analiza dynamiki, analiza konstrukcji murowych, metoda elementów dyskretnych, modelowanie numeryczne, dynamika zagadnień kontaktowych niegładkich
Abstrakt
Many historic structures are located in regions of significant seismic activity and are vulnerable to earthquake damage. To assess the safety of these structures, an understanding of the seismic performance of key elements such as masonry arches, vaults and domes is vital. While static stability of masonry arches can be studied analytically using the principles of limit analysis, numerical methods are needed to deal with more complex geometries and/or dynamic load cases. A promising numerical approach is the Discrete Element Method (DEM). Currently, DEM codes are rather specialised research tools, and further development and validation are needed to confirm their suitability. In this paper, the DEM code LMGC90 is used to analyse the responses of arches subjected to dynamic base motions, with the results compared to shaking table experiments on arches built from wooden voussoirs. It is shown that the code is able to model the sequence of hinge openings and the final collapse mechanism extremely well. However, the numerical simulations overestimate the base acceleration amplitudes required to cause collapse. This is thought to be due to the impossibility of modelling the exact experimental set-up, which is substantially affected by small imperfections in the contacts between adjacent voussoirs. The resultant error is found to be quite consistent between tests, and has been compensated by a simple calibration of the experimental models. Future work will seek improved methods of dealing with this issue, and extension of the DEM approach to arches and vaults made of concrete-like materials, with non-zero tensile strength.
