Effect of geometric imperfections on aluminium silo capacities

An aluminium silo with initial imperfections is analysed. Two types of imperfection are considered. The first one takes the form of local indentations in the shell; their size and range are adopted on the basis of the standard guidelines. The second type is a global imperfection described through the use of its eigenforms and by means of two-dimensional random fields. The calculations are limited to two cases of loading: negative pressure and wind. The choice of the loading has been suggested in Eurocodes. In the case of wind load, the probability distribution of its direction is taken into account.