Shear resistance of reinforced masonry beams with and without additional concrete or prestress

This 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.).     

Analysis and comparison of the NDPs of various national annexes of Eurocode 6 / Analyse und Vergleich der NDPs verschiedener nationaler Anhänge zu Eurocode 6

In the national annexes of Eurocode 6, the individual European Member States can define values for nationally determined parameters in various places or add regulations which are not in contradiction to the current European provisions. Consequently – despite a harmonized Eurocode 6 – the normative regulations of the individual Member States differ more or less. However, in the sense of practicability of the standards in Europe, it should be the aim to develop a European standard which is as uniform as possible and which has not to be applied in significantly different ways due to the national regulations. In order to better understand the interests of the other Member States for future generations of standards and to derive potentials of harmonization, the values of the Nationally Determined Parameters (NDPs) of various Member States are compared in this paper. In this context, the extent of the deviations between the different national annexes is examined and on this basis a possible potential of harmonization is identified.     

Confined Masonry subjected to Lateral Loads / Eingefasstes Mauerwerk unter Plattenbeanspruchung

Just as with shear stress on the edges of masonry walls, prestressing through the confinement and restraint of all four sides of the wall improves the load‐carrying capacity under lateral loads. The extra load arising from prestressing leads to increased flexural strength of the masonry. The confinement of the edges results in relatively smaller span moments. In this case, the torsional stiffness of the reinforced concrete frame is important. This is determined by the frame itself as well as by its integration within the building. As a supplement to [4], an examination of panel loading was also performed within the guidelines of a research project at the TU Dresden, Chair for Structural Design, on behalf of the Federal Office for Building and Regional Planning on the subject of “Confined Masonry as an Option for Increasing the Load‐Carrying Capacity of Stiffening Walls”[9]. The various influences are to be initially researched on the basis of various analytical observations and a small numerical study. A thorough, experimentally‐based clarification of the load‐carrying capacity of the panels was not possible within the framework of the research project.