Predicting the behaviour of structures under impact loads using geometrically distorted scaled models

When a scaled structure (model or replica) is used to predict the response of a full-size compound (prototype), the model geometric dimensions should relate to the corresponding prototype dimensions by a single scaling factor. However, owing to manufacturing technical restrictions, this condition cannot be accomplished for some of the dimensions in real structures. Accordingly, the distorted geometry will not comply with the overall geometric scaling factor, infringing the Pi theorem requirements for complete dynamic similarity. In the present study, a method which takes geometrical distortions into account is introduced, leading to a model similar to the prototype. As a means to infer the performance of this method, three analytical problems of structures subjected to dynamic loads are analysed. It is shown that the replica developed applying this technique is able to accurately predict the full-size structure behaviour even when the studied models have some of their dimensions severely distorted. (C) 2012 Elsevier Ltd. All rights reserved.

Behaviour of grouted dowels used in precast concrete connections

This research deals with the behaviour of grouted dowels used in beam-to-column connections in precast concrete structures. The research focuses primarily on the theoretical and experimental analysis of the resistance mechanism of the dowels. The experimental programme included 15 models for analysing the following variations in dowel parameters: a) dowel diameters of 16, 20 and 25 mm, b) dowel inclinations of 0 degrees (i.e. perpendicular to the interface), 45 degrees and 60 degrees, c) compressive strength of classes C35 and C50 for the concrete adjacent to the dowels, and d) the absence or presence of compressive loads normal to the interface. The experimental results indicate that the ultimate capacity and shear stiffness of the inclined dowels are significantly higher than those of the perpendicular dowels. Based on these results, an analytical model is proposed that considers the influence of the parameters studied regarding the capacity of the dowel.