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Shear strength assessment of bridge girders using refined design approaches The unfavourable age structure of bridges of the federal highway system in Germany and the considerable increase in goods traffic are the main reasons for the generally poor overall condition of numerous bridge structures. In addition, the further development of the standards in connection with the Eurocodes often results in computational deficits. More precise verification formats are offered by Level 2 of the assessment guideline, which was first published in 2011 and extended in 2015. Recent findings on the shear behaviour of prestressed concrete bridges with low shear reinforcement ratios in the range of ρw,min form the basis for the 2nd extension to the assessment guideline, which will appear in BEM‐ING Part 2. For the evaluation of the shear capacity of the main system, an extended truss model with additive concrete contribution is introduced, which is explained in the following and presented by means of two case studies. [ABSTRACT FROM AUTHOR]

Evolution of creep and shrinkage models for concrete structures in Austria and Germany – Evaluation of the current models regarding the sensitivity of the input parameter Concrete is one of the most important materials in civil engineering structures and finds its application in the building of bridges, ground engineering and building construction. As widely known, concrete is a material which changes its behavior with time in dependency of the environmental conditions. Especially the long‐term deformations caused by creep and shrinkage processes are of great interest regarding the durability and sustainability of infrastructures. Early versions of design codes gave some guidelines on how to treat deformations caused by these sources. In the beginning, these deformations were taken into account by an additional temperature drop. The first sophisticated approaches on how to deal with these long‐term processes were published in the standards for prestressed concrete structures. These early models were updated and improved to today's prevailing documents such as the Eurocode 2 and the fib Model Code. The first part of this paper gives an overview of the historical development of creep and shrinkage models in Austria and Germany until today's guidelines. The second part presents a sensitivity study of the current models regarding the input parameters for some given scenarios. Lastly, the differences between the models are highlighted based on an application example taken from literature. [ABSTRACT FROM AUTHOR]

Crack width verification and minimum reinforcement according to Eurocode 2 – current model versus new proposal for revision Limiting crack widths to an acceptable level and determining the required minimum reinforcement are important tasks in the design of reinforced and prestressed concrete structures. Experience with different types of structures from watertight concrete structures to prestressed concrete bridges shows that the concept currently applied in Germany and Austria is very effective and that significant changes are not necessary. The current draft for the revision of EC2, however, presents a new concept for crack width verification and minimum reinforcement. In contrast to the concept currently used in Germany and Austria, this new concept is based more on the analysis and good reproduction of the observations made in laboratory experiments and takes less account of the mechanical relationships of reinforced or prestressed concrete after cracking. For this purpose, numerous empirical factors are introduced, which not only complicate the understanding but also the application in practice. However, an improvement in the accuracy of the crack width prediction is not achieved and the minimum reinforcement is significantly underestimated, especially for prestressed cross‐sections and thick members. In this paper, the new concept in EC2 is explained in detail. Its main weaknesses and contradictions are discussed by a comparison with the concept currently applied in Germany and Austria as well as detailed analysis of 2D FEM simulations with discrete cracks and adequate regard of the bond stress‐slip relationship at the reinforcement‐concrete interface. This should provide the basis for a factual discussion before the introduction of the new EC2. [ABSTRACT FROM AUTHOR]

Punching shear behaviour of steel fibre reinforced flat slabs with punching shear reinforcement The guideline "Steel Fibre Reinforced Concrete" published by the German Committee for Reinforced Concrete (DAfStb) contains the current normative regulations for the punching shear design of steel fibre reinforced flat slabs. Due to a lack of sufficient experience and knowledge, a consideration of the combined action of steel fibres and shear reinforcement was explicitly excluded. While numerous punching shear tests on steel fibre reinforced flat slabs without shear reinforcement are available in literature, only eight tests in combination with shear reinforcement are known to the authors. These few tests used types of shear reinforcement which are not common for engineering practice in Germany, or showed bending failure, which limits the reliability of statements about the behaviour of such a combination. In this context and the expected favourable behaviour, seven tests were carried out to systematically investigate the punching shear behaviour of steel fibre reinforced flat slabs with stirrups and shear studs as shear reinforcement. The test program included one fibre reinforced test without punching shear reinforcement, two fibre‐free and four fibre reinforced tests with punching shear reinforcement. This paper describes the experimental investigations carried out and discusses the results obtained. [ABSTRACT FROM AUTHOR]

An alternative method of fire design of reinforced concrete columns with tabulated data – Explanations of new Annex C in DIN EN 1992‐1‐2/A1 In November 2019, an A1‐amendment to Eurocode 2 – DIN EN 1992‐1‐2: Structural design for fire exposure has been published. This A1‐amendment contains seven design tables in the new Annex C: „Buckling of columns under fire conditions" for fire resistance classes R30 to R240. With these design tables an alternative method is available for the fire design of reinforced concrete columns with a rectangular cross section in braced and non‐braced structures. The introduction by the building authorities in the administrative regulations of the federal states is probably expected in 2021/2022. The scientific background and the validation of the new Annex C and the associated restrictions are explained in this paper. On this basis, the tables of Annex C can now also be used in Germany (A2 amendment to the National Annex). The paper demonstrates the practical application of the new tables in two design examples and concludes with a brief outlook on the planned extension of the scope of these tables in the next Eurocode generation. [ABSTRACT FROM AUTHOR]

Determination of the characteristic concrete compressive strength of existing structures according to DIN EN 13791:2020 for small sample sizes – Evaluation and comparison with valid existing approaches The assessment of existing structures is becoming increasingly important, because in the sense of resource‐efficient handling of existing buildings, conversion should be given priority over demolition and new construction. Until now, the characteristic concrete compressive strength of existing structures in Germany has been calculated according to DIN EN 13791/A20:2017. DIN EN 13791:2020, which was introduced in February 2020, will replace DIN EN 13791:2008, which was previously valid in Europe, and DIN EN 13791/A20:2017, which was valid in Germany. Especially for small sample sizes of drill cores (3 ≤ n ≤ 7), the introduction of DIN EN 13791:2020 results in significant changes in the determination of the characteristic in‐situ concrete compressive strength. However, there is currently no background information available on the statistical robustness of the new methods, which is why this is to be checked within the framework of the research project DBV 317. [ABSTRACT FROM AUTHOR]

Punching strength of flat slabs with varying shear reinforcement ratios With the introduction of Eurocode 2 in Germany, the punching shear design provisions of flat slabs were revised. Since then, the punching shear strength with shear reinforcement is calculated from the combination of a constant concrete contribution and a steel contribution, which results from a strut inclination of 33°. Besides, a reduced steel strength depending on the effective depth of the flat slab is assumed for the calculation of the steel contribution to consider the anchorage conditions of the shear reinforcement elements. Due to a database analysis and an evaluation of the level of safety compared to the former DIN 1045‐1, additional factors have been implemented in German Annex to Eurocode 2 (EC2+NA(D)) for the first and second row of shear reinforcement leading to almost twice the amount of required shear reinforcement. Various test series on reinforced concrete flat slabs without shear reinforcement and with high amounts of shear reinforcement are available and can be used for the evaluation of the current provisions. Nevertheless, the evaluation of the code equations for the design of the shear reinforcement (failure inside the shear‐reinforced zone) is still not possible since only very few systematic punching tests with a varying amount of shear reinforcement have been conducted. To investigate the punching shear behavior of reinforced concrete flat slabs with stirrups as shear reinforcement, three systematic test series (eleven specimens) with varying shear reinforcement ratios were performed. Each test series included one reference test without shear reinforcement. In the tests, the shear reinforcement ratio was varied by changing the stirrup diameter only. Further investigated influences were the shear span‐depth ratio and the effective depth. In this paper, the results of the tests are presented, discussed and compared to the predictions according to Eurocode 2 and EC2+NA(D). Moreover, the punching design provisions according to Model Code 2010 are evaluated. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A safe look back of products requires their unique identification. Blood products are encoded in Germany with Eurocode since 1987. EU Directives 2004/23/EC und 2006/86/EC demanded unique identification and safe look back procedure also for tissues and cells. Eurocode IBLS e.V. and the DGTI working parties 'Tissue Preparations' and 'Automation and Data Processing' supplemented the already available Eurocode nomenclature for blood products with further data structures for tissue preparations and deliberated the federal authorities during the EU hearings. In result all EU member states can administer the coding system oneself, but have to take care about the 'key code' structure as defined and the common part at the begin of the ID number of the preparations. Eurocode today offers an EU-conform coding system considering various aspects of blood, tissue and cell preparations in an ISO-standardized form. [ABSTRACT FROM AUTHOR]