Makroelement für unbewehrte Mauerwerkswandscheiben unter Erdbebeneinwirkung

Successful verification of seismic safety of unreinforced mansonry buildings in Germany often necessitates application of nonlinear procedures (e.g. the deformation-based method), since the linear procedures provided by the European seismic design code do not allow for a sufficient utilization of the inherent structural reserves. However, this requires employment of numerical models that are capable of reproducing the seismic behavior of masonry buildings taking into account both the complex behavior of single shear walls and global interaction effects. Furthermore, those models should allow for the quick modeling and seismic analysis of any given masonry structure. Macroelements are particularly well-suited for this purpose. In order to provide a tool for simple but integral assessment of standard German masonry buildings, two different macroelements for unreinforced masonry shear walls were developed and implemented into the finite-element program ANSYS. The macroelements follow different approaches to describe the load bearing and deformation behavior of masonry walls as well as the wall-slab interaction. The first macroelement is double-T-shaped and basically consists of three rigid beams. Their lengths correspond to the wall height and wall length. Thus the actual geometry of the respective wall is adopted. The macroelement is attached to the neighboring floor slabs via nonlinear springs with the wall-slab interaction directly affecting its load bearing behavior. The second macroelement is linear and consists of a series of rigid beams and nonlinear springs. It is attached to the floor slabs rigidly. The flexural behavior of the wall and the wallslab interaction are regulated by rotational springs, the properties of which are defined through a fiber model analysis. These macroelements were then evaluated and compared on the basis of more than 50 single shear wall tests. Both elements proved capable of realistically simulating the seismic behavior of unreinforced masonry shear walls. In addition, the first macroelement was also used for a building simulation, demonstrating its capability as a proper simulation tool for the push-over analysis of masonry buildings.