Required Embedment Length of Column Reinforcement Extended Into Type II Shafts
Author: Juan Murcia-Delso
Publisher:
Published: 2013
Total Pages: 370
ISBN-13:
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Author: Juan Murcia-Delso
Publisher:
Published: 2013
Total Pages: 370
ISBN-13:
DOWNLOAD EBOOKAuthor: Juan Murcia-Delso
Publisher:
Published: 2013
Total Pages: 337
ISBN-13: 9781303710544
DOWNLOAD EBOOKEnlarged (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.
Author: Thomas T. C. Hsu
Publisher: Springer
Published: 2019-01-21
Total Pages: 410
ISBN-13: 9811332789
DOWNLOAD EBOOKThis 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.
Author:
Publisher: AASHTO
Published: 2011
Total Pages: 271
ISBN-13: 156051521X
DOWNLOAD EBOOKThis work offers guidance on bridge design for extreme events induced by human beings. This document provides the designer with information on the response of concrete bridge columns subjected to blast loads as well as blast-resistant design and detailing guidelines and analytical models of blast load distribution. The content of this guideline should be considered in situations where resisting blast loads is deemed warranted by the owner or designer.
Author: FIB – International Federation for Structural Concrete
Publisher: FIB - Féd. Int. du Béton
Published: 2019-05-27
Total Pages: 2322
ISBN-13: 2940643008
DOWNLOAD EBOOKThis 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.
Author: American Concrete Institute. Convention
Publisher:
Published: 2002
Total Pages: 264
ISBN-13:
DOWNLOAD EBOOK"Prepared by members of ACI Subcommittee 445-1, Strut and Tie Models, for sessions at the Fall Convention in Phoenix, October 27 to November 1, 2002, and sponsored by Joint ACI-ASCE Committee 445, Shear and Torsion and ACI Committee 318-E, Shear and Torsion."
Author: Koorosh Hossein Lotfizadeh
Publisher:
Published: 2019
Total Pages: 279
ISBN-13:
DOWNLOAD EBOOKLarge diameter bars are often used in large civil infrastructure projects such as bridges, power stations, large mat footings, and are occasionally used as reinforcement in buildings where the use of smaller size reinforcement would cause excessive congestion. The use of high-strength Grade 80 reinforcement can reduce the number of bars required in construction, likely reducing congestion, thereby reducing construction time. Current design guidelines only allow the use of A706 Grade 60 reinforcing bars in seismic critical members (SCMs), while allowing the use of straight A706 Grade 80 bars only in capacity protected members. The use of high-strength large-diameter bars in SCMs requires experimental validation since extrapolation of current prescriptive requirements for Grade 60 reinforcement cannot always be deemed satisfactory or appropriate. The research work presented herein comprises of a comprehensive investigation, which addresses, at the bar, bar-to-concrete, and at the component levels, the main areas of research needed to implement the use of ASTM A706 Grade 80 high-strength reinforcement into bridge seismic design practice, and presents findings from proof-of-concept experiments in support of this implementation. This dissertation presents an experimental and analytical investigation to characterize the response of large-diameter ASTM A706 Grade 80 reinforcement embedded in confined concrete, replicating the boundary conditions of bars developed into extended shafts, bent caps, and footings. The equivalent strain penetration term for this type of reinforcement, which is used to calculate the analytical plastic hinge length of columns, is determined and recommendations are provided to more closely represent experimentally measured results. The proof-of-concept experiments supporting the implementation of high-strength Grade 80 reinforcement in future design codes consist of a full-scale bridge column extending into an enlarged Type II pile shaft, and a 3⁄4-scale exterior column of a multi-column bent cap connection, both reinforced entirely with ASTM A706 Grade 80 bars. Findings from these experiments are used to calibrate and validate detailed finite element models which can be used to aid future bridge design practice. At the bar level, to characterize the buckling behavior, post-buckling fracture mechanism, and cyclic fatigue life of large-diameter Grade 80 reinforcing bars, a set of experiments were performed on both commonly available ASTM A706 Grade 80 bars and newly developed Grade 80 bars with a more smoothed-rib-radius. An extensive finite element study is also conducted to develop a simplified equation for design to prevent premature plastic buckling and subsequent fracture of column longitudinal reinforcement.
Author:
Publisher:
Published: 1904
Total Pages: 1242
ISBN-13:
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Publisher:
Published: 1906
Total Pages: 1148
ISBN-13:
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