Search

Load‐bearing capacity tables for unreinforced masonry according to DIN EN 1996‐3/NA:2019‐12 Practical design aids are important tools in the day‐to‐day business of structural design. The design of primarily vertically loaded masonry walls in usual building construction can be carried out with the help of so‐called load‐bearing capacity tables. A table value is read off exclusively as a function of the geometric conditions, which – multiplied by the masonry compressive strength – results in the load‐bearing capacity of the wall for cold design and in case of fire. By comparing the acting and resisting force, the verification of structural design can be provided in a simple and yet economical form. The bearing capacity tables based on the simplified calculation methods according to DIN EN 1996‐3/NA:2019‐12 [1], [2] and DIN EN 1996‐1‐2/NA:2013‐06 [3], [4] are presented in this paper. Compared to the previous edition of Part 3 of Eurocode 6, the extended scope of application is taken into account, as well as the normative changes to the construction method with partially supported slabs. [ABSTRACT FROM AUTHOR]

According to Eurocode 6, unreinforced masonry walls can be designed using different verification methods, whereby the simplified calculation methods are contained in Part 3 of DIN EN 1996 [1]. If the associated application limits and boundary conditions are fulfilled, a large part of the usual problems occurring in masonry construction can be dealt with without great effort. A limiting condition for the application of the simplified calculation methods is a maximum clear wall height of h = 2.75 m or h = 12 • t. Changes in user requirements for modern buildings with masonry walls nowadays often require greater wall heights, wherefore a verification according to the general rules from DIN EN 1996‐1‐1/NA [2] is necessary. This means a considerably higher effort for the structural engineer. A considerable amount of calculations was done to verify whether the results of the simplified calculation methods are also valid for greater wall heights. The results were transferred into a consistent standardization proposal with regard to extended application limits of DIN EN 1996‐3/NA, which is contained in a new draft Amendment A3 for the National Application Document for Germany. [ABSTRACT FROM AUTHOR]

For a new multi‐storey car park over the Central Bus Station (ZOB) in Kiel, a perforated clinker brick veneer facade not conforming to standards was planned. The design and technical characteristics of the facade have already been described in the article by Medzech and Schrade in this issue [1]. This article deals with the experimental investigations carried out to obtain a project‐related one‐off approval (ZiE). These experiments contain in particular large tests on storey‐height wall sections, which were subjected to eccentric compressive loading and partly to horizontal loads representing wind action. Supplementary small tests on unreinforced and reinforced masonry served to determine the bending capacity, the anchoring capacity of the reinforcement and the load‐bearing capacity of the wall anchors in the masonry. Due to the special facade construction with special bricks for the project, wall anchors, reinforcement bar couplers and unique test set‐ups had to be developed for the specific project. [ABSTRACT FROM AUTHOR]

Abstract: Load‐bearing capacity of unreinforced concrete compression members under biaxially eccentric loading Compression members, such as columns or walls, have to carry vertical loads primarily. Due to the rotation of the adjacent components, they are also subjected to bending moments. If the compression member is, in addition to the bending moment about the weak axis, also loaded by horizontal bracing forces in direction of the strong axis, bending moments about both axes (biaxial bending) occur. This paper deals with the load‐bearing capacity of slender, unreinforced and biaxially eccentrically loaded compression members made of concrete. Existing theoretical methods for determining the load‐bearing capacity of centrically and uniaxially eccentrically loaded compression members are shown as well as the corresponding normative regulations. On this basis, two practice‐oriented proposals for determining the load‐bearing capacity of biaxially eccentrically loaded unreinforced concrete compression members are presented. The proposals can easily be adopted into the standard and thus, the existing restricting limits of application can be neglected. [ABSTRACT FROM AUTHOR]

Dedicated to Prof. Dr.-Ing. Carl-Alexander Graubner on the occasion of his 60th birthday Masonry members have to resist vertical loads and bending moments about the weak axis due to rotation of adjacent slabs. If the compression member is part of the bracing system, there are also bending moments about the strong axis. This paper deals with the load-bearing capacity of biaxially eccentrically compressed unreinforced compression members with rectangular cross-sections. For linear-elastic material, the principles of an analytical model is presented, which considers geometrical and physical (cracking) non-linearity. The deflections of the wall can be determined by using moment-curvature relations, making possible the analytical analysis of compression members considering the effects of 2nd order theory. For a non-linear stress-strain relation, the calculation of the load carrying capacity of rectangular compression members under biaxial bending is complex and has to be determined numerically. The good accordance of the results of the analytical model with the numeric calculations is also shown for various eccentricities. In addition, a simplified proposal for the calculation of the load-bearing capacity of biaxially eccentrically compressed unreinforced compression members is shown. The proposal is based on the load-bearing capacity of uniaxially eccentrically compressed unreinforced compression members. Therefore it is possible to use the proposal considering existing models, for example according to Eurocode 2 or 6. [ABSTRACT FROM AUTHOR]

Since masonry is one of the oldest and most traditional construction types, corresponding safety concepts are usually based on experience instead of being calibrated by structural reliability methods. For this reason, reliability analyses of masonry structures are needed to check if safety factors should be adjusted. Masonry is a non-homogenous material. Because of that, it is very important to consider the spatial variability of material properties when assessing the reliability of masonry walls. Therefore, it is useful to know if and to what extent spatial variability increases or decreases the reliability of masonry walls and the required safety factors. The influence of spatial variability depends on the length of a wall due to the capability of load redistribution. Also, it is affected by the governing failure mode, which depends on the slenderness of the wall, and can be local compression or stability failure. This paper demonstrates the effect of spatial variability on the load-bearing capacity of masonry walls in terms of mean value, scatter and design value. For this purpose, walls of varying length and slenderness were analysed with and without the consideration of spatial variability by performing Monte Carlo simulations. Based upon that, safety factors were determined which are required to meet the target reliability defined by EN 1990. [ABSTRACT FROM AUTHOR]

For the design of unreinforced masonry walls under lateral earth pressure according to DIN EN 1996-3 [1], the active earth pressure is used, which is less than the earth pressure at rest. For the consideration of active earth pressure, a sufficient deflection of the wall is needed. It is unknown whether the deflections in reality are large enough to justify a reduction of the active earth pressure. Therefore a numerical model has been developed which considers the load-bearing behaviour of masonry walls, with several boundary conditions being considered to estimate the effective earth pressure. [ABSTRACT FROM AUTHOR]

Ecology, energy and sustainability are crucial socio-economic keywords, especially for the construction and real estate industry. In recent years, the masonry industry faced related sustainability issues intensively in order to keep its ability of operating in a market setting which is increasingly characterized by sustainability dogmata. Scientific analyses and studies on an objectified sustainability basis - such as established certification systems - show that masonry is absolutely competitive with all other market-relevant construction methods. Therefore, the first part of this paper deals with a sustainability assessment of buildings made of masonry as well as of other construction materials. Concerning the design and construction of masonry, further selected aspects are discussed which are important for the competitiveness of this building technique. Outlining the simple yet economic pre-dimensioning with the help of load capacity tables is one topic which is of utmost importance for an efficient structural design. Additional aspects are the design of laterally loaded exterior walls with low vertical forces and the verification of basement walls under high earth pressure load. New and easy to use design proposals are open for discussion. Finally, the educational portal 'masonry structures' of the Deutsche Gesellschaft für Mauerwerks- und Wohnungsbau (DGfM) (German society for masonry and residential construction), which supports the training of young engineers, is presented. [ABSTRACT FROM AUTHOR]

The verification of safety against buckling of unreinforced masonry walls according to the accurate design procedure of EN 1996-1-1 Appendix G is based on semi-empirical approaches, which do not always realistically describe the load-bearing behaviour. This statement is also supported by an objection of the country Denmark concerning the load capacity function which is regulated in Appendix G. Using new findings about the effects of non-linear material behaviour in case of stability failure this article investigates fundamental questions about the buckling behaviour of masonry walls and transfers these into a simple practical structural design proposal. As a result, the load capacity function can be considerably simplified, the influence of creep can be integrated and the number of input parameters can be reduced. [ABSTRACT FROM AUTHOR]

Hochwasserkatastrophen treten auch in Deutschland immer häufiger auf. Die dabei entstehenden Beanspruchungen sind im Mauerwerksbau insbesondere für Kellerwände, welche mit einem Bogenmodell bemessen werden, von Bedeutung. Da mit dem normativ vorgeschlagenen Nachweisverfahren kein hydrostatischer Druck berücksichtigt werden kann, wird zunächst eine Nachweismethodik vorgestellt, welche den Lastfall des drückenden Wassers realitätsnah abbildet. Darauf aufbauend werden Bemessungsdiagramme abgeleitet, mit deren Hilfe entweder die maximale Wasserstandhöhe in Abhängigkeit der normativ erforderlichen Mindestauflast bestimmt oder die erforderliche minimale Auflast bei gegebener Wasserstandhöhe abgelesen werden kann. Drückendes Wasser auf Kellerwände im Hochwasserfall stellt eine außergewöhnliche Einwirkung dar. Es kann gezeigt werden, dass die zugehörige Einwirkungskombination bei über die gesamte Wandhöhe hinterfüllten Wänden in vielen Fällen nur bemessungsrelevant wird, wenn das Wasser sehr hoch ansteigt. Bei teilweise hinterfüllten Kellerwänden sind auch bei hydrostatischem Wasserdruck meist kleine Auflasten für eine hinreichende Standsicherheit ausreichend. Design of basement walls under earth and water pressure. The past decades have shown a tremendous increase in the occurrence of floods in Germany. This development asks for a extension of the design procedure used for basement walls, which is based on an arc model. As the standard regulations do not take into account hydrostatic pressure, the development of a new model regarding water pressure is evident. For this purpose, design diagrams were derived either accounting for the already existing load from the normative method to determine the maximum possible water level or diagrams which show the required minimum dead load for a certain water level. Water pressure due to a flooding represents an extraordinary load with specific partial safety factors within the design situation. If the basement wall is completely backfilled it can be shown, that the extraordinary load of hydrostatic pressure is only relevant for the wall design, if the water level rises near the terrain surface. In case of partially backfilled walls often small dead loads are sufficient to ensure adequate reliability. [ABSTRACT FROM AUTHOR]

To transfer bending moments in building components consisting of a material without tensile strength always requires a simultaneously acting normal force. Accordingly, masonry walls exposed to horizontal loads (e.g. wind) require a minimum vertical load, so that the resultant stress at the mid-height of the wall remains the same within the cross-section. As part of the A2 amendment to DIN EN 1996-3/NA, this verification of walls subjected to low vertical loads, such as outer walls on the top floor exposed to high wind load was implemented in the National Annex. Part 3 of DIN EN 1996-3 includes a similar standard regulation for verification of the minimum vertical load, which is based on an arch effect within the wall cross-section. Based on this technical background and taking into account the main influencing parameters, a verification model is presented here which realistically describes the load-bearing behaviour of unreinforced masonry walls subjected primarily to bending. Apart from the bending moments due to wind load, an initial eccentricity of the wall as well as second order effects due to wall deformations also have to be taken into account. In addition, a simple approximation equation is provided for the practical determination of the required minimum vertical load. [ABSTRACT FROM AUTHOR]

From masonry industry's point of view certain boundary conditions - e.g. the permissible span of floors - which limit the application of the simplified calculation method according to DIN EN 1996-3/NA do not match in practice. Modern buildings often have thicker floors which lead to more advantageous conditions when determining the load bearing capacity of masonry walls. Nowadays multi-span floors with longer spans exceeding the restrictions of DIN EN 1996-3/NA are more often applied. In addition to the requirements of the masonry standard concerning the carrying behavior of wall-floor-joints, a regulation exists in the concrete code (DIN EN 1992-1-1/NA) limiting the admissible deflection of reinforced concrete floors and simultaneously restricting the rotation of the floor at the support. In order to enable structural engineers a simple design of masonry walls in case of onesided restrained floors with larger distances between supports, it is shown up to which span width the simplified calculation method according to DIN EN 1996-3/NA can be applied. A systematic parameter study of wall-floor-systems with spans exceeding 6.0 m demonstrated, that a design with DIN EN 1996-3/NA provides conservative results compared to the more precise calculation method according to DIN EN 1996-1-1/NA. [ABSTRACT FROM AUTHOR]

Due to the coming introduction of Eurocode 6 (DIN EN 1996) in Germany many structural engineers ask for design assistances in order to apply the regulations and to accomplish the calculations in a cost-effective manner. At the same time however, such design tables must result in efficient solutions with respect to the materials used because masonry has to compete with other building materials. This article adresses this issue. Design tables to determine the load bearing capacity using the very simplified and simplified calculation methods in accordance with DIN EN 1996-3/NA are presented. Additionally diagrams for assessing the required minimum load on external walls exposed to wind loads and for determining the size of basement walls subjected to lateral earth pressure are given. This leads to the conclusion that, in almost all practical cases, it is possible to determine the cross-section resistance of unreinforced masonry in accordance with Eurocode 6 quickly and effectively while still making the best possible use of the materials employed. [ABSTRACT FROM AUTHOR]

Die zeitnah vorgesehene bauaufsichtliche Einführung der neuen europäischen Normengeneration DIN EN 1996 (Eurocode 6) stellt Planer und Bauausführende im Mauerwerksbau vor neue Herausforderungen, bietet aber auch vielfältige Chancen. Gegenüber der bisher gültigen DIN 1053-1 müssen sich alle Beteiligten auf einige wenige, aber grundlegende Neuerungen im Sicherheitskonzept sowie in der Nachweisführung einstellen und diesbezügliche Erfahrungen sammeln. Nach kurzer Einarbeitung zeigt sich jedoch die Vorteilhaftigkeit der neuen Regelungen für einen einfachen und effizienten Nachweis von unbewehrten Mauerwerksbauteilen. Hinsichtlich der Bemessung von Mauerwerk sind größere Unterschiede in der Regelungsdichte sowie der Nachweisdetaillierung zwischen den einzelnen europäischen Staaten festzustellen, sodass bei der Erarbeitung der europäischen Vorschrift EN 1996 (EC 6) gewisse Kompromisse unvermeidlich waren. Der deutsche Nationale Anhang bot jedoch die Möglichkeit zur Ergänzung bzw. Zuschärfung des Normentextes, sodass das bisher in Deutschland übliche Anforderungsniveau weitestgehend erhalten werden konnte. Gleichzeitig ist es gelungen, die für übliche Bauwerke erforderlichen Nachweise deutlich zu vereinfachen und zu reduzieren. In diesem Beitrag werden die Neuerungen anhand von Diagrammen erläutert und die Nachweisführung in Form von Tabellen aufbereitet, um eine einfache und praxisnahe Anwendung von DIN EN 1996/NA zu ermöglichen. Design of unreinforced Masonry Structures according to EC 6 - simple and practical. Concerning masonry structures the upcoming introduction of the new European standards DIN EN 1996 (Eurocode 6) with national annexes is a major challenge for civil engineers and building contractors but also implies great opportunities. In comparison with the current DIN 1053-1 civil engineers and building contractors have to get used to a few but essential improvements as well as to gather experience with the new regulations. But after a short familiarization the practical engineers will realize the advantages of the new codes for a simple and efficient calculation. Especially in design and execution of masonry structures significant differences exist between the European countries and compromises for the harmonization had to be found. The German National Annex provides the possibility for amendments to keep the current performance level as far as possible and to ease the design for common unreinforced constructions. With this article the most important innovations are pointed out using diagrams, charts and tables in order to allow an easy and practical application of DIN EN 1996/NA. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with the design of basement walls subjected to lateral earth pressure. The current simplified calculation method according to DIN EN 1996‐3/NA only covers active earth pressure, which is the lower limiting value of the earth pressure. Designing according to DIN EN 1996‐1‐1/NA, higher coefficients of earth pressure (like earth pressure at rest) can be considered, with an additional verification of the shear resistance being necessary. This paper presents a theoretical model, which forms the basis for an analytical derivation of the loadbearing capacity, and explains the required minimum values of the acting normal force to ensure sufficient resistance to cover bending and shear. Based on these results, a simplified equation is proposed for the determination of the required minimum normal force, based on the design according to DIN EN 1996‐3/NA and providing identical values in case of an earth pressure coefficient of 1/3. The required minimum load resulting from this approach fulfils the described requirement to cover bending and shear. The presented solution is verified and the conditions for application are defined. Finally, the minimum required normal forces are evaluated and tabulated for common cases relevant to building practice. [ABSTRACT FROM AUTHOR]