Prediction of the failure mechanism of arches under base motion using DEM based on the NSCD method

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.

Wiele zabytkowych struktur znajdują się w regionach o znacznej aktywności sejsmicznej jest podatnych na uszkodzenia podczas trzęsienia ziemi . Do oceny bezpieczeństwa tych struktur konieczne jest wykonanie kluczowych elementów , takich jak łuki sklepienia. Podczas gdy statyczną stabilność łuków murowych można badać analitycznie wykorzystujący zasady analizy limitu, w bardziej złożonych kształtach i / lub przypadkach stosuje się obliczania dynamicznego obciążenia. Obiecujące podejście numeryczne to Discrete Element Method (DEM) .