Journal articles
Author(s) | Title | Journal | Issue | Page | Category |
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Walraven, Joost; Balázs, György L. | fib Model Code for Concrete Structures 2010: a landmark in an ongoing development | Structural Concrete | 1/2013 | 1-2 | Editorial |
Lima de Resende, Thomás; da Conceição Domingues Shehata, Lidia; Shehata, Ibrahim Abd El Malik | Shear strength of self-compacting concrete beams with small stirrups ratios | Structural Concrete | 1/2016 | 3-10 | Technical Papers |
AbstractIn comparison with a vibrated concrete (VC) of the same strength class, self-compacting concrete (SCC) typically has a lower coarse aggregate content and, possibly, a smaller maximum aggregate size. This may result in reduced aggregate interlock between the fracture surfaces of a SCC. Since aggregate interlock plays an important role in the shear strength of slender beams, SCC beams may have a shear strength lower than that of similar VC beams, but studies on that subject are still limited. x | |||||
Walraven, Joost | fib Model Code for Concrete Structures 2010: mastering challenges and encountering new ones | Structural Concrete | 1/2013 | 3-9 | Technical Papers |
AbstractThe Model Code for Concrete Structures 2010 is a recommendation for the design of structural concrete, written with the intention of giving guidance for future codes. As such, the results of the newest research and development work are used to generate recommendations for structural concrete at the level of the latest state of the art. While carrying out this exercise, areas are inevitably found where information is insufficient, thus inviting further study. This paper begins with a brief introduction to the new expertise and ideas implemented in fib Model Code 2010, followed by a treatment of areas where knowledge appeared to be insufficient or even lacking and where further research might be useful. x | |||||
Helland, Steinar | Design for service life: implementation of fib Model Code 2010 rules in the operational code ISO 16204 | Structural Concrete | 1/2013 | 10-18 | Technical Papers |
AbstractCEB/FIP Model Code 1990 (MC-1990) did represent the technology and focus some 20 years ago. However, it soon became evident that the document had some notable lacunas. In 1995 the general assemblies of the two organizations endorsed CEB/FIP bulletin No. 228, extensions to MC 1990 for high-strength concrete, and in 2000 a similar extension to MC 1990 for lightweight aggregate concrete as bulletin No. 4. x | |||||
Sangiorgio, Filippo; Silfwerbrand, Johan; Mancini, Giuseppe | Scatter in the shear capacity of slender RC members without web reinforcement: an overview study | Structural Concrete | 1/2016 | 11-20 | Technical Papers |
AbstractAll researchers who have tested the shear capacity of RC members without stirrups have observed a large scatter in the results. x | |||||
Schmidt, Philipp; Kueres, Dominik; Claßen, Martin; Hegger, Josef | Durchstanztragverhalten von Flachdecken mit variierenden Durchstanzbewehrungsgraden | Beton- und Stahlbetonbau | 1/2020 | 13-25 | Aufsätze |
AbstractMit der bauaufsichtlichen Einführung des Eurocode 2 in Deutschland wurde die Durchstanzbemessung von Flachdecken neu geregelt. Seitdem ergibt sich die Durchstanztragfähigkeit mit Durchstanzbewehrung aus der Summe eines konstanten Betontraganteils und eines Stahltraganteils, der unabhängig vom Bauteil aus einem 33°-Fachwerk resultiert. Für die Berechnung des Stahltraganteils wird gemäß Eurocode 2 eine reduzierte Stahlfestigkeit in Abhängigkeit von der statischen Nutzhöhe angesetzt, wodurch die Verankerungsqualität der Durchstanzbewehrung berücksichtigt wird. Auf Basis einer Datenbankauswertung und eines Vergleichs des Sicherheitsniveaus mit der damaligen DIN 1045-1 wurden im Deutschen Anhang zum Eurocode 2 (EC2+NA(D)) zusätzliche Erhöhungsfaktoren für die ersten beiden Durchstanzbewehrungsreihen ergänzt, die nahezu zu einer Verdopplung der Durchstanzbewehrungsmenge führen. Während zur Bewertung der Bemessungsgleichungen für die Ermittlung der Durchstanztragfähigkeit ohne Durchstanzbewehrung und auf dem Niveau der maximalen Durchstanztragfähigkeit zahlreiche Versuchsergebnisse vorliegen, sind bislang nur sehr wenige Versuchsreihen an Flachdeckenausschnitten mit einem Durchstanzversagen innerhalb des durchstanzbewehrten Bereichs vorhanden. 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 | |||||
Cervenka, Vladimir | Reliability-based non-linear analysis according to fib Model Code 2010 | Structural Concrete | 1/2013 | 19-28 | Technical Papers |
AbstractThe fib Model Code 2010 for Concrete Structures introduces numerical simulation as a new tool for designing reinforced concrete structures. The model of resistance based on non-linear analysis requires adequate model validation and a global safety format for verifying designs. The numerical simulations combined with random sampling offer the chance of an advanced safety assessment. Approximate methods of global safety assessment are discussed and compared in a case study. An example of a bridge design supported by non-linear analysis is shown. x | |||||
Muttoni, Aurelio; Ruiz, Miguel Fernández | The levels-of-approximation approach in MC 2010: application to punching shear provisions | Structural Concrete | 1/2012 | 32-41 | Articles |
AbstractIn order to address how new knowledge influences design expressions, design codes have in most cases become significantly more complex over the last decades. However, this tendency is leading to codes that are too complicated for preliminary design but still not sufficiently accurate for assessing existing structures (where even more realistic models of behaviour are sometimes required). An alternative code strategy is that proposed by codes based on a levels-of-approximation (LoA) approach. This approach is based on the use of theories based on physical parameters where the hypotheses for their application can be refined as the accuracy required increases. The approach proposes adopting safe hypotheses during the first stages of design, leading to relatively quick and simple analyses. In cases where such a degree of accuracy is not sufficient (e.g. design of complex structures, assessment of existing structures, significant potential economic savings), the hypotheses can be refined in a number of steps, leading to better estimates of the behaviour and strength of members. This approach, recently adopted in the first complete draft of Model Code 2010 for a number of design issues, is discussed within this paper with reference to punching shear provisions. x | |||||
Blomfors, Mattias; Engen, Morten; Plos, Mario | Evaluation of safety formats for non-linear finite element analyses of statically indeterminate concrete structures subjected to different load paths | Structural Concrete | 1/2016 | 44-51 | Technical Papers |
AbstractTo increase the efficiency of new structures and perform safety evaluations of existing structures, it is necessary to model and analyse the non-linear behaviour of reinforced concrete. The applicability of the safety formats in present design codes is unclear for indeterminate structures subjected to loading in several directions. The safety formats in fib Model Code 2010 have been evaluated for a reinforced concrete frame subjected to vertical and horizontal loading and the influence of load history studied. Basic reliability methods were used together with response surfaces to assess the failure probabilities and one safety format did not meet the intended safety level. The results indicate the importance of load history and it is concluded that more research is required regarding how load history influences the safety level of complex structures. x | |||||
Cairns, John | Bond and anchorage of embedded steel reinforcement in fib Model Code 2010 | Structural Concrete | 1/2015 | 45-55 | Technical Papers |
AbstractThis paper describes the changes to design provisions for embedded steel reinforcement in the fib Model Code for Concrete Structures 2010. The changes introduce new coefficients for steel grade and clear spacing between bars, and extend the range of concrete strengths covered. The way in which the contribution of hooks or anchorages is calculated has been revised and the contribution of end bearing to laps and anchorages of compression bars is recognized. The revised rules represent a move away from a distinction between laps and anchorages per se towards a distinction based on the presence or absence of transverse pressure perpendicular to the bar axis within the bond length. The benefits of staggering laps with only a proportion of bars lapped at a section are also reviewed. Finally, the potential impact of lap and anchorage performance on structural robustness is discussed, and it is concluded that this can only be achieved if bar yield precedes splitting mode bond failures. 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 | |||||
Ueda, Tamon | International code harmonization: the role of the Asian Concrete Model Code | Structural Concrete | 1/2011 | 47-54 | Articles |
AbstractMany national codes in Asia are heavily influenced by those from either Europe or the USA. The climatic, technological and economic conditions together with the material properties in Asia are, however, quite different from those in Europe and the USA, and even different among Asian countries. Thus, many Asian countries need their own national codes with suitable concepts and technologies. At the same time, many construction projects in Asia are carried out in multi-national environments in which various national codes are applied, meaning that international code harmonization is necessary. In order to work for the global issue, such as the construction of a sustainable world, Asia, as the largest economic zone in the 21st century, should take on a leading role. For this purpose, international code harmonization with the new direction of life cycle management (LCM) would provide an efficient way. x | |||||
Prince, M. John Robert; Singh, Bhupinder | Bond behaviour of normal- and high-strength recycled aggregate concrete | Structural Concrete | 1/2015 | 56-70 | Technical Papers |
AbstractThe effect of concrete grade on the bond between 12 mm diameter deformed steel bars and recycled aggregate concrete (RAC) has been investigated with the help of 45 pullout tests with concentric rebar placement for coarse recycled concrete aggregate (RCA) replacement levels of 25, 50, 75 and 100%. For all the three concrete grades, the measured bond-slip relationships indicate similar mechanisms of bond resistance in the RAC and the natural aggregate (NA) concrete. The most accurate and least conservative predictions of the measured bond strengths were obtained from the local bond-slip model in the fib Model Code for Concrete Structures 2010. Bond strength normalized to fc(3/4) resulted in an improved match with test data and increased with an increase in the RCA replacement levels and decreased with an increase in compressive strength. An attempt to explain this behaviour has been sought in terms of brittleness index, an analogous parameter from rock mechanics. An empirical bond stress versus slip relationship has been proposed for the 12 mm diameter bar and it is conservatively suggested that similar anchorage lengths for this bar in all three concrete grades can be adopted for the RAC and the NA concretes. x | |||||
Pérez Caldentey, Alejandro; Corres Peiretti, Hugo; Peset Iribarren, Joan; Giraldo Soto, Alejandro | Cracking of RC members revisited: influence of cover, &phgr;/&rgr;s, ef and stirrup spacing - an experimental and theoretical study | Structural Concrete | 1/2013 | 69-78 | Article |
AbstractThis article describes an experimental programme aimed at studying the effect of cover, ratio between diameter and effective reinforcement ratio (&phgr;/&rgr;s, ef) and the influence of stirrup spacing on the cracking behaviour of reinforced concrete elements. The experimental programme was conceived in order to contribute to the debate - fuelled by the publication in recent years of Eurocode 2 EN1992-1-1 and the revision of the Model Code under way when the tests were carried out (and now published as a finalized document) - regarding the influence of these parameters on cracking. Important theoretical aspects are discussed, including where the crack width is estimated by current code formulations and what relevance this may have on the correlation between crack opening and durability of RC structures, especially with regard to structures with large covers. The effect of stirrup spacing, a variable absent from current codes, is also discussed. x | |||||
Mihaylov, Boyan | Five-spring model for complete shear behaviour of deep beams | Structural Concrete | 1/2015 | 71-83 | Technical Papers |
AbstractThis paper presents a five-spring model capable of predicting the complete pre- and post-peak shear behaviour of deep beams. The model stems from a two-parameter kinematic theory (2PKT) for the shear strength and displacement capacity of deep beams under single curvature. Four of the springs of the model represent the shear resistance mechanisms of the beam, while the fifth spring models the flexural behaviour. The model predicts not only the load-displacement response, but also the deformation patterns of the beam and how these patterns change with increasing load. Validation studies are performed by using 28 tests from the literature, showing excellent results. The model is used to interpret the tests and to draw conclusions about the behaviour of deep beams. It is shown that shear strength variations of up to 60 % between nominally identical specimens can be caused by variations in the path of the critical shear cracks. It is also demonstrated that loss of bond of large reinforcing bars increases the shear capacity of deep beams. Finally, the five-spring model is shown to predict the post-peak shear behaviour effectively, which is important for the analysis of structures under extreme loading. 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 | |||||
Amin, Ali; Foster, Stephen J.; Muttoni, Aurelio | Derivation of the σ-w relationship for SFRC from prism bending tests | Structural Concrete | 1/2015 | 93-105 | Technical Papers |
AbstractThe material characterization of steel fibre-reinforced concrete (SFRC), which is required for its implementation in design codes, should be based on nominal properties that describe its post-cracking strength in tension. In the case of brittle and quasi-brittle materials, such as concrete, the tensile parameters are often derived indirectly. However, for materials with more ductility, such as SFRC, there is conjecture as to whether or not an indirect measure may be used to establish the stress versus crack opening displacement relationship, such as the use of a three- or four-point prism test combined with an inverse analysis. In this paper a simple and efficient inverse analysis technique is developed and shown to compare well with data obtained from direct tension tests. Furthermore, the methodology proposed by the fib Model Code for Concrete Structures 2010 has been investigated and recommendations made to improve its accuracy. x | |||||
Balázs, György L.; Bisch, Philippe; Borosnyói, 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; MarÃ, Antonio; Ozbolt, Josko; Pecce, Marisa; Pérez Caldentey, Alejandro; Taliano, Maurizio; Tkalcic, Damir; Torrenti, Jean Michel; Torres, Lluis; Toutlemonde, François; Ueda, Tamon; Vitek, Jan L.; VráblÃk, 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 | |||||
fib short course in Nicosia, Cyprus: Durability and retrofitting of concrete structures | Structural Concrete | 2/2011 | 129-135 | fib-news | |
Abstract• fib short course in Nicosia, Cyprus: Durability and retrofitting of concrete structures x | |||||
Albrecht, U. | Durchstanzen bei Flachdecken - Vergleich der Bemessung und Konstruktion | Beton- und Stahlbetonbau | 3/1999 | 130-140 | Fachthemen |
AbstractDie Bemessungsansätze und die Konstruktionsregeln für den Nachweis gegen Durchstanzen von Stahlbeton-Flachdecken unterscheiden sich deutlich voneinander. Die Querkrafttragfähigkeit, die gemeinsame Tragfähigkeit von Beton und Schubbewehrung und die daran geknüpfte baulilche Durchbildung werden für vier europäische und zwei nordamerikanische Normen sowie den CEB-FIP Model Code gegenübergestellt. Am Beispiel einer Flachdecke eines Bürogebäudes mit üblichen Abmessungen wird gezeigt, welche Möglichkeiten und Grenzen die Normen im einzelnen bieten und welche baupraktischen Konsequenzen die neue DIN 1045-1 und der EC 2 haben werden. x | |||||
Groli, Giancarlo; Pérez 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 | |||||
Walraven, Joost C.; Bigaj-van Vliet, Agnieszka | The 2010 fib Model Code for Structural Concrete: a new approach to structural engineering | Structural Concrete | 3/2011 | 139-147 | Articles |
AbstractThe fib Model Code is a recommendation for the design of reinforced and prestressed concrete which is intended to be a guiding document for future codes. Model Codes have been published before, in 1978 and 1990. The draft for fib Model Code 2010 was published in May 2010. The most important new element in this Model Code is “Time” in the sense of service life. Additionally, the Model Code contains an extended state-of-theart chapter on the structural materials concrete and steel but regards non-metallic reinforcement and fibres as reinforcement as well. Many loading conditions are considered, ranging from static loading to non-static loading, considering earthquake, fatigue and impact/explosion. Five methods are offered to verify structural safety. Attention is given to verification of limit states associated with durability, robustness and sustainability. Finally, verification assisted by numerical methods and by testing is considered. Other elements that are links in the chain of life cycle design are construction and conservation. In the part on conservation the conservation strategy is treated in combination with conservation management, condition survey and assessment, and evaluation and decision-making. x | |||||
Heek, Peter; Look, Katharina; Minelli, Fausto; Mark, Peter; Plizzari, Giovanni | Datenbank für querkraftbeanspruchte Stahlfaserbetonbauteile - Bewertung der Bemessungsansätze nach DAfStb-Richtlinie und fib Model Code 2010 | Beton- und Stahlbetonbau | 3/2017 | 144-154 | Fachthemen |
AbstractDer Einsatz von Makrofasern aus Stahl gewinnt seit der bauaufsichtlichen Einführung der Richtlinie “Stahlfaserbeton” des Deutschen Ausschusses für Stahlbeton (DAfStb) auch in tragenden Betonkonstruktionen zunehmend an Bedeutung. Insbesondere beim Nachweis ausreichender Querkrafttragfähigkeit erweist sich die Fasertragwirkung als günstig, da eine Querkraftbewehrung auch bei Balken rechnerisch vollständig durch Fasern gebildet sein kann - Bügel also entfallen. Haupteinflussparameter ist die Nachrisszugfestigkeit, die aufgrund vielfältiger interagierender Einflussparameter hohen Streuungen unterliegt und nach Ansätzen der DAfStb-Richtlinie bzw. den Modellen des Model Codes 2010 deutlich unterschiedlich einfließt. Der Beitrag vergleicht die Prognosegenauigkeiten rechnerischer Querkrafttragfähigkeiten, indem rechnerische Bruchlasten experimentellen Daten von Schubversuchen aus der Literatur gegenübergestellt werden. Die aufgebaute Schubdatenbank umfasst dabei über 250 Versuche mit praxistypischen Konfigurationen, d. h., dass Querschnittsgeometrie, Längs- und Bügelbewehrungsgehalt, Nachrisszugfestigkeit des Stahlfaserbetons sowie Betondruckfestigkeit variable Parameter sind. x | |||||
Gunkler, Erhard; Marx, Johann Jakob; Blum, Carsten | Shear resistance of reinforced masonry beams with and without additional concrete or prestress / Querkrafttragfähigkeiten von bewehrten Mauerwerksbalken mit und ohne Aufbeton oder Vorspannung | Mauerwerk | 3/2017 | 155-167 | Fachthemen |
AbstractThis article investigates the transferability of the Simplified Modified Compression Field Theory (SMCFT) [2], which is known in reinforced concrete design and included in the fib Model Code for Concrete Structures 2010 (Volume 3) [1], to reinforced or prestressed masonry beams (RM beams) with or without an additional layer of concrete. The investigation for this work is the obsolete shear design concept that has been used until now for reinforced masonry under shear loading, which does not adequately reflect the actual load-bearing behaviour of significant areas of masonry. The fundamentals of the SMCFT are explained and the transferability of the theory to RM beams is examined, taking into account in particular the different material properties of masonry compared to reinforced concrete. A first approach for future application is represented by the equations presented here for the determination of the shear force capacity of RM beams. The verification is performed through a comparison of the shear resistances determined experimentally (exp.) and by calculation (calc.). x |