Download or read book Influence of Material and Processing on Stress Corrosion Cracking of Prestressing Steel Case Studies written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2003 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Structural Concrete Volume 3 written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2010 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Concrete Structures for Oil and Gas Fields in Hostile Marine Environments written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2008-12-01 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Structural Concrete Textbook Volume 5 written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2012-06-01 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Structural Concrete Volume 2 written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2010-01-01 with total page 349 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Design of precast concrete structures against accidental actions written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2012-01-01 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Probabilistic performance based seismic design written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2012-05-07 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Structural Concrete Volume 1 written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2009-01-01 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Constitutive Modelling of High Strength high Performance Concrete written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2008-01-01 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Strength/High Performance Concrete (HSC/HPC) continues to be the object of particular interest and extensive research, and its use in construction is increasing continuously. fib Bulletin 42 summarises the available information on the material behaviour of HSC/HPC, and develops a set of code-type constitutive relations as an extension of CEB-FIP Model Code 1990. Literature on experimental data and international guidelines, standards and recommendations were reviewed, and already-existing constitutive relations and models were evaluated. In addition to a number of material laws chosen and adjusted for this report, some new constitutive relations were developed based on the collected data. The criteria for the choice of the existing relations as well as the development of the new constitutive relations involved their simplicity and operationality (code-type mathematical formulations). Furthermore, they had to be physically sound and if possible describe the behaviour of both high-performance and normal strength concretes by a unique relation. Finally, compliance with the specifications given in the CEB-FIP Model Code 1990 was examined. This State-of-art report is intended for engineers and represents a summary of the relevant knowledge available to and possessed by the members of the Task Group at the time of its drafting.

Download or read book Precast Concrete Railway Track Systems written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2006-01-01 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1986, the FIP Commission on Prefabrication issued the state-of-art report "Concrete Railway Sleepers", which included design considerations, manufacturing methods, rail fastening systems and field performance. During the two decades since that report, precast concrete has gained importance in the field of railway track systems for plain track, switches and crossings, tunnels and other applications. Developments in production methods for concrete sleepers in switch and crossing layouts to cope with the complex geometry and the industry's confidence in their performance have contributed to the huge increase in the use of this type of sleeper. The use of slab track for high-speed track has also grown, particularly where either new track is built or where existing track is renewed and long periods of track possession are possible. There has also been progress in the development of plant and equipment for the installation, renewal and maintenance of concrete sleepered track. With machines now able to replace existing track at a rate of 5000 sleepers (over 3 km track) per day, choosing concrete sleepers can reduce the time on site, meaning tracks can be reopened quickly whilst reducing labour requirements and costs. Today, precast concrete is considered to be the best performing and preferred material for railway sleepers, due to the following factors: long-term durability; improved geometric retention of track and greater weight vital for high-speed and heavy freight lines; improved elasticity of track; improved ride quality; low first cost; minimum life cycle cost; low cost of maintenance; environmental friendliness - no chemical treatment required and can be recycled. As all aspects of precast concrete railway track systems, from design through manufacture to installation and maintenance, have progressed since the publication of the FIP report, an update was considered timely, in order to provide a synthesis of currently available information. This new edition covers quality, design, production, durability, maintenance and environmental considerations, and includes survey on the use of precast concrete track systems in over 30 countries.

Download or read book Precast Concrete Bridges written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2004-01-01 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report was drafted by fib Task Group 6.4, Precast bridges: José Calavera (Convenor, Spain) André De Chefdebien (CERIB, France), David Fernández-Ordóñez (Prefabricados Castelo, S.A., Spain, Secretary), Antonello Gasperi (Consulting engineer, Italy), Jorge Ley (INTEMAC, Spain), Fritz Mönnig (Prof. Bechert & Partner, Germany), Pierre Passeman (CERIB, France), C. Quartel (Spanbeton BV, The Netherlands), Ladislav Sasek (VPU DECO Praha, Czech Republic), George Tootell (Buchan Concrete Ltd., UK), Arnold Van Acker (Belgium)

Download or read book Acceptance of cable systems using prestressing steels written by FIB – International Federation for Structural Concrete and published by FIB - Féd. Int. du Béton. This book was released on 2019-03-01 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cable-stayed structures have become increasingly popular over the last 30 years and have been used in all parts of the world. Modern cable-stayed bridges have a history of over 50-years and have been constructed with span lengths ranging from 15 m to over 1000 m. Many long span cable-stayed bridges have been built for railway and highway traffic applications. Stay cables have also been used on pedestrian structures, many of which are architecturally striking and have become landmark structures. There is growing use in building structures, particularly for cable-supported roofs. Most of the cable supported structures have been in the form of cable-stayed bridges; but in recent years, extradosed bridges have seen increased popularity among the designers. Led by the experience in Japan, more than 200 extradosed bridges have been constructed worldwide in the past 15 years. The first edition of these fib recommendations was published as fib Bulletin 30 in 2005 and was the first specification published by fib for stay cable systems. This new bulletin has been updated based on Bulletin 30 with the aim to reflect the current state of the art and encompass the latest knowledge in cable systems. In addition, it has been the aspiration of Commission 5 and Task Group 5.5 to harmonize the guidance in this updated bulletin with other stay cable recommendations from around the world, including those from Europe, Japan and the USA. This new bulletin is intended to supersede and replace fib Bulletin 30. It is recommended that it be used in lieu of fib Bulletin 30 for all future cable supported applications. The updated bulletin introduces several significant enhancements to the specifications: These recommendations are applicable to both stay cable and extradosed cable applications. In the past, there has been some debate over the boundary between cable-stayed and extradosed bridges. This bulletin presents a new continuous approach valid for both. A completely new testing requirement to assess the performance of cable systems under bending fatigue, including both anchorages and saddles, if applicable, has been added. Testing requirements for saddle systems have been reformulated. In addition to the bending fatigue test noted above, new testing procedures for stay cable saddles with isolated tensile elements are introduced. This includes tests for saddle axial fatigue, friction and tensile testing, and determination of the effective saddle friction coefficient. Expanded system qualification, including requirements for both stay cable and extradosed applications. Includes new provisions for MTE qualification and additional load transferring connection devices. Minimum number of tests is specified for each. A new in-situ damping measurement test has been added to verify the actual damping ratio of the damping devices installed. By testing on site, selected cables may be excited to vibrate without and with the damping devices so that the observed v vibration behaviour can be compared to the specified value. Other revisions have been made to reflect the current state of practice: Expanded quality control testing requirements Inclusion of epoxy-coated prestressing steel as a protection layer. Previous recommendations only considered zinc coatings. Specifications for epoxy coating material are given. Requirements for stainless steel components such as pipes, caps and plates Updated guidance for designing lightning protection systems Detailed recommendations for different levels of inspection of cable systems, including: initial, routine, detailed and exceptional inspections An updated list of references, relevant standards, and extended literature

Download or read book Retrofitting of Concrete Structures by Externally Bonded FRPs With Emphasis on Seismic Applications written by fib Fédération internationale du béton and published by fib Fédération internationale du béton. This book was released on 2006-01-01 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: fib Bulletin 35 is the first bulletin to publish documentation from an fib short course. These courses are held worldwide and cover advanced knowledge of structural concrete in general, or specific topics. They are organized by fib and given by internationally recognized experts in fib, often supplemented with local experts active in fib. They are based on the knowledge and expertise from fib's ten Commissions and nearly fifty Task Groups. fib Bulletin 35 presents the course materials developed for the short course "Retrofitting of Concrete Structures through Externally Bonded FRP, with emphasis on Seismic Applications", given in Ankara and Istanbul in June 2005. The course drew on expertise both from outside Turkey and from the large pool of local experts on this subject. In most countries of the world, the building stock is ageing and needs continuous maintenance or repair. Moreover, the majority of existing constructions are deficient in the light of current knowledge and design codes. The problem of structural deficiency of existing constructions is especially acute in seismic regions, as, even there, seismic design of structures is relatively recent. The direct and indirect costs of demolition and reconstruction of structurally deficient constructions are often prohibitive; furthermore they entail a substantial waste of natural resources and energy. Therefore, structural retrofitting is becoming increasingly widespread throughout the world. Externally bonded Fibre Reinforced Polymers (FRPs) are rapidly becoming the technique of choice for structural retrofitting. They are cleaner and easier to apply than conventional retrofitting techniques, reduce disruption to the occupancy and operation of the facility, do not generate debris or waste, and reduce health and accident hazards at the construction site as well as noise and air pollution in the surroundings. fib Bulletin 35 gives state-of-the-art coverage of retrofitting through FRPs and presents relevant provisions from three recent standardisation milestones: EN 1998-3:2005 "Eurocode 8: Design of structures for earthquake resistance - Part 3: Assessment and retrofitting of buildings", the 2005 Draft of the Turkish seismic design code, and the Italian regulatory document CNR-DT 200/04, "Instructions for Design, Execution and Control of Strengthening Interventions by Means of Fibre-Reinforced Composites" (2004).

Download or read book Serviceability Limit State of Concrete Structures written by FIB – International Federation for Structural Concrete and published by FIB - International Federation for Structural Concrete. This book was released on 2019-09-01 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Serviceability limit states are essential for appropriate function and durability of concrete structures. The attention is paid especially to the stress limitation, crack width analysis and deflection analysis. The document provides supplementary information to the fib Model Code 2010 (MC2010), where a limited space did not allow for a detailed description of individual procedures. The principles used in MC2010 in chapter 7.6 are explained in detail within this document. The stress analysis is focused on stresses in concrete and steel including the stress redistribution due to the long-term load and cracking of reinforced concrete and prestressed concrete elements. Crack width analysis explains the mechanism of cracking under mechanical loading and due to deformation restraint. Cracks in prestressed concrete elements are also discussed. Deflection analyses with different levels of accuracy are described including the shear effects. Examples illustrate the practical application of rules defined in the MC2010 of individual serviceability limit states. Simplified and more general methods are used. An important part of the bulletin shows the development and extension of the serviceability limit states after publishing of the MC2010 and alternative approaches. Special attention is paid to deflections of prestressed concrete beams, shear effects on deflection, slenderness limits and influence of the concrete cover. The final part deals with an application of numerical simulations.

Download or read book Fibre Reinforced Concrete From Design to Structural Applications written by FIB – International Federation for Structural Concrete and published by FIB - International Federation for Structural Concrete. This book was released on 2020-08-01 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first international FRC workshop supported by RILEM and ACI was held in Bergamo (Italy) in 2004. At that time, a lack of specific building codes and standards was identified as the main inhibitor to the application of this technology in engineering practice. The workshop aim was placed on the identification of applications, guidelines, and research needs in order for this advanced technology to be transferred to professional practice. The second international FRC workshop, held in Montreal (Canada) in 2014, was the first ACI-fib joint technical event. Many of the objectives identified in 2004 had been achieved by various groups of researchers who shared a common interest in extending the application of FRC materials into the realm of structural engineering and design. The aim of the workshop was to provide the State-of-the-Art on the recent progress that had been made in term of specifications and actual applications for buildings, underground structures, and bridge projects worldwide. The rapid development of codes, the introduction of new materials and the growing interest of the construction industry suggested presenting this forum at closer intervals. In this context, the third international FRC workshop was held in Desenzano (Italy), four years after Montreal. In this first ACI-fib-RILEM joint technical event, the maturity gained through the recent technological developments and large-scale applications were used to show the acceptability of the concrete design using various fibre compositions. The growing interests of civil infrastructure owners in ultra-high-performance fibre-reinforced concrete (UHPFRC) and synthetic fibres in structural applications bring new challenges in terms of concrete technology and design recommendations. In such a short period of time, we have witnessed the proliferation of the use of fibres as structural reinforcement in various applications such as industrial floors, elevated slabs, precast tunnel lining sections, foundations, as well as bridge decks. We are now moving towards addressing many durability-based design requirements by the use of fibres, as well as the general serviceability-based design. However, the possibility of having a residual tensile strength after cracking of the concrete matrix requires a new conceptual approach for a proper design of FRC structural elements. With such a perspective in mind, the aim of FRC2018 workshop was to provide the State-of-the-Art on the recent progress in terms of specifications development, actual applications, and to expose users and researchers to the challenges in the design and construction of a wide variety of structural applications. Considering that at the time of the first workshop, in 2004, no structural codes were available on FRC, we have to recognize the enormous work done by researchers all over the world, who have presented at many FRC events, and convinced code bodies to include FRC among the reliable alternatives for structural applications. This will allow engineers to increasingly utilize FRC with confidence for designing safe and durable structures. Many presentations also clearly showed that FRC is a promising material for efficient rehabilitation of existing infrastructure in a broad spectrum of repair applications. These cases range from sustained gravity loads to harsh environmental conditions and seismic applications, which are some of the broadest ranges of applications in Civil Engineering. The workshop was attended by researchers, designers, owner and government representatives as well as participants from the construction and fibre industries. The presence of people with different expertise provided a unique opportunity to share knowledge and promote collaborative efforts. These interactions are essential for the common goal of making better and sustainable constructions in the near future. The workshop was attended by about 150 participants coming from 30 countries. Researchers from all the continents participated in the workshop, including 24 Ph.D. students, who brought their enthusiasm in FRC structural applications. For this reason, the workshop Co-chairs sincerely thank all the enterprises that sponsored this event. They also extend their appreciation for the support provided by the industry over the last 30 years which allowed research centers to study FRC materials and their properties, and develop applications to making its use more routine and accepted throughout the world. Their important contribution has been essential for moving the knowledge base forward. Finally, we appreciate the enormous support received from all three sponsoring organizations of ACI, fib and Rilem and look forward to paving the path for future collaborations in various areas of common interest so that the developmental work and implementation of new specifications and design procedures can be expedited internationally.

Download or read book External Tendons for Bridges written by FIB – International Federation for Structural Concrete and published by FIB - International Federation for Structural Concrete. This book was released on 2020-12-01 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: The concept of post-tensioning has been recognized for over a century. Interestingly, early developments started with external tendons, but failed to be recognized as a major construction technique for two main reasons: - Low tensile performance of early steels in combination with a poor knowledge of concrete creep and shrinkage properties, - Lack of a durable corrosion protection. With the technological progress, external tendons became increasingly popular in the 1980’s, as a post-tensioning method enabling inspection and, if necessary, replacement of tendons without demolition of structural members. Towards the end of the last century, more than 50 bridges have been built with external tendons, first in France and soon gaining traction in other countries. FIP published a state-of the-art report in May 1996 to provide a review of the application of external tendons, describing specific material problems and methods for dealing with them. 25 years have passed and, while the engineering principles covered by the FIP report remain unchanged, the context has evolved: - External tendons and construction methods have kept evolving with better materials, ever longer spans, and tighter schedules. - Normalization frame in Europe changed, Severe durability issues have occurred in some countries from which the industry can extract good knowledge of the causes and how to avoid similar problems in the future. This new fib bulletin has been prepared with the aim to reflect the current state of the art and encompass the knowledge amassed in the last quarter of century with chapters covering from the design and approval of systems and materials to installation, quality control and monitoring. The last chapter is a compilation of structures worldwide covering all sorts of materials, typologies and construction methods, which might be a source of inspiration for owners and designers alike.

Download or read book Conceptual Design of Precast Concrete Bridge Superstructures written by FIB – International Federation for Structural Concrete and published by FIB - International Federation for Structural Concrete. This book was released on 2021-08-01 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete bridges are an important part of today's road infrastructure. An important part of those concrete bridges is to a large extent prefabricated. Precast concrete enables all the advantages of an industrialized process to be fully utilized. Contemporary concrete mixtures are used to realize high-strength bridge girders and piers that exactly meet the requirements set, both structurally and aesthetically, with a small ecological footprint. Sustainable and durable! On the construction site, there is no need for complex formwork, the execution time is drastically reduced and where road, water and rail traffic on or under the bridge has to be temporarily interrupted, it is only minimally inconvenienced during the execution of the project. Bridges capture the imagination. In addition to their pure functionality, overcoming a height difference, they offer designers unprecedented opportunities to shape their creativity, including when using precast concrete. This bulletin, prepared by the experts of Task Group 6.5 'Precast concrete bridges', takes a closer look at the conceptual (preliminary) design of prefabricated concrete bridges. The bulletin does not have the ambition to define the umbrella term 'conceptual design' but shows in a pragmatic way, using 24 examples spread all over the world, how leading designers use this methodology to select from the many possibilities to arrive at an ideal solution taking into account all design conditions. One often reads that experience is a necessary condition for good conceptual design. The pooled knowledge and experience in this bulletin already provide the reader with a good head start. Commission 6 thanks the former convener of the Task Group Hugo Corres, editor of this document, and the current co-conveners Marcello Waimberg and Ken-ichi Kata as well as all active members of the Task Group for sharing their knowledge and experience and for the successful realization of this bulletin.