Author: Sami El-BorgiPublisher:
ISBN:
Category :
Languages : en
Pages : 612
Book Description
Seismic Evaluation and Strengthening of Lightly Reinforced Concrete Structures
Author: Sami El-BorgiSeismic Assessment and Retrofit of Reinforced Concrete Buildings
Author: fib Fédération internationale du bétonPublisher: fib Fédération internationale du béton
ISBN: 9782883940642
Category : Technology & Engineering
Languages : en
Pages : 322
Book Description
In most parts of the developed world, the building stock and the civil infrastructure are ageing and in constant need of maintenance, repair and upgrading. Moreover, in the light of our current knowledge and of modern codes, the majority of buildings stock and other types of structures in many parts of the world are substandard and deficient. This is especially so in earthquake-prone regions, as, even there, seismic design of structures is relatively recent. In those regions the major part of the seismic threat to human life and property comes from old buildings. Due to the infrastructure's increasing decay, frequently combined with the need for structural upgrading to meet more stringent design requirements (especially against seismic loads), structural retrofitting is becoming more and more important and receives today considerable emphasis throughout the world. In response to this need, a major part of the fib Model Code 2005, currently under development, is being devoted to structural conservation and maintenance. More importantly, in recognition of the importance of the seismic threat arising from existing substandard buildings, the first standards for structural upgrading to be promoted by the international engineering community and by regulatory authorities alike are for seismic rehabilitation of buildings. This is the case, for example, of Part 3: Strengthening and Repair of Buildings of Eurocode 8 (i. e. of the draft European Standard for earthquake-resistant design), and which is the only one among the current (2003) set of 58 Eurocodes attempting to address the problem of structural upgrading. It is also the case of the recent (2001) ASCE draft standard on Seismic evaluation of existing buildings and of the 1996 Law for promotion of seismic strengthening of existing reinforced concrete structures in Japan. As noted in Chapter 1 of this Bulletin, fib - as CEB and FIP did before - has placed considerable emphasis on assessment and rehabilitation of existing structures. The present Bulletin is a culmination of this effort in the special but very important field of seismic assessment and rehabilitation. It has been elaborated over a period of 4 years by Task Group 7.1 Assessment and retrofit of existing structures of fib Commission 7 Seismic design, a truly international team of experts, representing the expertise and experience of all the important seismic regions of the world. In the course of its work the team had six plenary two-day meetings: in January 1999 in Pavia, Italy; in August 1999 in Raleigh, North Carolina; in February 2000 in Queenstown, New Zealand; in July 2000 in Patras, Greece; in March 2001 in Lausanne, Switzerland; and in August 2001 in Seattle, Washington. In October 2002 the final draft of the Bulletin was presented to public during the 1st fib Congress in Osaka. It was also there that it was approved by fib Commission 7 Seismic Design. The contents is structured into main chapters as follows: 1 Introduction - 2 Performance objectives and system considerations - 3 Review of seismic assessment procedures - 4 Strength and deformation capacity of non-seismically detailed components - 5 Seismic retrofitting techniques - 6 Probabilistic concepts and methods - 7 Case studies
Proceedings
Author: Publisher:
ISBN:
Category : Reinforced concrete construction
Languages : en
Pages : 188
Book Description
The ShakeOut Scenario Supplemental Study: Older Reinforced Concrete Buildings
Author: Displacement-based Seismic Design of Reinforced Concrete Buildings
Author: fib Fédération internationale du bétonPublisher: fib Fédération internationale du béton
ISBN: 9782883940659
Category : Technology & Engineering
Languages : en
Pages : 206
Book Description
A brief summary of the history of seismic design as given in chapter 1, indicates that initially design was purely based on strength or force considerations. When the importance of displacement, however, became better appreciated, it was attempted to modify the existing force-based approach in order to include considerations of displacement, rather than to totally reconsider the procedure on a more rational basis. In the last decade, then, several researchers started pointing out this inconsistency, proposing displacement-based approaches for earthquake engineering evaluation and design, with the aim of providing improved reliability in the engineering process by more directly relating computed response and expected structural performance. The main objective of this report is to summarize, critically review and compare the displacement - based approaches proposed in the literature, thus favouring code implementation and practical use of rational and reliable methods. Chapter 2 Seismic performance and design objectives of this report introduces concepts of performance levels, seismic hazard representation, and the coupling of performance and hazard to define performance objectives. In fact, for displacement analysis to be relevant in the context of performance-based design, the structural engineer must select appropriate performance levels and seismic loadings. A critical review of some engineering limit states appropriate to the different performance levels is therefore proposed. In chapter 3 Conceptual basis for displacement-based earthquake resistant design, the fundamental principles associated with displacement of the ground during an earthquake and the effects, in terms of displacement, in the structure, are reviewed. The historical development guides the presentation with a review of general linear and nonlinear structural dynamics principles, general approaches to estimate displacement, for both ground and structure, and finally a general presentation of the means to measure and judge the appropriateness of the displacements of the structure in section. Chapter 4 Approaches and procedures for displacement-based design can be somehow considered the fundamental part of the report, since a critical summary of the displacement - based approaches proposed by different researchers is presented there. Displacement - based design may require specific characterization of the input ground motion, a topic addressed in Chapter 5 Seismic input. In general, various pertinent definitions of input motion for non-code format analysis are included, while peak ground parameters necessary for code base shear equations are only addressed as needed for the definition of motion for analysis. Chapter 6 Displacement capacity of members and systems addresses the fundamental problem of evaluating the inelastic displacement capacity of reinforced concrete members and realistic values of their effective cracked stiffness at yielding, including effects of shear and inclined cracking, anchorage slip, bar buckling and of load cycling. In Chapter 7 Application and evaluation of displacement-based approaches, some of the many different displacement based design procedures briefly introduced in Chapter 4 are applied to various case studies, identifying and discussing the difficulties a designer may encounter when trying to use displacement based design. Results for five different case studies designed in accordance with eight different displacement based design methods are presented. Although in general case studies are considered a useful but marginal part of a state of the art document, in this case it has to be noted that chapter 7 is possibly the most innovative and fundamental part of the whole report. The conclusions of chapter 7 are the fundamental and essential conclusions of the document and allow foreseeing a bright future for displacement - based design approaches. The state-of-art report has been elaborated over a period of 4 years by Task Group 7.2 Displacement-based design and assessment of fib Commission 7Seismic design, a truly international team of experts, representing the expertise and experience of all the important seismic regions of the world. In October 2002 the final draft of the Bulletin was presented to the public during the 1st fibCongress in Osaka. It was also there that it was approved by fib Commission 7Seismic Design.
Reinforced Concrete Structural Walls: Test Database and Modeling Parameters
Author: Saman Ali AbdullahPublisher:
ISBN:
Category :
Languages : en
Pages : 333
Book Description
Reinforced concrete (RC) structural walls (also known as shear walls) have commonly been used as lateral force-resisting elements in buildings in regions of moderate-to-high seismic hazard because they provide substantial lateral strength and stiffness to buildings when subjected to strong ground shaking. Although relatively few wall tests were reported in the literature prior to 1990, a substantial number of tests have since been reported, primarily to assess the role of various parameters on wall deformation capacity, failure mode, strength, and stiffness. However, a comprehensive database that summarizes information and results from these tests does not exist. To address this issue, a comprehensive experimental wall database, referred to as the UCLA- RCWalls database, was created. The database currently contains detailed and parameterized information on more than 1100 wall tests surveyed from more than 260 programs reported in literature, and enables assessment of a spectrum of issues related to the behavior and performance of structural walls. The database was developed using software that enabled use of an engineering database structure with a user-friendly interface to manipulate data, i.e., filter, import, export, and review, and a secure background to store the data. The underlying premise of the ASCE 7-10 and ACI 318-14 provisions is that special structural walls satisfying the provisions of ACI 318-14 18.10.6.2 through 18.10.6.4 possess adequate deformation capacity to exceed the expected deformation demand determined using ASCE 7-10 analysis procedures. However, observations from recent laboratory tests and reconnaissance efforts following strong earthquakes, where significant damage occurred at boundary regions of thin walls due to concrete crushing, rebar buckling, and lateral instability, have raised concerns that current design provisions are inadequate. To address this concern, the database was filtered to identify and analyze a dataset of 164 tests on well-detailed walls generally satisfying ACI 318-14 provisions for special structural walls. The study revealed that wall lateral deformation capacity is primarily a function of the ratio of wall neutral axis depth-to-width of flexural compression zone (c/b), the ratio of wall length-to- width of flexural compression zone (lw/b), wall shear stress, and the configuration of boundary transverse reinforcement (e.g., use of overlapping hoops versus a single perimeter hoop with intermediate crossties), and that, in some cases, the provisions of ACI 318-14 may not result in buildings that meet the stated performance objectives. Based on these observations, an expression is developed to predict wall drift capacity associated with 20% lateral strength loss with low coefficient of variation, and a new reliability-based design methodology for structural walls is proposed. The approach has been adopted for ACI 318-19, where a drift demand- to-capacity ratio check is performed to provide a low probability that roof drift demands exceed roof drift capacity at strength loss for Design Earthquake hazard level. A large number of RC buildings constructed prior to the mid-1970s in earthquake-prone regions rely on lightly reinforced or perforated, perimeter structural walls to resist earthquake-induced lateral loads. These walls are susceptible to damage when subjected to moderate-to-strong shaking; a number of such cases were observed in 1999 Chi-Chi and Kocaeli Earthquakes, and more recently in 2010 Maule and 2011 Christchurch earthquakes. Despite these observations, limited studies have been reported in the literature to investigate the loss of axial (gravity) load carrying capacity of damaged walls and wall piers, primarily due to the lack of experimental data. To study axial failure of structural walls, the database was filtered to identify and analyze datasets of tests on shear- and flexure-controlled walls. Based on the results, expressions were derived to predict lateral drift capacity at axial failure of RC walls and piers. Furthermore, the ASCE/SEI 41 standard (and other similar standards or guidelines, e.g., ACI 369) represents a major advance in structural and earthquake engineering to address the seismic hazards posed by existing buildings and mitigate those hazards through retrofit. For nonlinear seismic evaluation of existing buildings, these standards provide modeling parameters (e.g., effective stiffness values, deformation capacities, and strengths) to construct backbone relations, as well as acceptance criteria to determine adequacy for a given hazard level. The modeling parameters and acceptance criteria for structural walls were developed based on limited experimental data and knowledge available in the late 1990s (FEMA 273/274-1997), with minor revisions since, especially for flexure-controlled walls. As a result, the wall provisions tend to be, in many cases, inaccurate and conservative, and can result in uneconomical retrofit schemes. Therefore, one of the objectives of this study involved utilizing the available experimental data in the UCLA- RCWalls database and new information on performance of structural walls to develop updated modeling parameters and acceptance criteria for flexure-controlled walls. The updated provisions include a new approach to identify expected wall dominant behavior (failure mode), cracked and uncracked flexural and shear stiffness values of flexure-controlled walls, and updated modeling parameters (backbone relations) and acceptance criteria for flexure-controlled walls. The updates are expected to be significant contributions to the practice of seismic evaluation and retrofit of wall buildings.
Seismic Design, Assessment and Retrofitting of Concrete Buildings
Author: Michael N. FardisPublisher: Springer Science & Business Media
ISBN: 1402098421
Category : Technology & Engineering
Languages : en
Pages : 757
Book Description
Reflecting the historic first European seismic code, this professional book focuses on seismic design, assessment and retrofitting of concrete buildings, with thorough reference to, and application of, EN-Eurocode 8. Following the publication of EN-Eurocode 8 in 2004-05, 30 countries are now introducing this European standard for seismic design, for application in parallel with existing national standards (till March 2010) and exclusively after that. Eurocode 8 is also expected to influence standards in countries outside Europe, or at the least, to be applied there for important facilities. Owing to the increasing awareness of the threat posed by existing buildings substandard and deficient buildings and the lack of national or international standards for assessment and retrofitting, its impact in that field is expected to be major. Written by the lead person in the development of the EN-Eurocode 8, the present handbook explains the principles and rationale of seismic design according to modern codes and provides thorough guidance for the conceptual seismic design of concrete buildings and their foundations. It examines the experimental behaviour of concrete members under cyclic loading and modelling for design and analysis purposes; it develops the essentials of linear or nonlinear seismic analysis for the purposes of design, assessment and retrofitting (especially using Eurocode 8); and gives detailed guidance for modelling concrete buildings at the member and at the system level. Moreover, readers gain access to overviews of provisions of Eurocode 8, plus an understanding for them on the basis of the simple models of the element behaviour presented in the book. Also examined are the modern trends in performance- and displacement-based seismic assessment of existing buildings, comparing the relevant provisions of Eurocode 8 with those of new US prestandards, and details of the most common and popular seismic retrofitting techniques for concrete buildings and guidance for retrofitting strategies at the system level. Comprehensive walk-through examples of detailed design elucidate the application of Eurocode 8 to common situations in practical design. Examples and case studies of seismic assessment and retrofitting of a few real buildings are also presented. From the reviews: "This is a massive book that has no equal in the published literature, as far as the reviewer knows. It is dense and comprehensive and leaves nothing to chance. It is certainly taxing on the reader and the potential user, but without it, use of Eurocode 8 will be that much more difficult. In short, this is a must-read book for researchers and practitioners in Europe, and of use to readers outside of Europe too. This book will remain an indispensable backup to Eurocode 8 and its existing Designers’ Guide to EN 1998-1 and EN 1998-5 (published in 2005), for many years to come. Congratulations to the author for a very well planned scope and contents, and for a flawless execution of the plan". AMR S. ELNASHAI "The book is an impressive source of information to understand the response of reinforced concrete buildings under seismic loads with the ultimate goal of presenting and explaining the state of the art of seismic design. Underlying the contents of the book is the in-depth knowledge of the author in this field and in particular his extremely important contribution to the development of the European Design Standard EN 1998 - Eurocode 8: Design of structures for earthquake resistance. However, although Eurocode 8 is at the core of the book, many comparisons are made to other design practices, namely from the US and from Japan, thus enriching the contents and interest of the book". EDUARDO C. CARVALHO
Technical Report
Author: Publisher:
ISBN:
Category : Earthquake engineering
Languages : en
Pages : 92
Book Description
Handbook on Seismic Retrofit of Buildings
Author: Amarnath ChakrabartiPublisher: Alpha Science International, Limited
ISBN:
Category : Science
Languages : en
Pages : 488
Book Description
The Handbook on Seismic Retrofit of Buildings is a compiled source of technical information for engineers and professionals in the buildings industry, decision making officials and students. The Handbook is divided into 17 chapters, covering - basic concepts of earthquakes, seismic design and retrofit of buildings, seismic vulnerability assessment, retrofit strategies for different types of buildings, geotechnical and foundation aspects, advanced applications, quality assurance and case studies.
Seismic Design of Reinforced Concrete Structures for Controlled Inelastic Response
Author: Comité euro-international du bétonPublisher: Thomas Telford
ISBN: 9780727726414
Category : Technology & Engineering
Languages : en
Pages : 196
Book Description
This detailed guide is designed to enable the reader to understand the relative importance of the numerous parameters involved in seismic design and the relationships between them, as well as the motivations behind the choices adopted by the codes.