Author: Jessica ThangjithamPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Seismic Design Recommendations for Grade 80 Reinforcing Steel in Concrete Bridge Columns
Author: Jessica ThangjithamHigh-Strength Steel Reinforcement in Critical Regions of Earthquake-Resistant Bridges
Author: Koorosh Hossein LotfizadehPublisher:
ISBN:
Category :
Languages : en
Pages : 279
Book Description
Large 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.
Impact of Grade 80 Reinforcing Steel Production Process on the Seismic Behavior of Bridge Columns
Author: Robyn Elise ManhardSeismic Design Aids for Nonlinear Pushover Analysis of Reinforced Concrete and Steel Bridges
Author: Jeffrey GerPublisher: CRC Press
ISBN: 1439837759
Category : Technology & Engineering
Languages : en
Pages : 396
Book Description
Nonlinear static monotonic (pushover) analysis has become a common practice in performance-based bridge seismic design. The popularity of pushover analysis is due to its ability to identify the failure modes and the design limit states of bridge piers and to provide the progressive collapse sequence of damaged bridges when subjected to major earthq
Influence of Reinforcing Steel Fracture on Seismic Performance of Concrete Structures
Author: Kuanshi ZhongPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Low-cycle fatigue and fracture of longitudinal reinforcing steel is a critical potential failure mode in concrete structures subjected to earthquake ground motions. Design to resist fracture depends on the reinforcing steel materials, the design details of the reinforced concrete members, and the cyclic deformation and strain demands imposed by the earthquake. Recently, concerns related to reinforcing bar fatigue and fracture have arisen due to two developments. One is the interest by the engineering and construction industry to utilize high-strength reinforcing steel materials in structures designed for regions with high seismic hazard. Since high-strength reinforcing bars tend to be less ductile and more prone to low-cycle fatigue, as compared to conventional Grade 60 bars, their adequacy for use in structures in high seismic regions needs to be confirmed. The second is related to concerns about long duration ground motions, which can increase the cyclic loading demands on steel reinforcement. Since current design methods do not explicitly consider the influences of ground motion duration, questions have been raised as to whether current seismic design requirements are adequate for structure in regions that may be affected by large magnitude earthquakes or geologic basin effects, which can lead to ground motion duration that are longer than considered in conventional designs. In the prevailing structural design and assessment methods, fatigue and fracture are only implicitly considered by checks of peak deformation measures (e.g., peak strain demand) or other proxy measures (e.g., cumulative plastic demand), which are not sufficient to resolve behavioral effects associated with material cyclic toughness and duration effects under random cyclic loading. This study (1) develops a reliable analytical framework and supporting computational tools for simulating fatigue and fracture in steel reinforcement, considering the steel material properties, reinforcing bar details in concrete structures, and random ground motion loading; (2) applies these methods to evaluate seismic design requirements for high-strength reinforcing bars, specifically Grade 80 and Grade 100 bars; (3) develops an analytical framework and algorithms for using nonlinear dynamic analysis results to systematically evaluate earthquake duration and ground motion spectral shape effects on structures; and (4) applies these methods to incorporate earthquake duration effects in the design of reinforced concrete bridge piers.
Development of Seismic Steel Reinforcement Products and Systems
Author: Publisher:
ISBN:
Category : Earthquake engineering
Languages : en
Pages : 108
Book Description
These papers will provide engineers and contractors with up-to-date information on new technologies that are available now to improve the performance of reinforced concrete structures, especially in zones of high seismicity and to make design and construction more cost effective.
Assessment of Seismic Response and Steel Jacket Retrofit of Squat Circular Reinforced Concrete Bridge Columns
Author: Ravindra VermaSeismic Performance of Circular Reinforced Concrete Bridge Columns Under Bidirectional Earthquake Loading
Author: Mahmoud Mohamad HachemPublisher:
ISBN:
Category :
Languages : en
Pages : 570
Book Description
Seismic retrofit and design recommendations for reinforced concrete bridge columns (PHD).
Author: Limin JinSeismic Performance of Concrete Buildings
Author: Liviu CrainicPublisher: CRC Press
ISBN: 0415631866
Category : Technology & Engineering
Languages : en
Pages : 266
Book Description
This book examines and presents essential aspects of the behavior, analysis, design and detailing of reinforced concrete buildings subjected to strong seismic activity. Seismic design is an extremely complex problem that has seen spectacular development in the last decades. The present volume tries to show how the principles and methods of earthquake engineering can be applied to seismic analysis and design of reinforced concrete buildings. The book starts with an up-to-date presentation of fundamental aspects of reinforced concrete behavior quantified through constitutive laws for monotonic and hysteretic loading. Basic concepts of post-elastic analysis like plastic hinge, plastic length, fiber models, and stable and unstable hysteretic behaviour are, accordingly, defined and commented upon. For a deeper understanding of seismic design philosophy and of static and dynamic post-elastic analysis, seismic behavior of different types of reinforced concrete structures (frames, walls) is examined in detail. Next, up-to-date methods for analysis and design are presented. The powerful concept of structural system is defined and systematically used to explain the response to seismic activity, as well as the procedures for analysis and detailing of common building structures. Several case studies are presented. The book is not code-oriented. The structural design codes are subject to constant reevaluation and updating. Rather than presenting code provisions, this book offers a coherent system of notions, concepts and methods, which facilitate understanding and application of any design code. The content of this book is based mainly on the authors’ personal experience which is a combination of their teaching and research activity as well as their work in the private sector as structural designers. The work will serve to help students and researchers, as well as structural designers to better understand the fundamental aspects of behavior and analysis of reinforced concrete structures and accordingly to gain knowledge that will ensure a sound design of buildings.