Stability of Bridge Column Rebar Cages During Construction

Stability of Bridge Column Rebar Cages During Construction

Author: Juan C. Builes Mejia

Publisher:

Published: 2010

Total Pages: 258

ISBN-13: 9781124401966

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The lateral behavior and stability of bridge column rebar cages were investigated to reduce the potential of failure and collapse during construction. Rebar cages are temporary structures made of longitudinal and transverse reinforcing bars that are connected by tie wire connections. Recent collapses during construction exposed the vulnerabilities of these temporary structures to accidental loads that may occur at this stage. Therefore, experimental and analytical investigations were conducted to understand the lateral behavior of bridge column rebar cages. Experimental work was performed on individual components of rebar cages, such as tie wire connections and reinforcing bars, under various types of loading. Two full-scale bridge column rebar cages were subjected to incremental loading to determine the lateral behavior, identify failure modes, and calibrate the analytical models. Using the results from the experimental study, nonlinear finite element analyses were developed to determine the effect of critical parameters on the lateral behavior of column rebar cages. The investigated parameters were: tie wire connections, internal braces, column diameter, longitudinal and transverse reinforcement ratios, and column height. The results of these analyses showed that the internal braces have a significant effect on the lateral behavior and failure mode of bridge column rebar cages. Guidelines for determining the lateral stiffness and improving the bridge column rebar cage stability are proposed.


Rebar Cage Construction and Safety

Rebar Cage Construction and Safety

Author: Michael J. Casey

Publisher: Amer Society of Civil Engineers

Published: 2012-09-01

Total Pages: 42

ISBN-13: 9780784412510

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Rebar Cage Construction and Safety: Best Practices presents guidelines for the safe handling of steel reinforcing-bar (rebar) cages throughout the design, fabrication, and erection process. The focus is on rebar cages used for large, cast-in-place concrete columns in a variety of settings, including bridge piers, elevated highway sections, and high-rise buildings. These cages are inherently unstable, usually held together by tie-wire alone. They are challenging to fabricate, to lift from the horizontal to the vertical position, and to support in the temporary condition until concrete is cast. Engineered temporary support systems, such as bracing or cable-guy systems, can mitigate the instability of standing rebar cages and resist lateral loads, ensuring better safety for the iron workers tasked with climbing the cages. Topics include: overview of rebar cages; organisational management for rebar cages; construction engineering; checklists of best practices for construction; and summary, conclusions, and recommendations. This volume describes best practices for construction engineering and construction practice regarding rebar cages.It will be useful to construction engineers working with large columns for the first time as well as construction contractors looking to establish policies and procedures related to rebar column safety.


Next Generation of Bridge Columns for Accelerated Bridge Construction in High Seismic Zones

Next Generation of Bridge Columns for Accelerated Bridge Construction in High Seismic Zones

Author: Mostafa Tazarv

Publisher:

Published: 2014

Total Pages: 406

ISBN-13:

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Longitudinal bar debonding allowed spread of yielding and prevented premature failure of reinforcements in UHPC-filled duct connections and grouted coupler column pedestal. The SMA-reinforced ECC column showed superior seismic performance compared to a conventional column in which the plastic hinge damage was limited to only ECC cover spalling even under 12% drift ratio cycles. The column residual displacements were 79% lower than CIP residual displacements on average due to the superelastic NiTi SMA longitudinal reinforcement, and higher base shear capacity and higher displacement capacity were observed. The analytical modeling methods were simple and sufficiently accurate for general design and analyses of precast components proposed in the present study. The proposed symmetrical material model for reinforcing NiTi superelastic SMA was found to be a viable alternative to the more complex asymmetrical model.


Comparison of Prefabricated Cage System with Existing Reinforcement Methods in Concrete Columns

Comparison of Prefabricated Cage System with Existing Reinforcement Methods in Concrete Columns

Author: Matthew John Fisher

Publisher:

Published: 2006

Total Pages:

ISBN-13:

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Abstract: A reinforced concrete column is composed of two main load bearing mechanisms; concrete and a steel reinforcing cage. The concrete is the primary vertical load bearing mechanism with the steel cage providing some vertical load carrying capacity while serving mainly to confine the core concrete. The steel cage consists of two types of bars; longitudinal, which carry any compressive or tensile loads, and transverse, which hold the longitudinal bars in place and also provide confinement of the core concrete under axial load. The transverse bars are bent and tied to the longitudinal bars. A new type of steel cage has recently been proposed by Halil Sezen PhD and Mohammad Shamsai PhD, both of The Ohio State University. The new method is termed Prefabricated Cage System (PCS) reinforcement, and it consists of a cage constructed from a solid steel tube. A grid is cut into the tube through the use of a laser-cutter, resulting in a reinforcing cage that is very similar to a rebar cage. The main differences between the two are: 1) The PCS cage is a solid entity, while the rebar cage is held together through the use of ties. 2) The steel in the PCS cage is in rectangular form while the steel in the rebar cage typically consists of round bars. The machine fabrication of PCS provides a more accurately constructed column, compared to the manually constructed rebar cage, at the same or less cost than a rebar column due to the reduced on-site construction time required by PCS. The research project will focus on the performance of PCS in circular columns. In all, six samples will be constructed and tested, consisting of two rebar reinforced columns and four PCS reinforced columns. Each test column will be 18 in. in height with a 6 in. diameter. There will be two test groups, each group containing one rebar column and two PCS columns. The strength of the steel, which is represented by the yield stress of the steel multiplied by the cross-sectional area of the steel, will be the same in each test group to allow for accurate comparisons. The purpose of this research is to not only compare the performance of a PCS reinforced column to a rebar reinforced column, but also to compare PCS cages with differently sized grid openings. The objective is to investigate whether the PCS column has a higher maximum load and a larger displacement capacity, due to the increased confinement provided by the rectangular shape of the PCS cage over the round shape of the rebar cage.


Handbook of International Bridge Engineering

Handbook of International Bridge Engineering

Author: Wai-Fah Chen

Publisher: CRC Press

Published: 2013-10-11

Total Pages: 1383

ISBN-13: 1439810303

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This comprehensive and up-to-date reference work and resource book covers state-of-the-art and state-of-the-practice for bridge engineering worldwide. Countries covered include Canada and the United States in North America; Argentina and Brazil in South America; Bosnia, Bulgaria, Croatia, Czech Republic, Denmark, Finland, France, Greece, Macedonia,


Engineering for Structural Stability in Bridge Construction

Engineering for Structural Stability in Bridge Construction

Author: Federal Highway Federal Highway Administration

Publisher:

Published: 2020-07-19

Total Pages: 669

ISBN-13:

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This manual is intended to serve as a reference. It will provide technical information which will enable Manual users to perform the following activities:Describe typical erection practices for girder bridge superstructures and recognize critical construction stagesDiscuss typical practices for evaluating structural stability of girder bridge superstructures during early stages of erection and throughout bridge constructionExplain the basic concepts of stability and why it is important in bridge erection* Explain common techniques for performing advanced stability analysis along with their advantages and limitationsDescribe how differing construction sequences effect superstructure stabilityBe able to select appropriate loads, load combinations, and load factors for use in analyzing superstructure components during constructionBe able to analyze bridge members at various stages of erection* Develop erection plans that are safe and economical, and know what information is required and should be a part of those plansDescribe the differences between local, member and global (system) stability


Temporary Works

Temporary Works

Author: Ray Filip

Publisher: ICE Publishing

Published: 2018-12-17

Total Pages: 0

ISBN-13: 9780727763389

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Temporary Works: Principles of design and construction provides authoritative and comprehensive guidance on temporary works for practising engineers.