Publikationsserver der RWTH Aachen University
Verformungsbasiertes seismisches Bemessungskonzept für Mauerwerksbauten
Abstract
dc:descriptionRecent earthquakes around the world have demonstrated the prominent role of seismic load cases in the design of buildings. Accordingly, the definition of seismic action in Germany, which is given in the code for seismic design (DIN 4149) in form of a response spectrum, has been updated for the recent edition of the standard. The consequence is a significant increase in the design earthquake loads for a large number of building configurations depending on the building site. The spectrum can be reduced by a so-called behaviour factor in order to consider the nonlinear material behaviour with its post-peak load-carrying capacity. Unfortunately, this procedure implicates that the stability of unreinforced masonry constructions with typical ground plans is no longer provable in earthquake zones 2 and 3 due to the global definition of this factor for masonry, given in the standard. Since the building- and material-specific characteristics are not sufficiently considered, there is a lack of exploitation of the nonlinear bearing reserves of masonry due to the simplified force-based design concept. In order to solve this problem a new displacement-based design procedure for masonry buildings under seismic loading on the basis of the capacity spectrum method is proposed. Both, the masonry and the building-specific load carrying capacity reserves can be exploited optimally within this procedure. The knowledge of the specific capacity curve of a masonry shear wall is a precondition for the application of the design procedure. The curve depends on the decisive failure mode under cyclic shear loading. For its computation finite element simulations are used and a damage-oriented material model based on the plasticity theory is developed. It is applied on the macro level in the context of a smeared homogeneous view of masonry as a continuum. The material model is validated by means of experimental data. In the second part of the thesis the seismic design procedure of masonry buildings is developed based on a generalized and modified form of the capacity spectrum method. A simplified procedure and a more exact one can be distinguished. Using the simplified procedure the building capacity spectrum is determined directly from the ground floor capacity curve, which is calculated from the capacity curves of the single walls, assuming, that the building is regular in elevation and that the lower floor fails first, while the upper floors remain elastic. The procedure considers torsional effects and the modified structural vibration shape due to damages. These assumptions can be confirmed by a comparison with the more exact procedure. Hereby, the building spectrum is determined from the capacity curve, which refers to the roof displacement. The nonlinear behaviour of all floors is included. The horizontal load distribution is changed adaptively, so that relocating effects due to sudden system changes are considered as well. Different floor configurations can also be taken into account. In order to facilitate the design process for the engineering practice the procedure is programmed with regard to the demands of DIN 4149. The computational cost are minimized by coupling the software to a data base, which stores the shear wall capacity curves for different geometry and load parameters. Additionally, different construction types as reinforced, strengthened or confined masonry can be merged into the procedure. Afterwards, the nonlinear static method is demonstrated by means of application examples and it is verified with nonlinear time-history computations. A comparison with the response spectrum procedure is carried out by calculating the seismic behaviour factor by means of the new developed procedure. The results show that the new method suits much more specifically to the seismic behaviour of masonry than the forced-based design procedure. Finally, the influence of torsional effects on the building capacity is investigated. It is pointed out, that walls, which are transverse to the impact direction, have a wide influence on the capacity curves, both, regarding the load capacity as well as the ductility.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2006
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Mistler, Michael
- Contributors dc:contributor
-
- Meskouris, Konstantin
Subjects
dc:subject × 10Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger