Influence of Material and Processing on Stress Corrosion Cracking of Prestressing Steel - Case Studies

Influence of Material and Processing on Stress Corrosion Cracking of Prestressing Steel - Case Studies PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 9782883940666
Category : Technology & Engineering
Languages : en
Pages : 52

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Book Description
This report is a review of selected failures in concrete structures in which prestressing steels break in a brittle way due to stress corrosion cracking. Most cases are from the German experience over a period of about 30 years. Analysis of these failures shows that they are often due to an accumulation of causes such as poor design, errors during construction, careless detailing and, in some cases, use of unsuitable materials. This report will have achieved its purpose if it serves to avoid these past errors and encourages the development of new ways to protect, test and regulate prestressing steels. The report is complemented with comments on the properties and corrosion behaviour of different types of prestressing steels. The goal of the study is to provide objective arguments for the discussion of failures that have occurred due to corrosion induced failure of prestressing steel. In such a way the general regulation given in DIN with respect to reinforcement for robustness may eventually be proven inappropriate. The general building authority approval for prestressed hollow filler block floors already supports such an idea. It is well known that the hollow block floor industry works without any reinforcing steel. The regulations in the standards should not limit in particular the use of these types of prestressing steel (cold-formed wires, strands) which have proven not associated with any substantial failures cases reported in the last 35 years. The report reviews the historical development with respect to corrosion induced failure of prestressing steel. Concerning the circumstances of the failure examples, this review partly reflects a specific problem in Germany. Also reviewed are other known interregional examples of failure which are incorrectly attributed to the prestressed construction method. All cases considered are discussed and the failure reasons thoroughly evaluated, also with reference to the results of most recent research. Another question addressed is whether one should be concerned over corrosion induced retarded failure even when using new generation prestressing steel with correct corrosion protection. Finally a contribution to the following very important question is presented: Do the future prestressed structures possess enough safety against structural failure if they are constructed without reinforcement for robustness but otherwise comply completely with the design standards? To aid a better understanding of this short report on typical failure cases and their origins, the main conditions are set out for corrosion-induced failure of prestressing steel in technical applications. The properties of different types of prestressing steel and their application limits are given in a special section dealing with the influence of building materials on damage development. This report will be of interest to all involved in the construction process. Fundamental scientific discussion has been avoided by reference to well accredited detailed information in the technical literature.

Influence of Material and Processing on Stress Corrosion Cracking of Prestressing Steel - Case Studies

Influence of Material and Processing on Stress Corrosion Cracking of Prestressing Steel - Case Studies PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 9782883940666
Category : Technology & Engineering
Languages : en
Pages : 52

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Book Description
This report is a review of selected failures in concrete structures in which prestressing steels break in a brittle way due to stress corrosion cracking. Most cases are from the German experience over a period of about 30 years. Analysis of these failures shows that they are often due to an accumulation of causes such as poor design, errors during construction, careless detailing and, in some cases, use of unsuitable materials. This report will have achieved its purpose if it serves to avoid these past errors and encourages the development of new ways to protect, test and regulate prestressing steels. The report is complemented with comments on the properties and corrosion behaviour of different types of prestressing steels. The goal of the study is to provide objective arguments for the discussion of failures that have occurred due to corrosion induced failure of prestressing steel. In such a way the general regulation given in DIN with respect to reinforcement for robustness may eventually be proven inappropriate. The general building authority approval for prestressed hollow filler block floors already supports such an idea. It is well known that the hollow block floor industry works without any reinforcing steel. The regulations in the standards should not limit in particular the use of these types of prestressing steel (cold-formed wires, strands) which have proven not associated with any substantial failures cases reported in the last 35 years. The report reviews the historical development with respect to corrosion induced failure of prestressing steel. Concerning the circumstances of the failure examples, this review partly reflects a specific problem in Germany. Also reviewed are other known interregional examples of failure which are incorrectly attributed to the prestressed construction method. All cases considered are discussed and the failure reasons thoroughly evaluated, also with reference to the results of most recent research. Another question addressed is whether one should be concerned over corrosion induced retarded failure even when using new generation prestressing steel with correct corrosion protection. Finally a contribution to the following very important question is presented: Do the future prestressed structures possess enough safety against structural failure if they are constructed without reinforcement for robustness but otherwise comply completely with the design standards? To aid a better understanding of this short report on typical failure cases and their origins, the main conditions are set out for corrosion-induced failure of prestressing steel in technical applications. The properties of different types of prestressing steel and their application limits are given in a special section dealing with the influence of building materials on damage development. This report will be of interest to all involved in the construction process. Fundamental scientific discussion has been avoided by reference to well accredited detailed information in the technical literature.

Model Code 2010 - Final draft

Model Code 2010 - Final draft PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 288394105X
Category : Technology & Engineering
Languages : en
Pages : 357

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Book Description
The objectives of MC2010 are to (a) serve as a basis for future codes for concrete structures, and (b) present new developments with regard to concrete structures, structural materials and new ideas in order to achieve optimum behaviour. MC2010 includes the whole life cycle of a concrete structure, from design and construction to conservation (assessment, maintenance, strengthening) and dismantlement, in one code for buildings, bridges and other civil engineering structures. Design is largely based on performance requirements. The chapter on materials is extended with new types of concrete and reinforcement (such as fibres and non-metallic reinforcements). The fib Model Code 2010 also gives corresponding explanations in a separate column of the document. Additionally, MC2010 is supported by background documents that have already been (or will soon be) published in fib bulletins and journal articles. MC2010 is now the most comprehensive code on concrete structures, including their complete life cycle: conceptual design, dimensioning, construction, conservation and dismantlement.

Structural Concrete, Volume 3

Structural Concrete, Volume 3 PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 2883940932
Category : Technology & Engineering
Languages : en
Pages : 391

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Book Description
The second edition of the Structural Concrete Textbook is an extensive revision that reflects advances in knowledge and technology over the past decade. It was prepared in the intermediate period from the CEP-FIP Model Code 1990 (MC90) tofib Model Code 2010 (MC2010), and as such incorporates a significant amount of information that has been already finalized for MC2010, while keeping some material from MC90 that was not yet modified considerably. The objective of the Textbook is to give detailed information on a wide range of concrete engineering from selection of appropriate structural system and also materials, through design and execution and finally behaviour in use. The revised fib Structural Concrete Textbook covers the following main topics: phases of design process, conceptual design, short and long term properties of conventional concrete (including creep, shrinkage, fatigue and temperature influences), special types of concretes (such as self compacting concrete, architectural concrete, fibre reinforced concrete, high and ultra high performance concrete), properties of reinforcing and prestressing materials, bond, tension stiffening, moment-curvature, confining effect, dowel action, aggregate interlock; structural analysis (with or without time dependent effects), definition of limit states, control of cracking and deformations, design for moment, shear or torsion, buckling, fatigue, anchorages, splices, detailing; design for durability (including service life design aspects, deterioration mechanisms, modelling of deterioration mechanisms, environmental influences, influences of design and execution on durability); fire design (including changes in material and structural properties, spalling, degree of deterioration), member design (linear members and slabs with reinforcement layout, deep beams); management, assessment, maintenance, repair (including, conservation strategies, risk management, types of interventions) as well as aspects of execution (quality assurance), formwork and curing. The updated Textbook provides the basics of material and structural behaviour and the fundamental knowledge needed for the design, assessment or retrofitting of concrete structures. It will be essential reading material for graduate students in the field of structural concrete, and also assist designers and consultants in understanding the background to the rules they apply in their practice. Furthermore, it should prove particularly valuable to users of the new editions of Eurocode 2 for concrete buildings, bridges and container structures, which are based only partly on MC90 and partly on more recent knowledge which was not included in the 1999 edition of the Textbook.

Concrete Structures for Oil and Gas Fields in Hostile Marine Environments

Concrete Structures for Oil and Gas Fields in Hostile Marine Environments PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 2883940908
Category : Technology & Engineering
Languages : en
Pages : 38

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Book Description
Concrete offshore structures have been successfully delivered to the international oil and gas industry for more than 35 years. Some 50 major concrete platforms of different shapes and sizes, supporting large production and storage facilities, are currently operating in hostile marine environments worldwide and have excellent service records. After some years with little development activity, today there is a renewed interest in robust structures for the Arctic environment, for Liquefied Natural Gas (LNG) terminals and for special floating barges and vessels. Currently, concrete solutions are being considered for projects north and east of Russia, north of Norway and offshore Newfoundland, among others. Concrete is also in increasing demand in built up coastal areas for a variety of purposes such as harbour works, tunnels and bridges, cargo terminals, parking garages and sea front housing developments where durability and robustness are essential. The mandate of fib Task Group 1.5 was to gather the experience and know-how pertinent to the development, design and execution of offshore concrete structures, and to elaborate on the applicability of concrete structures for the Arctic environments. The findings of the Task Group are presented in fib Bulletin 50. The report is based on experience gained from the design, execution and performance of a number of offshore concrete structures around the world and in particular in the North Sea. Ongoing inspections have shown excellent durability and structural performance, even in structures that have exceeded their design lives, in conditions often characterized by extreme wave loads, freezing conditions, hurricane force winds and seismic actions. This forms the "background" for discussing the applicability of concrete structures for the Arctic regions. Although to a large extent dedicated to oil- and gas- related structures, the report is also relevant to other marine applications where the same design principles, material selection criteria and construction methods apply. fib Bulletin 50 is not in itself a code, nor is it a textbook. Rather, extensive reference is made to proven and readily available design codes and construction guides, as well as relevant papers and proceedings and other fib publications.

Structural Concrete Textbook, Volume 5

Structural Concrete Textbook, Volume 5 PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 2883941025
Category : Technology & Engineering
Languages : en
Pages : 482

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Book Description
The third edition of the Structural Concrete Textbook is an extensive revision that reflects advances in knowledge and technology over the past decade. It was prepared in the intermediate period from the CEP-FIP Model Code 1990 (MC90) tofib Model Code for Concrete Structures 2010 (MC2010), and as such incorporates a significant amount of information that has been already finalized for MC2010, while keeping some material from MC90 that was not yet modified considerably. The objective of the textbook is to give detailed information on a wide range of concrete engineering from selection of appropriate structural system and also materials, through design and execution and finally behaviour in use. The revised fib Structural Concrete Textbook covers the following main topics: phases of design process, conceptual design, short and long term properties of conventional concrete (including creep, shrinkage, fatigue and temperature influences), special types of concretes (such as self compacting concrete, architectural concrete, fibre reinforced concrete, high and ultra high performance concrete), properties of reinforcing and prestressing materials, bond, tension stiffening, moment-curvature, confining effect, dowel action, aggregate interlock; structural analysis (with or without time dependent effects), definition of limit states, control of cracking and deformations, design for moment, shear or torsion, buckling, fatigue, anchorages, splices, detailing; design for durability (including service life design aspects, deterioration mechanisms, modelling of deterioration mechanisms, environmental influences, influences of design and execution on durability); fire design (including changes in material and structural properties, spalling, degree of deterioration), member design (linear members and slabs with reinforcement layout, deep beams); management, assessment, maintenance, repair (including, conservation strategies, risk management, types of interventions) as well as aspects of execution (quality assurance), formwork and curing. The updated textbook provides the basics of material and structural behaviour and the fundamental knowledge needed for the design, assessment or retrofitting of concrete structures. It will be essential reading material for graduate students in the field of structural concrete, and also assist designers and consultants in understanding the background to the rules they apply in their practice. Furthermore, it should prove particularly valuable to users of the new editions of Eurocode 2 for concrete buildings, bridges and container structures, which are based only partly on MC90 and partly on more recent knowledge which was not included in the 1999 edition of the textbook.

Structural Concrete, Volume 2

Structural Concrete, Volume 2 PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 2883940924
Category : Technology & Engineering
Languages : en
Pages : 349

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Book Description
The second edition of the Structural Concrete Textbook is an extensive revision that reflects advances in knowledge and technology over the past decade. It was prepared in the intermediate period from the CEP-FIP Model Code 1990 (MC90) tofib Model Code 2010 (MC2010), and as such incorporates a significant amount of information that has been already finalized for MC2010, while keeping some material from MC90 that was not yet modified considerably. The objective of the Textbook is to give detailed information on a wide range of concrete engineering from selection of appropriate structural system and also materials, through design and execution and finally behaviour in use. The revised fib Structural Concrete Textbook covers the following main topics: phases of design process, conceptual design, short and long term properties of conventional concrete (including creep, shrinkage, fatigue and temperature influences), special types of concretes (such as self compacting concrete, architectural concrete, fibre reinforced concrete, high and ultra high performance concrete), properties of reinforcing and prestressing materials, bond, tension stiffening, moment-curvature, confining effect, dowel action, aggregate interlock; structural analysis (with or without time dependent effects), definition of limit states, control of cracking and deformations, design for moment, shear or torsion, buckling, fatigue, anchorages, splices, detailing; design for durability (including service life design aspects, deterioration mechanisms, modelling of deterioration mechanisms, environmental influences, influences of design and execution on durability); fire design (including changes in material and structural properties, spalling, degree of deterioration), member design (linear members and slabs with reinforcement layout, deep beams); management, assessment, maintenance, repair (including, conservation strategies, risk management, types of interventions) as well as aspects of execution (quality assurance), formwork and curing. The updated Textbook provides the basics of material and structural behaviour and the fundamental knowledge needed for the design, assessment or retrofitting of concrete structures. It will be essential reading material for graduate students in the field of structural concrete, and also assist designers and consultants in understanding the background to the rules they apply in their practice. Furthermore, it should prove particularly valuable to users of the new editions of Eurocode 2 for concrete buildings, bridges and container structures, which are based only partly on MC90 and partly on more recent knowledge which was not included in the 1999 edition of the Textbook.

Design of precast concrete structures against accidental actions

Design of precast concrete structures against accidental actions PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 2883941033
Category : Technology & Engineering
Languages : en
Pages : 84

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Book Description
Since the 1980’s, several buildings throughout the world have been subject to gas explosions, impact by cars or airplanes, or car bomb attacks. In many cases the effect of the impact or explosion has been the failure of a critical structural member at the perimeter of the building. After the failure, the load supported by that member could not be redistributed and part or all of the structure has collapsed in a progressive manner. The phenomenon that occurs when local failure is not confined to the area of initial distress, and spreads horizontally and/or vertically through the structure, is termed progressive collapse. Progressive collapse is a relatively rare event, as it requires both an accidental action to cause local damage and a structure that lacks adequate continuity, ductility, and redundancy to prevent the spread of damage. It is technically very difficult and economically prohibitive to design buildings for absolute safety. However it is possible to construct precast concrete buildings that afford an acceptable degree of safety with regard to accidental actions. A structure is normally designed to respond properly, without damage, under normal load conditions, but local and/or global damages cannot be avoided under the effect of an unexpected, but moderate degree of accidental overload. Properly designed and constructed structures usually possess reasonable probability not to collapse catastrophically under such loads, depending on different factors, for example: the type of loading; the degree and the location of accidental loading in regard to the structure and its structural members; the type of structural system, the construction technology, and the spans between structural vertical members, etc. No structure can be expected to be totally resistant to actions arising from an unexpected and extreme cause, but it should not be damaged to an extent that is disproportionate to the original cause. The aim of fib Bulletin 63 is to summarize the present knowledge on the subject and to provide guidance for the design of precast structures against progressive collapse. This is addressed in terms of (a) the classification of the actions, (b) their effect on the structural types, (c) the strategies to cope with such actions, (d) the design methods and (e) some typical detailing, all supplemented with illustrations from around the world, and some model calculations.

Post-tensioning in Buildings

Post-tensioning in Buildings PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 9782883940710
Category : Technology & Engineering
Languages : en
Pages : 130

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Book Description
The development of prestressing technology has constituted one of the more important improvements in the fields of structural engineering and construction. Referring particularly to post-tensioning applications, it is generally recognized how it opens the possibility to improve economy, structural behaviour and aesthetic aspects in concrete solutions. In spite of the simplicity of its basic concepts and well-known advantages, the application extent of post-tensioning solutions cannot be considered harmonized in the different areas and structural applications. In fact, for various reasons, it appears that the potential offered by prestressing is far from being fully exploited, especially in building structures field. In many cases where post-tensioning would provide a visibly superior solution, it happens after all that a more conventional non-prestressed solution is often selected. The main objective of this fib Technical Report is therefore to show the benefits of using post-tensioning for the more common practical applications in concrete buildings. The document is mainly addressed to architects, contractors and owners. It is also drafted with the goal of motivating building designers to use post-tensioning: basic design aspects related to prestressing effects and design criteria are summarized and conceptual design aspects are emphasized. A set of practical examples is presented, showing the adopted solutions and their advantages when meeting the requirements of specific problems. The selected examples were precisely not chosen because they are outstanding structures. As a matter of fact, post-tensioning principles and technology can be used in any structure, independently of its importance, covering a wide range of building structural applications, improving the structure quality and promoting concrete as a structural material. The advantages of using post-tensioning, concerning structural behaviour, economy, detailing and constructive aspects, are illustrated by the presentation of several existing structures, most of them designed by Working Party members. General design calculations are not presented, but design results showing the improvement in structural behaviour are illustrated.

Probabilistic performance-based seismic design

Probabilistic performance-based seismic design PDF Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
ISBN: 2883941084
Category : Technology & Engineering
Languages : en
Pages : 124

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Book Description
In the last ten to fifteen years a vast amount of research has been undertaken to improve on earlier methods for analysing the seismic reliability of structures. These efforts focused on identifying aspects of prominent relevance and disregarding the inessential ones, with the goal of producing methods that are both more efficient and easier to use in practice. Today this goal can be said to be substantially achieved. During these years scientific activity covered all of the many aspects involved in such a multi-disciplinary problem, ranging from seismology, to geotechnics, to structural analysis and economy, all of them to be consistently organised into a probabilistic framework. As the output of this research was dispersed into a multitude of technical papers, fib Commission 7 thought it worthwhile to select the essential aspects of this large body of knowledge and to present them into a coherent and accessible document for structural engineers. To this end a task group of specialists was formed, whose qualifications come from their personal involvement in the above-mentioned developments throughout this period of time. From its inception the group decided that the bulletin should have had a distinct educational character and provide a clear overview of the methods available. The outcome is a compact volume that starts by introducing the concepts and definitions of performance-based engineering, continues with two chapters on assessment and design, respectively, presenting the methods in detail accompanied by illustrative examples, and concludes with an appendix with sample programming excerpts for their implementation. It is believed that at present fib Bulletin 68 represents a unique compendium on probabilistic performance-based seismic design.

3rd fib Congress Washington USA

3rd fib Congress Washington USA PDF Author: FIB – International Federation for Structural Concrete
Publisher: FIB - Féd. Int. du Béton
ISBN: 1617828211
Category : Technology & Engineering
Languages : en
Pages : 5718

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Book Description