Local Ductility and Global Behavior Factor of Steel Frame Structures Braced by Centered Bars System

When an earthquake occurs, civil engineering structures are subjected to forces that lead to a non linear behavior. This is often the case for designed steel structures. So, they absorb a larger part of the seismic energy transmitted to its resistant elements (columns and diagonals). This ability to dissipate energy through plastic deformation is expressed by the q behavior factor, used in the seismic design codes. In this paper a distribution of the local required ductility as a function of the behavior factor is given for steel structures braced by the stability bents of X shape

Les minéralisations Cu-(Ni-Bi-U-Au-Ag) d'Ifri (district du haut Seksaoua, Maroc) : apport de l'étude texturale au débat syngenèse versus épigenèse. <br /> The Cu---(Ni---Bi---U---Au---Ag) mineralization of Ifri (‘Haut Seksaoua' district, Morocco): contribution of a textural study to the discussion syngenetic versus epigenetic

The Cu ore of Ifri is a chalcopyrite stockwork hosted by Cambrian formations and was until now interpreted as a syngenetic massive sulphide deposit. Textural studies highlight two generations of pyrite early (Py I) and late (Py II) with respect to the regional deformation. The chalcopyrite stockwork overprinted Py II, outlining the epigenetic nature of the Cu mineralization. Regarding the origin of Cu-depositing fluids, the presence in the stockwork paragenesis of an U, W, Sn association and preliminary Pb/Pb dating of a brannerite belonging to this association suggest a contribution of the Tichka granite