The correlations among selected parameters of concrete were investigated for concrete mixes of the strength classes C20/25, C25/30, C30/37, C40/50 and C50/60. The focus was laid on correlations between basic mechanical parameters such as compressive strength, tensile strength and modulus of elasticity as well as parameters related to concrete fracture, represented here by specific fracture energy. Laboratory tests examining the fracture behaviour and mechanical properties were carried out in order to determine the fundamental concrete parameters. In particular, standard compression tests on test cubes and three-point bending tests on beams with central edge notch were performed. Additional material parameters were identified using the inverse analysis technique. Finally, correlation factors between different parameters of concrete were identified using the rank-order correlation method.

Dubai Municipality awarded to Porr Besix JV the Project for the Main Tunnel component of the Deep Storm Water System. The tunnel will collect both rainwater and groundwater from approximately 500 sq. km and transfer the captured flow to the sea. The Design Builder JV selected COWI as Designer of the entire Project and IC Consultant as Design Checker for the Tunnels. The Project includes approximately 10.3 km of 10-meter-inside diameter tunnel in rock, three construction shafts and one drop shaft. The main tunnel will convey stormwater and groundwater flows from the EXPO 2020 area near the intersection of Sheikh Mohammed Bin Zayed Road and Jebal Ali Lehbab Road to the sea close to the EGA facility. The tunnel will follow beneath the road easement along Jebal Ali Lehbab Road and along Sheikh Zayed Road and continue to the pumping station. The tunnel traversed through the Barzaman and Fars formation with an overburden of 33 m with maximum water pressure of 4.4 bar and was excavated by EPB TBMs. This project is characterized by its dimensions with an internal diameter of 10 m and 350 mm of segment thickness, and by the use of steel fibre reinforced concrete in the precast segmental lining. The use of fibres aims to reduce the CO2 footprint obtaining an optimized design from the environmental point of view. These facts are associated to a complex design of precast segments, in order to ensure their structural competence and their integrity according to the durability requirements, under large thrust forces (temporary loads) and permanent load. Hence, considering such complexities, the structural design has been carried out producing a 3D structural model by means of a sophisticated FEM structural software. Results of the model allow to identify areas of the segment where spalling and bursting stresses are generated along circumferential joints and maximum value of those stresses in the temporary load cases. Moreover, a structural design verification of the segment has been undertaken considering the contribution of steel fibres class 4c, as it is set up in the FIB model code, aiming to ensure that the precast segments are structurally competent and fulfil the durability requirements of the Project. The article details the design approach and the independent checker design verification approach. The experience gained during construction is also reported, describing challenging aspects of the Tunnel execution and an analysis of the lining damages.

Statischer Entwurf einer mit Stahlfasern verstärkten Tübbingauskleidung
Die Stadtverwaltung von Dubai vergab an die Arbeitsgemeinschaft Porr Besix das Projekt DS233/2 Deep Storm Water System - Main Tunnel. Der Tunnel wird sowohl Regen- als auch Grundwasser ableiten und fast 40 % des gesamten Stadtgebiets von Dubai entwässern. Das Projekt zeichnet sich durch seine Dimensionen mit einem Innendurchmesser von 10 m und einer Tübbingdicke von 350 mm sowie durch den Einsatz von stahlfaserverstärktem Beton in der vorgefertigten Tübbingauskleidung aus. Die Verwendung von Fasern zielt darauf ab, den CO2-Fußabdruck zu reduzieren, um ein aus ökologischer Sicht optimales Design zu erhalten. Um die statische Funktion und Integrität gemäß den Dauerhaftigkeitsanforderungen aufgrund der großen Vortriebspressenkräfte (temporäre Lasten) und unter permanenter Belastung zu gewährleisten, wurde ein 3D-Strukturmodell mithilfe einer FE-Software erstellt. Die Ergebnisse des Modells ermöglichen es, die Bereiche des Segments zu identifizieren, in denen Abplatzungen und Spaltzugspannungen entlang der Umfangsfugen entstehen, sowie den maximalen Wert dieser Spannungen in den temporären Lastfällen. Darüber hinaus wurde ein statischer Nachweis des Segments unter Berücksichtigung des Beitrags von Stahlfasern der Klasse 4c durchgeführt, wie es im FIB-Modellcode festgelegt ist, um sicherzustellen, dass die vorgefertigten Segmente die Anforderungen des Projekts an die statische Tragfähigkeit und Dauerhaftigkeit erfüllen. Der Artikel beschreibt detailliert den Entwurfsansatz und den Ansatz der unabhängigen Prüfung des Entwurfs.

This paper presents a critical comparison of the existing code provisions for the shear strength of concrete beams. The comparison is based on the computerized filtering-out of the inevitable statistical bias from the available multivariate database on shear strength, on an examination of the predicted size effects on shear strength and their underlying hypotheses and on the results of recent high-fidelity numerical simulations of shear failure. In addition to examining the existing models, the present comparison also provides several key considerations for testing the scientific soundness of any model of shear failure in concrete beams, which is necessary for future revisions to the design code provisions.

This paper presents a new theory for the shear capacity of reinforced concrete members without shear reinforcement. While recognizing that there are multiple failure mechanisms, the theory attributes the opening of a critical flexural shear crack as the lower bound of the shear capacity. It proposes that the shear displacement of an existing flexural crack can be used as the criterion for the unstable opening of the critical flexural shear crack. Based on the theory, the paper presents a simplified shear evaluation model. Compared with the current shear provisions in the design codes, the model is characterized by good accuracy and a solid physical background. It demonstrates a great flexibility for dealing with complex design conditions. As an example, the paper discusses the possibility of extending the theory to the shear resistance of higher-strength concrete. The suggested method provides a more logical and fluent transition from normal- to high-strength concrete and shows good agreement with experimental observations.

The punching shear design provisions according to various codes have been derived from the results of tests conducted on centrically loaded flat slabs. The application of these provisions for footings and ground slabs might lead to inconsistent results since more compact dimensions and soil-structure interaction lead to higher punching shear capacities. In this context, Eurocode 2 introduced a new design equation for column bases, which was derived from the evaluation of test results from centrically loaded footings.
Since centrically loaded footings represent an exception in practice, Eurocode 2 and ACI 318-14 consider load eccentricities by increasing the applied load, while the fib Model Code 2010 proposes a reduced length of the control perimeter to determine the punching shear resistance. The different approaches were derived from the evaluation of tests on eccentrically loaded flat slabs and have not been verified for footings yet.
Theoretical and experimental investigations on the punching shear behaviour of eccentrically loaded footings indicate a reduction of the multi-axial stress state along the column face with increasing load eccentricity. Based on punching tests on eccentrically loaded footings described in literature, non-linear finite-element simulations were performed and subsequently the influence of load eccentricities on the punching shear behaviour was examined in parametric studies. In this article, the results of the numerical simulations are presented and compared to experimental results and various code provisions.

No short description available.

The 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.

The 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.

A performance-based safety factor durability design format is proposed and developed with respect to carbonation of concrete. Deemed-to-satisfy rules based on a partial safety factor design approach are developed for the carbonation of concrete. This design format follows the design procedure proposed in EN 1990 [1]. For the design format, the limit state equation for the carbonation is introduced in its probabilistic and safety factor format. The PSF approach has been used to derive design charts. Values for minimum concrete cover depending on material resistance and exposure class are proposed for critical environmental conditions and a design service life of 50 years.

At present, prescriptive regulations with regard to concrete cover and composition are applied to provide sufficient durability of reinforced concrete members under exposure conditions with different degrees of severity. In view of current knowledge on deterioration mechanisms and their modelling, it is planned to change from these deemed-to-satisfy specifications to a performance-based design approach in future standards. In such specifications, concrete durability design is based on the statistically characterized performance of concrete, determined in standardized tests with respect to defined classes of concretes with similar performance.
This paper presents the results of a study in which concrete mixes were tested and analysed with respect to their carbonation resistance. Compositions with similar performance are grouped into carbonation resistance classes. These classes are described statistically and requirements for performance testing are given. In addition, composition requirements are introduced in order to determine concrete performance depending on mix composition prescriptively. Finally, an example is given for the assessment of concrete performance with regard to carbonation.
This work was carried out at the request of JWG under CEN TC 250/SC2 and CEN TC 104/SC1 as an input and starting point for the ongoing committee work to implement the methodology from the fib Model Code for Concrete Structures 2010 in the next generation (2021) of European concrete standards.

The paper reports on a benchmark of European deemed-to-satisfy rules for exposure class XC (carbonation exposed structural members). The benchmark of the descriptive rules was carried out following the probabilistic design approach for carbonation-induced corrosion developed in [1] and adopted in fib bulletin 34: Model Code for Service Life Design (2006) [2] and fib Model Code for Concrete Structures 2010 [3], respectively. To perform a representative study, three groups of European countries were selected, representing different parts of Europe, south (Spain, Portugal), middle (Netherlands, Great Britain and Germany) and northern Europe (Denmark, Norway). Reliability ranges for carbonation-induced depassivation of rebar were calculated for “favourable” and “unfavourable” design situations in exposure classes XC2, XC3 and XC4 [4]. In each design situation the deemed-to-satisfy rules of selected countries were followed. The probabilistic calculations were mainly based on short-term carbonation data. However, some calculations were also based on long-term observation. The latter was implemented for independent validation purposes. The calculated reliability ranges are very broad and in some “unfavourable” situations, the deemed-to satisfy requirements do not guarantee the required limit state (LS) arget reliabilities for the particular exposure. In “favourable” situations less stringent demands would have been sufficient.

Um 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.

Monitoring based lifetime assessment of concrete structures - Research Project MOSES
In order to use structures up to their real end of lifetime it is of great importance to know the degree of damage of the structure. By using the actual Codes and Specifications (e.g. CEB-FIP Model Code 2010) it is not possible to define the real degree of deterioration. A practicable way of determining the degree on-site is the employment of non-destructive testing methods (monitoring). This field until now is not finally explored. The constant monitoring from the erection of a structure up to the end of its lifetime is seen as a very promising possibility to assess the residual lifetime. In this article fatigue tests on concrete specimens, accompanied with ultrasonic and acoustic emission measurements will be investigated closer and a possible way for the determination of the degree of damage and lifetime assessment will be proposed.

Nach den heutigen aktuell gültigen Normen und Vorschriften (z. B. CEB-FIP-Model Code 2010 [1]) werden für den Ermüdungsnachweis und auch für die Bestimmung des Schädigungsgrades von Betonbauteilen Lastzyklen gezählt und lineare Schadens-Akkumulations-Hypothesen angewandt. Die so gewonnenen Ergebnisse entsprechen nicht der Realität, da Beton ein sehr stark nicht lineares Verhalten aufweist. Ein Weg, diese Ergebnisse zu verbessern, ist die Anwendung von Monitoring, um die Veränderung in der inneren Struktur des Betons mittels eines lastunabhängigen Messverfahrens überwachen zu können. In diesem Artikel wird ein Monitoring-Konzept vorgestellt, mit welchem es möglich ist, diese Ziele zu verwirklichen. Die zugehörigen Laborversuche wurden bereits in [2] beschrieben. Nun folgt deren tiefergehende Auswertung. Am Ende dieses Artikels werden dynamische Tests an vorgespannten Monoblockschwellen gezeigt. Diese wurden mithilfe des im Rahmen dieser Veröffentlichung beschriebenen Monitoring-Konzepts überwacht. Die dadurch erhaltenen Sensormesswerte wurden mit einer numerisch nichtlinearen Simulation der Schwelle korreliert.

Monitoring of the real degree of Fatigue deterioration within concrete structures - Research Project MOSES
According to actual codes and regulations (e.g. CEB-FIP-Model Code 2010 [1]) the verification concept for fatigue and the determination of the real degree of deterioration of Concrete structures is based on counted load cycles and the linear Palmgren-Miner summation. The results gained in this manner will never depict the reality because of the not considered heavily non-linear behavior of concrete. A way to improve the results is the application of monitoring sensors, which are able to image the changes in the inner part of the concrete matrix independently from applied loads. In this article a monitoring concept will be proposed which can achieve these objectives. The laboratory tests are already described in [2] and now a deeper assessment of the measured results will be made. At the end of this article dynamic tests with prestressed railway sleepers and mounted monitoring system are presented. The measurement data of the sensors will be correlated with results of a numerical nonlinear simulation of the sleeper.

When it comes to dynamically loaded concrete structures, determining the real degree of fatigue damage of a structure on site is a very demanding process that has not been explored in depth. Calculation concepts according to current codes and specifications (e.g. fib Model Code for Concrete Structures 2010 [1]) do not offer efficient results for this task. However, the permanent monitoring from the erection of a structure up to the end of its lifetime is seen as a very promising possibility for assessing the degree of damage constantly. This article takes a closer look at the concrete fatigue concept of fib Model Code 2010 [1], shows an FE simulation of a time-dependent fatigue process for an offshore wind turbine foundation and presents a fatigue monitoring concept including laboratory tests, which enables the detection of the real degree of deterioration in a concrete structure. During tests, the use of ultrasound was identified as the most appropriate method. Measuring wave velocity enables the determination of the dynamic E-modulus, which correlates to the degree of damage within the cross-section of the structure considered.

Bei Ermüdungsnachweisen von Betonstrukturen, vor allem im Bereich Offshore, wird die schrittweise Degradation von Materialparametern oftmals nicht berücksichtigt. Eine Auswirkung dieser Schädigung des Materials in Teilbereichen des Betonquerschnitts in Abhängigkeit des Belastungszustands ist eine Spannungsumlagerung innerhalb des Querschnitts und somit die Verlängerung der theoretischen Nutzungsdauer der Betonstruktur. Beton wird in seinen Eigenschaften mithilfe von Materialparametern näher bestimmt. Ein sehr wichtiger Materialparameter ist der E-Modul, auch Elastizitätskoeffizient genannt. Ein Weg, die Schädigung des Materials in einer FE-Analyse zu berücksichtigen, ist die schrittweise Anpassung und Minimierung des E-Moduls. Um ein Bauwerk zu bemessen, seinen internen Spannungsverlauf oder sein Verformungsverhalten vorherzusagen, ist es somit von großer Wichtigkeit, diesen Parameter genau zu bestimmen, seine Veränderung mit der Zeit und aufgrund seiner Belastungshistorie zu kennen. In diesem Beitrag wird zusätzlich zur Robustheits- und Redundanz-Definition auch eine Lebenszeitberechnung des Strabag-Testfundaments in Cuxhaven nach Model Code 1990 für die geplanten Ermüdungsversuche mit realistisch verändertem E-Modul ausgeführt. An der Fallstudie Cuxhaven wird mithilfe eines linearen, iterativen Modellbildungsprozesses die Nutzung der Robustheit des Systems für die Verlängerung der verbleibenden Nutzungsdauer gezeigt.

Concrete structures under cyclic loading - robustness and redundancy considerations for residual lifetime optimization
Concerning fatigue analysis of concrete structures, especially in offshore areas, the continuous degradation of material parameters is not taken into account. One effect of the damaged material structure in parts of the concrete cross section is the stress redistribution from highly loaded (damaged) areas to low loaded (undamaged) areas and therefore an elongation of the theoretical residual service life. Concrete is described by the use of material parameters. A very important parameter is the E-modulus, also called the modulus of elasticity. A possibility to consider the degradation process within the material concrete is the gradual adaption and minimization of the E-modulus. In order to analyze and dimension a structure, to predict the internal stress distribution and deflection behavior, it is very important to specify this parameter and to know the variation according loading history and time.
In addition to robustness and redundancy definition given in this article, a life time calculation of the Strabag gravity base test foundation in Cuxhaven according Model Code 1990 for the planned fatigue tests with realistic reduction of E-Modulus is performed. Concerning the case study “Cuxhaven” the use of system robustness in order to extend the residual service life is been demonstrated by means of a linear iterative modeling process.

Many 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.
The International Committee on Concrete Model Code for Asia (ICCMC) was established in 1994 as the first international body in Asia. The ICCMC issued the Asian Concrete Model Code (ACMC) in 2001, the first international structural code in Asia. The ACMC is an umbrella code with a performance-based concept and a multi-level document structure, which makes it suitable for the considerable diversity in Asia. It is also the first international code covering maintenance and repair, which makes the ACMC ready to adopt the LCM concept. The ACMC has been a model for various national codes. The main features of the ACMC, i.e. the performance-based concept, durability design concept, seismic design concept and the inclusion of maintenance/repair, are shared with JSCE Standard Specifications in Japan. The ICCMC has been working together with ISO/TC71 towards international code harmonization.

Most 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.

The present contribution focuses on a comparative study of shrinkage prediction models according to the European Standard Eurocode 2 (EC2), the recommendation by ACI committee 209 and fib Model Code for Concrete Structures 2010. The estimated ultimate drying shrinkage strains and the predicted evolution of drying shrinkage strains are compared with respective shrinkage strains measured on normal-strength concrete specimens of different sizes. For all prediction models, the estimated ultimate values are found to agree quite well with the ultimate drying shrinkage strains measured on thin concrete slices. Whereas the evolution of drying shrinkage strains measured on small concrete prisms agree quite well with the predicted values, substantial differences between code values and experimental data are encountered for larger specimen sizes.

The 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.

Die Auswertung zahlreicher mehraxialer Versuche hat ergeben, dass die auftretenden Versagensmechanismen unter mehraxialer Beanspruchung für alle Betonarten prinzipiell gleich sind. Dies gilt sowohl für Normal- bis ultrahochfesten Beton, für Leichtbeton als auch für Faserbeton. Das vorgestellte Bruchkriterium orientiert sich an diesen Versagensarten und wird über eine entsprechende Kalibrierung an das Verhalten des jeweiligen Betons angepasst. Im Zuge der Aktualisierung des CEB-FIP Model Codes 90 wird es Einzug in die Bemessungsvorschriften finden.

A Unified Multiaxial Fracture Criterion for all Concretes
The evaluation of numerous multiaxial tests has shown that the occurring failure mechanisms under a multiaxial load are basically the same for all types of concrete. This is true for normal to ultra high performance concrete, lightweight concrete, as well as for fibre concrete. The presented fracture criterion is based on these failure types and is adjusted by a corresponding calibration to the behaviour of each concrete. In the course of the upgrade of the CEB-FIP Model Code 90, it will find entry into the dimensioning specification.

The 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.

This 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.

Eurocode 2 and the corresponding National Annex were introduced in Germany in 2012. Most of the design provisions for these new standards were adopted from Model Code 1990 and provide a new design approach for ground slabs and footings. For the fib Model Code for Concrete Structures 2010, the punching shear design concept has been revised and introduced in Swiss standard SIA262:2013. This paper presents in detail the design equations for determining the punching capacity according to Eurocode 2, the German National Annex to Eurocode 2, fib Model Code 2010 and SIA 262:2013.
Parametric studies have been used to examine the influence of the main parameters (shear span-depth ratio, effective depth, longitudinal reinforcement ratio and concrete compressive strength) on the punching shear resistance of footings. To quantify the level of safety and the efficiency, the design provisions are compared with systematic test series.

Seit 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.

Punching shear design of footings - present code provisions: parametric study and comparison with test results
Since 2012, Eurocode 2 and the corresponding National Annex have been introduced in Germany. Most design provisions were adopted from Model Code 1990 and provide a new design approach for ground slabs and footings. For Model Code 2010, the design concept was again revised and introduced in the Swiss standard SIA262:2013. In this paper, the design equations for the determination of the punching capacity according to Eurocode 2, the German annex to Eurocode 2, Model Code 2010, and SIA 262:2013 are presented in detail.
Parameter studies are used to examine the influence of the main punching parameters (shear span depth-ratio, effective depth, longitudinal reinforcement ratio, and concrete compressive strength) on the punching shear resistance of footings. To quantify the safety level and the efficiency, the design provisions are compared to systematic test series.

Punching 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.
In addition to the measured steel strains in the flexural reinforcement and the stirrups, the increase in the slab thickness as well as the saw-cuts were examined to investigate the internal cracking and failure characteristic. In combination with previous tests conducted at RWTH Aachen University, this test series permits a description of the effect of the main parameters on the punching shear strength of footings. These parameters are the size effect of the effective depth, the concrete compressive strength, the flexural reinforcement ratio and the punching shear reinforcement.