Journal articles
Author(s) | Title | Journal | Issue | Page | Category |
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Siburg, Carsten; Hegger, Josef | Experimental investigations on the punching behaviour of reinforced concrete footings with structural dimensions | Structural Concrete | 3/2014 | 331-339 | Technical Papers |
AbstractPunching tests on 13 specimens under uniform soil pressure were conducted to evaluate the punching shear behaviour of footings with practical dimensions. The test series included square footings with and without punching shear reinforcement. The dimensions of the footings varied between 1.20 × 1.20 m and 2.70 × 2.70 m and the slab thickness varied between 0.45 and 0.65 m, resulting in shear span-depth ratios a&lgr;/d between approx. 1.25 and 2.00. x | |||||
Castel, Arnaud; Gilbert, Raymond Ian | Influence of time-dependent effects on the crack spacing in reinforced concrete beams | Structural Concrete | 3/2014 | 373-379 | Technical Papers |
AbstractThis paper aims to put into perspective the influence of long-term effects, such as concrete creep and shrinkage, on concrete cracking. Long-term experimental results obtained at the Centre for Infrastructure Engineering & Safety (CIES) are reported and compared to design estimates made using the fib Model Code for Concrete Structures 2010. The influence of factors such as stirrup spacing and concrete cover are discussed. Results show that time-dependent shrinkage-induced cracking can considerably modify the cracking patterns obtained in short-term tests. For crack control in real structures and for the development of models for inclusion in codes of practice, it is strongly recommended that account be taken of time-dependent effects. Limiting observations to those made in short-term tests may lead to erroneous conclusions that are simply not applicable for structures that are more than a few weeks old. x | |||||
Strauss, Alfred; Zimmermann, Thomas; LehkĂ˝, David; Novák, DrahomĂr; Ker ner, Zbyn k | Stochastic fracture-mechanical parameters for the performance-based design of concrete structures | Structural Concrete | 3/2014 | 380-394 | Technical Papers |
AbstractThe experimental results for quasi-brittle materials such as concrete and fibre-reinforced concrete exhibit high variability due to the heterogeneity of their aggregates, additives and general composition. An accurate assessment of the fracture-mechanical parameters of such materials (e.g. compressive strength fc and specific fracture energy Gf) turns out to be much more difficult and problematic than for other engineering materials. The practical design of quasi-brittle material-based structures requires virtual statistical approaches, simulations and probabilistic assessment procedures in order to be able to characterize the variability of these materials. A key parameter of non-linear fracture mechanics modelling is the specific fracture energy Gf and its variability, which has been a research subject for numerous authors although we will mention only [1, 2] at this point. The aim of this contribution is the characterization of stochastic fracture-mechanical properties of four specific, frequently used classes of concrete on the basis of a comprehensive experimental testing programme. x | |||||
Groli, Giancarlo; PĂ©rez Caldentey, Alejandro; Soto, Alejandro Giraldo | Cracking performance of SCC reinforced with recycled fibres - an experimental study | Structural Concrete | 2/2014 | 136-153 | Technical Papers |
AbstractThis paper presents an experimental campaign aiming to assess the cracking behaviour of flexural members made with self-compacting concrete (SCC) and reinforced with both rebars and steel fibres recycled from end-of-life tyres (ELT). The characteristics, constructability and performance of this new type of fibre are first discussed. The results of the tests carried out are then presented and discussed. The parameters that have been investigated are: &phgr;/&rgr;s,ef, concrete cover and fibre content. The results obtained show improvement in cracking behaviour, especially for low reinforcement ratios and large covers. Results are compared with the predictions of the recently published fib Model Code for Concrete Structures 2010. The main objective of this investigation is to evaluate the efficiency of a new type of fibre technology for crack width control of RC elements, with advantages in sustainability from the point of view of recycling and durability. x | |||||
Meneghetti, Leila Cristina; Garcez, Mônica Regina; da Silva Filho, Luiz Carlos Pinto; Gastal, Francisco de Paula Simões Lopes; Bittencourt, Túlio Nogueira | Fatigue life of RC beams strengthened with FRP systems | Structural Concrete | 2/2014 | 219-228 | Technical Papers |
AbstractFibre-reinforced polymers (FRP) in the form of externally bonded reinforcement have been used successfully in the rehabilitation of concrete structures. Although considerable data has been produced on the performance of strengthened RC structures, the reliability of strengthened structures can be significantly reduced due to the variability in the FRP properties, especially when the wet layup technique is used. In addition to this, structural engineers are concerned about the durability of FRP-strengthened structures under extreme loading conditions. Nonetheless, knowledge of the behaviour of strengthened elements under fatigue loading may be important to raise confidence in the strengthening systems. This paper presents the results of an experimental programme developed to investigate the behaviour up to failure of RC beams strengthened with high-performance carbon and aramid fibre sheets and subjected to static and cyclic loadings in terms of ultimate loads, deflections, cracking behaviour, failure modes and fatigue life by means of loading, crack width and deflection monitoring. Experimental data on fatigue life were used to validate analytical models developed for strengthened and unstrengthened beams. x | |||||
István, István; Windisch, Andor; Farkas, György | Resistance of reinforced concrete members with hollow circular cross-sections under combined bending and shear - Part I: experimental investigation | Structural Concrete | 1/2014 | 13-20 | Technical Papers |
AbstractPart I of this paper introduces an experimental programme carried out on RC members with thick-walled hollow circular cross-sections to study their behaviour under combined bending and shear. The study looked at ultimate resistance and propagation of characteristic crack pattern as well as the shape and behaviour of the failure sections as a function of wall thickness, amount of longitudinal and transverse reinforcement, shear span and axial force. Test results were used to verify a newly developed calculation model describing the behaviour of the members investigated at failure under combined bending and shear. This model will be presented in Part II. x | |||||
Cairns, John | Staggered lap joints for tension reinforcement | Structural Concrete | 1/2014 | 45-54 | Technical Papers |
AbstractStaggering lapped joints increases the complexity of detailing and steel fixing, and may require additional resources and slow construction on site. Major design codes encourage staggering lapped joints in tension by imposing a penalty on lap length depending on the proportion of bars lapped at the same section. There are, however, inconsistencies in the value of the coefficients to be applied, and little evidence is available for validation. A programme of 17 physical tests found no evidence of an increase in strength when laps were staggered, and when allowance is made for increases in transverse spacing, staggering was found to reduce lap strength. Differences in the distribution of bond stress through a lap joint and in the share of the tension force taken by continuous and lapped bars are demonstrated to be responsible for the reduction. x | |||||
Urban, Susanne; Wagner, Richard; Strauss, Alfred; Reiterer, Michael; Dehlinger, Christian; Bergmeister, Konrad | Monitoringbasierte Lebenszeitabschätzung von Betonstrukturen - Forschungsprojekt MOSES | Beton- und Stahlbetonbau | 9/2013 | 630-640 | Fachthemen |
AbstractUm Bauwerke bis zu ihrem wirklichen Lebensende zu nutzen, ist es von großer Bedeutung, den aktuellen Grad der Schädigung einer Struktur bestimmen zu können. Mithilfe der zurzeit gültigen Nachweis- und Bemessungskonzepte (z.B. CEB-FIP Model Code 2010) ist dies nicht möglich. Ein gangbarer Weg, den Schädigungsgrad einer Betonstruktur vor Ort zu bestimmen, ist der Einsatz von zerstörungsfreien Prüfmethoden (Monitoring). Dieser Bereich ist allerdings noch nicht zur Gänze erforscht. Das konstante Monitoring von der Entstehung eines Bauwerks bis hin zu dessen Lebensende wird als eine vielversprechende Möglichkeit der Lebenszeitabschätzung gesehen. In diesem Beitrag werden Ermüdungsversuche an Betonprüfkörpern, begleitet mit konstantem Monitoring durch Ultraschall- und Körperschall-Sensoren, näher betrachtet und ein möglicher Weg zur Bestimmung des Schädigungsgrades und der Lebenszeitabschätzung aufgezeigt. x | |||||
Siburg, Carsten; Ricker, Marcus | Zur Durchstanzbemessung von Einzelfundamenten - Normenvergleich und Vergleich mit Versuchen | Beton- und Stahlbetonbau | 9/2013 | 641-653 | Fachthemen |
AbstractSeit 2012 liegt Eurocode 2 zusammen mit dem nationalen Anhang in Deutschland vor. Die größtenteils aus dem Model Code 1990 übernommene Durchstanzbemessung regelt das Durchstanzen von Einzelfundamenten und Bodenplatten neu. Mit dem Model Code 2010 wurde das Bemessungskonzept zum Durchstanzen überarbeitet und in die zum 01.01.2013 eingeführte schweizerische Norm SIA 262:2013 übernommen. Im vorliegenden Beitrag werden die Bemessungsgleichungen zur Bestimmung der Durchstanztragfähigkeit nach Eurocode 2, dem deutschen Anhang zu Eurocode 2, Model Code 2010 und SIA 262 ausführlich vorgestellt. Durch Parameterrechnungen werden die Haupteinflüsse aus Schubschlankheit, statischer Nutzhöhe, Längsbewehrungsgrad und Betondruckfestigkeit auf die Durchstanztragfähigkeit von Einzelfundamenten näher untersucht und den rechnerischen Durchstanzwiderständen gegenübergestellt. Durch Vergleiche mit den Ergebnissen systematischer Versuchsserien werden das Sicherheitsniveau und die Wirtschaftlichkeit der Bemessungsgleichungen überprüft. x | |||||
Sakai, Koji | Sustainability in fib Model Code 2010 and its future perspective | Structural Concrete | 4/2013 | 301-308 | Technical Papers |
AbstractConsidering the depletion of resources and energy and the risks of climate change on a global scale, a thoughtless increase in the use of resources and energy in the construction sector is obviously unacceptable. The sector has until now constructed a system of technology focused on safety and comfort, with priority given to economic and social benefits. Such demands remain extremely important; however, in the future we ought to give additional consideration to the depletion of resources, energy consumption and other, ensuing environmental issues. This means that the sector needs to incorporate sustainability - including the environmental, economic and social aspects - into its systems of design and technology. The fib decided to incorporate a “concrete sustainability” concept in its new fib Model Code for Concrete Structures 2010. This paper explains sustainability as expressed in this code together with the background to it. In addition, the essence of sustainability with respect to future Model Codes is discussed. x | |||||
Bigaj-van Vliet, Agnieszka; Vrouwenvelder, Ton | Reliability in the performance-based concept of fib Model Code 2010 | Structural Concrete | 4/2013 | 309-319 | Technical Papers |
AbstractThe design philosophy of the new fib Model Code for Concrete Structures 2010 represents the state of the art with regard to performance-based approach to the design and assessment of concrete structures. Given the random nature of quantities determining structural behaviour, the assessment of structural performance cannot be well established by deterministic methods, instead requires a probabilistic approach. The performance-based approach is introduced in Part I of fib Model Code 2010 by applying the concept of performance requirements and reliability management during service life. Correct understanding of the reliability concept of fib Model Code 2010 is a basic prerequisite for applying its design philosophy in an appropriate manner. Therefore, the main objective of this paper is to explain some decidedly non-trivial issues related to safety and reliability management aspects. In this context, this paper indicates how this general philosophy in fib Model Code 2010 is further developed into a set of operational rules for the design and assessment of concrete structures. x | |||||
MĂĽller, Harald S.; Anders, Isabel; Breiner, Raphael; Vogel, Michael | Concrete: treatment of types and properties in fib Model Code 2010 | Structural Concrete | 4/2013 | 320-334 | Technical Papers |
AbstractSection 5.1 “Concrete” of the fib Model Code for Concrete Structures 2010 contains basic definitions and well-established constitutive relations for structural concrete. However, it also presents various new approaches and updated models compared with the earlier CEB-FIP Model Code 1990. This is particularly true for the strength, stress and strain characteristics of structural concrete, for creep and shrinkage and for sophisticated durability-related processes. The validity of the models has been extended to several types of concrete such as high strength concrete, self-compacting concrete and lightweight aggregate concrete. The durability-related models are either suitable for facilitating a full probabilistic service life design or for applying simpler code-type approaches. x | |||||
Triantafillou, Thanasis; Matthys, Stijn | Fibre-reinforced polymer reinforcement enters fib Model Code 2010 | Structural Concrete | 4/2013 | 335-341 | Technical Papers |
AbstractMost applications of fibre-reinforced polymers (FRP) deal with externally bonded reinforcement as a means of repairing and strengthening reinforced concrete (RC) structures or retrofitting RC structures in seismic regions. As internal reinforcement, FRP rebars or (more rarely) prestressing elements are used in special projects, combining material strength and durability characteristics. Over the last years, several national and international design guidelines have become available specifically for the design and application of FRP-strengthened or FRP-reinforced concrete structures. These efforts clearly demonstrate the interest in FRP as a novel reinforcing material for concrete construction. Hence, the time had come to introduce FRP reinforcement into the new fib Model Code for Concrete Structures 2010 as well. The main contributions to the fib Model Code 2010 relate to sections 5.5 “Non-metallic reinforcement” and 6.2 “Bond of non-metallic reinforcement”. The material presented in those two sections is further elaborated in this article. x | |||||
di Prisco, Marco; Colombo, Matteo; Dozio, Daniele | Fibre-reinforced concrete in fib Model Code 2010: principles, models and test validation | Structural Concrete | 4/2013 | 342-361 | Technical Papers |
AbstractIn the fib Model Code for Concrete Structures 2010, fibre-reinforced concrete (FRC) is recognized as a new material for structures. This introduction will favour forthcoming structural applications because the need of adopting new design concepts and the lack of international building codes have significantly limited its use up to now. In the code, considerable effort has been devoted to introducing a material classification to standardize performance-based production and stimulate an open market for every kind of fibre, favouring the rise of a new technological player: the composite producer. x | |||||
Matthews, Stuart; Bigaj-van Vliet, Agnieszka | Conservation of concrete structures according to fib Model Code 2010 | Structural Concrete | 4/2013 | 362-377 | Technical Papers |
AbstractConservation of concrete structures forms an essential part of the fib Model Code for Concrete Structures 2010 (fib Model Code 2010). In particular, Chapter 9 of fib Model Code 2010 addresses issues concerning conservation strategies and tactics, conservation management, condition surveys, condition assessment, condition evaluation and decision-making, making interventions and the recording of information for through-life management. x | |||||
Silva, Ricardo; Faria, Duarte M. Viúla; Ramos, A. Pinho; Inácio, Micael | A physical approach for considering how anchorage head size influences the punching capacity of slabs strengthened with vertical steel bolts | Structural Concrete | 4/2013 | 389-400 | Technical Papers |
AbstractThe introduction of new vertical steel bolts is an easy, practical and common solution for retrofitting and strengthening slabs for punching. Although a common option where punching strengthening is concerned, few studies exist regarding how the bolt's anchorage dimensions and its embedment in the concrete slab affect the strengthening efficiency. This work presents an analytical approach that is able to predict the punching capacity of slabs strengthened with post-installed vertical steel bolts, taking into account the anchorage dimensions and positioning plus the material properties. This approach results from the combination of two physical models: one provided in the fib Model Code for Concrete Structures 2010 regarding the punching capacity estimation, and another that allows the deformation (crushing) of the concrete beneath the head of the anchorage to be taken into account. The predicted values are compared with experimental results, showing that the analytical approach is able to simulate correctly the anchorage behaviour and its influence regarding a slab's loadbearing capacity. A parametrical analysis is carried out in order to study the importance of different factors such as concrete compressive strength, longitudinal reinforcement ratio and steel bolt length, always accompanied by the effect of anchorage head size and embedment. x | |||||
Sagaseta, Juan | The influence of aggregate fracture on the shear strength of reinforced concrete beams: an experimental and analytical research project | Structural Concrete | 4/2013 | 401-414 | Technical Papers |
AbstractHigh-performance concretes such as high-strength concrete (HSC) or lightweight aggregate concrete (LWAC) are generally used to reduce member sizes and self-weight, and to optimize the construction of reinforced concrete structures. The bond between the aggregate particles and the cement paste can be strong enough in HSC and LWAC to cause the aggregate to fracture at cracks, which in turn reduces the shear stress that can be transferred across cracks by means of aggregate interlock. Relatively smooth cracks can also develop in self-compacting concrete due to the low coarse aggregate content. The contribution of aggregate interlock to the shear strength of RC beams is uncertain and depends on parameters such as the amount of shear reinforcement or the contribution of arching action for loads applied close to the support. Existing tests on slender RC beams without shear reinforcement have shown that shear strength is reduced by aggregate fracture. However, there is a lack of similar test data for members with stirrups and for members with varying shear span/effective depth ratios. This paper reviews the findings and contributions in this area from the experimental and analytical research of the author's PhD thesis, which was awarded the fib Achievement Award for Young Engineers in 2011. x | |||||
fib-news: Structural Concrete 4/2013 | Structural Concrete | 4/2013 | 424-433 | fib-news | |
AbstractResults of the 2014 fib Awards for Outstanding Concrete Structures competition x | |||||
Sigrist, Viktor; Bentz, Evan; Ruiz, Miguel Fernández; Foster, Stephen; Muttoni, Aurelio | Background to the fib Model Code 2010 shear provisions - part I: beams and slabs | Structural Concrete | 3/2013 | 195-203 | Technical Papers |
AbstractThis paper examines the evidence for the one-way shear model developed for the fib Model Code for Concrete Structures 2010 and provides examples of its application. For the design and analysis for shear, for members with and without shear reinforcement, the fib Model Code 2010 procedures have been developed from physical-mechanical models that are based on observed behaviour at the meso-scale level; they represent a significant advance over previous standardized empirical methods. In addition, an approach referred to as “level of approximation” (LoA) is incorporated where advanced models are simplified in a consistent and conservative way such that the designer can select the effort needed to justify their design. To illustrate the practical use of the models and the LoA approach, two examples are presented. The first is a deck slab of a cut-and-cover tunnel where design and possible refinements are discussed for a given configuration. The second is a prestressed concrete bridge girder, which is considered for the cases of design and for the analysis of an existing structure. x | |||||
Muttoni, Aurelio; Ruiz, Miguel Fernández; Bentz, Evan; Foster, Stephen; Sigrist, Viktor | Background to fib Model Code 2010 shear provisions - part II: punching shear | Structural Concrete | 3/2013 | 204-214 | Technical Papers |
AbstractThis paper outlines the theoretical background to the punching shear provisions implemented in the fib Model Code for Concrete Structures 2010 and presents a practical example of their application. The aim is to explain the mechanical model that forms the basis for the punching design equations, to justify the relevance of the provisions and to show their suitability for the design and assessment of structures. x | |||||
Fardis, Michael N. | Performance- and displacement-based seismic design and assessment of concrete structures in fib Model Code 2010 | Structural Concrete | 3/2013 | 215-229 | Technical Papers |
AbstractThe scope of fib Model Code for Concrete Structures 2010 includes the fully fledged performance- and displacement-based seismic design of new structures and assessment of existing ones. This part of fib Model Code 2010 covers buildings, bridges or similar concrete structures and aims to provide well-defined performance levels for specific seismic hazard levels. Detailing of members for ductility is not based on opaque prescriptions, as in current codes, but on transparent, explicit verification of inelastic deformation demands against capacity limits. The reference analysis method is non-linear dynamic, but under certain conditions inelastic deformation demands may be estimated from linear analysis and the 5%-damped elastic response spectrum; in that case force demands on force-controlled, brittle failure modes are estimated from the plastic mechanism through equilibrium. In order to predict the seismic deformation demands with some confidence, the analysis should use realistic values for the member secant stiffness up to the yield point. The paper explains the background to the expressions given for this property in fib Model Code 2010 as well as of those for the deformation limits used when verifying seismic deformation demands. The modifications to the shear resistance approach of fib Model Code 2010, which takes cyclic loading into account, are also explained and justified. x | |||||
Randl, Norbert | Design recommendations for interface shear transfer in fib Model Code 2010 | Structural Concrete | 3/2013 | 230-241 | Technical Papers |
AbstractInterface shear transfer between differently aged concretes is a topic that crops up frequently and in different situations in structural design. In the fib Model Code for Concrete Structures 2010 the fundamental basics of concrete-to-concrete load transfer are given in section 6.3 and the corresponding design rules in 7.3.3.6. The different potential mechanisms contributing to the shear resistance along the interface, i.e. adhesive bond, aggregate interlock, friction and dowel action, are thus combined and their relationship taken into account by interaction factors. This article summarizes the most important results from past and ongoing studies and presents the background to the theory forming the design basis of fib Model Code 2010, the “extended shear friction theory” (ESF). x | |||||
Belletti, Beatrice; Damoni, Cecilia; den Uijl, Joop A.; Hendriks, Max A. N.; Walraven, Joost C. | Shear resistance evaluation of prestressed concrete bridge beams: fib Model Code 2010 guidelines for level IV approximations | Structural Concrete | 3/2013 | 242-249 | Technical Papers |
AbstractThe design shear resistance of an existing structure can be evaluated with analytical design procedures and numerical procedures provided by non-linear finite element analyses. The new fib Model Code 2010 proposes different calculation methods that fall into four different levels of approximation. As the level of approximation rises, so the complexity and the accuracy of the calculated shear resistance increases. Non-linear finite element analyses belong to the highest level of approximation, but although they are more and more becoming a customary tool in the daily design process, building codes do not provide guidance on how to perform these analyses. x | |||||
Corres-Peiretti, Hugo | Sound engineering through conceptual design according to the fib Model Code 2010 | Structural Concrete | 2/2013 | 89-98 | Technical Papers |
AbstractConceptual design is the approach that creates an idea in order to find a solution to a new proposal for a structure or solve a detail in a specific structure. It is a personal approach that is learned over time and with experience. It is not normally dealt with at university, but is vitally important for producing sound structures. x | |||||
Balázs, György L.; Bisch, Philippe; BorosnyĂłi, Adorján; Burdet, Olivier; Burns, Clare; Ceroni, Francesca; Cervenka, Vladimir; Chiorino, Mario A.; Debernardi, Piergiorgio; Eckfeldt, Lars; El-Badry, Mamdouh; Fehling, Ekkehard; Foster, Stephen J.; Ghali, Amin; Gribniak, Viktor; Guiglia, Matteo; Kaklauskas, Gintaris; Lark, Robert J.; Lenkei, Peter; Lorrain, Michel; MarĂ, Antonio; Ozbolt, Josko; Pecce, Marisa; PĂ©rez Caldentey, Alejandro; Taliano, Maurizio; Tkalcic, Damir; Torrenti, Jean Michel; Torres, Lluis; Toutlemonde, François; Ueda, Tamon; Vitek, Jan L.; VráblĂk, Luká | Design for SLS according to fib Model Code 2010 | Structural Concrete | 2/2013 | 99-123 | Technical Papers |
AbstractThis paper provides an overview of serviceability specifications given by the fib Model Code for Concrete Structures 2010 (fib MC2010 [1]). First, the reasons behind crack control and deflection control are discussed, then specific design rules are provided. Simple rules as well as detailed models are also presented. Numerical examples are provided in order to assist in the application of the design recommendations for crack control and deflection control (reinforced and prestressed concrete elements). x |