Rehabilitation of existing buildings is a business becoming more an more important for civil engineers. Especially historical constructions pose a special challenge as aspects of monument conservation have to be regarded. In Bavaria many historic structures date from the Baroque period. Therefore special attention should be paid to these constructions. Only little is known about the load bearing behavior of Baroque roof structures. Especially roofs which lack a continuous tiebeam have not been studied previously. In these situations small changes in the modeling assumptions can lead to great changes in the distribution of forces as the tiebeam at the basis of the roof is missing. In this work, different principles of construction are presented, and load transferring mechanisms are discussed. The results are based on an intensive literature research as well as on an extensive survey of this kind of roofs. For a realistic assessement of the forces in a structure, realistic input data are needed for the modeling process. Therefore, material data have been obtained and damages have been localized and evaluated. Furthermore, nonlinear load-displacement models taking plasticity effects and the condition of the joints into account have been worked out, and a new method to describe the three dimensional load carrying behavior of roof structures is presented. The load carrying behaviour of halved joints has not been studied so far. Therefore, experimental fullscale tests have been performed, as well as three dimensional finite element calculations. As a part of the interpretation process, a piecewise linear load-deflection diagram which can easily be used within the scope of frame analyses was developed. Finally, the work is rounded with computations on three existing and representative examples, including all the realistic input data collected. The main goal of investigation was to determine the influence of the nonlinear load-displacement models and of the new method for taking into account the three dimensional load carrying behavior on the calculations made. From the results for these special cases, more general observations and rules were obtained.
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