcement for different length to diameter ratios and amplitude of deformations. The tests performed herein correspond to the first successful examination of the response under large amplitude strain reversals, including the fracture under PBSF, for reinforcement of this size.

Download or read book CONCRETE Innovations in Materials Design and Structures written by FIB – International Federation for Structural Concrete and published by FIB - Féd. Int. du Béton. This book was released on 2019-05-27 with total page 2322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Proceedings contains the papers of the fib Symposium “CONCRETE Innovations in Materials, Design and Structures”, which was held in May 2019 in Kraków, Poland. This annual symposium was co-organised by the Cracow University of Technology. The topics covered include Analysis and Design, Sustainability, Durability, Structures, Materials, and Prefabrication. The fib, Fédération internationale du béton, is a not-for-profit association formed by 45 national member groups and approximately 1000 corporate and individual members. The fib’s mission is to develop at an international level the study of scientific and practical matters capable of advancing the technical, economic, aesthetic and environmental performance of concrete construction. The fib, was formed in 1998 by the merger of the Euro-International Committee for Concrete (the CEB) and the International Federation for Prestressing (the FIP). These predecessor organizations existed independently since 1953 and 1952, respectively.

Download or read book Connections between Steel and Concrete written by Rolf Eligehausen and published by ibidem-Verlag / ibidem Press. This book was released on 2012-02-27 with total page 1430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anchorage by fasteners and composite structures of steel and concrete have seen dramatic progress in research, technology and application over the past decades. The understanding of the fundamental principles underlying both disciplines has significantly improved. Concurrently, there has been rapid growth in the development of sophisticated new products and the establishment of international directives and codes to ensure their safe and economical use in a wide range of engineered structures. Although they deal with very similar problems, the two disciplines have developed independently from each other. To optimize the use of composite structures and fastenings to concrete, however, it is necessary to have knowledge of both: the local behavior of the fastening system and the global behavior of the structure. It became apparent that a forum offering the opportunity to expand and to exchange experience in the field of connecting steel and concrete would benefit all involved. Furthermore this forum would aid in the rapid dissemination of new ideas, technologies and solutions as well as explore new areas of research.This book forms the Proceedings of the 2 Symposium on “Connections between Steel and Concrete”. As the 1 Symposium in 2001 it brought together leading experts from all facets of the research, design, construction and anchor manufacturing community from around the world. Their lectures covered the topics:- test methods- behavior and design- dynamic loading: shock, earthquake, fatigue- durability- exceptional applications, strenghtening and structures- related topicsIn total 129 papers are gathered in these 2 volumes.

Download or read book Local Bond Between a Reinforcing Bar and Concrete Under High Intensity Reversed Cyclic Load written by Marcos P. Loizias and published by . This book was released on 1983 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Executive Summary On Phase 3 Evaluation and Retrofitting of Multilevel and Multiple column Structures written by and published by . This book was released on 1997 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the principal findings of a four year study for Caltrans of the seismic response of older multi-level, multi-column reinforced concrete bridge structures. Methods have been devised to improve prediction of the global response of these structures, to analyze and assess their local behavior, and to retrofit them to achieve adequate seismic behavior. The behavior of these structures has been found to be complex and influenced by a wide variety of parameters. Moreover, existing analysis methods often provide non-conservative estimates of behavior. The investigations conducted provide greater insight into the response characteristics of existing multiple column bridge structures. These have permitted development of improved analytical models and tools, retrofit strategies and design concepts.

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 Design Guide on the ACI 318 Building Code Requirements for Structural Concrete written by and published by . This book was released on 2020-06 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: