Critical comparison of major seismic codes for buildings


Book Description

fib Bulletin 69 illustrates and compares major buildings seismic codes applied in the different Continents, namely U.S., Japan, New Zealand, Europe, Canada, Chile and Mexico. Bulletin 69 was prepared by Task Group 7.6 of fib Commission 7, under the leadership of the late Professor Robert (Bob) Park which, in tandem with Professor Paulay, had developed in the seventies new fundamental design concepts, most notably capacity design approach and structural design for ductility, that had made the NZ seismic Code the most advanced one of the time. This new approach has highly influenced the development of Eurocode 8, to which Bob Park has significantly contributed. Bob Park was also well informed of the situation in Japan, USA, Canada and South America. Such a wide view is reflected in Bulletin 69 showing similarities and differences among the major seismic codes, accompanied as far as possible by comments, hopefully useful for fostering international harmonization. A comprehensive summary of the major codes is provided in the first chapter of the bulletin. All codes are separately presented according to a common framework: an introduction section, which describes the history, the philosophy, the process development, the performance-based criteria, the strength of materials and the incorporation of strength reduction factors of each code; a second section devoted to the demand side, which specify the seismic design actions and associated criteria of each code for areas of different seismicity and for structures with different ductility properties/requirements; a third section devoted to the capacity side, which describes the capacities of members and joints and associated criteria of each code, including member strengths in flexure, shear and bars anchorage, desirable hierarchies of strength attainment, deformation capacities of mechanisms of inelastic deformation, detailing of beams, columns and structural walls, detailing of beam-column joints for shear and the detailing of diaphragms. The second chapter is devoted to the comparison of the more significant issues dealt in the considered codes. This includes: seismic design actions and associated criteria, capacity design practice, beams, columns, confinement, structural walls and joints. It is felt that fib Bulletin 69 represents a useful, unique instrument for rapidly gaining an overview of the distinguishing features of the major world codes, under both their conceptual framework and application rules.




Seismic Design Methods for Steel Building Structures


Book Description

The book, after two introductory chapters on seismic design principles and structural seismic analysis methods, proceeds with the detailed description of seismic design methods for steel building structures. These methods include all the well-known methods, like force-based or displacement-based methods, plus some other methods developed by the present authors or other authors that have reached a level of maturity and are applicable to a large class of steel building structures. For every method, detailed practical examples and supporting references are provided in order to illustrate the methods and demonstrate their merits. As a unique feature, the present book describes not just one, as it is the case with existing books on seismic design of steel structures, but various seismic design methods including application examples worked in detail. The book is a valuable source of information, not only for MS and PhD students, but also for researchers and practicing engineers engaged with the design of steel building structures.




Precast Concrete in Tall Buildings


Book Description

There has been continued global growth in tall building construction over recent years. The variation in the use of such buildings is remarkable, from lavish hotels and apartments to socially affordable units. As the world struggles to cope with growing numbers of people, dwindling resources and movements from rural to urban habitats it is unavoidable that population densities will increase, and more efficient use of scarce land will be needed. Taller buildings are the inevitable consequence. Tall buildings can use several different types of material to form their framework and envelope. Those materials are mixed to provide an optimum building solution to suit client requirements such as structure, occupancy, vision, affordability, timing, sustainability and quality. Precast concrete is one of those materials, and has been used from whole frameworks to facades, and elements mixed with structural steelwork and cast in place concrete. This state of the art report shows how precast concrete can be effectively integrated into tall buildings using modern materials and techniques, drawing on the experience and expertise that is currently available in the global precast concrete industry. The report is aimed at not only building professionals and students, but also at contractors, investors, owners, public bodies and any other parties interested in the possibilities for use of precast concrete in tall building construction. Extensive case studies at the end of the Bulletin illustrate the benefits and applications discussed in the earlier chapters.




Planning and design handbook on precast building structures


Book Description

In 1994 fib Commission 6: Prefabrication edited a successful Planning and Design Handbook that ran to approximately 45,000 copies and was published in Spanish and German. Nearly 20 years later Bulletin 74 brings that first publication up to date. It offers a synthesis of the latest structural design knowledge about precast building structures against the background of 21st century technological innovations in materials, production and construction. With it, we hope to help architects and engineers achieve a full understanding of precast concrete building structures, the possibilities they offer and their specific design philosophy. It was principally written for non-seismic structures. The handbook contains eleven chapters, each dealing with a specific aspect of precast building structures. The first chapter of the handbook highlights best practice opportunities that will enable architects, design engineers and contractors to work together towards finding efficient solutions, which is something unique to precast concrete buildings. The second chapter offers basic design recommendations that take into account the possibilities, restrictions and advantages of precast concrete, along with its detailing, manufacture, transport, erection and serviceability stages. Chapter three describes the precast solutions for the most common types of buildings such as offices, sports stadiums, residential buildings, hotels, industrial warehouses and car parks. Different application possibilities are explored to teach us which types of precast units are commonly used in all those situations. Chapter four covers the basic design principles and systems related to stability. Precast concrete structures should be designed according to a specific stability concept, unlike cast in-situ structures. Chapter five discusses structural connections. Chapters six to nine address the four most commonly used systems or subsystems of precast concrete in buildings, namely, portal and skeletal structures, wall-frame structures, floor and roof structures and architectural concrete facades. In chapter ten the design and detailing of a number of specific construction details in precast elements are discussed, for example, supports, corbels, openings and cutouts in the units, special features related to the detailing of the reinforcement, and so forth. Chapter eleven gives guidelines for the fire design of precast concrete structures. The handbook concludes with a list of references to good literature on precast concrete construction.




Partial factor methods for existing concrete structures


Book Description

For a large part of the existing buildings and infrastructure the design life has been reached or will be reached in the near future. These structures might need to be reassessed in order to investigate whether the safety requirements are met. Current practice on the assessment of existing concrete structures however needs a thorough evaluation from a risk and reliability point of view, as they are mostly verified using simplified procedures based on the partial factor method commonly applied in design of new structures. Such assessments are often conservative and may lead to expensive upgrades. Although the last decades reliability-based assessment of existing concrete structures has gained wide attention in the research field, a consistent reliability-based assessment framework and a practically applicable codified approach which is compatible with the Eurocodes and accessible for common structural engineering problems in everyday practice is currently missing. Such an approach however allows for a more uniform, more objective and probably more widely applied assessment approach for existing concrete structures. Hence, in this bulletin two different partial factor formats are elaborated, i.e. the Design Value Method (DVM) and the Adjusted Partial Factor Method (APFM), enabling the incorporation of specific reliability related aspects for existing structures. The DVM proposes a fundamental basis for evaluating partial factors whereas the APFM provides adjustment factors to be applied on the partial factors for new structures in EN 1990. In this bulletin both methods are elaborated and evaluated and a basis is provided for decision making regarding the target safety level of existing structures.




2022 fib Awards for Outstanding Concrete Structures


Book Description

The fib has two major missions now. One is to work toward the publication of the Model Code 2020, and the other is to respond to the global movement toward carbon neutrality. While the former is steadily progressing toward completion, the latter will require significant efforts for generations to come. As we all know, cement, the primary material for concrete, is a sector that accounts for 8.5% of the world’s CO2 emissions. And the structural concrete that fib handles consume 60% of that. In other words, we need to know the reality that our structural concrete is emitting 5% of the world’s CO2. From now on, fib members, suppliers, designers, builders, owner’s engineers, and academic researchers will be asked how to solve this difficult problem. In general, most of the CO2 emissions in the life cycle of structural concrete come from the production stage of materials and the use stage after construction, i.e. A1 to A3 and B1 to B5 processes as defined in EN15978. Cement and steel sectors, which are the main materials for structural concrete, are expected to take various measures to achieve zero carbon in their respective sectors by 2050. Until then, we must deal with the transition with our low carbon technologies. Regarding the production stage, the fib has recently launched TG4.8 “Low carbon concrete”. And the latest low carbon technologies will be discussed there. On the other hand, in the use stage, there is very little data on the relationship between durability and intervention and maintenance so far. The data accumulation here is the work of the fib, a group of various experts on structural concrete. Through-life management using highly durable structures and precise monitoring will enable to realize minimum maintenance in the use stage and to minimize CO2 emissions. Furthermore, it is also possible to contribute to the reduction of CO2 emissions in the further stage after the first cycle by responding to the circular economy, that is, deconstruction (C), reuse, and recycle (D). However, the technology in this field is still in its infancy, and further research and development is expected in the future. As described above, structural concrete can be carbon neutral in all aspects of its conception, and it can make a significant contribution when it is realized. The fib will have to address these issues in the future. Of course, it will not be easy, and it will take time. However, if we do not continue our efforts as the only international academic society on structural concrete in the world to achieve carbon neutrality, the significance of our very existence may be questioned. Long before Portland cement was invented, Roman concrete, made of volcanic ash and other materials, was the ultimate low-carbon material, and is still in use 2’000 years later because of its non-reinforced structure and lack of deterioration factors. Reinforced concrete, which made it possible to apply concrete to structures other than arches and domes, is only 150 years old. Prestressed concrete is even younger, with only 80 years of history. Now that we think about it, we realize that Roman concrete, which is non-reinforced low carbon concrete, is one of the examples of problem solving that we are trying to achieve. We have new materials, such as coated reinforcement, FRP, and fiber reinforced concrete, which can be used in any structural form. To overcome this challenge with all our wisdom would be to live up to the feat the Romans accomplished 2’000 years ago. Realizing highly durable and elegant structures with low-carbon concrete is the key to meet the demands of the world in the future. I hope you will enjoy reading this AOS brochure showing the Outstanding Concrete Structures Awards at the fib 2022 Congress in Oslo. And I also hope you will find some clues for the challenges we are facing.




2018 fib Awards for Outstanding Concrete Structures


Book Description

The fib Awards for Outstanding Concrete Structures are attributed every four years at the fib Congress, with the goal of enhancing the international recognition of concrete structures that demonstrate the versatility of concrete as a structural medium. The award consists of a bronze plaque to be displayed on the structure, and certificates presented to the main parties responsible for the work. Applications are invited by the fib secretariat via the National Member Groups. Information on the competition is also made available on the fib’s website, and in the newsletter fib-news published in Structural Concrete. The submitted structures must have been completed during the four years prior to the year of the Congress at which the awards are attributed. The jury may accept an older structure, completed one or two years before, provided that it was not already submitted for the previous award attribution (Mumbai, 2014). The submitted structures must also have the support of an fib Head of Delegation or National Member Group Secretary in order to confirm the authenticity of the indicated authors. Entries consist of the completed entry form, three to five representative photos of the whole structure and/or any important details or plans, and short summary texts explaining: - the history of the project; - description of the structure; - particularities of its realisation (difficulties encountered, special solutions found, etc.). A jury designated by the Presidium selects the winners. The awards are attributed in two categories, Civil Engineering Structures (including bridges) and Buildings. Two or three ‘Winners’ and two to four ‘Special Mention’ recipients are selected in each category, depending on the number of entries received. The jury takes into account criteria such as: - design aspects, including aesthetics and design detailing; - construction practice and quality of work; - environmental aspects of the design and its construction; - durability and sustainability aspects; - significance of the contribution made by the entry to the development and improvement of concrete construction. The decisions of the jury are definitive and cannot be challenged. They are unveiled at a special ceremony during the fib Congress in Melbourne.




Punching shear of structural concrete slabs


Book Description

fib Bulletin 81 reports the latest information available to researchers and practitioners on the analysis, design and experimental evidence of punching shear of structural concrete slabs. It follows previous efforts by the International Federation for Structural Concrete (fib) and its predecessor the Euro-International Committee for Concrete (CEB), through CEB Bulletin 168, Punching Shear in Reinforced Concrete (1985) and fibBulletin 12, Punching of structural concrete slabs (2001), and an international symposium sponsored by the punching shear subcommittee of ACI Committee 445 (Shear and Torsion) and held in Kansas City, Mo., USA, in 2005. This bulletin contains 18 papers that were presented in three sessions as part of an international symposium held in Philadelphia, Pa., USA, on October 25, 2016. The symposium was co-organized by the punching shear sub-committee of ACI 445 and by fib Working Party 2.2.3 (Punching and Shear in Slabs) with the objectives of not only disseminating information on this important design subject but also promoting harmonization among the various design theories and treatment of key aspects of punching shear design. The papers are organized in the same order they were presented in the symposium. The symposium honored Professor Emeritus Neil M. Hawkins (University of Illinois at Urbana-Champaign, USA), whose contributions through the years in the field of punching shear of structural concrete slabs have been paramount. The papers cover key aspects related to punching shear of structural concrete slabs under different loading conditions, the study of size effect on punching capacity of slabs, the effect of slab reinforcement ratio on the response and failure mode of slabs, without and with shear reinforcement, and its implications for the design and formulation in codes of practice, an examination of different analytical tools to predict the punching shear response of slabs, the study of the post-punching response of concrete slabs, the evaluation of design provisions in modern codes based on recent experimental evidence and new punching shear theories, and an overview of the combined efforts undertaken jointly by ACI 445 and fib WP 2.2.3 to generate test result databanks for the evaluation and calibration of punching shear design recommendations in North American and international codes of practice.




fib Model Code for Concrete Structures 2010


Book Description

The International Federation for Structural Concrete (fib) is a pre-normative organization. 'Pre-normative' implies pioneering work in codification. This work has now been realized with the fib Model Code 2010. The objectives of the fib Model Code 2010 are to serve as a basis for future codes for concrete structures, and present new developments with regard to concrete structures, structural materials and new ideas in order to achieve optimum behaviour. The fib Model Code 2010 is now the most comprehensive code on concrete structures, including their complete life cycle: conceptual design, dimensioning, construction, conservation and dismantlement. It is expected to become an important document for both national and international code committees, practitioners and researchers. The fib Model Code 2010 was produced during the last ten years through an exceptional effort by Joost Walraven (Convener; Delft University of Technology, The Netherlands), Agnieszka Bigaj-van Vliet (Technical Secretary; TNO Built Environment and Geosciences, The Netherlands) as well as experts out of 44 countries from five continents.




External Tendons for Bridges


Book Description

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.