On the efficiency of coupled discrete-continuum modelling analyses of cemented materials

Computational load of discrete element modelling (DEM) simulations is known to increase with the number of particles. To improve the computational efficiency hybrid methods using continuous elements in the far-field, have been developed to decrease the number of discrete particles required for the model. In the present work, the performance of using such coupling methods is investigated. In particular, the coupled wall method, known as the “wall-zone” method when coupling DEM and the continuum Finite Differences Method (FDM) using the Itasca commercial codes PFC and FLAC respectively, is here analysed. To determine the accuracy and the efficiency of such a coupling approach, 3-point bending tests of cemented materials are simulated numerically. To validate the coupling accuracy first the elastic response of the beam is considered. The advantage of employing such a coupling method is then investigated by loading the beam until failure. Finally, comparing the results between DEM, DEM-FDM coupled and FDM models, the advantages and disadvantages of each method are outlined.

A Review on Seismic Behaviour of Coupled Wall Structures

Increase in population density and shortage of land are the two major problems in all developing countries including India. To mitigate these problems, the designers resort to high rise building. One of the most important criteria for designing a structural system is its resistance to lateral loads. Coupled walls structures is considered to be one of the potential option for resisting lateral loads in high-rise structure and have widely been used around the world in multi-story buildings. Coupled walls, mainly consist of pier walls which are connected by coupling beams at each floor level. These systems are typically located in the service core and sometimes on the perimeter of the buildings. The main benefit of coupled wall over cantilever walls are, a part of the total overturning moment is resisted by coupling action and there is energy dissipation along the height of the structure through the formation of plastic hinges at both ends of the coupling beams. The present work reviews different factors influencing the seismic performance of coupled wall structural system, importance of coupling ratio, different modeling techniques, a comparative study on different coupled wall systems and a brief overview of design methodologies. Considering structural performance, energy absorption capacity and higher shear stiffness to limit lateral deformation, coupled wall structures were considered to be efficient and economical structural system in high-rise building.