One of the most efficient methods of strengthening of buildings against earthquakes, is the addition of walls or cores. Its advantages are that the possibility of collapse is completely averted, as horizontal loads are transferred to the newer, stronger elements, while the deformation and damage of  its load-bearing and non load-bearing elements is minimized. A second emergent advantage is that existing structural elements do not need to be strengthened, as they now need to undertake reduced stresses during earthquake. There are of course issues that need to be addressed at both stages of design and construction, which should be answered in a clear, simple and practical way…