On the natural frequencies of infilled frames

Three approximate models are considered for the evaluation of the first few natural frequencies and associated mode shapes of infilled frames, a commonly occurring composite structural system formed by the combination of plane frames and filler walls. The reasonableness of the models is checked with the available experimental results and with the corresponding finite element solutions. The multiple strut model, wherein the infills are replaced by a set of equivalent multiple struts, can account for the frame–infill separation and infill openings and this model is seen to be an improvement over the single equivalent diagonal strut models proposed by earlier investigators. The shear—flexure cantilever analogy, by rationally evaluating the fundamental frequency, aids the equivalent lateral load procedures of the earthquake analysis. For dealing with the frames with central infill openings an equivalent plane frame model is discussed. Besides presenting the approximate models, the effect of frame—infill separation in reducing the fundamental frequency is investigated and an empirical relation is presented in this regard. Also some of the factors influencing the frame—infill contact lengths are studied and this indicates that the contact lengths are highly sensitive and indeterminate. Some constructional methods for avoiding separation and ensuring effective composite action between the frame and infill are also suggested.     

Multivariate Modelling of the Trace Element Chemistry of Arsenopyrite from Gold Deposits Using Higher-Dimensional Algebras

Mathematical Geosciences - In geochemistry, the elevated concentrations of certain elements in rock or mineral samples are used for the assessment of a mineralising system’s important...